Assessment of the antioxidant activity and genotoxicity of the extracts and isolated glycosides with a new flavonoid from Lotus aegaeus (Gris.) Boiss

Abstract

Chemical composition and genotoxic properties of L. aegaeus (Griseb.) Boiss. which is a member of legumes and used as a cover crop, an antimicrobial agent for animal wounds and forage in Central Anatolia were detected for the first time. Nine secondary metabolites together with a new compound for nature were isolated from the n-butanol extract of Lotus aegaeus (Griseb.) Boiss aerial parts. The structures of the isolated compounds were clarified as a known cyanogenic glucoside, linamarin (1), 2 known saponins: wistariasaponin C (8) and wistariasaponin D (9), 5 known flavonoids: quercetin-3-O-β-d-glucopyranoside-7-O-α-l-rhamnopyranoside (2), quercetin-3-O-β-d-galactopyranoside-7-O-α-l-rhamnopyranoside (3), kaempferol-3-O-β-d-galactopyranosyl-7-O-α-l-rhamnopyranoside (4), kaempferol-3-O-β-xylopyranosyl-(1→2)-α--l-rhamnopyranosyl-7-O-α-l-rhamnopyranoside (5), kaempferol 3-O-(5′'-acetyl) apiofuranoside 7-O-rhamnopyranoside(6) and a new flavonoid, kaempferol 3-O-(3′',5′'-diacetyl) apiofuranoside 7-O-rhamnopyranoside (7) by using 1D-2D Nuclear Magnetic Resonance (NMR) and Mass Spectroscopy (MS) methods. Antioxidant effects of the L. aegaeus (Griseb.) Boiss extracts and all isolated compounds were investigated by using 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and superoxide (SO) radical scavenging tests. Quercetin glycosides (2/3) exhibited the strongest antioxidant ability. The genotoxicity of the extracts and some isolated compounds (1,4,6/7,9) were determined in Drosophila melanogaster by the in vivo wing somatic mutation and recombination test (SMART). All genotoxicity test results revealed that L. aegaeus is a reliable source for drug development researches.