New lactoyl glycoside quercetin from Melia azedarach leaves

In the course of phytochemical investigations of Melia azedarach leaves, a novel cinnamoyl glycoside, cinnamoyl-1-alpha-L-rhamnoside (1), and a novel acylated quercetin triglycoside, quercetin-3-O-[rhamnosyl 1 -> 6(4 ''-lactoyl glucoside)]-4'-O-glucoside (2), have been isolated and characterized on the basis of spectroscopic methods, together with the six known flavonoid compounds kaempferol-3-O-rutinoside, 3-O-rhamnoside, quercetin-3-O-rutinoside, 3-O-rhamnoside, and the aglycones quercetin and kaempferol. All isolated compounds have been evaluated for their structures by chromatographic methods, chemical degradation, and UV and NMR spectroscopy. The antioxidant activity of the extract was studied as well.