The purpose of this study was to investigate the effects of Huangqi Liuyi decoction extract (HQD) on diabetic nephropathy (DN), and the tissue distribution difference of six main active ingredients of HQD between normal and DN mouse models. DN mice were administered HQD for 12 weeks to investigate its efficacy in the treatment of DN. Liquid chromatography-tandem mass-spectrometry (HPLC-MS/MS) was used to analyze the tissue distribution of the six active ingredients of HQD in normal and DN mice, including astragaloside IV, calycosin-7-O-β-D-glucoside, calycosin glucuronide, ononin, formononetin, and glycyrrhizic acid. DN mice treated with HQD showed significantly decreased fasting blood glucose (FBG), 24-h urinary protein (24 h U-Alb), blood urea nitrogen (BUN), serum creatinine (Scr), and triglyceride levels (TG) (p < 0.05). Moreover, there were no significant differences in pharmacodynamics between HQD and Huangqi Liuyi decoction. Treated mice also had decreased expression of collagen I, ɑ–smooth muscle actin (ɑ-SMA), and vimentin; and upregulated expression of E-cadherin in their kidneys. Compared to normal mice, distributions of the six ingredients in the liver, heart, spleen, lungs, kidneys, stomach, small intestine, brain, and muscle of DN mice were different. The results indicated that the HQD could be used for the treatment of DN and to improve renal function. The pathological state of diabetic nephropathy may affect tissue distribution of HQD active ingredients in mice.

Objective: To investigate the dominant metabolic enzymes of six effective components (astragaloside IV, glycyrrhizic acid, calycosin-glucuronide, formononetin, ononin, calycosin-7-O-β-D- glucoside) of Huangqi Liuyi decoction extract (HQD).Methods: Mouse liver microsomes were prepared. The effects of specific inhibitors of CYP450 enzymes on the metabolism of six effective components of HQD were studied using liver microsomal incubation in vitro.Results: The chemical inhibitors of CYP2C37 inhibit the metabolism of glycyrrhizic acid and astragaloside IV. Formononetin and astragaloside IV metabolism is inhibited by the chemical inhibitors of CYP2C11. The chemical inhibitors of CYP2E1 and CYP1A2 inhibit the metabolism of calycosin-glucuronide. Chemical CYP3A11 inhibitors prevent formononetin and glycyrrhizic acid from being metabolized. However, no inhibitor significantly affected the metabolism of ononin and calycosin-7-O-β-D-glucoside.Conclusion: CYP2C37 may be involved in the metabolism of astragaloside IV and glycyrrhizic acid, the metabolism of astragaloside IV and formononetin may be related to CYP2C11, the metabolism of calycosin-glucuronide may be related to CYP1A2 and CYP2E1, and CYP3A11 may be involved in the metabolism of glycyrrhizic acid and formononetin. This research provides an experimental basis for exploring the pharmacokinetic differences caused by metabolic enzymes.