ABSTRACT
<p><b>OBJECTIVE</b>To investigate the differences of total flavonoid (TF) content and antifree radical activity between the-leaves of bamboo and Gingo biloba, as well as their seasonal changes.</p><p><b>METHOD</b>Spectrophotometery and Chemiluminescence methods were adopted to determine TF and half inhibiting concentration (IC50) 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.</p><p><b>RESULT</b>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 IC50 values on O2-. and .OH of bamboo leaf were at 11.0 micrograms.mL-1 and 5.3 mg.mL-1, and Ginkgo biloba at 19.0 micrograms.mL-1 and 3.6 mg.mL-1, respectively.</p><p><b>CONCLUSION</b>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.</p>