Study On Polysaccharides Extraction From Shitake Mushroom Stem And Its In Vitro Anticancer Activity

Lentinus edodes are medicinal and edible fungi.Lentinan has biological activities such as improving immune function,reducing blood fat,antitumor,anti-aging,and antivirus,without any toxic side effects.Shitake mushroom stems were discarded as waste in the production of shiitake mushrooms,resulting in a great waste of resources.In order to fully exploit the potential value of shitake mushroom stems,and provided a reference for the industrial production of shitake mushroom stems polysaccharides.The main findings and innovations of this paper are as follows:1.Comparison of the anticancer activity of the crude polysaccharides extracted from shitake mushroom stems and shitake mushroom caps in vitro.Shitake mushroom stems also have a good extraction rate,indicating that the shitake mushroom stems have good extraction and processing value of polysaccharides.Polysaccharides extracted from shitake mushroom stems and shitake mushroom caps both can significantly inhibited the proliferation of eight isolated cancer cell lines HCT116,HT29,KM12L4,SW620,SW480,RKO,H4,and HepG2,showing strong anticancer activity.Flow cytometry assays showed that both shitake mushroom stems and shitake mushroom caps polysaccharide could impede mitosis in HCT116 cells,and the proportion of cells staying in G0/G1 phase increased significantly,which may be due to its tumor suppressor function.Through real-time quantitative PCR assay,it was found that the crude polysaccharides extracted from shitake mushroom stems and shitake mushroom caps both can significantly promote the expression of the anticancer related gene ATF4 and inhibit the expression of C-ymc.In the above experiments,indicating that shitake mushroom stems polysaccharides have at least the same exploitation value to the shitake mushroom caps.2.Comparison of the antioxidant and anticancer effects of crude polysaccharides and purified polysaccharides in vitro.In order to examine whether the proteins in the stems of shitake mushroom have biological activity,the Sevage method was used to remove the protein from the shitake mushroom stems sample to obtain the purified polysaccharides.It suggested that higher free radical scavenging rate of crude polysaccharides than the purified polysaccharides.The results indicate that the crude polysaccharides have better antioxidant and anticancer effects in vitro,and the development of crude polysaccharides products have better application prospects.3.Optimization the extraction technology of polysaccharides of shitake mushroom stems by response surface methodology.The response surface software was used to design and obtain 17 test points.The parameters obtained from the response surface analysis were liquid/material ratio(mL/g)43:1,extraction temperature 79°C,and extraction time 124 min.Using these parameters,the obtained polysaccharides content was 18.66%.The optimized parameters provide experimental and theoretical references for the large-scale extraction of shitake mushroom stems polysaccharides.4.The effects of different extraction methods on the antioxidant activity of shitake mushroom stems polysaccharides in vitro were studied.It indicates that the polysaccharides obtained by freeze-drying have stronger ability to scavenge free radicals than spray-dried polysaccharides,the freeze-drying method is more conducive to the preservation of the antioxidant activity.It indicates that the without alcohol-precipitated polysaccharides have a stronger ability to scavenge free radicals than the alcohols-precipitated,the without alcohol-precipitated method is more conducive to the preservation of the antioxidant activity.Under the premise of considering the balance of efficacy and economic cost,alcohol freeze-drying should be used to extract polysaccharides.5.The effects of storage time on antioxidant activity and anticancer activity of crude polysaccharides of shitake mushroom stems.The freshly extracted shitake mushroom stems crude polysaccharide samples were stored at-20°C for 40 days.It indicates that the crude polysaccharide still has good antioxidant activity.Due to the simple processing,low cost and good antioxidant effect,the crude polysaccharides from shitake mushroom stems have superior prospects.The freshly extracted shitake mushroom stems crude polysaccharides solution was stored at-20°C.The inhibition effects of polysaccharides on the proliferation of human hepatocellular carcinoma SMMC-7721 cells were detected within 40 days.The results showed that if storing the crude polysaccharides of shitake mushroom stems in liquid state,the storage temperature should be lower than-20°C,and the storage time should be less than 30 days.