Zhao Shuheng, Wu Xulong, Duan Xiaoyu, Zhou Caixia, Zhao Zhiqiao, Chen Hui, Tang Zizhong, Wan Yujun, Xiao Yirong, Chen Hong
College of Life Sciences, Sichuan Agricultural University, Ya'an, China.
Chengdu Agricultural College, Chengdu, China.
PeerJ. 2021 Apr 9;9:e11223. doi: 10.7717/peerj.11223. eCollection 2021.
Flavonoids are widely used in the market because of their antibacterial, antiviral, and antioxidant activities. But the production speed of flavonoids is limited by the growth of plants. CBL9 () is a flavonoid-producing endophytic fungi from H. Lév, which has potential to produce flavonoids.
In this study, we isolated total flavonoids from endophytic fungus CBL9 of H. Lév using macroporous resin D101. The process was optimized by response surface and the best extraction process was obtained. The antioxidant activities of total flavonoids were analyzed in vitro.
It was found that the best parameters were 25 °C pH 2.80, 1.85 h, and the adsorption ratio reached (64.14 ± 0.04)%. A total of 60% ethanol was the best elution solvent. The elution ratio of total flavonoid reached to (81.54 ± 0.03)%, and the purity was 7.13%, which was increased by 14.55 times compared with the original fermentation broth. Moreover its purity could rise to 13.69% after precipitated by ethanol, which is very close to 14.10% prepared by ethyl acetate extraction. In the antioxidant research, the clearance ratio of L9F-M on DPPH, ABTS, •OH, •O, (96.44 ± 0.04)% and (75.33 ± 0.03)%, (73.79 ± 0.02)%, (31.14 ± 0.01)% at maximum mass concentration, was higher than L9F.
The result indicated using macroporous resin in the extraction of total flavonoid from endophytic fungus is better than organic solvents with higher extraction ratio, safety and lower cost. In vitro testing indicated that the flavonoid extracted by macroporous resin have good antioxidant activity, providing more evidence for the production of flavonoid by biological fermentation method.
黄酮类化合物因其抗菌、抗病毒和抗氧化活性而在市场上被广泛应用。但黄酮类化合物的生产速度受植物生长限制。CBL9（）是一种从海南龙血树中分离得到的产黄酮类化合物的内生真菌，具有生产黄酮类化合物的潜力。
本研究采用大孔树脂D101从海南龙血树内生真菌CBL9中分离总黄酮。通过响应面法对工艺进行优化，得到最佳提取工艺。体外分析总黄酮的抗氧化活性。
发现最佳参数为25℃、pH 2.80、1.85 h，吸附率达到（64.14±0.04）%。体积分数60%的乙醇是最佳洗脱溶剂。总黄酮洗脱率达到（81.54±0.03）%，纯度为7.13%，与原始发酵液相比提高了14.55倍。此外，经乙醇沉淀后其纯度可升至13.69%，与乙酸乙酯萃取法制备的14.10%非常接近。在抗氧化研究中，最大质量浓度下L9F-M对DPPH、ABTS、•OH、•O的清除率分别为（96.44±0.04）%、（75.33±0.03）%、（73.79±0.02）%、（31.14±0.01）%，高于L9F。
结果表明，大孔树脂用于内生真菌总黄酮的提取优于有机溶剂，提取率高、安全性好且成本低。体外试验表明，大孔树脂提取的黄酮类化合物具有良好的抗氧化活性，为生物发酵法生产黄酮类化合物提供了更多证据。
