Isolation and Characterization of Phenolic Compounds from the Leaves of Salix matsudana

摘要

A bioassay-guided in vitro screen has revealed that a 70% methanol extract of the leaves of Salix matsudana shows considerable inhibitory activity against cyclo-oxygenases (COX-1 and COX-2). A subsequent phytochemical study led to the isolation of a new flavonoid, matsudone A (>1), together with five known flavonoids – luteolin (>2), isoquercitrin (>3), 7-methoxyflavone (>4), luteolin 7-O-glucoside (>5), 4',7-dihydroxyflavone (>6) – and two phenolic glycosides, leonuriside A (>7) and piceoside (>8). Their structures were elucidated on the basis of extensive 1D- and 2D-NMR studies, high resolution ESI mass spectroscopic analyses and comparisons with literature data. The isolated compounds >1->8 were tested for their inhibitory activities against COX-1 and COX-2. Compounds >1, >5 and >6 were found to have potent inhibitory effect on COX-2 and compounds >3->5 exhibited moderate inhibition against COX-1.