cardiovascular-agents and bilobalide

A sensitive LC-ESI-MS method with a solid-phase extraction was established for the determination of bilobalide, ginkgolide A and ginkgolide B in human plasma; bioavailability and pharmacokinetics of three different Ginkgo biloba L. preparations have been investigated. The preparations used in the present single-dose pharmacokinetic study were different formulations of Ginkgo biloba L. extracts (Geriaforce tincture, new Ginkgo fresh plant extract tablets and EGb 761) with various excipients. The analysis of Ginkgo terpene lactones was performed by LC-MS on a Zorbax SB-C18 column. The mobile phase consisted of water + 0.1% acetic acid and methanol 68/32 (v/v) to 49/51 (v/v) at a flow rate of 200 microL/min. Bilobalide, ginkgolide A and ginkgolide B were monitored using the selected-ion monitoring (SIM) mode at m/z of 325, 453 and 423, respectively.The amounts of the active compounds (terpene lactones) in the administered products were in the low-mg range per dose. The assay method was successfully applied to the study of the pharmacokinetics and bioavailability of bilobalide, ginkgolide A and ginkgolide B in humans. The resulting maximum concentrations (median) of bilobalide, ginkgolide A and ginkgolide B in plasma after administration of the maximum daily dose of the different Ginkgo products were 3.53, 3.62, and 1.38 ng/mL respectively after administration of Geriaforce tincture; 11.68, 7.36, and 4.18 ng/mL, respectively after taking Ginkgo fresh plant extract tablets; and 26.85, 16.44, 9.99 ng/mL, respectively after administration of EGb 761 tablets. These data are relevant to demonstrate relative bioavailabilities of different Ginkgo biloba L. preparations (Geriaforce tincture, new Ginkgo fresh plant extract tablets and EGb 761).

Topics: Adult; Biological Availability; Cardiovascular Agents; Chromatography, High Pressure Liquid; Cyclopentanes; Female; Furans; Ginkgo biloba; Ginkgolides; Humans; Lactones; Male; Mass Spectrometry; Phytotherapy; Plant Extracts; Tablets; Young Adult

Vascular diseases like thrombosis, myocardial infarction, cerebral ischemia or chronic venous insufficiency affect a high proportion of the population. They are all associated with more or less pronounced ischemic conditions. We have previously shown that some venotropic drugs display an anti-ischemic activity, i.e. they prevent the hypoxia-induced decrease in ATP content in cultured cells. The effect is due to the fact that these molecules maintain mitochondrial respiratory activity during hypoxia. Among them is bilobalide. Starting from the 3D structure of bilobalide, we designed new molecules presenting the same chemical features. They were synthesized and tested for their biological activity. As the parent compound, two of them, malonic acid dicyclopent-2-enyl ester (MRC2P119) and 2-oxo-3-oxa-bicyclo[3.1.0]hexane-1-carboxylic acid allyl ester (MRC2P57), were able to markedly increase the respiratory control ratio of isolated mitochondria. They are able to prevent the inhibition of complex I by amytal and of complex III by myxothiazol, but not the uncoupling of the respiration by carbonylcyanide m-chlorophenyl hydrazone (m-CCP). Moreover, MRC2P119 and MRCP2P57 inhibit, in a dose-dependent way, the hypoxia-induced decrease in ATP content in endothelial cells as well as the subsequent activation of these cells as evidenced by an inhibition of the increase in neutrophil adherence to the endothelial cells induced by hypoxia. Finally, MRC2P119 prevent the hypoxia- and the hypoxia-reoxygenation-induced decrease in viability of SH-SY5Y neuroblastoma cells. In conclusion, we identified two new molecules, which display anti-ischemic properties when tested in vitro on endothelial and neuronal cell types. This anti-ischemic activity is probably due to a protection of complexes I and III of the mitochondrial respiratory chain.

Topics: Adenosine Triphosphate; Animals; Bridged Bicyclo Compounds; Cardiovascular Agents; Cell Adhesion; Cell Hypoxia; Cell Survival; Cells, Cultured; Cyclopentanes; Diterpenes; Dose-Response Relationship, Drug; Electron Transport; Esters; Female; Furans; Ginkgolides; Humans; Ischemia; Malonates; Mitochondria, Liver; Neutrophils; Oxygen Consumption; Rats; Rats, Wistar; Structure-Activity Relationship; Tumor Cells, Cultured