蚕蛹虫草生物活性肽的制备及其性能分析

Preparation and antioxidant properties on polypeptides of Cordyceps militaris

摘要:

为了提高蚕蛹虫草的经济价值，以蚕蛹虫草子实体为材料，采用碱溶酸沉法提取蚕蛹虫草蛋白质，通过正交实验优化提取条件；通过蛋白质复合酶酶解蚕蛹虫草蛋白质，超滤法分离获得蚕蛹虫草小分子多肽液；通过测定抑菌圈和细胞毒性实验评价蚕蛹虫草多肽的抗菌及抗癌活性。结果显示，蚕蛹虫草蛋白质最佳提取条件为：pH 8.5，料液比为1:28，提取时间210 min，提取3次，蛋白质含量最高为 45.06%；蚕蛹虫草多肽液最佳酶解工艺为：碱性蛋白酶与木瓜蛋白酶比例4:3；酶解最佳温度55 ℃，pH 7.2，酶添加量 7000 U/mL，酶解时间为210 min，多肽含量最高为16.73%。在此条件下制备的蚕蛹虫草多肽（<3.0×103 Da）对大肠杆菌、枯草芽孢杆菌及金黄色葡萄球菌均表现出较好的抑菌效果，其抑菌圈分别为（12.08 ± 0.22）、（6.67 ± 0.12）和（10.32 ± 0.23）mm；对骨肉瘤Sao-S〔半数抑制浓度（IC50）为 0.49 mg/L〕和膀胱癌T24细胞（IC50为 0.23 mg/L）有很好的抑制作用。

Abstract:

Cordyceps militaris is rich in protein, polysaccharide, cordycepin and other active components, with anti-cancer and anti-oxidation functions. In order to improve the economic value of Cordyceps militaris, the protein was extracted from its fruiting body by alkali solution and acid precipitation method, and the extraction conditions were optimized by orthogonal test. The polypeptide was obtained by digesting those protein with protein complex enzyme. And the antimicrobial and anticancer activities of those polypeptides were evaluated by measuring inhibitory zone and cytotoxicity. The results showed that the optimal extraction conditions of protein were as follows: pH 8.5, solid-liquid ratio 1:28, extraction time 210 min, extraction three times, the highest protein yield was 45.06%. The optimum enzymatic hydrolysis process of Cordyceps militaris polypeptide solution was as follows: the ratio of alkaline protease to papain was 4:3; The optimum temperature of enzymolysis was 55℃, pH 7.2, the enzyme dosage was 7000 U/mL, the enzymolysis time was 210 min, and the highest yield of peptide was 16.73%. Under these conditions, the polypeptides prepared from Cordyceps militaris (< 3.0×103 Da) showed good antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus, with inhibitory zones of (12.08 ± 0.22), (6.67 ± 0.12) and (10.32 ± 0.23) mm, respectively. The results showed that the SAO-S (IC50 = 0.49 mg/L) and T24 (IC50 = 0.23 mg/L) were significantly inhibited by Cordyceps militaris polypeptide.