[Study on in vitro metabolic rate and metabolites or 9-dehydro-17-dehydro-andrographolide]

To investigate the metabolic rate and metabolites of 9-dehydro-17-dehydro-andrographolide, which is the main active ingredient in Xiyanping injection, by using the in vitro rat liver microsome incubation system. 9-dehydro-17-dehydro-andrographolide was incubated together with liver microsome mixed with NADPH. Its metabolic rate was studied by determining its residual concentrations with the UHPLC-MS/MS method; Its metabolites were identified by the UPLC-TOF-MS(E) method. The results showed that 9-dehydro-17-dehydro-andrographolide was metabolized faster than rat liver microsomes mixed with coenzymes, with t½ and CL of (19.7 ± 0.5) min and (35.1 ± 0.8) mL x min(-1) x g(-1) (protein), respectively. Based on the high resolution mass spectrum data and information from literatures, altogether nine metabolites of 9-dehydro-17-dehydro-andrographolide were identified in the incubation system, particularly hydroxylated and dehydrogenized products. The results of identification would provide a basis for screening out more active andrographolide derivatives.