Anthraquinones are quinones derived from anthracene, a planar aromatic molecule; they are colored pigments present in different parts of the plant, where they give a yellowish brown color, sometimes masked by other pigments, as in the case of the leaves. The characteristic action of anthraquinones is a stimulus to peristalsis and therefore laxative .
Anthraquinones extracted from aloe vera gel
Where are the anthraquinones
The plants where anthraquinones are concentrated are multiple.
The juice of Aloe vera, of bitter taste and yellowish color, produced by specialized cells below the thick epidermis, supplies the drug to anthraquinones of aloe. The juice is not to be confused with the mucilaginous gel present in the cells of the parenchymatous tissue immediately below the epidermis (this gel is sold by various companies under the trade name of "aloe juice").
Aloe gel is sold as a liquid in bottles or as a freeze-dried extract in some tablets; while the juice is marketed as a powder or tablets of yellow or dark brown color.
The aole is a succulent plant native to Africa and then irradiated throughout the world. The botanical classification of the different aloe species is particularly complex and not without confusion. Currently there are more than 360 species in the Aloe genus. Aloe vera (L.) NL Burm., The most used for the pharmaceutical production of juice and gel is one of these.
Another important laxative action plant is the frangola, Frangula alnus Mill. Shrub or small tree with oblong or obovate leaves with a bright dark green color, 3-7 cm long; up to 6 m high Originally from Europe, Western Asia and North Africa.
Cassia senna L. is a herbaceous plant with a laxative action, native to the northern Nile region and then cultivated in other parts of the world. The drug, also rich in anthraquinones, is represented by dried leaflets and pods (called follicles); the seeds, considered irritants, are often eliminated in the drug preparation process.
Other plants with a similar laxative action are the cascara and the Chinese rhubarb .
The anthraquinones useful in case of constipation: discover the other natural remedies
Properties of anthraquinones
Aloe, the anthraquinone present in aloe, has a distinctly bitter taste and is considered, among drugs with laxative action, the least pleasant. Aloe works by stimulating the secretion of electrolytes and water from the intestine, by increasing the internal pressure that stimulates peristalsis and therefore the passage of feces along the terminal part of the intestine. Furthermore, aloin also has a detoxifying and antibiotic action.
The frangola drug, consisting of the dried and preserved bark for 1 year, contains 3 to 7% of anthraquinone glycosides. The active ingredients act on the colon by stimulating intestinal peristalsis. Furthermore, some studies highlight the antitumor action of aloe emodin in the case of precancerous and cancerous cells of particular tumors. Aloe emodin originates from aloin by splitting a glycosidic bond which leads to the release of arabinose (a sugar) and aloe emodin; this principle has been isolated from the seeds of frangola and from the aloe.
Senna contains from 2 to 5% of diantronic glycosides (called sennosides A and B ). These active ingredients do not appear to be present in the fresh drug, but are formed during the drying process through the oxidation of monoantrons present in the fresh leaves and not in the dried ones.
Senna glycosides act as prodrugs . Once administered by mouth, the anthraquinone glycoside passes unchanged at the level of the stomach and small intestine, until it reaches the large intestine, where sugar is removed and metabolized by the bacterial flora in reina-antrone .
This metabolite is not absorbed and produces a stimulating action on the motility of the colon. There is an increase in the active secretion of electrolytes and water in the intestinal lumen and inhibition of reabsorption, with an increase in the intestinal contents and a stretching of the wall which in turn induces peristalsis.
Contraindications of anthraquinones
Excessive use of plants with laxative action can cause colic and inflammation .
All drugs with laxative action are not recommended during pregnancy and lactation, and in the case of chronic inflammations affecting the gastro-intestinal tract (Chron's disease).
An overdose of aloin can cause abdominal pain, bloody diarrhea, haemorrhagic gastritis and sometimes nephritis (inflammation of the kidneys).
The anthraquinones can induce, for prolonged use, an excessive loss of electrolytes (potassium), moreover, a hypomotility of the colon can be reached up to atonia. Consequently, prolonged use of anthraquinone drugs is strongly discouraged.
The faeces due to the presence of anthraquinones may be colored orange yellow, while the urine is colored orange.
