A series of flavonoids isolated from Indian medicinal plants: kaempferol-3-O-galactoside, hispidulin, nepetin, scutellarein, scutellarein-7-O-glucuronide, hibifolin and morelloflavone were studied for their activity as inhibitors of microsomal lipid peroxidation and scavengers of oxygen free radicals in vitro as well as in a model of xenobiotic toxicity in mouse. 2. All compounds inhibited lipid peroxidation in vitro. The most potent compounds were nepetin (non-enzymic lipid peroxidation) and morelloflavone (enzymic lipid peroxidation) with IC50's in the micromolar range. Some of the compounds behaved as scavengers of hydroxyl radical in the deoxyribose degradation assay, with a calculated rate constant for kaempferol-3-O-galactoside of 1.55 x 10(10) M-1 s-1. 3. Scutellarein and nepetin were found to be inhibitors of xanthine oxidase activity, whereas morelloflavone acted as a scavenger of superoxide generated by hypoxanthine/xanthine oxidase. 4. Treatment of mice with scutellarein, hispidulin, nepetin and kaempferol-3-O-galactoside after bromobenzene intoxication decreased serum glumate-pyruvate transaminase activity, although only the last flavonoid was able to significantly reduce hepatic lipid peroxidation products and to increase the reduced glutathione level. In contrast, morelloflavone increased bromobenzene toxicity.
摘要
对从印度药用植物中分离出的一系列黄酮类化合物进行了研究，这些化合物包括山奈酚 - 3 - O - 半乳糖苷、圣草酚、尼泊尔黄酮素、黄芩素、黄芩素 - 7 - O - 葡萄糖醛酸苷、紫锦草素和桑黄黄酮，考察了它们在体外作为微粒体脂质过氧化抑制剂和氧自由基清除剂的活性，以及在小鼠异源物毒性模型中的作用。2. 所有化合物在体外均能抑制脂质过氧化。最有效的化合物是尼泊尔黄酮素（非酶促脂质过氧化）和桑黄黄酮（酶促脂质过氧化），其IC50值在微摩尔范围内。在脱氧核糖降解试验中，一些化合物表现为羟基自由基清除剂，山奈酚 - 3 - O - 半乳糖苷的计算速率常数为1.55×10(10) M-1 s-1。3. 发现黄芩素和尼泊尔黄酮素是黄嘌呤氧化酶活性的抑制剂，而桑黄黄酮则作为次黄嘌呤/黄嘌呤氧化酶产生的超氧阴离子的清除剂。4. 在溴苯中毒后，用黄芩素、圣草酚、尼泊尔黄酮素和山奈酚 - 3 - O - 半乳糖苷处理小鼠可降低血清谷丙转氨酶活性，尽管只有最后一种黄酮类化合物能够显著降低肝脏脂质过氧化产物并提高还原型谷胱甘肽水平。相比之下，桑黄黄酮增加了溴苯的毒性。
