School of Forestry and Resource Conservation, National Taiwan University, Taipei 106, Taiwan.
J Agric Food Chem. 2010 Feb 10;58(3):1578-83. doi: 10.1021/jf903569k.
This study investigates bioactivities and active phytochemicals of the extracts of twigs and branches from the indigenous Taiwanese tree Acacia confusa Merr. The bioassay-guided fractionation yielded 8 potent antioxidative phytochemicals. Catechins are the major components in the extract of 5 cm branch bark, including catechin, catechin-3-O-rhamnopyranoside, epi-catechin, and quercetin-3-O-rhamnopyranoside, while flavonol glycosides are the major components in twig extract, namely, myricetin-3-O-glucopyranoside, myricetin-3-O-rhamnopyranoside, quercetin-3-O-rhamnopyranoside, myricetin-3-O-(2''-O-galloyl)-alpha-rhamnopyranoside, and luteolin. Of the test compounds, myricetin-3-O-(2''-O-galloyl)-alpha-rhamnopyranoside exhibited the highest antioxidant activity against DPPH radicals, showing a 2.8-fold lower IC(50) value of 5.3 microM related to that of quercetin. On the other hand, catechins apparently had no XOD inhibitory effect apart from their good antioxidant activities, while luteolin exhibited excellent activity against XOD with an IC(50) value of 11.6 microM. These results may provide useful information for future studies on the applications of A. confusa to be used as a source for natural health products.
本研究调查了台湾乡土树种相思树的嫩枝和小枝提取物的生物活性和活性植物化学物质。生物测定指导的分段得到了 8 种具有强大抗氧化活性的植物化学物质。在 5 厘米树枝皮提取物中，儿茶素是主要成分，包括儿茶素、儿茶素-3-O-鼠李糖苷、表儿茶素和槲皮素-3-O-鼠李糖苷，而在嫩枝提取物中，黄酮醇糖苷是主要成分，即杨梅素-3-O-吡喃葡萄糖苷、杨梅素-3-O-鼠李糖苷、槲皮素-3-O-鼠李糖苷、杨梅素-3-O-(2''-O-没食子酰基)-α-鼠李糖苷和木樨草素。在测试的化合物中，杨梅素-3-O-(2''-O-没食子酰基)-α-鼠李糖苷对 DPPH 自由基表现出最强的抗氧化活性，其 IC50 值为 5.3 μM，与槲皮素相比降低了 2.8 倍。另一方面，儿茶素除了具有良好的抗氧化活性外，显然对 XOD 没有抑制作用，而木樨草素对 XOD 表现出极好的活性，IC50 值为 11.6 μM。这些结果可能为未来将相思树作为天然保健品的应用研究提供有用的信息。
