Regulatory effect of intracellular polysaccharides from Antrodia cinnamomea on the intestinal microbiota of mice with antibiotic-associated diarrhea

Antrodia cinnamomea is a valuable and scarce medicinal and edible mushroom. Its main active substances are triterpenoids and polysaccharides with many biological activities, such as liver protection, immunity enhance-ment, antitumor, anti-inflammatory, and antiviral. The long-term use of antibiotics can easily lead to disorders in the intestinal flora and causes diarrhea, inflammation, immune decline, and other symptoms. In this study, A. cinnamomea intracellular polysaccharides (AIPSs) were extracted from mycelia in submerged fermentation, and the AIPSs with a neutral polysaccharide content of 82.74%+/- 0.63% were obtained. Then, the therapeutic effect of AIPSs on diarrhea in mice caused by lincomycin hydrochloride (LIH), and their regulatory and recovery effects on the intestinal flora, was studied with fructooligosaccharide as the positive control. In vivo experiments in mice showed that fed intragastrically with 0.25 g/kg (bodyweight of mice) of AIPSs significantly reduced the weight loss caused by antibiotics and restored the immune-organ index (P<0.05). The AIPSs also significantly lowered the degrees of the inflammatory cytokines IL-6 and TNF-alpha in mouse serum (P<0.01). Analysis of mouse intestinal flora showed that AIPSs treated diarrhea caused by LIH and regulated and improved the flora's struc-ture. These effects were primarily manifested in the increased relative abundance of good microorganisms (e.g., Lachnospiraceae_NK4A136_group, Osllospiraceae, and Lachnospiraceae) and reduced relative abundance of harmful microorganisms (e.g., Enterococcus) (P<0.05). This study further expanded the application value of the submerged fermentation products of A. cinnamomea. A new perspective and theoretical basis for developing new multifunctional prebiotics to regulate antibiotic-induced disorders in the intestinal flora was also provided.