胁迫条件对一土生青霉菌总酚积累及其清除自由基能力的影响

旨在阐明胁迫条件对一土生青霉菌总酚积累及其抗氧化活性的影响。采用固体培养基培养青霉菌,以紫外线辐射、添加H2O2水溶液和降低培养基营养物质含量作为胁迫手段,检测受到胁迫后,菌体总酚的积累及酚类清除自由基的能力。菌丝体总酚含量以Folin-Ciocalteu法测定,自由基清除率以分光光度法测定。结果表明,在胁迫条件下,各实验组菌丝体的总酚含量较对照组均有显著提高,添加H2O2组的总酚含量最高达63.86mg/g,紫外线辐射组的总酚含量最高达58.4mg/g,营养胁迫组的总酚含量最高达43.19mg/g。各实验组酚类提取物对羟自由基的清除率最高,其中添加1mmol/LH2O2组为35.28%,紫外线辐射40s组为69.97%,75%营养胁迫组为50.83%。因此,胁迫条件可增加该青霉合成酚类化合物及提高其抵抗胁迫的能力。

The effects of stressed conditions on the accumulation of phenolic compounds by Penicillium sp. No. T4 and their subsequent antioxidant activities

This study was designed to evaluate the effects of stress conditions on the accumulation of phenolic compounds by Penicillium sp. No. T4 in solid substrate and their subsequent antioxidant activities. H2O2, ultraviolet and medium of nutrition deficiency were used as oxidative stressors. Phenol levels were measured using Folin-Ciocalteu method. Capacities for scavenging free radicals were detected by spectrophotometric methods. The exposure of Penicillium sp. No. T4 to H2O2, at 1mmol/L or ultraviolet radiation for 40s and 50% nutrition deficiency substrate resulted in a higher production of phenolic compounds as compared with control, with levels reaching 63.86mg/g, 58.4mg/g and 43.19mg/g, respectively. Extracts from mycelia grown under stress conditions showed higher capacities for scavenging hydroxyl radical than other free radical, with a scavenging rate of 35.28% by the phenolic compounds from mycelia grown in 1mmol/L H2O2, 69.97% by those from mycelia under 40s ultraviolet radiation and 50.83% by those from mycelia under 75% medium nutrition deficiency. The results suggest that Penicillium sp. No. T4 accumulates more phenolic compounds under oxidative stresses and thereby enhances its resistance to oxidative stresses.