Gut microbiota dysbiosis has been reported as a risk factor in the development of type 2 diabetes mellitus (T2DM). Polysaccharides from Phellinus igniarius (P. igniarius) possess various properties that help manage metabolic diseases; however, their underlying mechanism of action remains unclear. Therefore, in this study, we aimed to evaluate the effect of P. igniarius polysaccharides (SH-P) on improving hyperglycemia in mice with T2DM and clarified its association with the modulation of gut microbiota and their metabolites using 16S rDNA sequencing and liquid chromatography–mass spectrometry. Fecal microbiota transplantation (FMT) was used to verify the therapeutic effects of microbial remodeling. SH-P supplementation alleviated hyperglycemia symptoms in T2DM mice, ameliorated gut dysbiosis, and significantly increased the abundance of Lactobacillus in the gut. Pathway enrichment analysis indicated that SH-P treatment altered metabolic pathways associated with the occurrence and development of diabetes. Spearman’s correlation analysis revealed that changes in the dominant bacterial genera were significantly correlated with metabolite levels closely associated with hyperglycemia. Additionally, FMT significantly improved insulin sensitivity and antioxidative capacity and reduced inflammation and tissue injuries, indicating improved glucose homeostasis. These results indicate that the ameliorative effects of SH-P on hyperglycemia are associated with the modulation of gut microbiota composition and its metabolites.

Introduction: Although Phellinus igniarius has been shown to treat hyperuricemia (HUA) and gout, a self-inflammatory disease caused by purine metabolism disorders, the underlying mechanisms remain unclear. Polysaccharides are among the main components of P. igniarius with anti-inflammatory and immunoregulatory properties. Methods: Here, we examined the therapeutic effects of polysaccharide SH-P-1-1 isolated from P. igniarius on HUA and gout, and explored the underlying mechanism, focusing on gut microbiota and metabolite regulation. Results: SH-P-1-1 significantly decreased uric acid and creatinine levels, reduced xanthine oxidase and adenosine deaminase activities, alleviated kidney damage, and reduced urate deposition in joints in model rats. It increased the abundance of Blautia and Muribaculaceae but reduced that of the Lachnospiraceae_NK4A136_group , Lactobacillus , and Turicibacter . SH-P-1-1 also significantly modulated the metabolic profile and was closely related to some metabolic pathways, such as tryptophan metabolism, relevant to HUA and gout. The beneficial activities of SH-P-1-1 correlated with gut microbiota composition and differential metabolites, including short-chain fatty acids. Discussion: Overall, this study demonstrates the potential of SH-P-1-1 as a natural supplement for preventing and managing HUA and gout.

Polysaccharides serve as the main bioactive compounds of Zingiber striolatum (Z. striolatum). However, their structures and functions require further research. The present work used response surface methodology (RSM) for optimizing polysaccharide extraction conditions from Z. striolatum through ultrasonic-assisted hot-water extraction and evaluating the antioxidant properties of Z. striolatum polysaccharides. According to our findings, optimal Z. striolatum polysaccharide extraction conditions included ultrasonic power of 200 W, extraction temperature of 79 °C, extraction duration of 2.5 h, and ultrasonic time of 20 min, with the extraction yield reached 19.96% ± 0.18%. The molecular weight (MW) of the purified polysaccharide ZS-P1-1 isolated from Z. striolatum was 5.63 × 10⁴ kDa, mainly composed of galactose (Gal), galacturonic acid (GalA) and glucuronic acid (GlcA) in a 0.453:0.162:0.114 molar ratio. Typically, 2,2-diphenyl-1-picrylhydrazyl radical (DPPH·) and hydroxyl radical (·OH) scavenging capacities and total reducing ability reached 30.49% ± 1.82%, 28.51% ± 1.40% and 0.64 ± 0.07 of ZS-P1-1 at 0.5 mg/mL, respectively. Moreover, ZS-P1-1 increased the reduced glutathione (GSH) level, enhanced the total superoxide dismutase (T-SOD), reduced the malondialdehyde (MDA) level, and alleviated the liver and kidney damage caused by oxidative stress in mice. Our results suggest that ZS-P1-1 shows excellent antioxidant properties and provides a certain theoretical foundation for developing and utilizing Z. striolatum polysaccharides.

Phellinus igniarius is a medicinal fungus rich in terpenoids with potential biological activities. In this study, the P. igniarius terpenoid-enriched extract (PITT) was optimized using single-factor experiments combined with response surface methodology based on a Box–Behnken design. The optimal extraction conditions were determined as extraction temperature 64 °C, extraction time 21 min, ethanol concentration 78%, and liquid-to-solid ratio 20 mL/g, yielding a total terpenoid content of 7.078 mg/g. The chemical profile of PITT was characterized by liquid chromatography–tandem mass spectrometry (LC–MS/MS), revealing the presence of multiple putative terpenoid compounds, including betulin, curdione, and several sesquiterpenoids. The antioxidant activity of PITT was evaluated using DPPH, ABTS, and hydroxyl radical scavenging assays, showing dose-dependent effects. Furthermore, an H₂O₂-induced oxidative stress model in RAW 264.7 cells was employed to assess cellular antioxidant activity. Pretreatment with PITT significantly reduced intracellular reactive oxygen species (ROS) levels, enhanced the activities of endogenous antioxidant enzymes (superoxide dismutase, catalase, and glutathione peroxidase), and decreased malondialdehyde (MDA) levels. These results indicate that PITT exhibits notable antioxidant activity and may serve as a potential natural antioxidant source for further development. However, further studies are required to elucidate the underlying mechanisms.