Abstract:

This study investigates the composition and dynamic variation characteristics of the main microbial communities during the processing of Scrophulariae Radix with different processing methods, analyzes the association between dominant microbial communities and the quality of Scrophulariae Radix, and further scientifically elucidates the impact of the traditional sweating process on the quality of Scrophulariae Radix. This study designed direct drying at 60 ℃, drying to semi-dry at 60 ℃ followed by repeated sweating for three days until dry, direct repeated sweating for three days until dry, steaming followed by direct drying at 60 ℃, steaming followed by drying to semi-dry at 60 ℃ and repeated sweating for three days until dry, and steaming followed by direct repeated sweating at 60 ℃ for three days until dry.This study employed high-throughput sequencing technology to investigate the effects of different processing methods on microbial diversity in Scrophulariae Radix samples. UPLC was used to analyze the contents of  aucubin, angoroside C, harpagide, harpagoside, and cinnamic acid;the phenol-sulfuric acid method was used for the analysis of total polysaccharides.The water content, ash, and extractives were analyzed according to the 2020 Edition of Pharmacopoeia of the People's Republic of China.The correlation between the dominant microbial communities and the medicinal quality factors was analyzed.The study found that the contents of aucubin, harpagide, and angoroside C were relatively higher in steamed Scrophulariae Radix, and the contents in samples steamed then dried to semi-dry followed by sweating were higher than those in samples steamed then directly dried. Among bacterial genera, Pseudomonas was significantly positively correlated with harpagide and extractives; Bacillus was significantly negatively correlated with water content. Among fungal genera, Plectosphaerella was significantly negatively correlated with harpagide and angoroside C.This study provides new insights for future research on microbial processing of Scrophulariae Radix and secondary metabolites during its sweating process.

Key words: Scrophulariae Radix, sweating processing, microbial diversity, quality of medicinal materials, correlation