Metabolism of kalopanaxsaponin K by human intestinal bacteria and antirheumatoid arthritis activity of their metabolites.

When kalopanaxsaponin K (KPK) from Kalopanax pictus was incubated for 24 h at 37 degrees C with human intestinal microflora, KPK was mainly metabolized to kalopanaxsaponin I (KPI) via kalopanaxsaponin H (KPH) rather than via kalopanaxsaponin J (KPJ), and then transformed to kalopanaxsaponin A (KPA) and hederagenin. Bacteroides sp., and Bifidobacterium sp. and Fusobacterium sp. transformed KPK to KPI and KPA and hederagenin via KPH or KPJ. However, Lactobacillus sp. and Streptococcus sp. transformed KPK to KPI, KPA, and hederagenin only via KPJ. The metabolite KPA of KPK showed potent antirheumatoid arthritis activity.