Microdontin A and B: Two New Aloin Derivatives from Aloe microdonta.

The leaf juice of ALOE MICRODONTA Chiov. is used in Somali traditional medicine as a remedy for jaundice and for topical treatment of skin diseases. Mucilage was precipitated from the fresh juice by addition of ethanol and the supernatant chromatographed on Amberlite XAD-2 to yield a fraction containing anthraquinone derivatives. Flash chromatography on silica gel followed by preparative TLC yielded aloin A and a new compound. Spectral data (mass, (1)H- and (13)C-NMR) identified this compound as a mixture of aloin A and B where the glucose of both compounds is esterified with 4-hydroxycinnamic acid at the 6'-position. The two compounds were denoted as microdontin A and B, respectively.