Flavonoids from the leaves of Physalis angulata Linn
Plants from the genus Physalis are particularly rich in secondary metabolites. Physalis angulata is a widely distributed annual plant belonging to the nightshade family Solanaceae. Physalis angulata have been used for centuries as medicinal herbs in the treatment of urinary tract infection, skin diseases, gonnorhea, ulcers, sores and as vermicidal drug [1,2]. The main purpose of this present study is to screen the leaves of this plant for phytochemical constituents that may be responsible for some of these biological activities. The dried leaves of Physalis angulata were sequentially extracted with dichloromethane and 70% methanol. The aqueous methanol extract was partitioned between ethyl acetate and n-butanol. From the n-butanol fraction, four Flavonoids were isolated through column chromatography over silica gel G and sephadex LH-20. Based on the spectroscopic data which include NMR and mass spectroscopy, the chemical structures were determined as quercetin (1), quercetin 3-O-methyl ether (2) isoquercetrin (3) and Kaempferol 7-O-rhamnoside (4). The structures were elucidated using spectroscopic technique and compared with literature [3 – 4]. Anti-oxidant activity using DPPH and anti-bacterial activity of the flavonoids were also investigated. These compounds were isolated for the first time from the leaves of this plant.
Key words:Physalis angulata, flavonoids, quercetin, quercetin methyl ether, isoquercetrin and Kaempferol -7-O-rhamnoside
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