Anti-rheumatoid arthritis effect of the Kochia scoparia fruits and activity comparison of momordin Ic, its prosapogenin and sapogenin

MeOH extract of Kochia scoparia was fractionated into CHCl3-, EtOAc- and BuOH extracts and the last fraction were hydrolyzed by 3%-NaOH (MeOH-H2O) to compare the bioactivities on antinociceptive and anti-inflammatory effects. Silica gel column chromatography of BuOH fraction afforded a large amount of 3-O-beta-D-xylopyranosyl (1-->3)-beta-D-glucuronopyranosyl oleanolic acid (momordin Ic, 4) and that of acid hydrolysate of BuOH fraction gave 3-O-beta-D-glucuronopyranosyl oleanolic acid (momordin Ib, 3), its 6'-O-methyl ester (2) and oleanolic acid (1). Silica gel column chromatography of alkaline hydrolysate afforded a large amount of 4. MeOH extract and both EtOAc- and BuOH fractions were active in the rheumatoidal rat induced Freund's complete adjuvant reagent (FCA) whereas CHCl3 fraction was inactive. Compound 1 and 4 showed significant activities in the same assay but oleanolic acid 3-O-glucuronopyranoside (3) showed no activity. These fashions were also observed in carrageenan-induced edema of the rat and in the antinociceptive activity tests undertaken in hot plate- and writhing methods. These results suggest that momordin Ic and its aglycone, oleanolic acid, could be active principles for rheumatoid arthritis.