Views: 9 Author: Cai Xiaoyu, Li Xuehan, Yu Meicui et al Publish Time: 2022-11-16 Origin: Cai Xiaoyu, Li Xuehan, Yu Meicui, et al. Research progress on the antibacterial effect of polysaccharides from edible and medicinal bacteria[J]. Food Safety Guide, 2021:183-186.
Edible and medicinal fungi can be regarded as edible fungi in a broad sense, and large edible and medicinal fungi in a narrow sense. In general, edible and medicinal fungi belong to a branch of fungi and belong to the category of microorganisms.
Fungal polysaccharides have a variety of biological activities. Research on the extraction methods and functions of polysaccharides from edible and medicinal fungi has been going on at home and abroad. The research progress on the antibacterial effect of polysaccharides from edible and medicinal fungi is reviewed to provide a certain basis for better utilization of antibacterial functions. scientific basis.
Antibacterial mechanism
Prevent harmful bacteria from entering cells
When the harmful bacteria have not yet approached the host cell, some polysaccharides will combine with the nutrient iron necessary for the harmful bacteria, thereby affecting the activity of the harmful bacteria. The stronger the binding ability of iron and polysaccharides, the less iron the harmful bacteria can obtain. The stronger the ability to inhibit bacteria, the less harmful bacteria reach the host cell. Some edible and medicinal polysaccharides can replace the receptor structure of some bacterial hosts, bind to bacterial adhesins, and prevent bacteria from infecting host cells.
Destroy the cell membrane and cell wall of harmful bacteria
The polysaccharides of some edible and medicinal fungi can destroy the cell wall and cell membrane of microorganisms. Some bacterial populations are surrounded by biofilms composed of certain biological macromolecules (mostly glycoprotein complexes). Biofilms make bacteria more adaptable to the environment. Polysaccharides from edible and medicinal bacteria can inhibit the activity of bacteria and destroy the bacteria. biofilm. There are also some polysaccharides that are easy to adsorb on the cell surface of microorganisms, forming antibacterial films, and affecting the metabolism and activity of microorganisms.
Affects gene expression of harmful bacteria
Low-molecular-weight polysaccharides extracted from edible fungi can enter the nucleus of microorganisms, target the negatively charged genetic material in the nucleus, and affect the replication, transcription, translation and other processes of genetic material, thereby achieving antibacterial effects. Small molecule polysaccharides can enter the interior of microorganisms through the porous cell walls of some microorganisms, change the internal colloidal state of microorganisms, make them flocculate, denature, and affect the survival status of microorganisms. If it is a polysaccharide with too large molecular weight, it will affect the expression of effective genes for microbial activity through complex coiling and winding, and the antibacterial effect will be weakened.
Antibacterial activity
Ganoderma lucidum polysaccharide
Baidan et al. used the disc agar method to determine the inhibition degree of Ganoderma lucidum polysaccharides to 8 microorganisms including Eustia carotans, Penicillium digitatum, Botrytis cinerea, Bacillus subtilis, Bacillus cereus, Escherichia coli, Rhizopus niger and Aspergillus niger Finally, it was found that Ganoderma lucidum polysaccharide had the most obvious inhibitory effect on the first two plant pathogens, Bacillus cereus and Bacillus subtilis. The test results of Zhao Chengping and others showed that in an acidic environment, the antibacterial effect of Ganoderma lucidum polysaccharide on Bacillus subtilis is better than that in an alkaline environment, which may be due to the fact that the acidic environment promotes the disintegration of the cell wall and cell membrane of the bacteria. According to the research of Su Ling et al., polysaccharides from Ganoderma lucidum fermented liquid extract (Ganoderma lucidum exopolysaccharides mixed with intracellular polysaccharides) have a good inhibitory effect on Escherichia coli. According to Pan Ming et al.'s research on the polysaccharides in the fermentation broth of Ganoderma lucidum, it is found that the polysaccharides in the fermentation broth of Ganoderma lucidum have the best antibacterial effect on Staphylococcus aureus, and also have obvious antibacterial effects on Bacillus subtilis. The polysaccharides of the same type of edible and medicinal fungi have selective inhibitory effects on the fungus due to the different locations and methods of extracting the polysaccharides. Wang Hongyan et al. explored the effect of Ganoderma lucidum polysaccharides on Fusarium oxysporum through greenhouse pot experiments. It was found that 200mg/mL Ganoderma lucidum polysaccharide solution treated the leaves of cotton seedlings, the activity of peroxidase was greater than that of the control group, and the resistance of cotton to Fusarium oxysporum was increased. Ning Yubo found that tomato leaves treated with Ganoderma lucidum polysaccharide solution had a lower chance of being infected with Botrytis cinerea. This is because the tomato leaves treated with Ganoderma lucidum polysaccharides increased the activity of peroxidase in the plant, and the activity of defense enzymes such as polyphenol oxidase and catalase was significantly increased. Ganoderma lucidum polysaccharide has a good effect on inhibiting plant pathogens.
Lentinan
Lei Lihui et al. isolated two kinds of bacteria, Staphylococcus aureus and Escherichia coli, from mastitis cases of dairy cows. They used lentinan to conduct antibacterial tests in vitro, and found that the bacteriostatic zone of lentinan for Staphylococcus aureus was It should be smaller than the inhibition zone of E. coli; the minimum inhibitory concentration (MIC) for the former is 37.5m/mL, and the MIC for the latter is 18.75mg/mL. Overall, it can be seen that lentinan has good in vitro inhibitory effect on both bacteria, but the inhibitory effect on Escherichia coli is the best.
Fungus polysaccharide
Luo Jingwen et al. found that the fungus has strong antibacterial ability against Escherichia coli, Staphylococcus aureus and Bacillus subtilis, and the antibacterial ability of fungus and black fungus against the three is similar, and the antibacterial ability is average. The antibacterial effects of the three polysaccharides on Escherichia coli were better than those of the other two strains. Cai Ming and others used Oxford cups to conduct antibacterial tests. Studies have found that fungus polysaccharides have inhibitory effects on Staphylococcus aureus and Escherichia coli. In the research experiment of black fungus polysaccharides on the regulation of intestinal flora in mice by Zhang Tingting et al., the Bacteroides phylum increased and the Firmicutes phylum decreased in mice fed a high-fat diet. After the mice ingested black fungus polysaccharide at the same time, the Hepatitis B phylum decreased, and the Firmicutes phylum increased relatively, indicating that the black fungus polysaccharide can regulate the intestinal flora of mice.
Pleurotus eryngii polysaccharide
Zhang Li et al. used the filter paper method to investigate the antibacterial effect of Pleurotus eryngii polysaccharides on 8 kinds of microorganisms, and found that Pleurotus eryngii polysaccharides only had inhibitory effects on Streptococcus albus and Bacillus aerogenes. Xu Rui used the disc method to conduct antibacterial research, and found that the extracted Pleurotus eryngii polysaccharides had good inhibitory effects on E. ) have almost no antibacterial effect. The results of these two studies are completely opposite. The reason should be that the results are inconsistent due to the different extraction methods of Pleurotus eryngii polysaccharides.
Dictyophora polysaccharide
Huang Qingbin et al. used absorbance to represent the concentration of Bifidobacterium adolescentis. When the crude polysaccharide of Dictyophora reached 0.25mg/mL, the 2mg/mL Bifidobacterium adolescent cells decreased significantly with the increase of the polysaccharide concentration, and the acid production of the bacteria in the polysaccharide environment was inhibited. Bai Xinwei used the agar filter method to carry out the antibacterial test, and found that the inhibitory effect of crude polysaccharides and three polysaccharide components on lactic acid bacteria was significantly stronger than that on Staphylococcus aureus, Bacillus subtilis, Escherichia coli and rhizobium.
Poriopolysaccharide
Zou Li et al. extracted crude polysaccharides from the mycelium of Inonotus obliquus, and used the plate surface smear method to explore the antibacterial effect on poplar rot fungus and larch dieback fungus. The antibacterial rate of crude polysaccharides on the former pathogen was only 3.64%, while the bacteriostatic rate for the latter bacteria reached 29.52%. The polysaccharides extracted from the fermentation broth were fractionated and purified with different concentrations of ethanol. It was found that the polysaccharides with a volume fraction of 70% ethanol had the best antibacterial effect. The bacteriostasis rates of Slight Disease were increased to 54.65% and 67.41%. The minimum inhibitory concentrations for poplar bark rot and larch blight were 65g/mL and 60g/mL, respectively. The antibacterial ability of the fractionated and purified Inonotus fusiformis was improved.
Tang Yuqin et al. extracted crude polysaccharides from the fruiting body of Phylonotus ulmifolia, and then used the filter paper method to explore the antibacterial ability of crude polysaccharides. The results showed that the crude polysaccharides had inhibitory effects on four kinds of bacteria including Escherichia coli, tetrad, Staphylococcus aureus and Bacillus aspartate, among which the inhibitory effect on Escherichia coli was the best. The bacteriostatic effect on yeast was not much different from the bacteriostatic effect on Escherichia coli. It may be due to the difference in the antibacterial effect caused by the different cell wall structures. The cell walls of the first four fungi are thick, and the glucan and mannan in the cell walls of yeast are easily damaged by the external environment. The cell walls of the four prokaryotic bacteria are mainly composed of Thin peptidoglycan composition, easily affected by bacterial polysaccharides. Zhao Youwei et al. found that compared with normal mice, the proportion of Proteobacteria and ε-proteobacteria in the total intestinal flora increased in mice treated with cyclophosphamide, and the proportion of Proteobacteria and ε-Proteobacteria in the total intestinal flora increased. After polysaccharide enema treatment, the proportion of Proteobacteria and ε-Proteobacteria in the total intestinal flora decreased, indicating that it had an inhibitory effect on these two flora. Tang Shaojun et al. extracted the extracellular crude polysaccharides from Pleurotus spp., and used the Oxford cup method to conduct an in vitro antibacterial test. The results showed that it had obvious antibacterial zones against Staphylococcus aureus, Candida albicans and yeast. For Escherichia coli, para Vibrio haemolyticus did not form a zone of inhibition, and the extracellular crude polysaccharides of Vibrio pilosula were selective for the inhibition of microorganisms.
From the antibacterial aspect of 6 kinds of edible and medicinal bacteria, it is found that the polysaccharides of edible and medicinal fungi have a good effect on inhibiting plant pathogens, and can be used in combination with plant antibacterial agents to act as antibacterial inducers, reduce the use of plant antibacterial agents, and protect the environment , to slow down the emergence of plant resistance. It can also be used as a drug to regulate the intestinal flora, because the polysaccharides of edible and medicinal bacteria can regulate the intestinal flora, inhibit the increase of the proportion of harmful bacteria, improve the environment of the intestinal flora, and restore the normal glucose and lipid metabolism mechanism in the body. Extraction of natural fungi has no toxicity of chemically synthesized drugs. Since edible and medicinal bacteria have a good antibacterial effect on some bacteria, at present, some specific antibiotics can be combined to achieve a common antibacterial effect, which can effectively alleviate the adverse effects of certain bacterial drug resistance on people's health.
