Aldose reductase inhibitors from Ganoderma lucidum

Ganoderma lucidum (Leyss;Fr) Karst. (Ganodermataceae) is a woody mushroom, also known as „Lingzhi“ in Chinese, „Saru-no-koshikake“, „Reishi“ or „Mannetake“ in Japanese, and „Youngzhi“ in Korean. It is a member of the genus Ganoderma and has been traditionally used as a popular folk medicine for the promotion of health in the Orient. This mushroom has been shown to have the strongest inhibition of aldose reductase among edible and medicinal mushrooms. Aldose reductase is the first enzyme of the polyol pathway. This enzyme catalyzes the reduction of glucose to sorbitol in coupling with the oxidation of NADPH to NADP⁺. To test for this property, the ethanol, chloroform and aqueous extract of the fruiting bodies were assayed using a human recombinant aldose reductase spectrophotometically. Both the ethanol (83.3% inhibition) and chloroform extracts (78.5% inhibition) exhibited significant inhibitory activity at a concentration of100µg/ml in this assay. From this data, the ethanol and chloroform extract were chosen for further investigation. Compounds isolated through activity-guided fractionation have been identified by a combination of 1D- and 2D-NMR, mass spectrometry, and other spectrophotometric methods.

Acknowledgements: Thanks to Hitachi Scholarship Foundation, Japan for providing grant to attend this congress.