Studies On Se-Enriched Pleurotus Ostreatus

It has been a research hotspot in the fields of foodstuff science and medicine pharmacy to develop the edible and medicinal Se-enriched products in recent years because of the effects of improving immunity, anti-aging and anticancer of selenium. In this research Se-enriched Pleurotus ostreatus were systematically studied which included strains screening, optimization of liquid culture medium, the production processes, acute toxicity test and the pharmacologic experiments on the effects of improving immunity, antioxidation and anti-tumor of Se-enriched Pleurotus ostreatus powder.Ten strains of Pleurotus ostreatus were screened using solid and liquid media containing selenium. Results: the growth of P5 and P9 were better than other strains in solid medium and the colony diameter were larger; the growth of P1, P5 and P9 grew better than other strains in liquid medium and the dry weight were bigger. P5 were selected as the experimental strain because the size of the mycelial pellets of P5 in soybean meal medium were uniform and it grew fast in substratum.Six different Se-concentrations were set up in the comparative experiments between cultivation with liquid and solid seed. Results: the dry weight of Pleurotus ostreatus fruit body from liquid seed groups were increased than those of solid seed groups by 12.15 %, 17.13 %, 14.91 %, 11.83 %, 7.27% % and 15.15 %, respectively, and the cultivation period were shorten by 18.37 %, 16.67 %, 19.34 %, 18.93 %, 15.19 % and 28.69 %, respectively. So the method of liquid seed inoculation was selected to continue the following experiments.The effects of different concentrations of selenium in solid substratum and liquid seed on the dry weight, the contents of organic selenium, polysaccharides and protein of Pleurotus ostreatus fruit body were studied. Results: the concentration of selenium in solid substratum was the main influence factor on the contents of organic selenium in fruit body, and the low (20μg/g), median (50μg/g) Se-concentrations in solid substratum could increase the dry weight of Pleurotus ostreatus fruit body and the high (80μg/g) Se-concentration could decrease the yield. The contents of organic selenium of Pleurotus ostreatus fruit body increased with the increase Se-concentrations in liquid seed and solid substratum. The low (20μg/g) and median (50μg/g) Se-concentrations in liquid seed could increase the dry weight of Pleurotus ostreatus fruit body and the high (80μg/g) Se-concentration could decrease the yield. The contents of polysaccharides and protein were not significantly changed by diferent concentrations of selenium in solid substratum and liquid seed and there were no obvious regulation.The liquid medium of P5 was optimized as follows: glucose 2%, soybean 3%, K₂HPO₄ 0.1% and MgSO₄·7H₂O 0.05%. In this condition, the dry weight of mycelia were 1.62 g/100ml which were inceased by 20.09% (P<0.01), and Se-content of mycelia were 200.88μg/g which were inceased by 33.65% (P<0.01).The acute toxicity of Se-enriched Pleurotus ostreatus was tested. The results showed that there were no death and organ pathology in control group and drug groups after maximally tolerating in 14 days. The MTD of Se-enriched Pleurotus ostreatus powder by ig administration was greater than 6154 mg/kg in mice, and the se-enriched Pleurotus ostreatus powder was belong to nonpoisonous materials according to the grade standards of mice acute toxicity by iq.The effects of improving immunity, antioxidation and anti-tumor of se-enriched Pleurotus ostreatus powder were tested. The results showed that organ index of Se-enriched Pleurotus ostreatus powder groups were significantly higher than that in distilled water group, Na₂SeO₃ group and normal Pleurotus ostreatus group; The extracts with H₂O, 80 % methanol and 75 % ethanol from the Se-enriched Pleurotus ostreatus powder could decrease 74.80 %, 70.13 % and 70.16% of 0.2 mg·mL^-1 DPPH free radicals, significantly higher than those from normal Pleurotus ostreatus power and mycelia grown in Se submerged culture (P<0.01); Plasma and liver GSH-Px, SOD activity of Se-enriched Pleurotus ostreatus powder groups were significantly higher than those of distilled water group, Na₂SeO₃ group and normal Pleurotus ostreatus group, and MDA content in plasma and liver were lower than those of the other groups; The inhibition ratio of the Se-enriched Pleurotus ostreatus powder on lung adenocarcinoma cell line A549 were 15.18 %, 301.92 %, 182.26 %, 78.96 % and 15.96 % higher than normal Pleurotus ostreatus powder at the dosage of 0, 0.0004, 0.004, 0.04, 0.4 and 4μM (P<0.01); The inhibition ratio of the Se-enriched Pleurotus ostreatus powder on high differentiated nasopharyngeal carcinoma cell line CNE-1 were 21.20 %, 245.00 %, 181.69 %, 83.23 % and 17.47 % higher than normal Pleurotus ostreatus powder at the dosage of 0, 0.0004, 0.004, 0.04, 0.4 and 4μM (P<0.01); The Se-enriched Pleurotus ostreatus powder could significantly improve immunity and antioxygenic function in mice, and the inhibition ratios of the Se-enriched Pleurotus ostreatus powder on lung adenocarcinoma cell line A549 and high differentiated nasopharyngeal carcinoma cell line(CNE-1) were significantly higher than normal Pleurotus ostreatus powder group.Contents of major chemical components and inorganic elements in Se-enriched Pleurotus ostreatus powder were determined. The contents of protein, fat, polysaccharides, crude fibre, ash, moisture reached 20.02%, 2.24%, 12.84%, 11.68%, 6.34% and 6.87%, respectively, and the contents of heavy metal were lower than the standard. The content of Ca was high.On the basis of researches a new nutrient fortified food, Se-enriched Pleurotus ostreatus capsule(trade name Yan Nian, batch number Ningweishizhengzi 2009/640100 SQ002) was developed, and the certificate was successfully approved to Ningxia native products Co. Ltd in Ningxia Hui Nationality Autonomous Region. The enterprise standard Q/NZFT 0006S—2009 was established and it has been used in industrial production.