Studies On Chemical Constituents And Therelated Application Of Lentinus Edodes

Lentinus edodes (Shiitake) is a traditionally well-known edible mushroom of high nutritious value which has a history of more than two thousand years. It is accepted because of its high contents of carbohydrates, protein, amino acid, sterol constituents, and low content of fat. It is reported to have lots of bioactivities, such as antioxidant, anticancer, antibacterial and hepatoprotective activities. Aimed to study the constituents and promote the utilization of Lentinus edodes, this study was to identify the compounds and provide some investigation that will be helpful for the application of Lentinus edodes.Firstly, this study compared the antioxidant activity, antibacterial activity and total phenolics contents of petroleum ether, ethyl acetate, n-buthl alcohol and water extracts of ethanol refluxing extraction and ethanol quenching extraction. Results showed that two methods were complementary, and they had different selectivity of the constituents in Lentinus edodes. The two methods were combined in this study to extract Lentinus edodes and then the petroleum ether and ethyl acetate extracts were isolated and purified. Eleven chemical compounds were isolated, ten of which were identified as stearic acid (1), ergosterol (3), ergosterol peroxide (4), palmitic acid (5), mannitol (6),5,6;8,9-diepoxy-ergost-22-ene-3,7-diol (7), cerebroside B (8),3,5,9-trihydroxy-ergosta-7,22-dien-6-one (9), adenosine (10), eritadenine (11), and cerebroside B and adenosine were firstly isolated from Lentinus edodes.Secondly, comparative studies on chemical composition and antioxidant properties of stipes and caps of Lentinus edodes as affected by different drying methods were carried out in this study. The fresh Lentinus edodes were processed by three methods: freeze dried (-50°C), room temperature drying (28°C), and hot air drying (50°C,100°C,150°C). The results showed that the contents of total phenolics, amino acids and neutral sugar in stipes were higher than those of caps of Lentinus edodes, which suggested that the stipes were more nutritional than caps in some content. Freeze drying condition was good for the stability of eritadenine and protein in Lentinus edodes and hot air drying condition at50°C was good for the stability of total phenolics, amino acids, unronic acid and neutral sugar. The antioxidant activities of Lentinus edodes could be affected by the drying methods and the high temperature dried samples showed better antioxidant activities. Hot air drying at50°C was found the optimal condition in the bioactivity assays tested, and different drying methods should be choosed for different goals.Lastly, different extraction methods were compared on other nutritional constituents such as fatty acid, amino acid, polysaccharide and flavor compounds. The method of comprehensive extraction for fatty acid, amino acid and polysaccharide was investigated, in which the pretreatment of high pressure and enzymolysis were added, and the yields of three compounds were increased. The method on flavor extraction with the assistance of enzyme was studied. The results showed that the assistance of enzyme could increase the extraction rate of flavor compounds, the papain was helpful to the extraction of carbohydrate-containing compounds, and the cellulose and pectase were helpful to the extraction of of sulphur-containing compounds.In this study,10compounds were isolated and identified, the drying method and the extraction of effective compounds were comparatively investigated. The results would be beneficial for the structure-activity relationship and related food research on Lentinus edodes.