Optimization of extraction process and in vitro antioxidant activity of polysaccharides from Lonicera japonica layered fungi
Phellinus loniceranus (Bond.) Bond Et Sing is a fungus belonging to the genus Trichoderma, and its dried fruiting body is one of the medicinal varieties of Sanghuang, which is also a commonly used medicinal herb of the Tujia ethnic group. It is included in the 2009 edition of the “Quality Standards for Traditional Chinese Medicine in Hubei Province”. It has the effects of detoxification, softening hardness, promoting blood circulation, stopping bleeding, and stopping gastric diarrhea; Indications include the accumulation of symptoms such as gonorrhea, diarrhea, and diarrhea caused by spleen deficiency. Modern pharmacological research has shown that multiple varieties of Sanghuang, including Lonicera japonica, have excellent pharmacological effects such as antioxidant, anti-tumor, hepatoprotective, and immune regulation. The main active ingredient of these medicinal fungi is polysaccharides, which belong to heteropolysaccharides and are polymerized from monosaccharides such as glucose, mannose, galactose, xylose, and arabinose. The research shows that the polysaccharide obtained from the fruit body, mycelium and fermentation broth of Phellinus igniarius is a kind of biological macromolecule with multiple pharmacological activities, which has significant effects on antioxidant, anti-aging, anti-tumor, immune regulation, anti-inflammatory, anti diabetes, liver protection and antibacterial.

In recent years, the preparation, structural characterization, and outstanding biological activity of polysaccharides in mulberry yellow fruiting bodies, cultured mycelia, and fermentation broth have attracted widespread attention. The application scope of products mainly composed of Sanghuang and Sanghuang polysaccharides in the food industry is gradually expanding. Sanghuang has been listed as a healthy food and medicine in Japan, South Korea and other places. However, the development of deeply processed Sanghuang products in China is still relatively scarce. Meanwhile, due to the scarcity of wild mulberry mulberry resources and immature cultivation techniques. There are many types of wild Sanghuang, and the physicochemical properties and activities of Sanghuang polysaccharides obtained from different strains and cultivation methods vary greatly. In order to better develop and utilize Sanghuang resources, it is necessary to further strengthen basic research on Sanghuang. Based on this, this article studied the extraction process of PLP and its in vitro antioxidant activity, in order to provide theoretical basis for the further development and application of this bacterium, and to provide theoretical support for the better application of Sanghuang in food, medicine, health products and other fields.

The unique anti-cancer effect of Sanghuang polysaccharide has made it a hot topic in functional food research at home and abroad, and its antioxidant and other effects have laid the foundation for its application in modern health products. Its outstanding antioxidant effect also makes it have great potential in the development of skin cleaning and maintenance products such as medical dressings, facial cleansers, facial mask and firming creams. However, the current understanding of the physicochemical properties and functional localization of Sanghuang polysaccharides is still very limited and requires systematic and in-depth exploration. Based on this, this study used the residue of the fruiting body of the Sanghuang fungus Lonicera japonica after 95% ethanol degreasing as the raw material. Hot water extraction was used, and the optimal extraction process for PLP was obtained through single factor and response surface experiments: extraction temperature of 100 ° C, extraction time of 120 minutes, and solid-liquid ratio of 1:20 g/mL. Under these conditions, the PLP extraction rate was (3.16 ± 0.05)%; Five polysaccharides were extracted using this process and their antioxidant capacity was studied using four in vitro detection systems. The order of their activity was ABTS free radical scavenging>DPPH free radical scavenging>reducing ability>hydroxyl free radical scavenging. The results indicate that polysaccharides from Lonicera japonica have good dose-dependent in vitro antioxidant capacity and tyrosinase inhibitory activity within a certain concentration range. However, the ability to scavenge different free radicals varies, especially the ability to scavenge hydroxyl radicals is unsatisfactory. At present, the specific mechanism of the antioxidant activity of fungal polysaccharides is not clear. Its antioxidant mechanism may include the direct or indirect action of polysaccharide molecules on free radicals, such as increasing the activity of antioxidant enzymes in the body and reducing the necessary metal ions for lipid peroxidation or polysaccharide molecule complexation to produce reactive oxygen species. The structural characteristics of polysaccharides, such as their charge, molecular weight, and the presence of non carbohydrate substituents, are closely related to their antioxidant properties. Meanwhile, the in vitro antioxidant activity of polysaccharides is highly dependent on their solubility, sugar ring structure, molecular weight, positively and negatively charged groups, protein moieties, and covalently linked phenolic compounds. Therefore, further in-depth exploration is needed to investigate the antioxidant activity and structure-activity relationship of different polysaccharide components in Lonicera japonica.