纤维素酶辅助提取沉香叶黄酮及其抗氧化活性测定

Cellulase-assisted extraction and antioxidant activity of fl avonoids from aloes leaves

以黄酮得率为评价指标,利用纤维素酶辅助乙醇提取法从沉香叶中提取黄酮,在单因素的基础上,选取乙醇浓度、温度、p H、底物质量浓度4因素,运用正交试验设计优化提取工艺;采用DPPH自由基法、ABTS自由基法测定沉香叶黄酮的抗氧化活性。结果表明,沉香叶黄酮的提取工艺为:乙醇浓度70%(v/v)、酶解温度55℃、酶解p H5、酶添加量200 U/g,底物质量浓度3 g/100 m L,酶解时间3 h,此条件下沉香叶黄酮的得率为3.86%(w/w);沉香叶黄酮提取物具有较强的清除DPPH自由基和ABTS自由基能力,其IC50值分别为0.17、0.18 mg/m L。

The present study was carried out to obtain the optimal process conditions for extracting the maximum amount of fl avonoids from aloes leaves. For the extraction of fl avonoids, dried and powdered aloes leaves was refluxed with aqueous ethanol following hydrolysis with cellulase. Based on single factor test, an orthogonal design experimental was adopted to optimize extraction process, including dependent four variables（ethanol concentration, extraction temperature, p H and substrate concentration）. Antioxidant activities of fl avonoids from aloes leaves were evaluated by two different methods, such as DPPH and ABTS radical scavenging assay. The results showed that the optimum fl avonoids extraction conditions were obtained as follows： the extraction solvent 70% ethanol（v/v）, the added ratio of cellulose 200 U/g, the extraction temperature 55 ℃, p H value 5, time 3 h and the substrate concentration 3 g/100 m L. Under these conditions, the yield of fl avonoids was 3.86%（w/w）. And the experiments of antioxidant activity showed that the extracted fl avonoids presented the strong antioxidant activity to the DPPH and ABTS radical, and the IC50 was 0.17 mg/m L and 0.18 mg/m L, respectively.