Exploration of the intestinal flora to reveal the important contribution of Radix Astragali to Huangqi Jianzhong Tang in treating chronic atrophic gastritis rats

Radix Astragali (Huangqi in Chinese, HQ) is a commonly used Chinese herbal medicine for thousands of years. In this study, A classic prescription Huangqi Jianzhong tang (HQJZ) was selected to evaluate the important effect of HQ on rats with chronic atrophic gastritis (CAG) from the perspective of intestinal flora in cecal contents samples. Traditional pharmacological indicators, including weight change, pathological examination and biochemical indicators showed that HQ exerted favorable contribution to HQJZ against CAG, where the efficiencies of HQ and HQJZ were better than HY (HQJZ prepared without HQ). An accurate strategy was adopted to screen out the differential metabolites in the metabolomis analysis of intestinal flora in cecal contents samples based on the optimal screening factors, including VIP (importance of variables in projection), FC (fold change), AUROC (area under the receiver operating characteristic curve) and -ln(p-value), which were evaluated based on their interpreting, grouping, and predicting abilities of the performed orthogonal partial least-squares-discriminate analysis (OPLS-DA) models. Ten altered differential metabolites were obtained and associated with the intestinal flora, which HQ exerted the important metabolic contributions to HQJZ. The efficacy on the diversity of intestinal flora and their correlations with the altered metabolites further showed the important role of HQ in HQJZ composition. This work provided valuable approach for looking for potential biomarkers associated with metabolomics research with more accuracy, and provided new insights into the mechanisms to explain the efficacy of HQ contributing to HQJZ formula.