苦笋壳提取物不同极性相抗氧化与降血糖活性研究

研究苦笋壳不同提取相的抗氧化作用和对α-葡萄糖苷酶和α-淀粉酶的活性抑制作用。以70%(体积分数)乙醇和水分别对苦笋壳进行提取,并测定提取物中的黄酮、总酚及总糖含量。以ABTS阳离子自由基、DPPH自由基、·OH清除能力、铁离子抗氧化能力(ferric reducing ability of plasma,FRAP)等方法评价其抗氧化活性,测定乙酸乙酯、正丁醇、石油醚3种萃取相对α-葡萄糖苷酶和α-淀粉酶的抑制活性。结果表明,水提方式总糖含量为(97.3±0.28)%,高于醇提方式。总酚和黄酮含量在醇提相中较高,分别是(28.53±1.67)%和(27.22±2.02)%。从对α-葡萄糖苷酶抑制活性上看,醇提相大于水提相。醇提方式下抗氧化活性:乙酸乙酯相>正丁醇相>石油醚相,乙酸乙酯相对·OH清除能力可达(67.32±1.57)%,乙酸乙酯相对α-葡萄糖苷酶和α-淀粉酶的抑制活性最强,IC₅₀值分别是(0.158±0.003)、(0.104±0.006)mg/mL,酶抑制动力学结果表明苦笋壳乙酸乙酯相对α-葡萄糖苷酶抑制类型为竞争性抑制类型,对α-淀粉酶抑制类型为非竞争性抑制类型。苦笋壳可用于开发降血糖产品的天然资源。

Antioxidant and hypoglycemic activities of different polar phases of bitter bamboo shoot husk extract

To study the antioxidant effects of different extraction phases of bitter bamboo shoots shells and their inhibitory effects onα-glucosidase andα-amylase activities,the bitter bamboo shoots shells were extracted with 70%ethanol and water,and the flavonoids,total phenols,and total sugars in the extract were determined.The antioxidant activity was evaluated by radical ion ABTS⁺,DPPH·,·OH scavenging ability and FRAP antioxidant capacity.The inhibitory activities of ethyl acetate,n-butyl alcohol and petroleum ether againstα-glucosidase andα-amylase were determined.The results showed that the total sugar content of water extraction was higher(97.3±0.28)%than that of alcohol extraction.The contents of total phenols and flavonoids in the alcohol extraction phase were(28.53±1.67)%and(27.22±2.02)%,respectively.In terms of the inhibitory activity ofα-glucosidase,the alcohol extraction phase was higher than the water extraction phase.The antioxidant activity under alcohol extraction was as follows:ethyl acetate phase>n-butyl alcohol phase>petroleum ether phase.The ethyl acetate relative·OH scavenging ability reached(67.32±1.57)%,the ethyl acetate had the strongest inhibitory activity toα-glucosidase andα-amylase(IC₅₀ value was(0.158±0.003)and(0.104±0.006)mg/mL,respectively).The kinetic results of the inhibition of bitter bamboo shoots shells:protease phase was competitive inhibition type relative toα-glucosidase inhibition type,and non-competitive inhibition type toα-amylase inhibition type.Bitter bamboo shoots shells can become a natural resource for the development of hypoglycemic products.