Three chromone components from Aloe vera leaves

Three new chromone components, 8-C-glucosyl-7-O-methyl-(S)-aloesol, isoaloeresin D and aloeresin E were isolated from the leaves of Aloe vera. Their structures have been established from spectroscopic studies; the structures of 8-C-glucosyl-7-O-methyl-(S)-aloesol, isoaloeresin D and aloeresin E were shown to be 8-C-beta-D-glucopyranosyl-2-[(S)-2-hydroxy]propyl-7-methoxy-5- methylchromone, 8-C-beta-D-[2'-O-(E)-p-coumaroyl]glucopyranosyl-2- [(S)-2-hydroxy]propyl-7-methoxy-5-methylchromone and 8-C-beta-D-[2'-O-(E)-cinnamoyl]glucopyranosyl-2- [(S)-2-hydroxy]propyl-7-methoxy-5-methylchromone, respectively. The inhibitory action of these compounds against tyrosine oxidation by mushroom tyrosinase was examined. Copyright (C) 1996 Elsevier Science Ltd