Vice chairman of quality assurance and accreditation unit

Supervisor for EPSF-Mansoura

Lecturer - Pharmacogosy department,

Faculty of Pharmacy, Mansoura University

3

Mona Farouk 2

Classification according to chemical nature

Holosides

the aglycone is sugar

Heterosides

the aglycone is not a sugar

Alcoholic

(e.g: Salicin)

Aldehydic(e.g: Gluco-vanillin)

Phenolic

Simple phenolic

(e.g: Arbutin) Anthracene or

anthraquinone

(e.g: Gluco-aloe-emodin)

Flavonoidal

(e.g: Rutin)

Coumarin

(e.g: umbelliferon

SteroidalSaponin

Cyanogenetic

(e.g: Amygdalin

Thio-glycosides

(e.g: Sinigrin).

The phenolic aglycones are classified into:

1. Simple phenolic glycosides.

2. Coumarin glycosides

3. Lignans and neolignans xxx

4. Anthraquinones glycosides

5. Flavones and related flavonoid glycosides

1-Salicin 2-Coniferin 3. Arbutin

Source: bearberry (Uva ursi) leaves.

Hydrolysis: acids or emulsin it yields hydroquinone

and glucose.

Chemical test: + FeCl3 gives violet col.

Uses:

1. diuretic

2. renal antiseptic is due to the

hydroquinone given by

hydrolysis.

3. Arbutin is used for skin whitening. It is proved to be a good

inhibitor for melanin synthesis and may be used in

hyperpigmentation disorders.

These constitute a group of glycosides, of which the aglycone is

either coumarin or

a coumarin derivative (Hydroxy and methoxy coumarins).

Coumarin umbelliferon Daphinin

Detection: The aqueous solution of all coumarins and its derivatives

have blue or violet fluorescence in UV 366 nm.

Intensifies by aq. ammonia solution.

Umbelliferon is a natural coumarin

Source: in some resins of Galbanum, and Asafetida

Coumarin importance

A natural fragrant substance has a sweet odor,

and has been used in perfumes industry.

Coumarin is used in the pharmaceutical industry as a precursor

in the synthesis of a number of synthetic anticoagulant

pharmaceuticals similar to dicoumarol, e.g. warfarin, they act

in the liver by interfering with the action of vitamin K.

Coumarins e.g:diosmin, are an edema modifier. They stimulate

macrophages to degrade extracellular albumin, allowing faster

resorption of edematous fluids.

Its strong absorption of ultraviolet light at several wavelengths

led to its use as a sunscreen agent.

Anthraquinones are widely distributed in plants.

Mainly used as purgative drugs

e.g: Senna, Rhubarb, Cascara, Frangula and Aloes

These anthraquinone derivatives, occur

in both the free state and as glycosides

Properties of Anthrquinone derivatives:

They are usually red or yellow colored.

When free, they are of low solubility in water.

These for mentioned subgroups may occur in the form :

1) Free aglycones: e.g: anthraquinones.

2) O-glycosides. 3) C- glycosides

They are usually more soluble in hot water and dilute

alcohols, glycosides show greater solubility in water.

Anthraquinone derivatives give reddish coloration with

alkali, a fact on which Borntrager’s Reaction is based

Tests for identity:

1)Bornträger’s test: pink or red in aqueous layer.

2)Modified Bornträger’s test: pink or red in aqueous layer.

3)Micro-sublimation: The sublimate form needle crystals that

acquires red color with a drop of alkali

Quantitative determination of anthracene glycosides

Colorimetric method:

After hydrolysis with acid, the aglycone is allowed to react with

KOH to give red or violet color.

The intensity of this color is directly proportional to the

concentration of anthraquione, and can be measured

colorimetrically.

Anthranol contents can, similarly, be determined but after

oxidation with FeCl3 or H2O2

1, 8-anthraquinone derivatives exert a more or less violent laxative or

purgative activity.

Anthraquinone glycosides may be considered prodrugs: the sugar

moiety is essential for the pharmacological action, as it serves to

transport the aglycone to the site of action in the large intestine.

They exert their action by:

(A) Increasing the peristaltic movement of the large

intestine causing soft evacuation.

(B) Stimulate the secretion of water and electrolytes into the large

intestine.Side effect:

Habit-forming, and long-term use may result in

laxative dependence and loss of normal bowel function.

Pharmacological properties:

i) Emodin:

Frangulin: gives on hydrolysis frangula-emodin and rhamnose

Aloe-emodin: in Cascara bark, Senna leaves and Aloes

ii) Rhein: found in rhubarb.

They are reduced form of anthraquinone.

During storage of crude drugs:

Anthranols Anthraquinones (by oxidation).

Tests for identity: Borax test: Extract + borax Green fluorescence

e.g: Chrysarobin:

Use: Keratolytic in cases of psoriasis and skin dermatitis.

3) Oxanthrones: Rarely found

They are derived from two anthrone molecules which may be identical

(e.g. two rhein anthrone moieties .... and called Homo-dianthrone) or

Different (e.g., one rhein anthrone linked to one aloe-emodin-anthrone

moiety……and so called Hetero-dianthrone).

Homo-Dianthrones (Dimers of two similar anthrone moieties)

One of the best known example is senna that contains sennoside

(A or B) derived from molecule of glucose and molecules of rhein-

anthrone. On hydrolysis, sennoside (A or B) yields the

corresponding aglycones sennidine (A or B). Each sennidin

molecule (A or B) is formed of two rhein anthrone moieties.

Hetero-Dianthrones

(Dimers of two different anthrone moieties)

Beside sennoside A and sennoside B, senna contains

sennoside C and sennoside D, which are the glycoside of genins,

named sennidin C and sennidin D, built up of a rhein anthrone +

an aloe-emodin anthrone.