Flavonoid Glycosides in Citrus Fruits Peelings

Structure and Hypotensive Effects of Flavonoid Glycosides on Zabon (Citrus gradis Osbeck.), Grapefruit (Citrus paradishi Macf.) and Hassaku (Citrus hassaku Hort.) Peelings

Abstract

As one of the studies on physiological acitive substances in citrus peel, the present paper describes structures and hypotensive effects of flavonoid glycosides on zabon, grapefruit and hassaku peels. Five flavonoid glycosides were isolated and their structures were established as 6, 8-di-C-glucosylapigenin (1), 3, 8-di-C-glucosylapigenin (2), limocitrin 3-O- {[5-α-glucosyl-3-hydroxy-3-methylglutaryl (1→2)] -β-glucoside} (3), apigenin 7- [2-O-α-rhamnosyl-β-glucoside] (4) and naringenin 7-β-glucoside (5) by UV, 1H-NMR and ^BC-NMR spectroscopies and chemical evidence. Compounds 4 and 5 were intravenously injected in SHR-SP (1.0mg dose/100g body weight), and 4 was found to lower rat blood pressure.