Name: Tangut rhubarb
Diseases and effects: chronic constipation, intestinal atony, flatulence.
Active substances: anthraglycosides, tanoglycosides, reumemodin aglycones, chrysophanol, rhein, chrysophanoic acid, resinous substances, pigments.
Family: buckwheat (Polygonaceae).\r
Botanical description
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Perennial large herbaceous plant 1-1.5 m high (sometimes up to 2.5 m) with a fast-growing annual aerial part.\r
The root system is a powerful, vertical, wide multi-headed rhizome with several fleshy roots.\r
The stems are straight, tall, thick, hollow, with reddish spots and stripes.\r
Basal leaves are very large, juicy, lobed-separate, long-petiolate, green. Stem – small, ovoid.\r
The flowers are small, white or red, numerous, collected at the tips of the stems and in the axils of the leaves in large inflorescences – panicles (brushes).\r
The fruit is a trihedral red-brown nut.\r
The smell of rhubarb is specific, it tastes bitter and tart, crunches on the teeth and stains saliva yellow. Blossoms in July, traditionally in the second, and sometimes in the 30% year of life. Above-ground parts of rhubarb die off for the winter.\r
It is widely cultivated in the CIS countries (Ukraine, the European part of Russia, Belarus) and Western Europe as a medicinal, ornamental and food plant. It grows wild in the mountains of Siberia and in the states of Central Asia. Roots and rhizomes are harvested for medical purposes.\r
Chemical composition
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Tangut rhubarb contains anthraglycosides (3% in rhizomes) and tanoglycosides, as well as their free aglycones (reumemodin, chrysophanol, rhein, etc.), chrysophanoic acid, resinous substances and pigments. Anthraglycosides are ester-like compounds, which, after the elimination of sugar, form emodin and other anthracene derivatives.\r
Pharmacological properties
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Tanoglycosides have astringent, antidiarrheal and antiseptic properties. Anthraglycosides, on the contrary, have a laxative effect, increase intestinal motility. The laxative effect begins 8-10 hours after ingestion and is mainly due to emodin, rhein and chrysophanoic acid, which, by irritating the interoreceptors of the large intestine mucosa, cause an increase in its peristalsis and a faster passage of feces.\r
In small doses, rhubarb products have an astringent effect due to tanoglycosides. In large doses, rhubarb has a laxative effect, which is associated with the action of anthraglycosides. The laxative and astringent effect of rhubarb depends not only on the dose, but also on the solubility of the compound. Aqueous extracts from rhubarb contain more tannins than anthraglycosides, and alcoholic extracts are somewhat richer in anthraglycosides. In addition, galenic forms of the plant increase bile secretion. In large doses, all rhubarb herbal products cause local irritation of the mucous membrane of the large intestine and therefore increase blood flow to the pelvic organs, which is especially dangerous during pregnancy.\r
The product chrysarobin was obtained from the reduction products of chrysophanic acid and emodin. In low concentrations, this product has a vasoconstrictive property and gives a pronounced anti-inflammatory and keratolytic effect, in higher concentrations it can even cause dermatitis. Chrysarobin isolated from the plant is still widely used in dermatological practice.\r
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For the preparation of medicines, roots with rhubarb rhizomes are used. Rhubarb is harvested at the age of 4 years, the rhizome is dug out along with the roots, washed in cold water, cleaned of the ground and damaged, sluggish, spongy small roots and rotten parts, freed from the outer black bark, cut into pieces 10-12 cm long, over for several days they are dried in the sun, after which they are dried. With all this, pieces of rhubarb can be strung on a thread. The final drying of the raw materials is carried out at a temperature of 35 ° C.\r
Currently, rhubarb is cultivated on an industrial scale.\r
Application in medicine
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For medicinal purposes, rhubarb root was used in ancient Greece. In Europe, the plant appeared during the Middle Ages. In Russia, in the 18th century.\r
Rhubarb is used as a laxative and choleretic agent for chronic constipation. When using rhubarb products in patients, due to irritation of the receptors of the mucous membrane of the large intestine, its peristalsis reflexively increases. The anthraglycosides contained in the roots of rhubarb have practically no effect on the peristalsis of the stomach and small intestine. In medical practice, rhubarb products are traditionally prescribed to obtain a mild and gradual laxative effect in intestinal atony, flatulence and chronic constipation. Assign mainly to patients in the elderly and children.\r
Rhubarb preparations are used in powders, pills, decoctions alone and in combination with other substances as laxatives. Sometimes rhubarb products are taken in small doses (0.05-0.20 g) as astringents that reduce intestinal motility. Their astringent action is associated with tanoglycosides, which, by binding to proteins, precipitate them, forming a precipitate that protects the receptors of the intestinal mucosa.\r
In large doses, rhubarb products can cause vomiting, diarrhea, colicky abdominal pain, tenesmus, increased blood flow to the pelvic organs. To avoid this, the dose of a laxative is selected individually. Prolonged uncontrolled use of laxatives can contribute to the development of chronic inflammatory processes in the intestinal mucosa. In addition, addiction to the laxative effect of the plant is likely, and its effectiveness may noticeably decrease over time, forcing patients to increase the dose of the drug.\r
Contraindications to the use of rhubarb: acute appendicitis and cholecystitis (danger of perforation), acute peritonitis, the presence of mechanical obstacles to the movement of intestinal contents (obstruction, infringement of the intestine), bleeding from the gastrointestinal tract, pregnancy, since laxatives reflexively increase uterine contraction.\ r
Dosage forms, method of administration and doses
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Rhubarb (Tabulettae radicis Rhei) tablets are yellow-brown in color. Contain 0.3 or 0.5 g of finely ground rhubarb root. Used for constipation, 1-2 tablets per dose, traditionally at night after eating.\r
Dry rhubarb extract (Extractum Rhei Siccum) – hydroalcoholic extract. It is a large powder of yellowish-brown color, a peculiar smell, a bitter taste. Dose depending on age – from 0.1 to 1-2 g per reception.\r
Rhubarb tincture bitter (Tinctura Rhei amara) is prepared from rhubarb rhizome and root, gentian root powder, calamus rhizome powder and 70% alcohol. Transparent liquid of red-brown or red color, a peculiar slightly aromatic smell, bitter taste. Take 1/2-1 teaspoon 2 times every day before meals with intestinal atony, flatulence, chronic constipation.\r
Rhubarb syrup (Siropus Rhei) contains 1.25 parts of dry rhubarb extract, 2 parts of alcohol, 3 parts of dill water, 94 parts of sugar syrup and is a brown-red liquid with a peculiar smell and taste. It is mainly used in pediatric practice for digestive disorders, accompanied by flatulence and a tendency to constipation. The dose of the product is selected individually, traditionally 1/2-1 teaspoon before meals 3 times every day.\r
Decoction. 1 st. a spoonful of a mixture of chopped rhubarb root, buckthorn bark, chamomile leaves, shepherd’s purse grass, centaury herb, celandine root, hoof leaves (1 tablespoon of each component) per 1 cup of boiling water. Taken in 2 doses after 4 hours (second dose – in the evening).\r
Rhubarb root preparations are stored in a cool, dark place.