Department of Organic Chemistry, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.
Pharm Biol. 2012 Feb;50(2):141-6. doi: 10.3109/13880209.2011.579618.
Millettia barteri (Benth.) Dunn (Fabaceae) is an African medicinal plant used in folk medicine to treat many diseases. This species, as well as other Mellettia species, has been of interest to researchers because of their wide range of traditional uses.
Phytochemical, antimicrobial and 2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH)-radical scavenging investigations of the hexane and EtOAc extracts of the stem bark of M. barteri were carried out here for the first time.
The isolation of compounds was done through silica gel column chromatography and their structures were established using spectroscopic analysis, especially, 1D NMR in conjunction with 2D experiments (COSY, HMQC and HMBC), and physical data compared with literature values. The broth micro dilution method was used for antimicrobial test while DPPH radical scavenging assay was used for antioxidant test.
Seven compounds, including two guanidine alkaloids: millaurine (2) and milletonine (7); one flavonoid: afzelin (6); four sterols: β-sitosterol (1), β-sitosterol glucoside (3), mixture of stigmasterol (4) and β-sitosterol (5) palmitates have been isolated from stem bark of hexane and ethyl acetate extracts of M. barteri. These extracts showed antimicrobial activity on the set of germs tested with minimum inhibitory concentration values varying from 64 to 512 µg/mL, as well as antioxidant activity (IC50 62.74 and 77.23 µg/mL). Compounds 2 and 7, tested for the first time, demonstrated antimicrobial and antioxidant activities.
The present study clearly demonstrated that M. barteri and some of its isolates possess antimicrobial and antioxidant properties and may act as potential antioxidant for biological systems susceptible to free radical-mediated reactions.
密花豆（Benth.）邓恩（豆科）是一种非洲药用植物，在民间医学中用于治疗许多疾病。由于其广泛的传统用途，该物种以及其他密花豆属物种一直引起研究人员的兴趣。
首次对密花豆茎皮的正己烷和乙酸乙酯提取物进行了植物化学、抗菌和 2,2-二苯基-1-苦基肼水合物（DPPH）自由基清除研究。
通过硅胶柱色谱法分离化合物，并通过光谱分析，特别是 1D NMR 与 2D 实验（COSY、HMQC 和 HMBC）相结合，以及与文献值比较物理数据来确定其结构。肉汤微量稀释法用于抗菌试验，DPPH 自由基清除试验用于抗氧化试验。
从密花豆茎皮的正己烷和乙酸乙酯提取物中分离得到了 7 种化合物，包括 2 种胍生物碱：米劳宁（2）和米列通宁（7）；1 种类黄酮：阿夫泽林（6）；4 种甾醇：β-谷甾醇（1）、β-谷甾醇葡萄糖苷（3）、混合物豆甾醇（4）和 β-谷甾醇（5）棕榈酸酯。这些提取物对所测试的一组细菌表现出抗菌活性，最小抑菌浓度值从 64 到 512μg/mL 不等，同时还具有抗氧化活性（IC50 为 62.74 和 77.23μg/mL）。首次测试的化合物 2 和 7 表现出抗菌和抗氧化活性。
本研究清楚地表明，密花豆及其一些分离物具有抗菌和抗氧化特性，可能作为易受自由基介导反应影响的生物系统的潜在抗氧化剂。
