Leaves of aloe vera are large, succulent, suulate, sessile,20-50 cm long and 5-10 cm wide. Apex in the form of a sharp and acute spine. Both the surfaces are strongly cuticularized.Dried leaf juice dark chocolate brown to black in colour and of irregular masses. Odour characteristic; taste very bitter.
Actions and Uses,Cathartic action of the drug, limited to large intestine, is attributed to anthraquinone glycosides, chiefly aloin. Latter is not absorbed in upper gut but hydrolysed to the active aglycone at the site of action in the colon and rectum by intestinal bacteria. The anthrones irritate the mucus membrane leading to an increase in the secretion of mucus, thus stimulating peristalsis. Also they induce an active secretion of water and electrolytes into the lumen of the gut, and inhibit the absorption of electrolytes and water by the colon.
Prolonged use of aloe barbadensis may severely affect the electrolyte balance and loss of potassium may ultimately reduce the laxative action and disturb the cardiac rhythm in heart patients. Larger doses leads to accumulation of blood in pelvic region and reflux stimulation of uterine muscles and may bring about abortion or premature birth in late pregnancy.Toxic doses can also cause kidney damage. Active principles generally appear in the milk during lactation. Due to these reasons the drug is contraindicated in pregnancy, lactation,kidney complaints and irritable bowel conditions.