Centre for Drug Research, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
Molecules. 2009 Oct 9;14(10):3964-74. doi: 10.3390/molecules14103964.
Studies on the antioxidant and antimicrobial activities of Mitragyna speciosa leaf extracts are lacking. In this study the antioxidant properties of water, methanolic and alkaloid M. speciosa leaf extracts were evaluated using the DPPH (2,2-diphenyl-1- picrylhydrazyl) radical scavenging method. The amount of total phenolics and flavanoid contents were also estimated. The DPPH IC(50) values of the aqueous, alkaloid and methanolic extracts were 213.4, 104.81 and 37.08 microg/mL, respectively. The total phenolic content of the aqueous, alkaloid and methanolic extracts were 66.0 mg, 88.4, 105.6 mg GAE/g, respectively, while the total flavanoid were 28.2, 20.0 and 91.1 mg CAE/g respectively. The antioxidant activities were correlated with the total phenolic content. This result suggests that the relatively high antioxidant activity of the methanolic extract compared to aqueous and alkaloid extract could be possibly be due to its high phenolic content. The aqueous, alkaloid and methanolic extracts were screened for antimicrobial activity. The extracts showed antimicrobial activity against Salmonella typhi and Bacillus subtilis. The minimum inhibitory concentrations (MICs) of extracts determined by the broth dilution method ranged from 3.12 to 6.25 mg/mL. The alkaloid extract was found to be most effective against all of the tested organisms.
关于三叶苦树叶子提取物的抗氧化和抗菌活性的研究还很少。在这项研究中，使用 DPPH（2,2-二苯基-1-苦基肼）自由基清除法评估了水、甲醇和生物碱三叶苦树叶子提取物的抗氧化特性。还估计了总酚类和类黄酮含量。水提物、生物碱提物和甲醇提物的 DPPH IC50 值分别为 213.4、104.81 和 37.08μg/mL。水提物、生物碱提物和甲醇提物的总酚含量分别为 66.0、88.4 和 105.6mgGAE/g，总类黄酮含量分别为 28.2、20.0 和 91.1mgCAE/g。抗氧化活性与总酚含量相关。这一结果表明，与水提物和生物碱提物相比，甲醇提取物具有相对较高的抗氧化活性，这可能与其高酚含量有关。对水提物、生物碱提物和甲醇提物进行了抗菌活性筛选。提取物对伤寒沙门氏菌和枯草芽孢杆菌表现出抗菌活性。通过肉汤稀释法确定的提取物的最小抑菌浓度（MIC）范围为 3.12 至 6.25mg/mL。生物碱提取物对所有测试的生物都最有效。
