栓皮栎橡子壳多酚的体外抗氧化与抑菌活性研究

In Vitro Antioxidative and Antibacterial Activities of Polyphenols in Quercus variabilis Bl. Acorn Shell

摘要:

为开发橡子壳功能成分，采用溶剂萃取、化学定性、光谱分析及体外清除自由基、抑菌试验探索了秦巴山区栓皮栎橡子壳多酚的功能特性。结果表明：橡子壳可提取4.39%的粗多酚，经乙酸乙酯、正丁醇和水萃取分离可得到3类萃取物，经紫外光谱和红外光谱分析表明均含有酚羟基、羰基、芳烃C=C骨架、C-H键和C-O-C键结构，为多酚类物质；HPLC分析表明乙酸乙酯萃取物以鞣花酸为主，含有4种多酚，正丁醇萃取物中含阿魏酸、鞣花酸、没食子酸、表没食子酸儿茶素、儿茶素、绿原酸、表儿茶素、原儿茶酸、咖啡酸、表儿茶素没食子酸酯、山奈酚等11种酚类物质，水萃取物以阿魏酸含量最高，含4种多酚；体外清除DPPH·能力为Vc>水萃取物>正丁醇萃取物>粗提物>乙酸乙酯萃取物，清除ABTS+·能力为Vc>正丁醇萃取物>水萃取物>乙酸乙酯萃取物>粗提物，清除·OH能力为Vc>水萃取物>粗提物>正丁醇萃取物>乙酸乙酯萃取物；粗提物及溶剂萃取物均对金黄色葡萄球菌、单增李斯特菌、大肠杆菌和沙门氏菌具有不同程度抑制活性，抑菌能力为乙酸乙酯萃取物>正丁醇萃取物>粗提取物>水萃取物。证明橡子壳多酚含量高，种类多，具有较强抗氧化和广谱抑菌活性。

Abstract:

In order to develop the functional ingredients from acorn shell, the functional characteristics of polyphenols in Quercus variabilis Bl. acorn shell from the Qinba Mountain area in China were investigated by solvent extraction, chemical qualitative analysis, spectral analysis, in vitro free radical scavenging assay and antibacterial activity analysis. The results showed that crude polyphenol extract (up to 4.39%) could be obtained from the acorn shell. The crude extract was further separated into three fractions by ethyl acetate, n-butanol and water extractions, which were all proven to be polyphenols containing phenolic hydroxyl group, carbonyl group, aromatic C=C skeleton, C-H bond and C-O-C bond structure, by UV-vis and IR spectral analyses. The HPLC analysis showed that the ethyl acetate extract mainly had ellagic acid, containing 4 kinds of phenols. The n-butanol extract contained 11 kinds of phenols such as ferulic acid, ellagic acid, gallic acid, epigallocatechin gallate, catechin, chlorogenic acid, epicatechin, protocatechuic acid, caffeic acid, epicatechin gallate and kaempferol. The water extract had the highest content of ferulic acid, along with 4 kinds of phenols. The DPPH free radical scavenging capacity was in the order of Vc>water extract>n-butanol extract>crude extract>ethyl acetate extract. The ABTS+ free radical scavenging capacity was in the order of Vc> n-butanol extract>water extract>ethyl acetate extract>crude extractive. The hydroxyl free radical scavenging capacity was in the order of Vc>water extract>crude extract>n-butanol extract>water extract. The crude extract and its derived three fractions exhibited different degrees of antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli and Salmonella i.e. ethyl acetate extract>n-butanol extract>crude extract>water extract. These results indicated that the acorn shell is rich in polyphenols, and the polyphenols belong to different classes and exhibit strong antioxidant activities and broad-spectrum antibacterial activities.