Aloihin

Aloihin, commonly written aloins in English, refers to a group of hydroxyanthracene glycosides found in the latex of Aloe plants, especially Aloe vera and Aloe ferox. The two principal components are aloin A and aloin B, which are diastereomeric glycosides derived from aloe-emodin linked to a glucose unit. Aloin A is also called barbaloin, and aloin B is known as isobarbaloin.

Chemically, each aloin molecule consists of a β-D-glucopyranose moiety attached to aloe-emodin, an anthraquinone. The two diastereomers differ in configuration at one chiral center, giving distinct but related compounds that co-occur in Aloe latex.

Natural occurrence and extraction occur mainly in the yellow latex that lies just under the outer rind of Aloe leaves. This latex is the source of commercial aloins, which have historically been used as stimulant laxatives. In practice, aloins are often removed or reduced in products marketed as aloe gel or cosmetic ingredients, since the gel portion of Aloe leaves is typically depleted of these glycosides.

Pharmacology and use: Aloins act as laxatives by promoting intestinal water secretion and increasing peristaltic activity after metabolic conversion to active hydroxyanthraquinones. Their laxative effect has led to their inclusion in some over‑the‑counter products and traditional remedies, though efficacy and safety remain topics of regulatory scrutiny.

Safety and regulation: Hydroxyanthracene glycosides, including aloins, have raised safety concerns, and internal use of aloe latex products containing aloins is restricted or tightly regulated in many jurisdictions. Aloe vera leaf gel, which lacks significant amounts of aloins, is widely used in cosmetics and some foods.