Dryness-alleviating effect of processed Aurantii Fructus from Lingnan based on correlation of fecal metabolomics and dryness

Abstract

With the approach of untargeted metabolomics and correlation analysis, this study aimed to explore the mechanism of Aurantii Fructus from Lingnan region in alleviating dryness by analyzing the different effects of raw Aurantii Fructus(RAF) and processed Aurantii Fructus(PAF) on fecal endogenous metabolism in normal rats. Eighteen Sprague-Dawley(SD) rats were randomly divided into a control group(C), an RAF group(10 g·kg~(-1)), and a PAF group(10 g·kg~(-1)). After seven days of administration, the effects of RAF and PAF on dryness-related indexes were compared, including water intake, fecal water content, salivary secretion, the expression of AQP5, VIP, and 5-HT in the submandibular gland, as well as the expression of AQP3, VIP, and 5-HT in the colon. The fecal samples in each group were determined by LC-MS. Multivariate statistical analysis and Pearson correlation coefficient were used for screening the differential metabolites and metabolic pathways in alleviating dryness of RAF. The results indicated that both RAF and PAF showed certain dryness, and the dryness of RAF was more significant. Moreover, PAF could alleviate dryness of RAF to a certain extent by reducing the water intake, fecal water content, and the expression of AQP3, VIP, and 5-HT in the colon and increasing the salivary secretion and the levels of AQP5, VIP, and 5-HT in the submandibular gland. According to the analysis of fecal metabolomics, 99 and 58 metabolites related to dryness were found in RAF and PAF respectively, where 16 of them played an important role in alleviating dryness of RAF. Pathway analysis revealed that the mechanism of PAF in alleviating dryness of RAF was presumably related to the regulation of riboflavin metabolism, purine metabolism, arginine biosynthesis, pyrimidine metabolism, alanine metabolism, aspartate metabolism, glutamate metabolism, and retinol metabolism pathways. This study suggested that PAF might alleviate dryness of RAF by affecting the metabolic levels of the body, which provides a new basis for further clarifying the processing mechanism of PAF.