Hedychium Koen. (ZINGIBERACEAE Lindl.) IN ... - gust.edu.vn

MINISTRY OF EDUCATION AND

TRAINING

VIETNAM ACADEMY

OF SCIENCE AND TECHNOLOGY

GRADUATE UNIVERSITY SCIENCE AND TECHNOLOGY

-----------------------------

TRINH THI HUONG

A STUDY ON BIOLOGICAL CHARACTERISTICS

AND ESSENTIAL OIL COMPOSITION OF Zingiber Boehm. AND

Hedychium Koen. (ZINGIBERACEAE Lindl.)

IN THE NORTH CENTRAL OF VIETNAM

Major: Botany

Code: 9.42.01.11

SUMMARY OF BIOLOGY DOCTORAL THESIS

Supervisors: 1. Dr. Do Ngoc Dai

2. Dr. Nguyen Thi Thanh Huong

HANOI - 2021

This dissertation has been carried out at The Graduate University of

Science and Technology - Vietnam Academy of Science and Technology

Supervisors: 1. Dr. Do Ngoc Dai

2. Dr. Nguyen Thi Thanh Huong

The 1st Reviewer:

The 2nd Reviewer:

The 3rd Reviewer:

The dissertation will be defended at the Board of Examiners of Graduate

University of Science and Technology, Vietnam Academy of Science and

Technology at …. on ...

The dissertation can be found at the National Library of Vietnam and

Library of Graduate University of Science and Technology

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INTRODUCTION

1. The urgency of the dissertation topic

Zingiberaceae Lindl., consists of perennial herbaceous plants with transverse

rhizomes or tubers, mainly distributed in tropical and subtropical countries. Zingiber

Boehm. and Hedychium Koen. are commonly used in traditional medicine and in food

processing.

Nowadays, the demand for using essential oil products of plants is increasing day

by day. Furthermore, essential oils from species in the Zingiber and Hedychium have

shown antimicrobial, antifungal, antioxidant and insecticidal activities. Thus, they are

likely to be Used as safer alternatives to synthetic antibiotics, antifungals, mosquito

repellents, pesticides, and in beauty treatments.

The North Central region is the intersection of the flora stream from the North to

the South, and is also home to many special-use forests, so the flora is very rich and

diverse. However, many species in the ginger genus Zingiber (Zingiber) and the genus

Wormwood (Hedychium) have not been fully studied for the plant and essential oil

chemistry. Therefore, the author chose the topic: "A study on biological

characteristics and essential oil composition of Zingiber Boehm. and Hedychium

Koen. (Zingiberaceae Lindl.) in the North Central of Vietnam”.

2. Researching objectives

- Describing some biological characteristics and distribution of Zingiber and

Hedychium species from north-central Vietnam.

- Determining the essential oil chemical composition; antimicrobial and anti-

mosquito larvae activities of essential oils of some Zingiber and Hedychium species

from north-central Vietnam.

3. Scientific and practical significances of the study

- Scientific significances

+ Updating, supplement and systematic data on the diversity of Zingiber and

Hedychium from north-central Vietnam;

+ Providing new data on the content and chemical composition of essential oils

of thirty nine samples of twelve Zingiber and Hedychium species from north-central

Vietnam;

+ Providing new data on the antimicrobial activities of thirteen essential oil

samples of five Zingiber and Hedychium species; and anti-larvae activity of six

essential oil samples of four Zingiber species from north-central Vietnam.

- Practical significances

On the basis of the scientific arguments obtained, the research results of the

dissertation contribute information for admistratorsin developing strategies to

conservation, development and exploitation of valuable species of Zingiber and

Hedychium, Zingiberaceae Lindl., from north-central Vietnam in particular and in

Vietnam in general.

4. Structure of the dissertation

The dissertation consists of 141 pages, 24 tables, 5 pictures, and 20 pictures are

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structured into the following main sections: Introduction (02 pages); Chapter 1:

Literature review (22 pages); Chapter 2: Subjects, contents and study methods (08

pages); Chapter 3: Results and discussion (106 pages); Conclusions and

recommendations (02 pages); New contributions of the dissertation; List of published

works related to the dissertation; References (170 documents, updated to May 2021);

and Appendix parts

CHAPTER 1: LITERATURE REVIEW

1.1. Studying plants on Zingiberaceae Lindl.

1.1.1. In the world

C. Linnaeus (1753) was the first to classify family Ginger. In 1835, Lindley took

the genus Zingiber name as the standard genus to name the family Ginger is

Zingiberaceae. Since then, there have been many studies on Zingiberaceae Lindl.,

typically P. Sirirugsa (1998), K. Larsen et al. (1998), J. Kress et al. (2002), K. Larsen

and S.S. Larsen (2006), A. Lamb et al. (2013), J. M. Christenhusz and J. W. Byng

(2016), ... According to The Plant List, Zingiberaceae consists of 52 genera with 1587

accepted name species.

1.1.2. In Vietnam

J. Loureiro (1793), Gagnepain (1908), Lê Khả Kế et al. (1975), Phạm Hoàng Hộ

(1993, 2000), Nguyễn Quốc Bình (2005, 2017), …

There are no systematic studies on Zingiberaceae in north-central Vietnam, but

only individual statistics on this family, such as Nguyễn Nghĩa Thìn and Mai Văn Phô

(2003), Nguyễn Nghĩa Thìn and Nguyễn Thanh Nhàn (2004), Đỗ Ngọc Đài and Lê Thị

Hương (2010), Đậu Bá Thìn et al. (2013), Võ Minh Sơn et al. (2015), Lê Thị Hương et

al. (2015), Đậu Bá Thìn et al. (2017), Nguyễn Danh Hùng et al. (2018).

1.2. Studying plants on Zingiber and Hedychium

1.2.1. Zingiber Boehm.

1.2.1.1. In the world

Boehm (1760), T. L. Wu and K. Larsen (2000), P. Triboun (2006), R. Kumar et al.

(2015), M. M. Aung and N. Tanaka (2019), …

1.2.1.2. In Vietnam

Gagnepain (1908); Phạm Hoàng Hộ (1993); J. Škorničková, Nguyễn Quốc Bình

et al. (2015); Lý Ngọc Sâm (2017); …

In north-central Vietnam: Some separate statistics on Zingiber in the studies of

Đậu Bá Thìn et al. (2013, 2017), Võ Minh Sơn (2015), Nguyễn Danh Hùng et al.

(2018), …

1.2.2. Hedychium Koen.

1.2.1.1. In the world

Koenig (1783), C. T. L. Wu and K. Larsen (2000), M. F. Newman et al. (2007),

P. Thomas et al. (2015), …

1.2.1.2. In Vietnam

Phạm Hoàng Hộ (2000), Nguyễn Quốc Bình (2017), …

In north-central Vietnam: There are some separate statistics on this genus in the

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studies of Đậu Bá Thìn et al. (2013, 2017), Võ Minh Sơn (2015), Nguyễn Danh Hùng

et al. (2018), …

1.3. Using values of Zingiber and Hedychium Species

A lot of Zingiber and Hedychium species are used as medicine, flavoring agent,

and flavoring agent. In addition, a few Hedychium species are also used in cosmetics,

perfumes and ornamental plants. They are used very popularly in China, Japan,

Indonesia, Thailand, and Vietnam.

1.4. General information of essential oils

1.4.1. Essential oil plant definition

The essential oil plants are plants containing specialized structures thatare

responsible for secreting and accumulating essential oils.

1.4.2. Define and characteristics of essential oils

Essential oils can be defined as a mixture of volatile and natural substances,

characterized by a strong odor and produced by aromatic plants as secondary

metabolites.

1.4.3. Chemistry of Essential Oils

According to V. P. S. Rao and D. Pandey (2006), there are more than 200

components present in the mixture of pure essential oils. They can be categorized into

two classes:

Volatile fraction: 90 - 95% of total oil weight. It contains monoterpenes,

sesquiterpenes, and their oxygenated derivatives.

Nonvolatile residue: 1 - 10% of of total essential oil in weight. It contains fatty

acids, hydrocarbons, sterols, waxes, flavonoids, and carotenoids.

1.5. Study on Zingiber and Hedychium essential oils

Most Zingiber and Hedychium species contain essential oils. Content and

chemical composition of essential oils in each species are different and often different

in the same species if collected in different geographical regions.

1.6. Natural, economic and social conditions in north-central Vietnam

1.6.1. Geographical location

Including 6 provinces: Thanh Hoá, Nghệ An, Hà Tĩnh, Quảng Bình, Quảng Trị

and Thừa Thiên - Huế.

1.6.2. Topography, geomorphology

There are 3 main types: Mountain: mostly lowland; Hills: occupies a fairly large

area; and Plain: medium size.

1.6.3. Climate, rivers

Climate: Both the tropical monsoon climate with cold winters in the northern

climate of Vietnam, and the anomalous characteristics of the monsoon tropics with wet

and wet seasons of the East Truong Son. Rivers: There is an average altitude across the

basin reaching 300-700 m, with a great slope (18-22%).

1.6.4. Natural and socio-economic conditions

The total area is 51,180.5 km2, with a total population of 10,500,000 people.

There are many ethnic groups such as: Kinh, Tày, Thái, Thổ, Mường, Dao, H'mông,

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Khơ Mú, Đan Lai, Bru-Vân Kiều, Cơ Tu, Tà Ôi, Chút.

1.6.5. Plant conditions

Five National Parks: Bến En, Pù Mát, Vũ Quang, Phong Nha Kẻ Bàng and Bạch

Mã. Nine Nature Reserves: Pù Luông, Pù Hu, Xuân Liên, Pù Hoạt, Pù Huống, Kẻ Gỗ,

Bắc Hướng Hóa, Đa krông và Phong Điền.

CHAPTER 2: SUBJECTS, CONTENTS AND METHODS

2.1. Study subjects

Zingiber and Hedychium species from north-central Vietnam. Total number of

samples has been researched over 200 with a total of about 100 sample numbers.

2.2. Study timing and placing

The project was conducted from May 2017 to October 2020.

2.3. Study contents

- Researching on the plant diversity of Zingiber and Hedychium from north-

central Vietnam.

- Studying the bio-ecological characteristics and value using of Zingiber and

Hedychium species from north-central Vietnam.

- Determinaing the content and chemical compositions of essential oils of some

Zingiber and Hedychium species from north-central Vietnam.

- Testing the antimicrobial and anti-mosquito larvae activities of essential oils

of some Zingiber and Hedychium species from north-central Vietnam.

2.4. Study methods

2.4.1. Biological study methods:

2.4.1.1. Method of inheriting documents

Inheriting the research results on natural and social conditions in the study area,

plant samples stored in domestic and foreign museums, published studies relating to

the PhD topic.

2.4.1.2. Field investigation method

Based on the map and topographic conditions, the main survey lines were selected

so that the lines must pass through the habitats of the study area. From the main line,

the herringbone-styled sub-glands are opened in both directions and pass through

different communities. On average, 1.5km of the main line has 2 sub-lines opened.

Investigate species of two study genus located within 10m on each side of each transect.

2.4.1.3. Methods of sampling and classification

Plant samples were collected and processed according to the method of Nguyễn

Nghĩa Thìn (2007).

2.4.1.4. Methods to assess the diversity of flora

Evaluating species diversity of genera according to the method of Nguyễn Nghĩa

Thìn (2007).

2.4.1.5. Method of learning about the use value of flora

Based on published documents and through interviews with the people.

2.4.2. Methods of identifying the chemical compositions of essential oils:

2.4.2.1. Sample collection and essential oil distillation

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Samples for essential oil distillation included separate parts of the plant (leaves,

stem, rhizomes, flowers, fruits). 0.5-3 kg fresh sample was collected. Samples were

labeled with identified number (similar to species identified number) and the collected

time. After collecting, samples were chopped and distilled by the method of attracting

refluxed water in Clevenger equipment in 2 - 4 hours at standard pressure according to

Vietnam Pharmacopoeia (2017).

2.4.2.2. Quantitative method of essential oils

Essential oils of different parts were quantified according to the First method of

Vietnam Pharmacopoeia V (2017).

2.4.2.3. Methods of chemical composition analysis of essential oils.

Preparation of analytical samples for gas chromatography: Dissolving 1.5 mg of

dried essential oil by anhydrous Na2SO4 in 1 ml of pure hexane for chromatographic

analysis.

+ Gas chromatography (GC) with FID detector: Made on Agilent Technologies

HP 6890N Plus with FID detector, capillary column HP-5MS length of 30 m, internal

diameter (ID) = 0.25 mm, layer film 0.25mm thin with carrier gas is hydrogen. The

temperature of the sample pump chamber is 250º C. Detect temperature is 260º C.

Program temperature 60º C (2 minutes), increase 4º C/minute to 220º C, stop at this

temperature for 10 minutes.

+ Gas chromatography mass spectrometry (GC/MS): It is carried out on Agilent

Technologies HP 6890N/HP 5973 MSD conjugated gas chromatography system with

separation column and chromatographic operating conditions as mentioned above and

with helium as carrier gas.

The qualitative determination of essential oil components was done by the

following methods:

- Based on the values of the Retention Index, determinng with a sequence of n-

alkanes in the same chromatographic condition.

- Based on mass spectra, comparing with mass spectra found in data banks (NIST

08 and Wiley 9th Version) or comparing with the references.

The percentage of components in essential oils were calculated based on the area

or height of the chromatographic peak (detector FID) without using any adjustment

factors.

2.4.3. Biological activity test methods

2.4.3.1. Testing the resistance to test microorganisms

Antimicrobial activity of Zingiber and Hedychium essential oils was carried out

on three Gram-negative organisms, Salmonella enterica (ATCC 13076), Pseudomonas

aeruginosa (ATCC 27853), and Escherichia coli (ATCC 25922); three Gram-positive

organisms, Bacillus cereus (ATCC 14579), Enterococcus faecalis (ATCC 299212),

and Staphylococcus aureus (ATCC 25923); and the pathogenic yeast, Candida

albicans (ATCC 10231), using the microbroth dilution assay (Clinical and Laboratory

Standards Institute, 2009).

The essential oil sample is diluted in DMSO (Dimethyl sulfoxide) in the

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decreasing concentration range (µg / ml): 256-128-64-32-16-8-4-2. The antimicrobial

assays were carried out in triplicate. Bacteria and fungi were standardized to 5 × 105

CFU/mL for bacteria and 1 × 103 CFU/mL for the yeast. After 24 hours of incubation

at 37°C, the MIC value was determined by observation. The MIC value was determined

at the well with the lowest reagent concentration that completely inhibited the growth

of microorganisms after 24 hours of culture and accurately determined based on cell

turbidity data by Bioteck spectrophotometer and Raw data software. The IC50 values

were determined by the percentage of microorganisms that were inhibited for growth

based on the BioTeK turbidity data from the BioTeK spectrometer and the Raw data

computer software using the following equations:

% inhibition = x 100%ODcontrol(-) - ODtest agent

ODcontrol(-) - ODcontrol(+)

IC50 = Highconc - (Highinh% - 50%) x (Highconc - Lowconc)

(Highinh% - Lowinh%)

Comment: % inhibition: inhibitory concentration; OD: optical density; Control (-):

cells with medium but no antimicrobial agent; , test agent is a known concentration of

antimicrobial agent; Control (+): culture medium without cells; Highconc/Lowconc:

concentration of test agent at high concentration/low concentration; Highinh% / Lowinh%:

% %inhibition at high concentration/% inhibition at low concentration.

2.4.3.2. Test of mosquito larvicidal resistance

Mosquito larva resistance activity was determined by Reed-Muench method.

Adult mosquitoes: Aedes aegypti, Aedes albopictus and Culex quinquefasciatus

were maintained in insect cages (40 x 40 x 40 cm) and fed by 10% of sugar solution

and rat blood. Hatching eggs were spread out by tap water. Aedes albopictus larvae

were kept on plastic trays (24 × 35 × 5 cm). Their larvae were fed by dog biscuits and

yeast flour at a ratio of 3: 1. All steps were held at 25 ± 2°C, 65 - 75% relative humidity,

and a dark cycle of 12 : 12 at the Research Center for entomology and parasites, Duy

Tan University.

The anti-mosquito larva activity of rhizomes essential oils of Zingiber and

Hedychium species was evaluated according to WHO protocol (2005) with minor

changes. For the assay, the essential oil fraction was dissolved in EtOH (1% stock

solution) was placed in a 200 ml beaker and was added water containing 20 larvae

(fourth instar). For each test, a controller using EtOH was also run for comparison.

Mortality rates were recorded after 24 hours and after 48 hours of exposure while not

supplemented with nutrients. The experiments were carried out at 25 ± 2° C. Each test

was replicated four times in every concentrations (70, 60, 50, 40, 30 and 25 μg/mL).

The average lethal concentration (LC50) was determined by the Reed-Muench method.

2.4.4. Data analysis:

Data were analyzed on Microsoft Office Excel 2016 software.

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CHAPTER 3: RESULTS AND DISCUSSIONS

3.1. Some biological characteristics of Zingiber and Hedychium species from

north-central Vietnam

3.1.1. Morphological characteristics of Zingiber and Hedychium from north-

central Vietnam

3.1.1.1. Morphological characteristics of Zingiber Boehm.

Herbs perennial; pseudostems formed by leaf sheaths, up to 3 m; rhizomes

branched, tuberous, aromatic, lying horizontally below the ground. Leaves: spacing,

distichous, held in plane parallel to rhizome; petiole absent or very short, swollen,

cushionlike; leaf blade oblong, lanceolate, or linear. Inflorescences arising from

rhizomes on peduncle clothed with scalelike sheaths, rarely breaking through leaf

sheaths without peduncle; bracts closely imbricate, rarely without roofing (Zingiber

castaneum), green or other color, 1-flowered, persistent; bracteole not tubular. Calyx:

tubular, split on 1 side, apex 3-toothed. Corolla proximally tubular, distally 3-lobed,

central lobe white or cream, usually wider than lateral lobes. Lateral staminodes adnate

to labellum, forming a 3-lobed labellum; central lobe retuse or cleft at apex. Filament

short; connective with elongate appendage wrapped around style; anther 2 cells,

parallel. Ovary 3-loculed. Fruit a capsule. Seeds black, covered by aril; aril white,

margin irregularly lacerate.

3.1.1.2. Morphological characteristics of Hedychium Koen.

Herbs perennial; pseudostems 1-2 m, rarely more than 3 m; rhizomes thick, fleshy.

Leaves: distichous, held in plane parallel to rhizome; ligule conspicuous, petiole absent

or very short, leaf blade usually oblong or lanceolate. Inflorescences: breaking through

leaf sheaths without peduncle; bracts imbricate, rarely lax (Hedychium stenopetalum),

1- or more flowered; bracteoles tubular. Calyx tubular, usually split on 1 side, apex

truncate or 3-toothed. Corolla tube long, slender; lobes reflexed at anthesis, linear.

Lateral staminodes petaloid, larger than corolla lobes. Labellum suborbicular, large,

apex usually 2-cleft; claw long or short. Filament usually long, 2-cell anther,

connective appendage absent. Ovary 3-loculed. Capsule globose, 3-valved. Seeds

numerous; aril lacerate.

3.1.2. Ecological characteristics, distribution of Zingiber and Hedychium from

north-central Vietnam

3.1.2.1. Ecological characteristics, distribution of Zingiber Boehm.

Habitat: grows in primary forest, secondary forest; under the canopy of humid

forests, wet humus, along streams, moist limestone mountain cavities, planted in

gardens. Usually at 100-900 m, rarely less than 100 m (Zingiber mekongense) or less

than 300 m (Zingiber collinsii, Zingiber cornubracteatum).

Phenology: Flowering usually begins in spring (Mar-May), rarely in summer

(Zingiber montanum, July) or autumn (Zingiber cornubracteatum, Sep). Flowering

time lasts from 2-9 months, 2 months: Zingiber vuquangense (Apr-May), Zingiber

montanum (July-Aug); 3 months: Zingiber castaneum (May-July), Zingiber nitens

(May-July), Zingiber cornubracteatum (Sep-Nov); 4 months: Zingiber castaneum

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(Apr-July), Zingiber officinale (May-Aug), Zingiber zerumbet (May-Aug); 6 months:

Zingiber nudicarpum (Apr-Sep), Zingiber collinsii (May-Oct), Zingiber ottensii (May-

Oct); 9 months: Zingiber mekongense and Zingiber neotruncatum (Apr-Dec). Fruit

season: after flowering 1-2 months; from May to Mar next year: Zingiber

neotruncatum; Jun-Sep: Zingiber vuquangense; Jun-Nov: Zingiber castaneum,

Zingiber nitens; Jun-Feb next year: Zingiber mekongense; Oct-Dec: Zingiber

cornubracteatum; Oct-Jan of next year: Zingiber zerumbet.

3.1.2.2. Ecological characteristics, distribution of Hedychium Koen.

Habitat: grows in primary forest, secondary forest; wet humus, wet soil, along

streams, under thin forest canopy, humus-covered rock recesses, planted in gardens;

prefer less (Hedychium coronarium) or more shade (Hedychium stenopetalum,

Hedychium gardnerianum), Hedychium flavum prefers less shade to light shade.

Phenology: Flowering usually begins in summer (July-Aug), rarely winter

(Hedychium villosum, Feb). The flowering period lasts for 2-6 months; 2 months:

Hedychium stenopetalum (July-Aug); 3 months: Hedychium villosum (Feb-Apr),

Hedychium flavum (Aug-Oct), Hedychium gardnerianum (Aug-Oct); 6 months:

Hedychium coronarium (July-Dec). Fruit season: 1-2 months after flowering; from

April-June: Hedychium villosum; Oct-Dec: Hedychium flavum, Hedychium

stenopetalum, Hedychium gardnerianum; Sept-Feb next year: Hedychium coronarium.

3.1.3. Diversity of Zingiber and Hedychium from north-central Vietnam

Twenty-four species have been identified in north-central Vietnam. Including a new

species for science Zingiber vuquangense N.S.Lý, T.H.Lê, T.H.Trịnh, V.H.Nguyễn &

N.Đ.Đỗ and two new record for the flora of Vietnam, namely Zingiber mekongense

Gagnep. and Zingiber cornubracteatum Triboun. (Table 3.1)

Table 3.1. List of Zingiber and Hedychium species from north-central Vietnam

TT Latin name Vietnam

name Using Diversity

1 Zingiber acuminatum Val.* Gừng lá nhọn CTD II

2 Zingiber eberhardtii Gagnep.* Gừng

eberhardt CTD I, II

3 Zingiber castaneum Škorničk. &

Q.B. Nguyễn Gừng trung bộ CTD I-III

4 Zingiber cochinchinensis Gagnep.* Gừng nam bộ CTD V

5 Zingiber collinsii Mood &Theilade Gừng collin THU, CTD II, VI

6 Zingiber cornubracteatum Triboun Gừng lá bắc cựa CTD I, II, IV

7 Zingiber gramineum Norohan* Gừng lúa THU, CTD I, II, VI

8 Zingiber laoticum Gagnep.* Gừng lào THU, CTD IV

9 Zingiber mekongense Gagnep. Gừng mê kông THU, CTD I, II

10 Zingiber montanum (J.Koenig) Link

ex A.Dietr. Gừng núi THU, CTD I-VI

11 Zingiber neotruncatum T.L. Wu, K.

Larsen & Turland

Gừng nhọn đầu

mới CTD II

9

TT Latin name Vietnam

name Using Diversity

12 Zingiber nitens M. F. Newman Gừng lá sáng

bóng THU, CTD II, III

13 Zingiber nudicarpum D. Fang Gừng quả trần AND,

CTD II, IV, VI

14 Zingiber officinale Rosc. Gừng THU, CTD,

GVI, AND I-VI

15 Zingiber ottensii Valeton Gừng ottensi THU, CTD II, VI

16 Zingiber rubens Roxb.* Gừng đỏ

THU,

CTD,

AND

I, II

17 Zingiber rufopilosum Gagnep.* Gừng lông hung CTD, THU I, II

18

Zingiber vuquangense N.S.Lý,

T.H.Lê, T.H.Trịnh, V.H.Nguyễn &

N.Đ.Đỗ

Gừng vũ quang THU, CTD I-IV

19 Zingiber zerumbet (L.) Smith Gừng gió THU,

CTD, GVI I-VI

20 Hedychium coronarium Koenig Bạch điệp

THU,

CTD,

AND,

CAN, GVI

I-VI

21 Hedychium flavum Roxb. Ngải tiên vàng CAN,

CTD, GVI II

22 Hedychium gardnerianum Rosc. Ngải tiên

gadner CTD, CAN II

23 Hedychium stenopetalum Lodd. Ngải tiên cánh

hoa đẹp

CTD,

CAN,

THU

I-IV, VI

24 Hedychium villosum Wall. Ngải tiên lông CTD, THU II

Comment: * Species inherited from the document in north-central Vietnam. Using:

THU: Medicinal plants, CTD: essential oil plants, AND: Edible plants, GVI: spice

plants, CAN: ornamental plants. Distribution: I: Thanh Hoa; II: Nghe An; III: Ha Tinh;

IV: Quang Binh; V: Quang Tri; VI: Thua Thien - Hue.

Zingiber species in north-central Vietnam is quite diverse, with 19/35 species

accounting for 54,29% of the total species of Vietnam; meanwhile, Hedychium species

is less diverse, with 5/12 species, accounting for 41,67%.

3.1.4. Zingiber and Hedychium species from north-central Vietnam were recorded

with additional distribution zones

Seven species have been recorded with additional distribution zones for the north-

central Vietnam Flora, namely: Zingiber castaneum, Zingiber collinsii, Zingiber

montanum, Hedychium coronarium, Hedychium flavum, Hedychium stenopetalum and

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Hedychium villosum; two new record for the flora of Vietnam are Zingiber

cornubracteatum and Zingiber mekongense; and a new species is the Zingiber

vuquangense.

3.1.5. Using values of Zingiber and Hedychium species from north-central

Vietnam

There are different uses for 5 groups: essential oil plants accounted for the largest

proportion with 24 species, accounting for 100%; followed by the medicinal plants

consisted of 15 species, accounting for 62.5%; edible plants also consisted of 5 species,

accounting for 20.8%; both spice and ornamental plants consisted of 4 species,

accounting for 16.7% each.

3.1.6. Characteristics of Zingiber and Hedychium species from north-central

Vietnam

3.1.6.1. Zingiber species

1. Zingiber castaneum Škorničk. & Q.B.Nguyễn

Description: Perennial herb, pseudostems up to 1 m. Leaves sessile; leaf blade

elliptic, 20-25 × 7-8 cm. Inflorescences breaking through leaf sheaths, 7-10 cm; bracts

green (yellow in maturity), glossy, sparse; bracteole ovate, 1,0-1,2 × 0,8-0,9 cm. Calyx

entire, 0.9-1.1 cm. Corolla tube 2.9 cm; lobes triangular, 1.8-2.2 × 1.1-1.3 cm. Labellum

ovate, 1.7-2.1 × 1.2-1.4 cm, purple with pale yellow stripes from base to 1/3, edge white

spots; lateral staminodes 1.0-1.1 × 0.2-0.3 cm, yellow, connate to labellum by basal.

Filament 0.2-0.3 cm; anther 1.5-1.6 cm; connective appendage purple, 0.8-0.9 cm. Ovary

cylindrical, glabrous. Capsule heart, glabrous. Seeds reddish-brown. Fl. May-July, fr.

Jun-Nov.

2. Zingiber collinsii Mood &Theilade

Description: Perennial herb, pseudostems 1-2 m. Leaf blade elliptic, 35-42 × 5.8-

7.5 cm; underneath pale purple and pubescent. Inflorescences arising from rhizomes,

12-15 × 4.5-4.8 cm; bracts ovate, 3.6-3.8 × 3.0-3.2 cm, orange-red or burgundy, hairy.

Calyx 2.0-2.2 × 0.7-0.8 cm. Corolla tube 4.0-4.2 cm; lobes 2.1-2.6 × 0.7-0.8 cm.

Labellum ovate, 2.4-2.6 × 1.8-2.0 cm, cream-yellow with purple stripes from center to

apex. Lateral staminodes obovate, 1.7-1.8 × 0.8-0.9 cm, connate to labellum by basal

½. Filament very short; anther 1.1-1.2; connective appendage 1.0-1.1 cm, purple.

Ovary 0.5-0.6 × 0.5 cm, hairy. Fl. May-Oct.

3. Zingiber cornubracteatum Triboun & K. Larsen

Description: Perennial herb, pseudostems up to 3 m high. Leaf blade ovate-

oblong to elliptic, 40-45 × 10-18 cm; underneath brown pubescent; petiole 2-2.5 cm.

Inflorescences arising from rhizomes; bracts obovate, 5.0-10.0 × 3.0 cm, apex concave

inward, pale pink; bracteoles oblong, 3.0-4.0 × 0.8-1.0 cm, hairy. Calyx 2.0-2.5 cm,

hairy. Corolla tube ca. 5.0 cm, hairy; lobes elliptic, red. Labellum obovate, 2.5 × 1.2-

1.8 cm, base cream-yellow, red; lateral staminodes 1.8-2.0 × 0.22-0.25 cm, cream-

yellow, connate to labellum by apical 2/3. Filament ca. 0.3-0.4 cm; anther 1.5 × 0.5

cm; connective appendage ca. 1.5 cm. Capsule obovate or oval, 2.5-3.0 × 2.0-2.5 cm,

pale-pink. Seeds pale red to reddish-brown. Fl. Sep-Nov, fr. Oct-Dec.

11

4. Zingiber mekongense Gagnep.

Description: Perennial herb, pseudostems up to 1.5 m. Leaf blade elliptic-oblong

to obovate-oblong, 35-62 × 5,5-12 cm; underneath white ensely pubescent.

Inflorescences arising from base of pseudostems, peduncle usually fully embedded in

ground; bracts ovate, 3.5-4.1 × 0.5-1.8 cm, white or pink-white, apex red, brown

slightly hairy; bracteoles ovate, 3.5-3.8 × 0.5-0.8 cm, slightly hairy. Calyx split on 1

side, apex 3-toothed; 2.1-2.5 × 0.5-0.6 cm; slightly hairy. Apex corolla tube pubescent;

lobes ovate, red or cream yellow, base and apex lightly hairy. Labellum obovate, 2.2-

2.6 × 1.5-2.2 cm, base cream-white, purple with yellow spots; lateral staminodes 1.5-

2.2 × 0.5-1.0 cm, connective to the labellum by basal 1/3. Filament so short, lightly

hairy; connective appendage is as long as the anther, 1,2-1,5 cm, pale-purple. Ovary

ensely pubescent. Mature capsules 3.5-5.0 × 1.3-1.5 cm, purple-red, upper half lightly

hairy. Seeds red, 0.4-0.5 × 0.3-0.4 cm. Fl. Apr-Dec, fr. Jun-Feb.

5. Zingiber montanum (J.Koenig) Link ex A.Dietr.

Description: Perennial herb, pseudostems 1-2 m. Leaf blade lanceolate-oblong,

19-30 (-40) × 2.5-5 (-8) cm; underneath slightly hairy. Inflorescences arising from

rhizomes; bracts obovate, 3.5-4 × 2.4-2.6 cm, light reddish brown, darker on upper

half, white pubescent. Calyx ca. 1.3-1.5 cm, split on 1 side, apex 3-toothed. Corolla

tube 2.4-2.6 cm; lobes ovate, cream yellow. Labellum 1.8-2 × 1.5-1.7 cm, pale yellow,

apex emarginate 0.2-0.3 cm; lateral staminodes elliptic, connective to the labellum by

basal ½. Filament ca. 0.1 cm; anther 0.8-0.9 cm; connective appendage 0.6-0.7 cm.

Ovary elliptic, 0.4-0.5 × 0.25-0.3 cm, white hairy. Fl. July-Aug.

6. Zingiber neotruncatum T.L. Wu, K. Larsen & Turland

Description: Perennial herb, pseudostems 0.7-1.8 m, hairy. Petiole hairy; leaf

blade lanceolate-oblong, 30-45 × 3.5-5.8 cm, pubescent along below ribs.

Inflorescences arising from rhizomes; bracts ovate, 3–4 × 2.5–3.5 cm, green; bracteoles

ovate-oblong, 2.7-2.8 × 1.9-2.2 cm, white, margin pubescent. Flowers white. Calyx ca.

2.5 cm, apex 2-toothed. Corolla tube ca. 4.3 cm, pale-yellow, hairy inside; lobes ca.

2.5 × 0.8-1.5 cm. Labellum obovate, ca. 3.5 × 2.4 cm, apex emarginate; lateral

staminodes obovate, apex rounded, entire connate to labellum. Filament white, ca. 2

mm; anther pale-yellow; connective appendage ca. 1.3 cm. Ovary cylindrical, 0,5 × 0,4

cm. Mature capsules ovate, pale-orange. Fl. Apr -Dec, fr. May-Mar.

7. Zingiber nitens M. F. Newman

Description: Perennial herb, pseudostems up to 1.5m high. Leaf blade elliptic-

oblong, 18-25 × 2-3 cm; underneath slightly hairy, thicker along below midrib.

Inflorescences arising from rhizomes; bracts ovate, dark green, 3.3 × 3.5 cm, 3-4

flowered. Calyx split on 1 side to ½ long, apex 3-toothed. Corolla tube ca. 3.0-3.1 cm;

lobes nearly triangular, 1.8-2.1 × 0.5-0.6 cm, pale yellow. Labellum elliptic, 1.8 × 1.1-

1.25 cm, dark purple with yellow stripes from base, edge pale yellow spots (viền có

chấm vàng); lateral staminodes connective to the labellum by basal ¼, 0.7-0.9 × 0.15-

0.25 cm. Filament 0.25-0.3 × 0.3 cm; connective appendage is as long as anther, dark

purple. Ovary cylindrical, 0.35 × 0.25 cm, cream yellow. Capsule triangular, white,

12

apex green. Seeds black. Fl. May-July, fr. Jun-Nov.

8. Zingiber nudicarpum D. Fang

Description: Perennial herb, pseudostems up to 2.8 m. Leaf blade elliptic-oblong,

30-45 × 7.0-9.5 cm, underneath white slightly hairy. Inflorescences arising from

rhizomes; bracts ovate to elliptic, 5.5-6.2 × 3.0-5.3 cm, red or pink, hairy; bracteoles

ovate-oblong, ca. 3.2-3.5 cm, slightly hairy. Calyx ca. 3.5-3.8 cm, apex slightly 2-

toothed. Corolla tube ca. 4.5-5.7 cm; lobes ovate, cream-yellow, center one ca. 3.5-4.1

cm, lateral ones ca. 2.6-3.2 cm. Labellum triangular, ca. 3.0-3.5 × 1.5-1.8 cm, cream-

yellow with purple dotted, apex emarginate; lateral staminodes connective to the

labellum by basal ½, ca. 2.6-2.8 cm. Stamen ca. 2.4-2.9 cm; connective appendage

shorter than anther, purple. Ovary white, ca. 0,5-0,8 × 0,5 cm, slightly hairy. Capsule

white when young, ca. 1,4-1,6 × 0,8-1,3. Fl. Apr-Sep.

9. Zingiber officinale Rosc.

Description: Perennial herb, pseudostems 40-50 cm. Leaf blade lanceolate-

oblong, 15-30 × 1.5-2.5 cm. Inflorescences arising from rhizomes. Bracts pale green,

2.2-2.5 × 1.2-1.8 cm; bracteoles equaling bracts. Calyx ca. 0.7-0.9 cm. Corolla tube ca.

2.2-2.5 cm; lobes ca. 1.6-1.8 × 7-8 mm. Labellum nearly rounded, ca. 1-1,2 cm, red-

brown to purple-brown with red speckle, base cream stripes; lateral staminodes ca. 5-

6 × 3-4 mm, free nearly to base. Anther ca. 7-9 mm; connective appendage dark red,

ca. 6-7 mm. Ovary glabrous, 2-3 mm. Fl. May-Aug.

10. Zingiber ottensii Valeton

Description: Perennial herb, pseudostems up to 2 m. The leaf blade lanceolate-

oblong, 36-43 × 6-7.5 cm, underside slightly purple and pilous. Inflorescences arising

from rhizomes; bracts obovate, red, ca. 3.6-3.8 × 3.0-3.2 cm, hairy; bracteoles white,

apex pale pink, ca. 3.1-3.3 cm. Calyx ca. 2.0-2.2 × 0.7-0.8 cm. Corolla tube ca. 4.0-4.2

cm; lobes ovate, ca. 2.1-2.2 × 0.7-0.9 cm. Labellum obovate, ca. 2.4-2.6 × 1.8-2.0 cm,

pale yellow with pale pink stripe, apex rounded with a short cleft; lateral staminodes

obovate, ca. 1.7-1.8 × 0.8-0.9 cm, connective to the labellum by basal 2/3. Stamen

sessile; anther ca. 1.1-1.2 cm; connective appendage 1.0-1.1 cm. Ovaries triangular-

oblong, sparely villose. Fl. May-Oct.

11. Zingiber vuquangense N.S.Lý, T.H.Lê, T.H.Trinh, V.H.Nguyễn & N.Đ.Đỗ

Description: Perennial herb, pseudostems up to 3 m. Leaf blade broadly elliptic

to elliptic–ovate, 26-50.8 × 9-14.7 cm, margin scattered hairs near the base.

Inflorescences arising from rhizomes, peduncle usually fully embedded in ground;

bracts oblong, 3.5–4.3 × 1.1–1.3 cm, shorter than bracteoles, brown-red at upper 1/3,

pale yellow towards base, sparse hairs at base, densely pubescent distally, apex

rounded, margin slightly serrate, ciliate. Calyx ca. 1.65-1.75 cm, split on 1 side, apex

2-toothed. Corolla tube ca. 3.7-3.9 cm, hairy; lobes triangular to ovate, center one 4.3-

4.5 × 0.9-1.0 cm, lateral ones 3.6-3.7 × 0.6-0.75 cm. Labellum obovate, 3.8-4.1 × 1.8-

2.0 cm, base pale yellow, pink-purple with small pale-yellow spots; lateral staminodes

obovate to oblong, 2.0-2.2 × 0.8-1.1 cm, connate to labellum by apical ¾. Filament ca.

0.25-0.3 cm; connective appendage is as long as the anther, ca. 1.5-1.7 cm, pink-purple

13

or yellow. Ovary cylindrical, 7–7.5 × 3–3.5 mm, hairy. Mature capsules sessile or

pedicel 2 mm long, somewhat trigonous ovoid, 3.2–4 × 1.2–1.9 cm, light purple. Seeds

irregular obovoid, 4–5 × 3.5–4 cm, pink-red. Fl. Apr-May, fr. Jun-Sep.

12. Zingiber zerumbet (L.) Smith

Description: Perennial herb, pseudostems up to 1.30 m. Leaves closely imbricate;

leaf blade lanceolate or oblong-lanceolate, 22-23 × 6-8 cm, underneath pilose.

Inflorescences arising from rhizomes; bracts closely imbricate, green when young, red

when old, obovate, 3,2-3,4 × 2,4-2,6 cm, slightly hairy; bracteoles white, ovate, ca. 2.4-

2.5 cm. Calyx 1.7–1.9 cm, split on 1 side, apex 3-toothed. Corolla tube ca. 3.2 cm;

lobes ovate, pale yellow, 1.4-1.9 × 0.3-0.8 cm. Labellum nearly rounded, ca. 1.7 × 1.7

cm, base white, apex pale-yellow and 2-toothed, margin wrinkled; lateral staminodes

connective to the labellum by basal ¾, 0.5-0.7 × 0.2-0.3 cm. Filament very short, anther

ca. 1.1-1.3 cm; connective appendage ca. 0.9-1.0 cm. Ovary ca. 0.3-0.4 × 0.2-0.3 cm.

Capsule elliptic. Seeds black. Fl. May-July (Aut), fr. Oct-Jan.

3.1.6.2. Hedychium species

1. Hedychium coronarium Koenig

Description: Perennial herb, pseudostems 1.5-2 m. Leaf blade lanceolate, 40-45

× 5.5-7 cm; underneath white slightly hairy, easy fallen. Inflorescences macelike;

bracts green, 4 - 4.5 x 2.5 - 4 cm, arranged roofing, 4-5 flowered; bracteoles tubular,

membranous. Flowers white, fragrant. Calyx ca. 2.7-4 cm; split on 1 side, apex 3- dent,

edge hairy. Corolla tube 7-8 cm; lobes linear, ca. 4-5 cm, center one spoonlike, apex

hooded. Labellum obheart, 4-6 × 4-6 cm, apex incised to the middle, butterflylike;

lateral staminodes linear, apex incised slightly V-shaped. Filament 2.8-3 cm; anther

1.2-1.5 cm, pale red-yellow, created an obtuse angle with filament. Ovary pubescent.

Capsule narrowly ovate, 2-3 × 1.2-1.5 cm. Seeds sub-globose; aril red, lacerate. Fl.

July-Dec, fr. Sep-Feb.

2. Hedychium flavum Roxb.

Description: Perennial herb, pseudostems 1.4-1.6 m. Leaf blade narrowly elliptic

oblong, 30-45 × 8-12 cm, glabrous. Inflorescences oval, flowers numerous; bracts

ovate oblong, 4-6 × 1.5-3 cm, green, roofed when young, slightly detached when

flowers bloom, 3-5 flowered. Calyx split on 1 side, hairy. Corolla tube 7-8 cm; lobes

linear, yellow. Labellum wide obovate or obheart, 3-4 cm, bright yellow, darker at base

to middle, base attenuate into a claw, apex divided 2 lobes; lateral staminodes

oblanceolate, yellowish. Filament 2.8-3.2 cm, orange-yellow; anther 1.2-1.5 cm,

created an obtuse or nearly square angle with filament. Ovary cylindrical, 1.5-2 mm,

hairy. Capsule, ellipsoid. Fl. Aug-Oct, fr. Oct-Dec.

3. Hedychium gardnerianum Rosc.

Description: Perennial herb, pseudostems 0.8-1 m. Leaf blade lanceolate to

lanceolate-oblong, 20-45 (-55) × 10-15 cm. Inflorescence 35-45 cm long; bracts lax,

oval-oblong, 3-5 cm; bracteoles shorter than bracts. Flowers yellow. Calyx 3-3.5 cm,

split on 1 side, apex 3-toothed, hairy externally. Corolla tube longer than bracts,

glabrous; lobes linear, 3.5-4.5 cm, involute. Labellum wedgelike, 2.5-3 cm, yellow,

14

apex split 2-lobed; lateral staminodes oblanceolate, 2.5-3 × 1.2-1.5 cm. Filament up to

6 cm long, purple, slender; anther slightly involute, 0.8-0.9 cm. Ovary 0.2-0.3 cm,

glabrous. Fl. Aug-Oct, fr. Oct-Dec.

4. Hedychium stenopetalum Lodd.

Description: Perennial herb, pseudostems 1-1.5 m. Leaf blade oblong, 45-70 × 6-

14 cm, underneath long pubescent. Inflorescence 20-35 cm long; bracts oblique, lax,

oval-oblong, 5-6.5 × 1.3-1.5 cm, green, 3-5 flowered; bracteoles shorter than bracts.

Flower white tinged yellow at base, fragrant. Calyx 3.2-3.5 cm; apex acute to 3-lobed;

pubescent. Corolla tube 4-4.5 cm; lobes linear, 2.8-3 cm. Labellum obovate, 1.8-2 × 2

cm, white, base yellow-green, apex split 2-lobed, acute; lateral staminodes lanceolate-

oblong to linear, 1.8-2 cm. Filament 4.5-5 cm; anther linear, 0.7-0.9 cm, slightly

involute. Ovary oval, 0.2-0.3 cm. Fl. July-Aug, fr. Oct-Dec.

5. Hedychium villosum Wall.

Description: Perennial herb, pseudostems up to 2 m. Leaf blade elipptic-oblong,

20-35 × 3.5-6 cm. Inflorescences 15-25 cm; bracts oblique, elipptic-oblong, 1.5-2.5 ×

0.7-0.8 cm, brown pubescent, 2-3 flowered; bracteoles equal to about 1/3 of the bracts,

pubescent. Flowers white with pale yellow blotch on lip, fragrant. Calyx membranous,

2.2-2.5 cm, 3-toothed, deeply split in one side, hairy. Corolla tube 3.2-3.5 cm,

pubescent; lobes 1.4-2.5 cm, involute. Labellum ovate-elliptic oblong, 2.5-3 × 1.5-2

cm, base attenuate into a claw, apex incised to 1/3; lateral staminodes spathulate,

oblanceolate. Filament 4.5-5 cm, red; anther sagittate. Ovary long pubescent. Fl. Feb-

Apr, fr. Apr-Jun.

3.2. Chemical compositions of essential oils of Zingiber and Hedychium species

from north-central Vietnam

3.2.1. Essential oils of Zingiber species

The constituents of the thirty-five essential oils isolated from 10 species Zingiber

were identified and quantified. Four species were first studied: Zingiber castaneum,

Zingiber cornubracteatum, Zingiber mekongense and Zingiber vuquangense. Essential

oils are slightly yellow, lighter than water, fragrance. Over two-hundred compounds

in essential oil Zingiber, each with 17-114 compounds, accounting for 74.0-99.8% of

essential oils, which are compiled in Table 3.18 and 3.19.

Table 3.18 The main ingredients of Zingiber essential oils from north-central Vietnam

TT Species

Sa

mp

le

Tota

l su

bst

an

ces

iden

tifi

ed

Co

nce

ntr

ati

on

of

iden

tifi

ed s

ub

stan

ces

Mon

ote

rpen

e

hyd

roca

cb

on

es

Oxygen

ate

d

mon

ote

rpen

es

Ses

qu

iter

pen

e

hyd

roca

rbon

s

Oxygen

ate

d

sesq

uit

erp

enes

Mon

o-s

esq

uit

erp

enes

Mon

o-s

esq

uit

erp

enoid

s

Mon

ote

rpen

es

Ses

qte

rpen

es

(%)

1 Zingiber

castaneum

473L 41 95,4 49,2 0,1 41,1 4,6 90,3 4,7 49,3 45,7

2 473S 40 99,8 9,0 1,6 73,0 16,8 82,0 18,4 10,6 89,8

15

TT Species

Sa

mp

le

Tota

l su

bst

an

ces

iden

tifi

ed

Co

nce

ntr

ati

on

of

iden

tifi

ed s

ub

stan

ces

Mon

ote

rpen

e

hyd

roca

cb

on

es

Oxygen

ate

d

mon

ote

rpen

es

Ses

qu

iter

pen

e

hyd

roca

rbon

s

Oxygen

ate

d

sesq

uit

erp

enes

Mon

o-s

esq

uit

erp

enes

Mon

o-s

esq

uit

erp

enoid

s

Mon

ote

rpen

es

Ses

qte

rpen

es

(%)

3 473R 36 96,9 54,0 34,0 5,8 2,8 59,8 36,8 88,0 8,6

4 473F 34 98,3 5,7 8,5 35,7 30,8 41,4 39,3 14,2 66,5

5 741L 40 96,8 23,5 0,4 64,9 8,0 88,4 8,4 23,9 72,9

6 741S 45 94,1 10,1 0,8 66,2 16,5 76,3 17,3 10,9 82,7

7 741R 33 98,3 77,4 14,4 3,9 2,6 81,3 17,0 91,8 6,5

8 Zingiber

collinsii

748L 35 98,1 49,0 1,8 36,3 7,6 85,3 9,4 50,8 43,9

9 748R 51 97,7 58,3 10,9 7,4 21,1 65,7 32,0 69,2 28,5

10

Zingiber

cornubrateatum

830L 51 98,5 29,1 0 57,2 9,9 86,3 9,9 29,1 67,1

11 830R 47 96,1 49,3 30,8 4,0 10,1 53,3 40,9 80,1 14,1

12 832L 31 95,7 81,9 0,5 11,8 1,1 93,7 1,6 82,4 12,9

13 832S 36 98,2 81,2 0,5 13,7 1,9 94,9 2,4 81,7 15,6

14 832R 43 95,1 75,1 8,6 2,9 4,7 80,7 12,8 86,6 6,9

15

Zingiber

mekongense

730L 31 98,1 60,4 0,0 32,7 4,1 93,1 4,1 60,4 36,8

16 730S 44 87,0 19,8 0,7 54,1 10,2 73,9 10,9 20,5 64,3

17 730R 43 89,9 30,1 0,9 39,5 16,1 69,6 17,0 31,0 55,6

18 730F 46 87,0 17,8 0,8 53,9 10,7 71,7 11,5 18,6 64,6

19 Zingiber

montanum

734L 44 74,0 43,4 9,4 8,3 8,4 51,7 17,8 52,8 16,7

20 734R 26 84,5 56,2 26,3 0,9 0,0 57,1 26,3 82,5 0,9

21 Zingiber

nitens

750L 43 98,9 59,0 0,2 36,3 3,3 95,3 3,5 59,2 39,6

22 750R 17 96,7 10,2 86,5 0,0 0,0 10,2 86,5 96,7 0,0

23

Zingiber

nudicarpum

760L 45 93,8 50,3 3,8 32,9 6,6 83,2 10,4 54,1 39,5

24 760S 37 94,4 0,5 12,0 65,1 13,9 65,6 25,9 12,5 79,0

25 760R 33 92,1 84,8 1,7 4,0 1,6 88,8 3,3 86,5 5,6

26 777L 99 98,4 39,4 2,0 41,4 11,6 80,8 13,6 41,4 53,0

27 777S 114 99,2 29,6 34,8 20,0 14,0 49,6 48,8 64,4 34,0

28 777R 88 99,5 23,9 25,3 28,5 21,3 52,4 46,6 49,2 49,8

29 Zingiber

ottensii

772L 32 89,4 25,3 0 60,5 2,6 85,8 2,6 25,3 63,1

30 772R 38 99,7 54,1 24,8 4,8 15,9 58,9 40,7 78,9 20,7

31

Zingiber

vuquangense

472L 46 91,5 39,5 4,1 34,3 9,2 73,8 13,3 43,6 43,5

32 472S 31 94,4 47,4 5,4 30,0 11,6 77,4 17,0 52,8 41,6

33 472R 38 95,0 22,0 24,7 19,1 22,6 41,1 47,3 46,7 41,7

34 472F 42 93,9 39,8 27,0 22,4 3,4 62,2 30,4 66,8 25,8

35 Zingiber

zerumbet 704R 31 94,6 24,9 17,7 8,3 43,7 33,2 61,4 42,6 52,0

Maximum value 114 99,8 84,8 86,5 73,0 43,7 95,3 86,5 96,7 89,8

16

TT Species

Sa

mp

le

Tota

l su

bst

an

ces

iden

tifi

ed

Co

nce

ntr

ati

on

of

iden

tifi

ed s

ub

stan

ces

Mon

ote

rpen

e

hyd

roca

cb

on

es

Oxygen

ate

d

mon

ote

rpen

es

Ses

qu

iter

pen

e

hyd

roca

rbon

s

Oxygen

ate

d

sesq

uit

erp

enes

Mon

o-s

esq

uit

erp

enes

Mon

o-s

esq

uit

erp

enoid

s

Mon

ote

rpen

es

Ses

qte

rpen

es

(%)

Smallest value 17 74,0 0,5 0,0 0,0 0,0 10,2 1,6 10,6 0,0

Average value 43,7 94,6 40,9 12,0 29,2 10,6 70,1 22,6 53,0 39,7

Comment: L: leaves; S: pseudostems; R: rhizomes; F: fruits

Monoterpenes and sesquiterpenes constitute the main compounds in most of

Zingiber essential oils. Monoterpenes accounted for from 10.6% (pseudostems oil of

Zingiber castaneum in Pu Huong Nature Reserve) to 96.7% (rhizome oil of Zingiber

nitens), averaging 53.0%. Sesquiterpenes accounted for from 0% (rhizome oil of Zingiber

nitens) to 89.8% (pseudostems oil of Zingiber castaneum in Pu Huong Nature Reserve),

averaging 39.7%.

Hydrocarbon compounds (Mono-sesquiterpenes) often accounts for a higher part,

accounting for 10.2 - 95.3%, averaging 70.1%; oxygenated compounds (Mono-

sesquiterpenoids) accounted for 1.6 - 86.5%, averaging 22.6%. Three essential oils had

higher oxygenated than hydrocarbon compounds: rhizome of Zingiber nitens, rhizome of

Zingiber vuquangense and rhizome of Zingiber zerumbet. In addition, some essential oils

had high oxygenated compounds such as rhizomes and fruits of Zingiber castaneum in Vu

Quang (36.8-39.3%), rhizomes of Zingiber collinsii (32.0 %), rhizomes of Zingiber

cornubracteatum in Pu Mat National Park (40.9%), rhizomes of Zingiber montanum

(26.3%), pseudostems of Zingiber nudicarpum in Bach Ma (25.9%), pseudostems and

rhisomes of Zingiber nudicarpum species in the South East (48.8-46.6%), rhizome of

Zingiber ottensii (40.7%), fruit of Zingiber vuquangense (30.4%).

Table 0.18. The major components in Zingiber essential oils from north-central

Vietnam

TT Species Sample The main ingredient of essential oils

1

Zingiber

castaneum

473L

β-Pinene (30,6%), α-pinene (9,5%), β-caryophyllene

(9,4%), bicycloelemene (9,1%), bicyclogermacrene

(7,7%) và germacrene D (6,5%).

2 473S

β-Caryophyllene (14,7%), δ-cadinene (9,8%),

bicycloelemene (8,4%), α-cubebene (7,8%), trans-α-

bergamotene (6,1%), γ-elemene (6,1%) và β-selinene

(6,0%), zerumbone (5,2%), β-pinene (4,9),

bicyclogermacrene (4,3%), α-cedrol (3,5%) và α-

humulene (3,2%).

3 473R Camphene (15,1%), 1,8-cineole (13,6%), linalool

(11,3%), δ3-carene (8,5%) và α-pinene (7,8%).

17


4 473F (E)-Nerolidol (23,2%), (Z)-9-octadecenamide (17,3%)

và β-caryophyllene (10,8%).

5 741L

Bicyclogermacrene (24,8%), germacrene D (12,9%),

cis-β-elemene (11,2%), β-pinene (10,3%), α-pinene

(9,6%) và δ-elemene (6,5%).

6 741S

Bicyclogermacrene (15,8%), cis-β-elemene (9,8%),

germacrene D (9,2%), α-humulen (7,5%), δ-Elemene

(5,4%) và α-zingiberene (4,6%).

7 741R

Sabinen (22,9%), camphen (21,2%), α-pinene (7,8%), β-

pinene (6,5%), bornyl acetate (6,1%), γ-Terpinene

(5,5%) và terpinene-4-ol (4,0%).

8

Zingiber

collinsii

748L

α-Pinene (25,6%), β-caryophyllene (16,8%), β-pinene

(16,1%), bicyclogermacrene (6,9%) và cis-α-elemene

(4,9%).

9 748R

Camphene (22,6%), β-pinene (16,3%), α-pinene (9,0%),

humulene oxide II (9,0%), bornyl acetate (5,2%),

limonene (4,1%) và caryophyllene oxide (3,2%).

10

Zingiber

cornubrateatum

830L Bicyclogermacrene (18,9%), β-pinene (18,8%), β-

caryophyllene (13,9%) và germacrene D (13,7%).

11 830R

Linalool (11,6%), β-pinene (8,8%), (E)-nerolidol

(8,4%), α-pinene (8,2%), bornyl acetate (7,9%), myrcene

(7,7%), 1,8-cineol (6,1%), δ-3-carene (5,3%) và

limonene (5,1%).

12 832L β-Pinene (67,3%), α-pinene (10,1%), cis-β-elemene

(3,9%) và bicyclogermacrene (2,7%).

13 832S β-Pinene (66,8%), α-pinene (9,9%), cis-β-elemene


14 832R β-Pinene (33,1%), sabinene (11,9%) và α-pinene (9,8%).

15

Zingiber

mekongense

730L β-Pinene (43,1%), cis-β-elemene (13,6%), α-pinene

(12,9%), β-caryophyllene (9,2%) và α-humulene (4,8%).

16 730S

cis-β-Elemene (22,6%), β-caryophyllene (17,2%), β-

pinene (13,7%), α-humulene (5,2%), α-pinene (3,9%) và

(E)-nerolidol (3,9%).

17 730R

β-Pinene (19,5%), cis-β-elemene (11,8%), β-

caryophyllene (9,5%), α-zingiberene (9,4%), (E)-

nerolidol (5,8%) và α-pinene (4,6%).

18 730F β-Caryophyllene (24,1%), cis-β-elemene (19,4%), β-

pinene (10,0%), (E)-nerolidol (4,6%) và α-pinene (3,4%).

19 Zingiber

montanum

734L β-Pinene (13,8%), β-phellandrene (11,3%), α-pinene

(7,3%) và cryptone (4,2%).

20 734R Sabinene (41,1%), terpinen-4-ol (22,7%), γ-terpinene

18


(3,4%) và β-pinene (2,9%).

21 Zingiber

nitens

750L β-Pinene (48,5%), α-pinene (10,7%), bicyclogermacrene

(7,0%), α-zingiberen (6,4%) và germacrene D (4,7%).

22 750R Terpinen-4-ol (77,9%), γ-terpinene (4,6%) và cis-para-

menth-2-el-1-ol (2,0%).

23

Zingiber

nudicarpum

760L β-Pinene (34,0%), β-caryophyllene (13,9%), α-pinene


24 760S β-Caryophyllene (52,6%), linalool (11,0%), α-humulene

(5,9%) và caryophyllene oxide (4,4%).

25 760R β-Pinene (58,3%) và α-pinene (18,7%).

26 777L

β-Pinene (26,6%), β-caryophyllene (24,3%), α-pinene

(5,0%), germacrene D (3,6%), caryophyllene oxide

(3,6%), bicyclogermacrene (3,3%) và α-humulene

(3,2%).

27 777S

1,8-Cineole (21,2%), α-pinene (10,6%), β-pinene

(9,0%), caryophyllene oxide (8,0%), p-cymene (6,0%),

β-selinene (5,4%) và α-copaene (3,1%).

28 777R

β-Pinene (9,8%), 1,8-cineole (6,8%), endo-fenchyl

acetate (6,5%), β-caryophyllene (4,9%), α-humulene

(4,8%), selin-11-en-4β-ol (neointermediol) (4,4%), α-

pinene (4,0%), borneol (4,0%), γ-cadinene (3,1%) và δ-

3-carene (3,1%).

29

Zingiber

ottensii

772L β-Caryophyllene (28,0%), β-pinene (17,1%) và cis-β-

elemene (17,0%).

30 772R

Sabinene (21,6%), terpinene-4-ol (17,1%), zerumbone

(12,5%), β-pinene (11,7%), γ-terpinene (5,5%) và 1,8-

cineole (4,3%).

31

Zingiber

vuquangense

472L β-Pinene (24,7%), β-caryophyllene (12,3%), α-

humulene (7,7%) và α-pinene (6,9%).

32 472S

β-Pinene (26,1%), β-caryophyllene (13,9%), α-

humulene (8,2%), α-pinene (5,2%), camphene (4,8%) và

elemon (4,5%).

33 472R

Bornyl acetate (20,9%), zerumbone (14,1%), α-

humulene (9,6%), β-pinene (8,0%), (Z)-9-

octadecenamide (6,6%) và β-caryophyllene (4,5%).

34 472F β-Pinene (19,6%), 1,8-cineole (15,6%), β-caryophyllene

(10,4%), α-pinene (10,3%) và camphene (5,4%).

35 Zingiber

zerumbet 704R

Zerumbone (40,6%), camphene (9,3%), a-humelene

(6,8%), camphor (5,8%), (Z)-β-ocimene (5,8%) và

santolina triene (5,7%)

Comment: L: leaves; S: pseudostems; R: rhizomes; F: fruits

19

β-pinene often occupy a large proportion in the most of Zingiber essential oils,

accounting for 0.5-67.3%, average 19.6% / essential oil sample. There are also

compounds appearing most of the essential oil samples such as: myrcene in 34 samples,

accounting for 0-7.7%, average of 1.3%/sample; both α-pinene and β-caryophyllene in

33 samples, accounting for 0-25.6% and 0-52.6% respectively, average of 7.4 and

9.0%; α-humelene in 32 samples, accounting for 0-9.6%, average 3.0%; and

caryophyllene oxide in 31 samples, accounting for 0-8.0%, average 1.7%.

Compounds commonly found in high concentrations in leaf essential oils include::

β-pinene (accounting for 10.3-67.3%, average 27.0%), α-pinene (accounting for 2.7-

25.6%, average 10.1%) and β-caryophyllene (accounting for 0.4-28.0%, average

9.5%); in pseudostems essential oils: β-pinene (accounting for 0.5-66.8%, average

17.8%) and β-caryophyllene (accounting for 1.6-52.6%, average 14.8%); and in

rhizome essential oils: β-pinene (accounting for 0.6-58.3%, average 14.0%).

In more than 200 identified compounds in Zingiber essential oils, there are several

oxygenated compounds against major chronic diseases and cancers, which account

high amounts in essential oils, such as 1,8-cineole (accounting for 13.6% in Zingiber

castaneum rhizome essential oil from Vu Quang National Park, 15.6% in Zingiber

vuquangense fruit essential oils, 21.2% in Zingiber nudicarpum rhizome essential oil

from Nam Đông district), terpinen-4 -ol (accounting for 17.1% in Zingiber ottensii

rhizome essential oil, 22.7% in Zingiber montanum rhizome essential oil, 77.9% in

Zingiber nitens rhizome essential oil), bornyl acetate (accounting for 20.9% in Zingiber

vuquangense rhizome essential oil), and zerumbone (accounting for 12.5% in Zingiber

ottensii rhizome essential oil, 14.1% in Zingiber vuquangense rhizome oil, 40.6% in

Zingiber zerumbet rhizome essential oil).

3.2.2. Essential oils of Hedychium species

The volatile constituents of four essential oils from Hedychium, namely those of

Hedychium stenopetalum (leaf and rhizome oils) and Hedychium villosum (leaf and

rhizome oils) were identified. Essential oil of Hedychium villosum was first studied.

Essential oils are lighter than water, colorless and fragrant.

Essential oils are mainly monoterpene (accounting for 74.6-94.0%), sesquiterpene

(accounting for 0.5-14.7%) and alkylbenben (accounting for 5.0-6.9%). Hydrocarbon

compounds accounted for more dominant content, accounting for 66.7-86.5%,

oxygenated compounds only accounted for 7.9-33.3%. In leaf oil, the oxygenated

compounds accounted for only 7.9-10.3%; while in rhizome essential oils, they

accounted for 22.8-33.3%.

β-Pinene, α-pinene and o-cymene accounted for a large in four essential oils. In

particular, o-cymene is an alkylbenzene, accounting for a high and relatively stable

percentage in essential oils (5.0-6.9%). This compound has little aromatherapy and

medicinal uses, but it may be characteristic of this genus essential oil.

In addition, there are a number of oxygenated compounds that account for high

concentrations in essential oils such as linalool (accounting for 28.5% of Hedychium

stenopetalum rhizome oil), 1.8-cineole (accounting for 10.7% of Hedychium villosum

20

rhizome oil). These compounds are fragrant and bioactive, so they are also medicinally

valuable in addition to their aromatherapy uses.

3.3. Biological activity of essential oils of several Zingiber and Hedychium species

from north-central Vietnam

3.3.1. Antimicrobial activity

Thirteen essential oils from five Zingiber and Hedychium species were tested for

antibacterial activity against a panel of Gram-positive (Enterococcus faecalis,

Staphylococcus aureus, and Bacillus cereus), and Gram-negative (Escherichia coli,

Pseudomonas aeruginosa, and Salmonella enterica) bacteria, and for anticandidal

activity against Candida albicans (Table 3.23).

Table 3.23. Antimicrobial activities of Zingiber and Hedychium essential oils from

north-central Vietnam.

Species

Ess

enti

al o

il

sam

ple

s

Gram-positive Gram-negative Fungi E

. fa

eca

lis

AT

CC

299

212

S.

aure

us

AT

CC

259

23

B.

cere

us

AT

CC

145

79

E.

coli

AT

CC

259

22

P.

aer

ug

ino

sa

AT

CC

278

53

S. en

teri

ca

AT

CC

130

76

C. alb

ican

s

AT

CC

102

31

MIC (µg/ml)

Zingiber collinsii 748L 32 32 32 - 64 - 8

748R 64 128 64 - 32 - 128

Zingiber

cornubraceatum

830L 64 64 128 128 - - 16

830R 32 64 128 64 256 - 16

832L 128 128 - 64 - - -

832S 128 128 - 256 - - -

832R 32 32 64 256 - - 256

Zingiber nudicarpum 760L 32 16 16 - 128 - 16

760R 2 8 1 64 16 - 16

Zingiber ottensii 772L 64 64 64 - 16 - 64

772R 8 64 32 - - - 8

Hedychium stenopetalum 793L 32 128 64 - - - 128

793R 64 128 128 - - - 256

IC50 (µg/ml)

Zingiber collinsii 748L 15,67 15,67 15,67 - 32,99 - 4,67

748R 33,56 65,78 33,45 - 15,67 - 64,56

Zingiber

cornubraceatum

830L 20,78 9,34 45,67 45,67 - - 5,67

830R 9,56 13,56 43,67 20,45 100,34 - 7,89

832L 45,67 45,67 - 18,78 - - -

832S 46,78 19,78 - 47,89 - - -

832R 10,45 9,34 18,79 68,99 - - 99,34

Zingiber nudicarpum 760L 16,33 8,54 8,57 - 65,44 - 8,67

760R 1,33 4,35 0,567 33,22 8,66 - 8,99

21

Species

Ess

enti

al o

il

sam

ple

s

Gram-positive Gram-negative Fungi

E.

faec

ali

s

AT

CC

299

212

S. aure

us

AT

CC

259

23

B.

cere

us

AT

CC

145

79

E.

coli

AT

CC

259

22

P.

aer

ug

ino

sa

AT

CC

278

53

S. en

teri

ca

AT

CC

130

76

C. alb

ican

s

AT

CC

102

31

MIC (µg/ml)

Zingiber ottensii 772L 32,66 32,33 33,77 - 7,99 - 32,33

772R 2,57 17,89 15,56 - - - 3,56

Hedychium stenopetalum 793L 7,88 56,89 18,97 - - - 45,67

793R 16,23 50,78 89,78 - - - 126,67

Comment: L: Leaf; S: Pseudostems; R: Zhizome.

The essential oils generally showed good to excellent activity against the Gram-

positive organisms compared to Gram-negative. C. albicans was also relatively

sensitive to the Zingiber and Hedychium essential oils. The essential oil with the best

overall antimicrobial activity was Zingiber nudicarpum rhizome essential oil from

Bạch Mã National Park with MIC < 10 µg/mL against all three Gram-positive

organisms, a Gram-negative (P. aeruginosa) and C. albicans, and MIC = 33.22 µg/mL

against E. Coli.

3.3.2. Mosquito Larvicidal Activity

Several of the Zingiber essential oils were assayed for insecticidal activity against

larvae of Aedes aegypti, Aedes albopictus, and Culex quinquefasciatus mosquitoes.

The test periods were 24 h and 48 h. The percentage mortality as well as the minimum

lethal concentrations is shown in Table 3.24.

Table 3.24. Percentage mortality and Larvicidal activities of Zingiber essential

oils from north-central Vietnam.

Time Ginger (Zingiber)

Essential

oil

samples

Dead

100%

(µg/ml)

LC50

(µg/ml)

LC90

(µg/ml) X2 P

Aedes aegypti

24h

Zingiber castaneum 741R 200 121,430 145,280 9,512 0,001

Zingiber nitens 450L 50 17,580 23,250 9,343 0,000

450R 100 29,600 37,600 2,012 0,044

Zingiber nudicarpum 760L 12,5 5,543 9,214 0,44 < 0,001

760R 50 20,391 29,964 0,040 < 0,001

48h


Zingiber nitens 450L 50 15,120 18,700 2,095 0,036

450R 100 26,320 36,920 5,938 0,000

Zingiber nudicarpum 760L 12,5 5,200 9,071 0,214 < 0,001

760R 50 19,321 29,498 0,017 < 0,001

Aedes albopictus

24h Zingiber collinsii 748R 100 25,510 40,220 11,34 < 0,001

22


Zingiber nudicarpum 760L 50 18,986 26,917 0,001 < 0,001

760R 100 28,392 62,508 0,835 < 0,001

48h

Zingiber collinsii 748R 100 20,030 24,510 8,73 < 0,001



760R 50 22,163 56,100 10,726 < 0,001

Culex quinquefasciatus

24h


Zingiber castaneum 741R 100

(55%) 88,860 117,680 8,502 0,001

Zingiber nitens 450R 100

(92,5%) 64,180 92,680 5,363 0,000


760R 50 6,158 13,118 7,846 < 0,001

48h


Zingiber castaneum 741R 100

(81,3%) 48,080 72,130 6,871 0,001

Zingiber nitens 450R 100

(92,5%) 59,060 84,310 5,963 0,000


760R 50 4,393 6,867 0,093 < 0,001

The essential oils showing the best larvicidal activity against Ae. aegypti were

Zingiber nudicarpum leaf essential oil from Bạch Mã National Park (24-h LC50 =

18.986 µg/mL). The leaf essential oil of Zingiber nudicarpum also demonstrated

remarkable activity against Ae. albopictus (24-h LC50 = 12.7 µg/mL). Both Zingiber

nudicarpum leaf essential oil and rhizome essential oil were very active against Cx.

quinquefasciatus larvae, with LC50 values of 5.587 and 6.158 µg/mL, respectively.

CONCLUSIONS AND RECOMMENDATIONS

Conclusions

1. Identified 24 species in north-central Vietnam, 19 species of Zingiber and 5

species of Hedychium. Describe a new species for science, namely Gừng vũ quang

(Zingiber vuquangense N.S.Lý, T.H.Lê, T.H.Trinh, V.H.Nguyễn & N.Đ.Đỗ); New

recorded two species to the Vietnamese flora: Zingiber cornubracteatum Triboun & K.

Larsen and Zingiber mekongense Gagnep. Seven additional species of distribution for

the flora of north-central Vietnam

2. Habitat: grows in primary forest, secondary forest; under the canopy of humid

forests, wet humus, along streams, moist limestone mountain cavities, planted in

gardens. Flowering of most Zingiber species usually begins in spring (Mar-May),

rarely in summer (Zingiber montanum, July) or autumn (Zingiber cornubracteatum,

Sep); while flowering of Hedychium species usually begins in summer (July-August),

23

rarely in winter (Hedychium villosum, February).

3. In addition to essential oil using value (24 species, 100%), many species of 24

species also give other using values such as medicine, 15 species (62.5 %); food, 5

species (20.8 %); ornamental, 4 species (16.7 %); and spices, 4 species (16.7 %).

4. Determination of content and chemical composition of 39 essential oil samples

of 12 species of Zingiber and Hedychium genus. Essential oils of 5 species: Zingiber

castaneum, Zingiber cornubracteatum, Zingiber mekongense, Zingiber vuquangense

and Hedychium villosum were first studied. The essential oils were predominantly mono-

and sesqui-terpenes, of which, the hydrocarbon compounds content is often higher than

the oxygenated compounds. There are 4 essential oil samples with higher oxygen content

than hydrocarbons: rhizome of Zingiber nitens, pseudostem of Zingiber nudicarpum

from Nam Dong, rhizome of Zingiber vuquangense and rhizome of Zingiber zerumbet.

5. Several essential oil samples of a number of studied species contain valuable

oxygenated compounds, such as 1,8-cineole, bornyl acetate, linalool, terpinen-4-ol and

zerumbone, in rhizome species of Zingiber castaneum from Vu Quang National Park,

Zingiber montanum, Zingiber nitens, Zingiber ottensii, Zingiber zerumbet, Hedychium

villosum, Hedychium stenopetalum; in rhizomes and fruits of Zingiber vuquangense; and

in pseudostem of Zingiber nudicarpum from Nam Dong.

6. Testing bioactive properties: Thirteen essential oils from 5 species were tested

for antimicrobial activity; of which, Zingiber nudicarpum rhizome essential oil from

Bach Ma National Park ad the best overall antimicrobial activity, with MIC <10 µg/mL

against all three Gram-positive, P. aeruginosa and C. albicans, and MIC = 33.22 µg /

mL against E. Coli; Testing the mosquito larvicidal activity of 6 essential oil samples of

4 Zingiber species showed that: leaf essential oil samples of Zingiber nudicarpum from

Bach Ma National Park had anti-larval activity of the 3 most powerful mosquitoes (24h,

LC50 (µg/ml), Aedes aegypti: 5.543, Aedes albopictus: 18.986, Culex quinquefasciatus:

5.587).

Recommendations

- It is necessary to fully study and systematize on the content and chemical

composition of essential oils at different development stages of plants at the same site;

as well as the same plant part in different locations to determine the essential oil

accumulation behavior of the species. From there evaluate plant resources.

- There is a need to thoroughly study and evaluate the content and quality of

essential oils, as well as the economic benefits of essential oils with high levels of

oxygenated compounds, which have potential for practical applications such as

zerumbone, terpinen-4-ol, 1,8-cineole. Since then, it helps managers to plan strategies

and policies to develop essential oil plant material areas to generate budget revenue,

create jobs and improve people's lives.

24

NEW CONTRIBUTIONS OF THE THESIS

1. A new species: Zingiber vuquangense N.S.Lý, T.H.Le, T.H.Trinh,

V.H.Nguyễn & N.Đ.Đỗ; new recorded 02 species for flora of Vietnam: Zingiber

mekongense Gagnep. and Zingiber cornubracteatum Triboun & K. Larsen; recorded

the distribution of 7 species in the North Central region of Vietnam;

2. Providing new data set on the content and chemical composition of essential

oils in the leaves, pseudostems, rhizome and fruits of 39 samples of 12 species in

Zingiber and Hedychium genus from north-central Vietnam. For the first time,

providing data set on essential oils of 5 species: Zingiber castaneum, Zingiber

cornubracteatum, Zingiber mekongense, Zingiber vuquangense and Hedychium

villosum;

3. Providing new data set on antimicrobial activity of 13 essential oil samples

of 5 species: Zingiber collinsii, Zingiber cornubracteatum, Zingiber nudicarpum,

Zingiber ottensii, and Hedychium stenopetalum; and mosquito larvicidal activity of 6

essential oil samples of 4 species: Zingiber castaneum, Zingiber collinsii, Zingiber

nitens, and Zingiber nudicarpum.

LIST OF PUBLISHED WORKS

1. Trịnh Thị Hương, Nguyễn Thị Thanh Hương và Lê Thị Hương, Các hợp

chất dễ bay hơi của loài Gừng gió (Zingiber zerumbet (L.) Smith) ở VQG Bến En,

Thanh Hóa, Tạp chí Khoa học ĐHQGHN: Khoa học Tự nhiên và Công nghệ, 2017,

33(1S), 263-267.

2. Lê Thị Hương, Trịnh Thị Hương, Đậu Bá Thìn, Đào Thị Minh Châu và

Đào Thị Thoan, Đa dạng họ Gừng (Zingiberaceae) ở VQG Pù Mát, Nghệ An, Tạp chí

Khoa học ĐHQGHN: Khoa học Tự nhiên và Công nghệ, 2018, 34(1), 84-89.

3. Lê Thị Hương, Trịnh Thị Hương, Đỗ Ngọc Đài, Nguyễn Việt Hùng and

Lý Ngọc Sâm, Zingiber vuquangense (Sect. Cryptanthium: Zingiberaceae), a new

species from North Central region in Vietnam, 2019, Phytotaxa, 338(4), 295-300

(SCIE, Q2).

4. Lê Thị Hương, Nguyễn Thị Thu Huyền và Trịnh Thị Hương, Nghiên cứu

tính đa dạng họ Gừng (Zingiberaceae) ở VQG Bạch Mã, tỉnh Thừa Thiên Huế, 2019,

Tạp chí Khoa học Lâm Nghiệp, Số 2, 14-19.

5. Trinh T. Huong, Le T. Huong, Nguyen V. Hung, Ly N. Sam and Isiaka

A. Ogunwande, Study on Essential Oils from the Leaves, Stems, Rhizomes and Fruits

of Zingiber mekongense, 2019, Journal of Essential Oil-Bearing Plants, 22(4), 1123-

1128 (SCIE, Q4).

6. Lê Thị Hương, Trịnh Thị Hương và Lý Ngọc Sâm, Zingiber

cornubracteatum Triboun & K. Larsen (Zingiberaceae) loài bổ sung cho hệ thực vật

Việt Nam, 2019, Tạp chí Nông nghiệp và Phát triển Nông thôn, Số 23, 111-114.

7. Le T. Huong, Trinh T. Huong, Nguyen T.T. Huong, Nguyen H. Hung,

Pham T.T. Dat, Ngo X. Luong and Isiaka A. Ogunwande, Mosquito larvicidal

activity of the essential oil of zingiber collinsii against aedes albopictus and culex

quinquefasciatus, 2020, Journal of Oleo Science, 69(2), 153-160 (SCIE, Q2).

8. Lê Thị Hương, Trịnh Thị Hương, Nguyễn Thị Thanh Hương và Lý Ngọc

Sâm, Zingiber mekongense Gagnep. (Zingiberaceae): ghi nhận vùng phân bố cho

hệ thực vật Việt Nam, 2020, Tạp chí Khoa học ĐHQGHN: Khoa học Tự nhiên và

Công nghệ, 36(2), 1-6.

9. Le Thi Huong, Nguyen Thanh Chung, Trinh Thi Huong, Ly Ngoc Sam,

Nguyen Huy Hung, Isiaka Ajani Ogunwande, Do Ngoc Dai, Le Duy Linh and

William N. Setzer, Essential Oils of Zingiber Species from Vietnam: Chemical

Compositions and Biological Activities, Plants, 2020, 9 (1269), 1–37 (SCIE, Q1).

Documents

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