Novel flavonoids with antioxidant activity from a Chenopodiaceous plant

OBJECTIVE: Atriplex lentiformis (Torr.) S.Wats (Chenopodiaceae) is a wild plant which is in use by Bedouin in treatment of general fatigue, therefore, there is a need to explore the potential antioxidant activity of the extracts and isolated compounds of this plant. METHODS: Column chromatography and spectroscopic analysis were used for isolation and identification of the compounds. The antioxidant activity was evaluated in vitro using the ABTS(?+) (2,2'-azino-bis-3-ethyl-bezthiazoine-6-sulphuric acid) radical scavenging model. Liver and kidney functions were investigated after oral administration of total alcohol, successive extracts, and isolated compounds. Results: Two new flavonoids, quercetin-6,4'-dimethoxy-3-fructo-rhamnoside 1 and quercetin-4'-methoxy-3-fructo-rhamnoside 2 in addition to five known compounds (kaempferol-4'-methoxy-3-rutinoside 3, kaempferol-7-O-rhamnoside 4, kaempferol-3,7-O,O-dirhamnoside 5, quercetin 6, and kaempferol 7) were isolated. Oral administration of total ethanol, diethyl ether, chloroform, ethyl acetate and n-butanol extracts showed no signs of toxicity up to (5?g/kg. b.wt.). All extracts and isolated compounds showed varied antioxidant activity ranged from 129 to 952 μmol Trolox equivalent/gram dry weight with maximum level for the two new isolated flavonoids (985 and 895 μmol Trolox equivalent/gram dry weight). Animals received both total ethanol and n-butanol extracts showed a significant increase in ALT, AST, blood urea, and serum creatinine levels.