Inhibitory constituents of aldose reductase in the fruiting body of Phellinus linteus.

In an effort to characterize active principles for diabetic complication from medicinal mushroom, aldose reductase inhibitors were isolated from the fruiting body of Phellinus linteus and identified as hispidin (5), phelligridimer A (6), davallialactone (7), methyldavallialactone (8), hypholomine B (9), interfungins A (10), and inoscavin A (11), together with protocatechuic acid (1), protocatechualdehyde (2), caffeic acid (3), and ellagic acid (4). Their structures were elucidated by spectroscopic analyses. Among them, davallialactone (7), hypholomine B (9), and ellagic acid (4) exhibited potent rat lens aldose reductase and human recombinant aldose reductase inhibitory activity with IC50 values of 0.33, 0.82, 0.63 microM and 0.56, 1.28, 1.37 microM, respectively.