Scutellariae radix (SR) has been proven to be highly effective in treating inflammation because of its superior medicinal properties. The two main commercial specifications of SR are Kuqin (KQ) and Ziqin (ZQ). According to traditional Chinese medicine theories, KQ has a better effect than ZQ on dispelling upper energizer lung damp heat, however, its mechanism of action is not known. Thus, this study investigated the role of KQ-induced alterations in endogenous metabolites and gut microbiota in regulating LPS-induced acute lung injury (ALI). KQ treatment ameliorated lung injury more effectively than ZQ and demonstrated satisfactory organ protection properties. KQ treatment reversed the tryptophan metabolite abnormalities in ALI and reshaped the composition of gut microbial communities. Additionally, the abundance of the enriched Akkermansia muciniphila was significantly and inversely correlated with the rate-limiting enzyme of the tryptophan/kynurenine pathway, indoleamine 2,3-dioxygenase 1 (IDO1) activity (p = 0.0214, R² =0.7712). Furthermore, the beneficial and causative effects of A. muciniphila were confirmed by antibiotic and microbial intervention experiments. Live and pasteurized A. muciniphila, both supplements could ameliorate the inflammatory response and down-regulate IDO1 expression, thereby restoring tryptophan metabolic imbalance. In conclusion, the current study demonstrated for the first time that KQ may act on the A. muciniphila abundance, regulate IDO1 activity, and thus ameliorate ALI. Interestingly, A. muciniphila supplementation could be a promising therapeutic option for lung diseases through the gut-lung axis.

Fungal polysaccharides are a class of natural compounds with diverse biological activities, widely utilized in the pharmaceutical, food, and cosmetic industries. Their unique bioactivities, including immunomodulatory, antitumor, antioxidant, and antimicrobial properties, have made them a popular subject of research and application. The physicochemical properties, structural characteristics, and biological activities of these polysaccharides are significantly influenced by various processing methods, with grinding and drying techniques playing crucial roles in determining the final product's quality and functionality. Grinding techniques during the preprocessing stage significantly impact the particle size, solubility, viscosity, rheological properties, and bioavailability of polysaccharides. Methods such as ball milling and ultrasonic milling can alter the yield, molecular structure, and dissolution rate of polysaccharides. During drying, temperature parameters are key factors affecting the physicochemical properties and biological activities of fungal polysaccharides. Different drying methods, such as hot air drying, freeze drying, and spray drying, each have their advantages and drawbacks. Therefore, careful selection of grinding and drying processing methods is essential to ensure higher yields and better bioactivity of fungal polysaccharides during extraction. However, most research on polysaccharides focuses primarily on extraction and purification, often overlooking drying and grinding. This study aims to discuss and compare the principles of different drying and grinding processes and summarize their effects on fungal polysaccharides. The methods used during the preprocessing stage and the drying stage significantly impact the yield, physicochemical properties, and chemical composition of these polysaccharides. These findings provide valuable references for researchers and industry professionals, aiding in the selection of optimal methods to improve the reliability and stability of final products, thereby enhancing their application value.