Medicinal Plant Research 2025, Vol.15, No.1, 1-11 http://hortherbpublisher.com/index.php/mpr 3 biological activity. One study found that polysaccharides extracted using HWE had a relatively large molecular weight, reaching 703.45 kDa (Kang et al., 2019). Enzymatic extraction, on the other hand, utilizes specific enzymes to break down the cell walls of G. lucidum, releasing the polysaccharides. Compared to hot water extraction, this method may be more efficient and selective. A study comparing different extraction methods-including hot water extraction, ultrasound-assisted extraction, and enzyme-assisted extraction-showed that enzyme-assisted extraction produced polysaccharides with higher content and antioxidant activity, outperforming traditional hot water extraction, particularly in terms of immunomodulatory effects (Liu et al., 2021). For example, polysaccharides extracted through enzyme-assisted methods significantly enhanced macrophage proliferation and cytokine secretion, especially promoting the production of NO, TNF-α, and IL-6. 3 Gut Microbiota and Its Role in Human Health 3.1 Composition and diversity of gut microbiota The human gut microbiota is a complex ecosystem primarily composed of bacteria, with the major phyla being Firmicutes, Bacteroidetes, Actinobacteria, and Proteobacteria. Specific species within these phyla play crucial roles in maintaining gut health. For instance, beneficial bacteria such as Bacteroides and Blautia are known to support metabolic functions and immune health, while harmful bacteria like Aerococcus and Proteus can contribute to disease states (Chen et al., 2019; Lv et al., 2019). Gut microbiota perform essential functions, including the fermentation of indigestible carbohydrates to produce short-chain fatty acids (SCFAs), which are vital for colon health and energy metabolism. They also play a role in synthesizing vitamins, metabolizing bile acids, and modulating the immune system. The metabolic activities of gut microbiota are influenced by their composition, which can be altered by dietary components such as polysaccharides fromGanoderma lucidum(Chen et al., 2019; Guo et al., 2020; Guo et al., 2021). 3.2 Factors influencing gut microbiota balance Diet is a primary factor influencing the composition and function of gut microbiota. High-fat diets can lead to dysbiosis, characterized by a decrease in beneficial bacteria and an increase in harmful species. Conversely, dietary polysaccharides from Ganoderma lucidum have been shown to modulate gut microbiota positively, increasing the abundance of beneficial bacteria like Bacteroides and reducing harmful bacteria such as Ruminococcus (Lv et al., 2019; Sang et al., 2021; Zheng et al., 2022). Antibiotics can severely disrupt the gut microbiota, leading to decreased microbial diversity, dysbiosis, and potentially impairing gut barrier function and immune responses. However, combining antibiotics with prebiotics such as Ganoderma lucidum polysaccharides can mitigate these adverse effects by promoting the growth of beneficial bacteria and enhancing the integrity of the gut barrier (Li et al., 2023). For example, studies have found that the use of ciprofloxacin (an antibiotic) alone damages the gut barrier, while GLPs alleviate the negative effects of antibiotics on the gut by increasing the concentration of tight junction proteins such as ZO-1 and Occludin. 3.3 Interaction between gut microbiota and immune system The gut microbiota plays a crucial role in the development and function of the immune system, promoting the maturation of immune cells and contributing to the production of immunoregulatory compounds. Gut microbiota dysbiosis is linked to various immune disorders, including inflammatory bowel disease (IBD) and metabolic syndrome (Tong et al., 2019). Studies have shown that GLPs can enhance immune function by modulating the gut microbiota, thereby increasing the activity of macrophages and the cytotoxicity of natural killer (NK) cells (Wu et al., 2020; Su et al., 2021). Further research by Guo et al. (2021) demonstrated that GLPs can improve gut microbiota imbalance, increase the production of short-chain fatty acids, and alleviate endotoxemia. And GLPs reduce the risk of immune-related diseases by inhibiting inflammation-related signaling pathways, such as the TLR4/MyD88/NF-κB pathways
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