ANTHRAQUINONE GLYCOSIDES

Lec. ( 4 ) ANTHRAQUINONE GLYCOSIDES



Anthraquinone glycosides upon hydrolysis yield aglycone, which are di, tri or tetra hydroxy anthraquinone or derivative of these compounds. The free anthraquinone aglycone exhibits little therapeutic activity.
The sugar residue facilitates translocation and absorption of aglycone at the site of action. These compounds are stimulant, cathartic or purgation and they exert their action by increasing the tone of smooth muscle in the wall of large intestine.

Chemical Tests: -
There are two chemical tests for anthraquinone glycosides.
1- When alkali is added to the powdered drug or to the section of drug red colour produced serve to locate the anthraquinone derivative in the tissue e.g. in the case of carcara bark, when treated with alkali the medullary rays assume red colour.
2- Borntrager Test: -
Powdered drug is mixed with ether, which is filtered, and to the filtrate add caustic soda and aqueous ammonia. Red, pink or violet colour produced indicates the presence of anthraquinone glycoside.

1- Aloe
Aloe ferox
Aloe barbadensis
Aloe perryi
Dried juice of leaves
Family: Liliaceae.

Collection and Drying: -
Leaves are cut from 9-10 months old plant in March and April. They are placed in V-shaped trough is placed on an inclined so that the juice from the leaves may be led into a vessel. This juice is then evaporated to a sufficient degree and then is placed in a metal container and allowed to harden. The odour of drug is characteristic and taste is bitter.
Constituents: -
Aloe contains a no. of anthraquinone glycosides. The principal of which Barbaloin. It is Aloe emodin anthrone c-10 glycoside. So it is an example c-glycoside.

Uses: -
1-Purgative
2-Cathartic
3-Fresh mucilaginous juice of the leaves is used for the treatment of skin burns, skin abrasion and other skin irritations.
4-Used in compound Benzoin tinctures.

Chemical Tests: -
1- When 2 ml of Nitric acid is added to 5ml. 1% aq solution of Aloe it gives pale brown colour.
2-When few crystals of sod. nitrite along with a little acetic acid is added to 5ml 1% soln. of aloe. It gives brown colouration due to isobarbaloin.

2- Cascara

Rhamnus purshiana, Cascara sagrada
Family: Rhamnaceae
Dried bark

Collection: -
Bark is collected from mid April to the end of August. Cut into small pieces and dried in shade to retain colour. Its fracture is short and glandular in outer layers and somewhat fibrous in phloem region. Odour of bark is slight and characteristic. Taste is bitter.

Constituents: -
Primary glycosides i.e. cascaroside A and B and cascaroside C and D. These primary glycosides are more effective.

Cascaroside A and B are related to Barbaloin while cascaroside C and D are related to chrysoloin.
Plants also contain two Aloins.
1- Barbaloin.
2- Chrysoloin.
Chrysophanol, Aloe emodine and emodine in free state are least effective.

Uses Of Cascara: -

1- Purgative
2-Cathartic
Veterinary work.
The primary glycosides are more active then aloins while the free anthraquinone have little purgative property. The cascarosides have a sweet and more pleasant taste than the aloins and it is evaluated that aloins and cascarosides should be extracted separately.

3- Rhubarb

Rheum emodi
Rheum webbianum (Indian Rhubarb)
Rheum palmatum
Rheum officinale.
Family: Ploygonaceae
Dried rhizome and roots.

Collection: -
Plants are perennial herbs. Underground portion consists of strong vertical rhizomes and roots are collected from 6-9 years old plants and dried artificially or in the sun. the drug has a frim texture, non-shrunken appearance, dried yellow surface, aromatic odour.
Taste is bitter and is astringent.

Constituents: -
Principal constituent is related to Rhein anthrone.
Drug also contain astringent principal i.e. rheotannic acid, gellic acid, glucogallin and other constituents like emodin, aloe-emodin, chrysophonol in free state and their glycosides but in trace amount.

Uses: -
1- Cathartic
2- purgative
In addition to this secondary astringent action in indigestion. Due to astringent action this drug is not commonly used.
Chemical Test: -
A little powder is shaken with 10ml of ferric chloride solution mixed with 5ml of hydrochloric acid and heated on a water bath for 10min. after filtration and cooling filtrate is extracted with 10ml of carbon tetrachloride. The organic layer is separated, washed with 5 ml of water and shaken with 5ml of solution of ammonia. Official rhubarb gives a rose pink to cherry red colour.

4-Senna

Cassia acutifolia,
Cassia angustifolia.
Family: Leguminosae
Dried leaflets.

Collection: -
Senna is collected mainly in September. The branches bearing leaves and pods are collected by cutting the tops of plants about 15cm above the ground.
The stems and fruits (pods) are separated from leaflets by means of seives. This step is separation. Then garbling takes place. Then tossed in shallow trays. The leaflets being lighter remains on the top of the tray while sand particles settle down. Blue green leaflets are best leaves. The branches bearing leaves and pods are dried in the sun.

Constituents: -
Principal constituents are sennoside A, B, C and D.

Uses: -
Senna is an effective purgative for either habitual constipation or occasional use. It lacks astringent after effect of rhubarb.









Flavonoid glycosides

Flavonoid glycosides are a group of chemical compounds that occur in small but significant amounts in fruits and vegetables. More than 4,000 different flavonoids have been identified, some of which have been researched in detail and are believed to have beneficial effects on human health. Some of the health related benefits associated with this group of compounds include strengthening of the immune system, protection against cancer, and a reduction in capillary fragility.
A variety of different foods contain these compounds. Fruits, vegetables, seeds, legumes and soy products are known to contain flavonoid glycosides. Onions, apples, green tea, and red wine are known to be rich in these nutrients, however.
Known to have antioxidant properties, flavonoid glycosides are believed to help protect individuals from diseases, such as cancer. Antioxidants are known to stabilize unstable molecules, known as free radicals, which can potentially damage genetic materials and cells. Thus, this group of compounds can strengthen a person s immune system.
Although many types of flavonoid glycosides have been identified, few have been studied in any depth. The flavonoids that have been researched in detail include rutin, hesperatin, anthocyanaosides, and genistein. Each of these has been found have specific benefits for human health.
Flavonoid glycosides
In this case, the aglycone is a flavonoid. This is a large group of flavonoid glycosides. Examples include:
• Hesperidin (aglycone: Hesperetin, glycone: Rutinose)
• Naringin (aglycone: Naringenin, glycone: Rutinose)
• Rutin (aglycone: Quercetin, glycone: Rutinose)
• Quercitrin (aglycone: Quercetin, glycone: Rhamnose)
Among the important effects of flavonoids are their antioxidant effect. They are also known to decrease capillary fragility.

Rutin: is found in buckwheat and research has demonstrated that this particular flavonoid glycoside may have several implications for human health. Capillary fragility, or the weakening of delicate blood vessels, is common in the elderly or those who suffer from a vitamin C deficiency. Consumption of rutin is believed to strengthen weakened blood vessels and also reduce the risk of heart disease. Hemorrhoids are also often treated with rutin.
Hesparitin: is found in citrus fruits and is also a known antioxidant. Studies have indicated that it can reduce blood pressure and lower cholesterol. In addition, hesparitin has anti-inflammatory effects and, as such, is thought to reduce pain in the joints and muscles, particularly among those who suffer from arthritic conditions.
Genistein: is found in soy, and this particular flavonoid glycoside is believed to delay the growth of certain cancerous cells. Studies have suggested that genistein may inhibit the growth of cells associated with breast, colon, cervix, brain, and prostate cancers. Studies using rodents have also indicated that genistein may be effective in treating some types of leukemia.
Anthrocyanosides: are found in bilberries and known to have several positive health implications. Anthocyanoside flavonoid glycosides are believed to help maintain healthy skin, teeth, eyes, and hair. In addition, anthocyanosides are thought to improve cardiovascular health and help to protect against conditions such as diabetes.Since they are rich in antioxidants, flavonoid glycosides are believed to help boost a person s immune system. With such bolstered immune function, it is thought people can protect themselves from serious illnesses. For this reason, a diet rich in foods that contain flavonoid glycosides may benefit many people. Those considering a major dietary change or taking supplements, however, should check with a physician or nutritionist to be sure of dosages and safety.




Cyanophore glycosides


AKA CYANOGENIC GLYCOSIDES or CYANOGENETIC
O-glycosides yielding HCN gas on hydrolysis
The presence of cyanide(-C?N ) makes the plant toxic to animals (demonstrates in plant defense against plant herbivores)
? plant tissue is damaged, cyanogenic glycoside and enzymes are put in contact and cyanohydric acid is released.

? In most cases, hydrolysis is accomplished by beta-glucosidase, producing sugars and a cyanohydrin that spontaneously decomposes to HCN, and a ketone or aldehyde






Classification Types:

? A. By glycone/presence of sugar
? B. By type of glycosidic bond
? O-LINKAGE/GLYCOSIDIC BOND
? C. By chemical nature of aglycone
? CYANOGENIC GLYCOSIDES
TYPE
Mandelonitrile


Pharmacologic Uses
? Flavouring agent
? Laxative
? Sedative
? Anti-inflammatory
? Roles in cancer treatment but not proven
Extraction procedure:
1. Maceration 2. Distillation 3. Soxhlet extraction
Test for Cyanogenic Glycosides
1. Impregnated Picrate Paper Test (Guignard’s Test)
2. HPLC
Professor Dr. Saad Ali Ihsan

Ph.D. in Pharmacognosy & Medicinal Plants