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
1
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
2
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
TT Species Sample The main ingredient of essential oils
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
(4,4%) và bicyclogermacrene (3,0%).
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
TT Species Sample The main ingredient of essential oils
(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
(10,9%) và bicyclogermacrene (9,6%).
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 castaneum 741R 200 110,310 125,330 2,497 0,01
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 castaneum 741R 100 49,850 71,710 6,468 0,001
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
Zingiber castaneum 741R 100 43,930 68,120 7,571 0,001
Zingiber nudicarpum 760L 50 11,443 20,897 6,356 < 0,001
760R 50 22,163 56,100 10,726 < 0,001
Culex quinquefasciatus
24h
Zingiber collinsii 748R 100 50,110 71,530 7,61 < 0,001
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
Zingiber nudicarpum 760L 100 5,587 13,567 7,093 < 0,001
760R 50 6,158 13,118 7,846 < 0,001
48h
Zingiber collinsii 748R 100 36,180 55,110 10,78 < 0,001
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
Zingiber nudicarpum 760L 100 4,837 11,247 9,072 < 0,001
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
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