Phenolic compounds from Miconia myriantha inhibiting Candida aspartic proteases

Assay-guided fractionation of the ethanol extract of the twigs and leaves o f Miconia myriantha yielded two new compounds, mattucinol-7-O-[4 " ,6 " -O- (S)-hexahydroxydiphenoyl]-beta -D-glucopyranoside (1) and mattucinol-7-O-[4 " ,6 " -di-O-galloyl]-beta -D-glucopyranoside (2), along with mattucinol-7 -O-beta -D-glueopyranoside (3), ellagic acid (4), 3,3'-di-O-methyl ellagic acid-4-O-beta -D-xylopyranoside, and gallic acid. Complete H-1 and C-13 NMR assignments of compound 1, which possesses a hexahydroxydiphenoyl unit, we re achieved using the HMBC technique optimized for small couplings to enhan ce the four-bond and two-bond WC correlations. Compounds 1 and 4 showed inh ibitory effects against Candida albicans secreted aspartic proteases, with IC50 of 8.4 and 10.5 muM, respectively.