Brunetti Luigi, Orlando Giustino, Menghini Luigi, Ferrante Claudio, Chiavaroli Annalisa, Vacca Michele
Department of Drug Sciences, G. D'Annunzio University, School of Pharmacy, Chieti, Italy.
Planta Med. 2006 Nov;72(14):1296-9. doi: 10.1055/s-2006-951688. Epub 2006 Oct 4.
Isoprostanes are prostaglandin (PG) isomers generated from oxygen radical peroxidation of arachidonic acid, which are reliable markers of membrane oxidative damage. Aging is characterized by an imbalance between the generation of reactive oxygen species and antioxidant detoxification pathways. Ginkgo biloba leaf extract is reputed as a neuroprotective antioxidant agent. We have tested the effects of a Ginkgo biloba extract {containing 24.1 % flavonoids and 181 % terpene lactones [bilobalide (0.542 %), ginkgolide A (0.570 %), ginkgolide B (0.293 %), ginkgolide C (0.263 %), and ginkgolide J (0.138 %)]} on the production of 8-iso-PGF2alpha from rat brain synaptosomes obtained from young (3 months old) or aged (12 and 24 months old) rats, both in the basal state and after oxidative stress induced by either hydrogen peroxide or amyloid beta-peptide. Our findings show that Ginkgo biloba extract pretreatment is able to completely reverse both basal and hydrogen peroxide-stimulated isoprostane production (IC50 of 81.92 microM and 31.89 microM, respectively). Amyloid beta-peptide-induced isoprostane production was also inhibited, both in young and aged rats, to a level even lower than that in unstimulated synaptosomes. This suggests that the oxygen radical scavenging properties of the Ginkgo biloba extract are fully effective in young, as well as in old rats, showing a greater inhibition of isoprostane production in the latter.
异前列腺素是由花生四烯酸的氧自由基过氧化反应生成的前列腺素（PG）异构体，是膜氧化损伤的可靠标志物。衰老的特征是活性氧生成与抗氧化解毒途径之间的失衡。银杏叶提取物被誉为一种神经保护抗氧化剂。我们测试了一种银杏叶提取物（含有24.1%的黄酮类化合物和181%的萜类内酯[白果内酯（0.542%）、银杏内酯A（0.570%）、银杏内酯B（0.293%）、银杏内酯C（0.263%）和银杏内酯J（0.138%）]）对从年轻（3个月大）或老年（12和24个月大）大鼠获得的大鼠脑突触体在基础状态下以及在过氧化氢或淀粉样β肽诱导的氧化应激后8-异前列腺素F2α生成的影响。我们的研究结果表明，银杏叶提取物预处理能够完全逆转基础状态和过氧化氢刺激下的异前列腺素生成（IC50分别为81.92 microM和31.89 microM）。在年轻和老年大鼠中，淀粉样β肽诱导的异前列腺素生成也受到抑制，抑制水平甚至低于未刺激的突触体。这表明银杏叶提取物的氧自由基清除特性在年轻大鼠和老年大鼠中均完全有效，且在老年大鼠中对异前列腺素生成的抑制作用更强。
