Pincemail J, Thirion A, Dupuis M, Braquet P, Drieu K, Deby C
Experientia. 1987 Feb 15;43(2):181-4. doi: 10.1007/BF01942843.
A Ginkgo biloba extract (Gbe) containing flavonoids, among other compounds, was tested for the release of activated oxygen species (O-2, H2O2, OH.) during the stimulation of human neutrophils (PMNs) by a soluble agonist. The extract slows down O2 consumption (respiratory burst) of stimulated cells by its inhibitory action on NADPH-oxidase, the enzyme responsible for the reduction of O2 to O-2. Consequently, superoxide anion (O-.2) and hydrogen peroxide (H2O2) production is significantly decreased when the PMNs stimulation is done in the presence of the extract at concentrations of 500, 250 and 125 micrograms/ml. Moreover, the hydroxyl radical generation (OH.) is very much decreased at concentrations as low as 15.6 micrograms Gbe/ml, which indicates that the extract also has free radical scavenging activity. Gbe is able at least to reduce very severely the activity of myeloperoxidase contained in neutrophils. This enzyme, secreted into the intra and extracellular medium, catalyzes the oxidation of chloride (Cl-) by H2O2 to yield strong oxidants (HOCl, chloramines) which are implicated in inflammatory processes.
一种含有黄酮类化合物及其他成分的银杏叶提取物（Gbe），在可溶性激动剂刺激人中性粒细胞（PMN）过程中，被检测其活性氧物质（O₂、H₂O₂、OH·）的释放情况。该提取物通过对NADPH氧化酶（负责将O₂还原为O₂⁻的酶）的抑制作用，减缓受刺激细胞的O₂消耗（呼吸爆发）。因此，当在浓度为500、250和125微克/毫升的提取物存在下刺激PMN时，超氧阴离子（O₂⁻）和过氧化氢（H₂O₂）的产生显著减少。此外，在低至15.6微克Gbe/毫升的浓度下，羟基自由基的生成（OH·）也大幅减少，这表明该提取物还具有自由基清除活性。Gbe至少能够非常严重地降低中性粒细胞中所含髓过氧化物酶的活性。这种酶分泌到细胞内和细胞外介质中，催化H₂O₂将氯离子（Cl⁻）氧化生成强氧化剂（HOCl、氯胺），这些强氧化剂与炎症过程有关。
