Hepatoprotective aliphatic glycosides from three Goodyera species

Hepatoprotective aliphatic glycosides 3-(S)-3-beta-D-glucopyranosyloxybutanolide (1) and its congener, 3-(S)-3-beta-D-glucopyranosyloxy-4-hydroxybutanoic acid (2) were isolated as major constituents from the whole plants of three Goodyera species, G. schlechtendaliana Reichb. fil., G. matsumurana Schltr. and G. discolor Ker-Gawl. The structures of 1 and 2 have been determined by NMR, MS spectroscopic and chemical means. Compound 1 was converted into its methyl ester form (5) during the purification step, when the lactone ring was cleaved by catalysis of silica gel with the CHCl3-MeOH-H2O as a solvent. On the other hand, 1 was obtained in a high yield by the same purification procedure without MeOH. Based on this fact, a simple and economic method for the purification of 1 was confirmed. Compounds 1 and 2 were found to have a hepatoprotective effect on liver injury induced by carbon tetrachloride in primary cultured rat hepatocytes.