艾叶水提物和酸提物的抗氧化及抗菌活性比较

Comparetive of Antioxidat and Antibacterial Activities of Aqueous and Acidic Extracts from Artemisia argyi

为比较研究艾叶水提物和酸提物抗氧化及抗菌的作用。分别采用去离子水和柠檬酸溶液提取艾叶,得到两种提取物,测各自的总黄酮、总多酚和多糖含量;通过DPPH自由基、羟自由基及ABTS自由基来评价提取物的抗氧化能力;利用牛津杯法测定提取物的抑菌活性,并探讨其抑菌机制。结果表明:艾叶水提物中总黄酮、总多酚及多糖含量分别为208.03、51.77和398.72 mg/g,艾叶酸提物分别为80.39、25.44和453.45 mg/g。在一定浓度范围内,艾叶水提物和艾叶酸提物均有较强抗氧化能力,对DPPH自由基清除率的半数抑制浓度(median inhibition concentration,IC_(50))分别为33.10和54.52μg/mL;对羟自由基清除率的IC_(50)值分别为2.92和1.63 mg/mL;对ABTS自由基清除率的IC_(50)值分别为0.17和0.32 mg/mL。艾叶水提物无明显抑菌效果;但艾叶酸提物对金黄色葡萄球菌、志贺氏菌、沙门氏菌具有显著抑菌活性,最小抑菌浓度分别为0.10、0.10和0.20 g/mL。通过测定抑菌动力学、细胞膜通透性实验证实酸提物能有效抑制致病菌生长、改变细胞膜通透性;扫描电镜和聚丙烯酰胺凝胶电泳证实酸提物能破坏细菌细胞壁形态、抑制细菌的蛋白质合成。柠檬酸溶液提取法比水提法更适用于艾叶活性成分的提取,艾叶酸提物更具有食品防腐剂和抗氧化剂的潜力。

In order to compare the antioxidant and antibacterial effects of the aqueous extract and acidic extract of Artemisia argyi.Deionized water and citric acid solution were used to obtain two extracts from Artemisia argyi,and the contents of total flavonoids,total polyphenols and polysaccharides in these extracts were measured.The antioxidant capacity of each extract was evaluated by the DPPH,hydroxyl and ABTS radical scavenging assays.The Oxford cup method was used to determine the antibacterial activity of the extract and examine the underlying antibacterial mechanism.The results showed that the contents of total flavonoids,total polyphenols and polysaccharides were 208.03,51.77 and 398.72 mg/g,respectively,in the aqueous extract of Artemisia argyi,and 80.39,25.44 and 453.45 mg/g,respectively,in its acidic extract.Within a certain concentration range,both the aqueous extract and acidic extract of Artemisia argyi had strong antioxidant capacities,with their median inhibition concentration(IC50)values 33.10 and 54.52μg/mL,respectively,for DPPH radical,2.92 and 1.63 mg/mL,respectively for hydroxyl radical,0.17 and 0.32 mg/mL,respectively,for ABTS radical.The aqueous extract of Artemisia argyi exhibited insigficant antibacterial effect;whilst the acidic extract exerted significant antibacterial activity against Staphylococcus aureus,Shigella and Salmonella,with the minimum inhibitory concentration being 0.10,0.10 and 0.20 g/mL,respectively.The examinations of antibacterial kinetics and cell membrane permeability confirmed that the acidic extract could effectively inhibit the growth of pathogenic bacteria and change the cell membrane permeability.Scanning electron microscopy and polyacrylamide gel electrophoresis experiments revealed that the acidic extract can destroy the morphology of bacterial cell walls and inhibit bacterial protein synthesis.The extraction using the citric acid solution is more suitable for the extraction of the active ingredients from Artemisia argyi than the aqueous extraction,and the acidic extract has a greater potential as food preservatives and antioxidants.