Medication Description: Rhubarb Roots (Radices Rhei)
ROOTS REWENE (Radices Rhei).
Collected in autumn or early spring at least 3 years old, peeled, cut into pieces dried roots and rhizomes of Tangut rhubarb cultivated in our country (Rheum palmatum L., var tanguticum maxim) of a herbaceous perennial plant, Sem. buckwheat (Polugonasee).
The roots and rhizomes of rhubarb contain antraglycosides, tanoglycosides, chrysophany acid, resinous, coloring and other substances.
Antraglycosides are ether-like compounds, which, after sugar removal, form emodin and other anthracene derivatives. The total content of anthracene derivatives in rhubarb roots is at least 2% (in terms of istizin).
The main active ingredients are emodin (trioxymethylanthraquinone) and chrysophanoic acid (dioxymethylanthraquinone). They irritate the intestinal interoreceptors and cause increased motility, having a predominant effect on the large intestine and causing its more rapid emptying.
The laxative effect after taking rhubarb drugs comes after 810 hours. Slow action and a predominant effect on the large intestine is usually explained by the fact that the disintegration of anthracosides in the intestine occurs gradually and the active substances accumulate in the amount necessary for a laxative effect, only when they reach the large intestine . Colon mucosal receptors are most sensitive and respond to concentrations of emodin to which small intestinal receptors do not respond. In addition, antraglycosides after absorption in the small intestine are converted in the body into emodin, which is secreted in the large intestine and enhances its motility.
Rhubarb preparations are prescribed in powders, pills, decoctions, alone and in combination with other substances as laxatives mainly in chronic (habitual) constipation. Usually they are recommended for the night, well tolerated and do not violate the processes of absorption and normal activity of the small intestine. Resin contained in the plant may have some irritating effect on the intestines.
Sometimes rhubarb preparations are taken in small doses (0.05 - 0.2 g) as astringents, reducing intestinal motility. Their astringent effect is due to the presence of tanoglycosides, which, by binding to proteins, precipitate them, forming a precipitate that protects the receptors of the mucous membrane.
When taking rhubarb preparations, urine, sweat and milk of nursing mothers turn yellow (presence of chrysophane acid), turning into red when alkali is added (formation of hydroxymethanthraquinones).
Apply the following preparations of rhubarb.
Rhubarb powder (pulvis radicis Rhei). Powder yellow-orange or red. Crunches on the teeth due to the content of calcium oxalate crystals.