Human intestinal bacteria play an important role in the metabolism of herbal medicines, leading to the variations in their pharmacological profile. The present study aimed to investigate the metabolism of Xiao-Cheng-Qi decoction(XCQD) by human intestinal bacteria and to discover active component combination(ACC) contributing to the anti-inflammatory activity of XCQD. The water extract of XCQD was anaerobically incubated with human intestinal bacteria suspensions for 48 h at 37 °C. A liquid chromatography-hybrid quadrupole time-of-flight mass spectrometry(LC-Q-TOF/MS) method was performed for identification of the metabolites. In addition, the anti-inflammatory effects of XCQD and biotransformed XCQD(XCQD-BT) were evaluated in vitro with cytokines in RAW264.7 cells induced by lipopolysaccharide(LPS). A total of 51 compounds were identified in XCQD and XCQD-BT. Among them, 20 metabolites were proven to be transformed by human intestinal bacteria. Significantly, a combination of 14 compounds was identified as ACC from XCQD-BT, which was as effective as XCQD in cell models of inflammation. In conclusion, this study provided an applicable method, based on intestinal bacterial metabolism, for identifying combinatory compounds responsible for a certain pharmacological activity of herbal medicines.
A competitive enzyme-linked immunosorbent assay(ELISA) was developed to determine ruscogenin(RUS) by using the monoclonal antibody(McAb). The monoclonal antibody against RUS, secreted from the established hybridoma cell lines, was identified as being of the IgG1 isotype. The McAb exhibited high specificity to RUS, showing a very slight cross reactivity with diosgenin(15.7%), and no cross-reactivity to sarsasapogenin, diammonium glycyrrhizinate, oleanolic acid and notoginsenoside R1. The established ELISA, at an IC50 value of 157.55 ng.mL-1 and a detection limit(IC20) of 20.57 ng.mL-1, was compared with HPLC analyses, and a good correlation between ELISA and HPLC-ELSD analyses of RUS in the extract of Radix Ophiopogonis was obtained. The experimental data indicated that the ELISA method exhibits more advantages over HPLC-ELSD, such as low detection limit, high specificity, low background, and no requirement for sample pre-treatment, and is more suitable for the determination of natural components in Chinese traditional medicines and in biological samples for pharmacokinetic studies.
