白千层黄酮类化学成分及其抗菌活性OA

This study focused on the isolation,purification,identification,and antimicrobial activity evaluation of flavonoids from the tropical medicinal plant Melaleuca leucadendron Linn.The flavonoid constituents in the ethanol extract of this plant were separated and purified using various chromatographic techniques,including normal-phase silica gel column chromatography Sephadex LH-20 gel column chromatography,and semi-preparative HPLC.The structures of the isolated compounds were identified by NMR and MS techniques.A total of fifteen flavonoids were isolated and identified from M.leucadendron:europetin 3-O-α-L-rhamnopyranoside(1),myricitrin(2),quercetin-3-O-rhamnopyranoside(3),myricetin 3-O-(3′′-O-galloyl)-α-rhamnopyranoside 7-methyl ether(4),myricetin 3-O-(2′′-O-galloyl)-α-rhamnopyranoside 7-methyl ether(5),myricetin 3-O-(2′′-O-galloyl)-a-L-rhamnopyranoside(6),quercetin-3-O-β-D-glucoside(7),(-)-epigallocatechin 3-O-gallate(8),epicatechin gallate(9),(-)-gallocatechin 3-O-gallate(10),8-methyl-5,7-dihydroxydihydroflavonoid(11),pinocembrin(12),quercetin(13),(-)-epigallocatechin(14)and gallocatechin(15).Except for compounds 2 and 13,all other compounds were isolated from the genus Melaleuca for the first time.Additionally,the 1H and 13C NMR data of compound 1 are reported here for the first time.Antimicrobial activity tests showed that compounds 8-10 exhibited significant inhibitory activity against four species of pathogenic bacteria.