Novel flavonoids with antioxidant activity from a Chenopodiaceous plant

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.

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.

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.