Chemical constituents from whole plants of Rehmannia chingii / 中草药

ABSTRACT

Objective: To investigate the chemical constituents of Rehmannia chingii. Methods: The compounds were isolated from an aqueous extract from the whole plants of R. chingii by a combination of various chromatographic techniques including column chromatography over silica gel and Sephadex LH-20 and reversed-phase HPLC. Their structures were identified by spectroscopic analysis including MS and NMR data. Results: Seventeen compounds were isolated and identified as 8-methyloctahydrocyclopenta[c] pyran-1,3,6,8-tetraol (1), 3,4-dihydroxy-phenethyl alcohol (2), 3-methoxyl-4-hydroxyphenyl alcohol (3), phenylethyl-8-O-β-D-glucopyranoside (4), 3,4-dihydroxy-β-phenethyl-O-α-L-rhamnopyranosyl-(1→3)-O-β-D-glucopyranoside (5), 2-phenylethyl-O-β-D-xylopyranosyl-(1→6)-β-D-glucopyranoside (6), deacyl-martynoside (7), acteoside (8), isoacteoside (9), martynoside (10), isomartynoside (11), jionoside C (12), jionoside A1 (13), jionoside B1 (14), 3,4-dihydroxy-β-phenethyl-O-α-L-rhamnopyranosyl-(1→3)-O-β-D-galacopyranosyl-(1→6)-4-O-caffeoyl-β-D-glucopyranoside (15), cistanoside F (16), and isocistanoside F (17). Conclusion: Among the isolated seventeen compounds, compound 1 is a new compound named rehmachinin, and compounds 16-17 are isolated from the plants of Rehmannia Libosch. ex Fisch. et Mey. for the first time. In the preliminary assays, compounds 9, 12, and 14-16 exhibit the obvious inhibition against aldose reductase.