ISOLATION AND STRUCTURE IDENTIFICATION OF FLAVONOL GLYCOSIDES FROM GLANDLESS COTTON SEEDS

AIM To isolate and determine the structure of flavonol glycoside from glandless cotton seeds. METHODS The flavonol glycosides were extracted from glandless cotton seeds with 60% ethanol and purified by polyaromatic resin, polyamide, silica gel and Sephadex LH-20 on column chromatography. UV,¹H and ¹³CNMR ,¹³C-¹H COSY, HMBC, ¹H-¹H COSY and TOCSY spectra were used for the structural identification. RESULTS Five flavonol glycosides (I-V) were obtained. They were identified as kaempferol 3-O-β-D-apiosyl(1→2)-α-L-rhamnosyl(1→6)-β-D-glucoside (I), quercetin-3-O-β-D-apiosyl(1→2)-α-L-rhamnosyl(1→6)-β-D-glucoside (II), quercetin-3-O-β-D-apiosyl(1→2)-α-D-glucoside (III), rutin (IV) and quercetin-3-O-β-D-glucoside (V). CONCLUSION Compound I is a new natural product. Compounds II and III were isolated from this genus for the first time.