Synthesis and Biological Activities of Natural Flavonoid Diosmetin and Its Derivatives

Four natural flavonoids 3'-O-methyldiosmetin (I), diosmetin-7-O-beta-D-glucoside (2), diosmetin-7-O-beta-D-galactoside (3), 3'-O-methyldiosmetin-7-O-beta-D-glucoside (4), and eight new diosmetin derivatives 3'-O-methyldiosmetin-7-O-beta-D-galactoside (5), diosmetin-7-O-beta-D-acetylglucoside (6), diosmetin-7-O-beta-D-acetylgalactoside (7), 3'-O-methyl- diosmetin-7-O-beta-D-acetylglucoside (8), 3'-O-methyldiosmetin-7-O-beta-D-galactoside (9), 7-O-isopentyldiosmetin (10), 7-O-prenyldiosmetin (11) and 7-O-farntesyl-3'-O-methyldiosmetin (12) were synthesized from hesperidin by reaction steps including dehydrogenation, selective methylation, glycoside hydrolysis, glycosylation under phase transfer catalytic condition, O-prenylation and O-farnesylation, respectively. Their structures were confirmed by NMR, IR and MS techniques. The synthesized compounds were evaluated for biological activity against four human cancer cell lines by the standard MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenytetrazolium bromide] method, and the results showed that 6, 10 and 11 exhibited moderate cytotoxicity against SMMC-7721, MCF-7 and SW480 cancer cell lines.