竹叶和银杏叶总黄酮含量及其抗自由基活性的比较研究

Comparison study on Total Flavonoid Content and Anti-free Redical Activity of the Leaves of Bamboo,phyllostachys nigra, and Ginkgo bilabo

目的 :研究竹叶和银杏叶黄酮含量和抗自由基活性的差异及季节性变化规律 ,以期为竹叶的开发提供依据。方法 :选取同一地块中生长的紫竹和银杏 ,逐月定时、定株、定量采集叶样 ,用硝酸铝 亚硝酸钠比色法测定总黄酮 (TF)含量 ,分别采用X XOD Luminol的O2 · 产生体系和VC Cu2 + H2 O2 酵母多糖的·OH产生体系 ,用化学发光法测定提取物清除活性氧自由基的能力。结果 :竹叶的TF全年变化在 0 .6 7%～ 1.71% (以叶干基计 ,下同 ) ,6月最低 ,7月最高 ,随后显著下降 ,11月至翌年 4月维持在较高的水平 (1.38%～ 1.5 6 % ) ;而银杏叶从 4月初抽芽至 11月下旬落叶 ,TF变化在 1.4 8%～ 2 .4 9% ,随着芽苞向成叶的渐进 ,TF逐渐提高 ,在 6 ,7月达到最大值 ,随后逐渐回落 ,至 11月下旬临落叶前又出现 1个高峰。竹叶对O2 ·和·OH的半抑制浓度 (IC50 )分别为 11.0 g·mL-1和 5 .3mg·mL-1,银杏叶为 19.0 g·mL-1和 3.6mg·mL-1。结论 :竹叶的总黄酮含量及其清除活性氧自由基的能力均与银杏叶具有可比性 。

Objective:To investigate the differences of total flavonoid (TF) content and antifree radical activity between theleaves of bamboo and Gingo biloba, as well as their seasonal changes. Method:Spectrophotometery and Chemiluminescence methods were adopted to determine TF and half inhibiting concentration (IC 50 ) on active oxygen free radicals of the leaves of bamboo, phyllostachys nigra (Lodd. ex.Lindl.) Munro, and Ginkgo biloba. Two kinds of leaves were picked in the same plot at the same time monthly.Result:The TF of bamboo leaf varied in the range of 0.67%～1.71% (in dry basis of leaf, below as same) throughout a year, the minimum apparing in June and the maximum in July, then going down obviously, and remaining at a much high lever during November to next April. However, the TF of Ginkgo bilabo leaf varied in 1.48%～2.49% during whole growing period, early April to late November. It ascended with the growth of leaf, reaching the top during June and July, the going down slowly, and finally another peak appeared before defoliation. The average IC 50 values on O 2 · and ·OH of bamboo leaf were at 11.0 μg·mL -1 and 5.3 mg·mL -1 , and Ginkgo biloba at 19.0 μg·mL -1 and 3.6 mg·mL -1 ,respectively.Conclusion:The TF content and anti free radical activity the bamboo leaf are comparable with the leaf of ginkgo biloba, which is a kind of potential resources for natural antioxidant and free radical scavenger.