Antioxidant phenolic glycosides from Moricandia arvensis.

The new phenolic glycosides quercetin 3,4'-di-O-beta-d-glucopyranoside-7-O-alpha-l-rhamnopyranoside (moricandin) (1), beta-d-glucopyranosyl 4-O-beta-d-glucopyranosylcaffeate (2), methyl 3-O-beta-d-glucopyranosyl-5-hydroxycinnamate (3), and beta-d-glucopyranosyl 4-O-beta-d-glucopyranosylbenzoate (4), together with the previously known beta-d-glucopyranosyl 4-hydroxybenzoate (5), methyl 4-O-beta-d-glucopyranosylcaffeate (6), 1-O-caffeoyl-beta-d-glucopyranoside (7), and 2-phenylethyl-beta-d-glucopyranoside (8), were isolated from the flowers of Moricandia arvensis. Their structures were elucidated by extensive spectroscopic analysis and chemical methods. Compounds 1-8 were evaluated for antioxidant activity using DPPH, TEAC, and reducing power assays, where the caffeic acid derivative 7 and the quercetin triglycoside 2 proved to possess the most potent scavenging activity.