铁苋菜不同极性萃取物的抗氧化及抑菌活性研究

Study on antioxidant and antibacterial activities of extracts from different polar Acalypha australis L.

采用1,1-二苯基-2-三硝基苯肼(DPPH)法、β-胡萝卜素漂白法和清除一氧化氮自由基(NO)法来测定不同极性铁苋菜萃取物的抗氧化活性;通过微孔比浊法比较铁苋菜萃取物对3种革兰氏阴性细菌(大肠杆菌、铜绿假单胞菌和幽门螺杆菌)和4种革兰氏阳性细菌(表皮葡萄球菌、枯草芽孢杆菌、藤黄微球菌和金黄色葡萄球菌)的抑菌效果。结果表明,铁苋菜不同极性萃取物均有较好的清除DPPH、NO自由基和抑制β-胡萝卜素漂白的效果,浓度为2.0mg/mL时,正丁醇萃取物清除DPPH自由基和抑制β-胡萝卜素漂白能力最佳,DPPH自由基清除率为94.60%,β-胡萝卜素抑制率为83.15%,乙酸乙酯萃取物清除NO自由基能力最强,清除率为82.72%。抑菌试验结果显示,铁苋菜各萃取物均有较好抑菌效果,对革兰氏阳性菌抑菌效果优于革兰氏阴性菌,其中石油醚萃取物对大肠杆菌、表皮葡萄球菌和金黄色葡萄球菌抑制作用最佳,MIC值分别为0.625,0.315,1.250mg/mL。铁苋菜萃取物具有较好的抗氧化及抑菌效果。

1,1-diphenyl-2-trinitrophenylhydrazine (DPPH) method,β-carotene bleaching method and nitric oxide (NO) method were used to determine the antioxidant activities of different extracts from Acalypha australis L.;All the extracts were evaluated for their bacteriostatic effect using microporous turbidimetry method, and three gram-negative bacteria: Escherichia coli , Pseudomonas aeruginosa , Helicobacter pylori and four gram-positive bacteria: Staphylococcus epidermidis , Bacillus subtilis , Micrococcus luteus , Staphylococcus aureus were determined in our research. The results showed all the extracts we determined had the activities of better scavenging DPPH, NO free radicals and inhibition of β-carotene bleaching. At the concentration was 2.0 mg/mL, the n-butanol extract had the strongest power to scavenge DPPH free radicals and inhibit β-carotene oxidation activity. The DPPH free radical scavenging rate was 94.60% and the β-carotene inhibition rate was 83.15%. Furthermore, the ethyl acetate extract had the strongest ability to scavenge NO radicals, and the clearance rate was 82.72%. In addition, the results of bacteriostatic experiments showed that all the extracts had good antibacterial effect, and its inhibitory effect against Gram-positive bacteria was higher than that of Gram-negative bacteria. Especially, the petroleum ether extract had the best inhibitory effect on Escherichia coli , Staphylococcus epidermidis and Staphylococcus aureus , and the minimum inhibitory concentration (MIC) values were 0.625, 0.315 and 1.250 mg/mL , respectively. In conclusion, the extracts of Acalypha australis L. have better anti-oxidation and antibacterial effects and this research was profitable for the further study of the separation of avtive compounds from Acalypha australis L..