弯萼金丝桃总黄酮提取及抗氧化、降糖活性

摘要：为获得弯萼金丝桃总黄酮（TF）最佳提取工艺及抗氧化活性、降糖活性，探究5种提取工艺(超声辅助提取、酸解提取、酶解提取、热水提取、热醇提取)对TF提取量的影响，通过单因素和响应面实验优化提取工艺。采用高效液相色谱(HPLC)测定并分析7种主要黄酮苷元的分布及含量，并进一步研究TF与体外抗氧化活性（DPPH?清除能力、ABTS自由基清除能力、羟基自由基清除能力、还原能力）的相关性及对α-葡萄糖苷酶的体外降糖能力。结果表明，超声辅助提取TF提取量最高。响应面优化最佳提取工艺为：温度68 ℃，时间23 min、乙醇体积分数24 %、液料比63:1 mL/g，在该条件下，TF提取量为34.85 mg RT/g（以每克弯萼金丝桃中黄酮类化合物相当于芦丁RT质量表示）；高效液相色谱法分别鉴定出TF中7种主要黄酮类化合物，其中TF中含量最高的黄酮化合物为槲皮素-3-O-洋槐糖-7-0-鼠李糖苷、槲皮素，分别为3.897 mg/g、2.874 mg/g；TF质量浓度与DPPH?清除能力、ABTS自由基清除能力、羟基自由基清除能力、还原能力呈显著正相关，对α-葡萄糖苷酶的降糖能力可达到92.6 %。

Extraction and antioxidant and hypoglycemic activity of total flavonoids from Hypericum benthamii

In order to obtain the best extraction process of flavonoids (TF) and antioxidant activity, hypoglycemic activity, explore the influence of five extraction process on the TF extraction(Ultrasound-assisted extraction, acid extraction, enzymatic extraction, hot water extraction, hot alcohol extraction), optimized the extraction process through single factor experiment and response surface experiment; determination and analysis of the distribution and contents of seven major flavonoid glycosides by HPLC;and further study the correlation between TF and in vitro antioxidant activity (DPPH clearance ability, ABTS radical clearance ability, hydroxyl radical scavenging ability, reducing ability) and in vitro glucose reduction ability of α-glucosidase. The results showed that ultrasound-assisted extraction had the highest TF content, and the response surface was optimized for the best extraction process: temperature 68 ℃, time 23 min, ethanol volume fraction 24 %, liquid ratio 63:1 mL/g. Under this condition, the TF content was 34.85 mg RT/g (Equivalent rutin RT mass per gram of TF compound expressed); the HPLC identified 7 major flavonoids in TF, The most abundant flavonoid compounds in the TF were quercetin-3-O-palmitoyl-7-O-rhamnoside and quercetin with 3.897 mg/g and 2.874 mg/g; TF mass concentration and DPPH clearance capacity, ABTS radical scavenging ability, hydroxyl radical scavenging ability and reducing ability showed significantly positive correlation, and the hypoglycemic capacity of α-glucosidase could reach 92.6 %.