The Ginkgo biloba extract, EGb 761, fails to reduce brain infarct size in rats after transient, middle cerebral artery occlusion in conditions of unprevented, ischemia‐induced fever

Abstract

There is much biochemical evidence, but very few studies in animal models of stroke in vivo, to suggest that Ginkgo biloba (EGb 761) may offer neuroprotection against regional, ischemic brain damage; additional investigations are needed to ensure future clinical trials. This study reports the effects of EGb 761 given acutely or chronically before ischemia. Rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h and the brain infarct size was assessed 24 h later. Dipyrone (100 mg/kg, i.p.) was injected 30 min before ischemia, and 2.5 and 5.5 h after ischemia, to reduce ischemia-induced fever. EGb 761 (Tebonin) was given acutely (200 mg/kg, p.o., 60 min before ischemia) or chronically (100 mg/kg, p.o., once daily, for 14 days before ischemia). Acute or chronic treatment with EGb 761, either alone or in combination with dipyrone, did not reduce the infarct size compared with saline alone (p > 0.05). Dipyrone failed to prevent ischemia-induced fever during the intra-ischemic period (p > 0.05 vs saline; p < 0.001 vs sham). In the reperfusion phase, dipyrone reduced fever to normothermic levels in the group treated acutely with EGb 761 (p < 0.01 vs saline, p > 0.05 vs sham) but not after chronic EGb 761 (p < 0.01 vs sham), indicating possible pharmacokinetic interaction. In conclusion, within the context of unprevented, ischemia-induced fever, the present results demonstrate that EGb 761 has no significant effect on brain infarct size.

Mitochondria- and Oxidative Stress-Targeting Substances in Cognitive Decline-Related Disorders: From Molecular Mechanisms to Clinical Evidence

“…[42]. Most toxicological, pharmacological, and clinical investigations have focused on the neuroprotective value of two main standardized extracts labeled EGb761 and LI 1370 [43–45]. The EGb761 extract consists of 24% flavone glycosides (mainly quercetin, kaempferol, and isorhamnetin) and 6% terpene lactones (2.8-3.4% ginkgolides A, B, and C and 2.6-3.2% bilobalide), while the extract LI 1370 is composed of 25% ginkgo flavone glycosides as well as 6% terpenoids.…”

Pharmacokinetic and ocular microdialysis study of oral ginkgo biloba extract in rabbits by UPLC-MS/MS determination

“…Ginkgolides, including A, B, C and J, are the potent and specific antagonists in platelet activating factor, [1,2] that is believed to act as a neuro-protectant. [3][4][5] In recent years, standardized extract of ginkgo leaf is nearly the top-selling herbal drug in the world [6] and the products of GBE have widely been used in botanical medicines and dietary supplements, especially for the prevention and treatment of cardiovascular disease and cerebral insufficiency. [7][8][9][10][11] From a theoretical point, the pharmacological properties of GBE could be expectedly beneficial for the eye as well.…”

“…GT consists of a triterpenoid (bilobalide) and three interpenetrates (ginkgolide). Ginkgolides, including A, B, C and J, are the potent and specific antagonists in platelet activating factor, that is believed to act as a neuro‐protectant . In recent years, standardized extract of ginkgo leaf is nearly the top‐selling herbal drug in the world and the products of GBE have widely been used in botanical medicines and dietary supplements, especially for the prevention and treatment of cardiovascular disease and cerebral insufficiency …”