Professor Suleiman Olimat Anthraquinones Professor Suleiman Olimat

Anthraquinone glycosides

Biosynthesis

Pharmacologial Characteristic of Oxygenated Anthracene Cathartics The glycosides reach the colon via passage through the intestinal tract and, to so me extent, via the circulation after absorption in the small intestine. The glycosides are hydrolyzed in the lumen of the gut by the bacterial enzymes. Of course the acidity of the stomach also catalyzes the hydrolysis of some of the glycosides. The cathartic effect is via a direct stimulation of the colon. The action is observed in 6-8 hours after oral ingestion and medication is usually conveniently taken prior to retiring in the evening. These compounds and their metabolites may appear in the breast milk during lactation and affect the infant.

Cont… The metabolites may color the urine (red, orange, pink, brown, black) Griping is the major adverse effect. Melanosis coli may develop in patients taking these drugs over extended periods of time. Melanosis coli is characterized by a melanotic pigmentation of the colonic mucosa and is confirmed via proctosigmoidoscopy. The pigmentation is benign and usually reversible within 4-12 months after cessation of therapy.

Types of anthraquinone glycoside 1- O-glycosides where the aglycone moiety is 1,8 dihydroxyanthraquinone derivatives, e.g.,

Emodin-oxanthrone-9-glucoside 2- O-glycoside where the aglycone moiety partially reduced 1,8 dihydroxy anthraquinone, e.g., Oxanthrone-type.

Barbaloin 3- C-glycoside where the aglycone structure (anthrone der.)

Sennoside A&B 4- O-glycosides where the aglycone moiety is di-anthrone der. (i.e., dimmer) e.g., Sennosides where there is C-C bridge between the anthranol units.

Senna Leaf Consists of the dried leaflet of Alexandrian or Khartoum senna, Cassia senna (C.acutifolia), Tinnevelly senna (C.angustifolia).

Chemistry Dimeric anthracene glycosides derived from two anthrones moieties which may be:

Sennoside A&B Similar anthrone moiety (Homo-dianthrones) i.e., 2- rhein anthrone moieties condensate through two C-10 atomes. Thus it can be exist in two optical forms, Sennoside A (L- form) & Sennoside B (meso form).

Sennoside C&D Or different (Hetero-dianthrones) i.e., one rhein-anthrone & one emodin anthrone, Sennoside C (L- form) and Sennoside D (meso form).

Cascara The dried bark of Rhamnus purshiana Family Rhamnaceae. B. P. specified that the collection must be made at least one year before the bark is used (fresh bark contains an emetic principle).

Csacara

Chemistry 1- cascarosides A&B (glycosides of barbaloin) 2- cascarosides C&D (glycosides of chrysaloin)

Frangula Bark The bark of Frangula purshiana Frangulin (frangula emodin rhamnoside). Glucofrangulin (frangula emodin glucorhamnoside).

Frangula

Rhubarb The rhizomes of Rhubarb (Rheum spp.) family Polygonaceae. Consist of glycoside of rhein, rhein anthrone, chrysophanol and aloe emodin. The presence of tannins in rhubarb makes the drug constipating. So in small doses, rhubarb exerts no purgative action but acts only as intestinal astringent, but large doses cause purgation.

Chemistry

Aloes Aloe is the dried latex of the leaves of a number of species of the genus Aloe (Liliaceae). The major glycoside being the C-glycoside barbaloin.

Note The 1ry glycosides are more active than the aloins while the free anthraquinon have little purgative activity.

Uses The laxative action of the crude drugs is always higher than from their content of anthracene der. The different anthracene der. contained by the crude drug are said to exert a synergistic action. Thus, the naturally occurring anthracene glycosides were found superior to the synthesis of numerous hydroxyl anthracene der. Some of these synthetic compounds act too drastically and also caused kidney damage. The only compound which is used to some extent in current medicine is danthrone. It is also used as a standared in colorimetric assays of anthraquinone glycosides. .

Danthrone

Effect of storage on the active of anthracene glycosides Prolonged storage of anthracene bearing drugs may bring oxidation of anthranols and anthrones to give the less active anthraquinones. Thus, the activity of drugs decreases by time. However, anthraquinone glycosides do not cause any griping action (like anthranol and anthone), thus no antispasmodic such as belladonna is prescribed with them. Drugs as senna, Aloe and cascara preparations retain their activity for a long time. Cascara and frangula must be aged for one year before it is used for medicinal preparation.

Official anthraquinone drugs in B.P and U.S.P. Senna leaf & senna fruit (pod). Aloes. Cascara tablets, elixir, dry exract, liquid extract. Rhubarb powdered, tincture. Danthrone Frangula bark

Asphodelus spp. Asphodelus aestivus Brot. (Syn. Asphodelus microcarpus Salzm), Family Liliaceae, is a perennial herb with short vertical rhizome is widely distributed throughout Jordan. Flowering period is January-April.

Ramosin Ramosin is the major one and the extract of the plant is standardized according to the percentage of Ramosin is a reference standard.  

Expected uses To treat sore gums and mouth ulcers. Due to the presence of anthraquinone glycosides. To treat sore gums and mouth ulcers. To treat oral infectious diseases like dental caries and periodontitis. To treat oral aphthous.