广东虫草富硒培养及其粗多糖抗氧化活性的比较

Selenium-enriched Culture of Cordyceps guangdongensis and Comparison of Antioxidant Activity of Its Crude Polysaccharides

摘要:

该研究对不同外源硒（Na2SeO3）质量浓度下培养得到的广东虫草子实体生长状况及腺苷（Adenosine, AD）、多糖（Polysaccharide, PS）、虫草酸（Cordycepic Acid, CA）等活性成分进行了考察，确定广东虫草菌株的最佳富硒质量浓度，同时检测了其子实体在最佳富硒质量浓度下的总硒含量及其存在形态，并对其粗多糖体外抗氧化活性进行了初步探究。结果表明，随着培养基中Na2SeO3质量浓度的增加，富硒广东虫草子实体的生物学转化率、AD、PS、CA含量均表现出先升后降的趋势。在Na2SeO3质量浓度为30 mg/kg时，生物学转化率、AD、PS均达到最高值，为最佳富硒质量浓度。此时，广东虫草子实体中的有机硒占比为100%，有7种硒形态，分别为硒代蛋氨酸（Selenomethionine, SeMet）、硒代胱氨酸（Selenocystine, SeCys2）、四价Se（IV）、硒甲基硒代半胱氨酸（Se-methylselenocysteine, SeMeCys）、六价Se（VI）以及两种未知硒形态。体外抗氧化活性评估表明，同一质量浓度下，相比未富硒广东虫草粗多糖（Cordyceps guangdongensis Crude Polysaccharide, CPS），富硒广东虫草粗多糖（Se-enriched Cordyceps guangdongensis Crude Polysaccharide, CPS-Se）具有更高的抗氧化活性，其对DPPH、ABTS+和羟基自由基的清除能力、总还原能力以及总抗氧化能力均有不同程度地增强（P<0.01），呈现良好的剂量依赖性。这为富硒广东虫草产品开发及其多糖的进一步纯化鉴定和活性验证提供了理论依据。

Abstract:

In this study, the growth status and active components such as adenosine (AD), polysaccharide (PS) and cordycepic acid (CA) of Cordyceps guangdongensis cultured at different mass concentrations of exogenous selenium (Na2SeO3) were investigated. The optimal mass concentration of selenium for enrichment in Cordyceps guangdongensis was determined, and the total content of selenium and its existing form in the fruiting body obtained at the optimal selenium mass concentration were examined. Meanwhile, the in vitro antioxidant activity of the polysaccharide from the fruit body was preliminarily investigated. The results indicated that, with the increase of the mass concentration of Na2SeO3 in the medium, the biological conversion rate, and the contents of AD, PS and CA in the selenium-enriched Cordyceps guangdongensis fruit body showed a trend of an initial increase followed by decrease. When the mass concentration of Na2SeO3 was 30 mg/kg, the biological conversion rate, AD content, and PS content all reached the highest values, indicating that this was the optimal mass concentration. In this case, the proportion of organic selenium was 100%, and there were 7 forms of selenium, namely SeMet, SeCys2, Se (IV), SeMeCys, Se (VI), and two unknown forms of selenium. Compared to the Cordyceps guangdongensis crude polysaccharide (CPS), the Se-enriched Cordyceps guangdongensis crude polysaccharide (CPS-Se) had higher in vitro antioxidant activities, i.e. the scavenging abilities towards the DPPH, ABTS+ and hydroxyl free radicals, the total reducing ability, and the total antioxidant ability were enhanced to different extents (P<0.01), showing good dose-dependence. This study provides a theoretical basis for the development of selenium-enriched Cordyceps guangdongensis products, and for further purification, identification, and activity verification of its polysaccharides.