Aloeresin I, an anti-inflammatory 5-methylchromone from Cape aloe

A new diglucoside having a 5-methylchromone moiety was isolated from a commercial sample of Cape aloe, the dried exudate from Aloe ferox Miller, and named aloeresin I. Its structure was established as 1 on the basis of spectral and chemical evidence. Aloeresin I (1) (1 mumol/cm(2)) reduces in vivo the oedematous response (39%) induced by Croton oil in the mouse ear with the same potency as aloesin, one of the most abundant Cape aloe constituents, and to a higher extent than aloeresin H (2). Indomethacin (0.3 mumol/cm(2)), the reference anti-inflammatory compound, provokes 61% oedema inhibition.