Submitted to: Journal of Ethnopharmacology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 4/11/2006
Publication Date: 10/1/2006
Citation: Son, D-J., Lim, Y., Park, Y-H., Chang, S-K, Yun, Y-P., Hong, J-T., Takeoka, G.R., Lee, K-G., Lee, S-E, Kim, M-R., Kim, J-H, Park, B-S. 2006. Inhibitory effects of tabebuia impetiginosa inner bark extract on platelet aggregation and vascular smooth muscle cell proliferation through suppressions of arachidonic acid liberation and ERK1/2 MAPK activation. Journal of Ethnopharmacology. 108(1):148-151. Interpretive Summary: Cardiovascular diseases are the leading cause of death in developed countries and are progressively increasing their impact on mortality in developing countries despite changes in lifestyle and the use of preventative pharmacological approaches. Atherosclerosis, a disease of the large arteries, is the common pathological substrate underlying cardiovascular disease and is the most prevalent disease of our time. Its thrombotic complications are responsible for an exceedingly high number of deaths and disabilities. In this study we found that the sub-fractions of a methanolic taheebo extract significantly inhibited rabbit platelet aggregation and rat aortic VSMC proliferation in a dose dependent manner. These results suggest that taheebo constituents may be useful as lead materials and new agents for the prevention and treatment of cardiovascular diseases such as thrombosis and atherosclerosis.
Technical Abstract: The antiplatelet and antiproliferation activities of Tabebuia impetiginosa Martius ex DC (taheebo) were investigated using washed rabbit platelets and rat aortic vascular smooth muscle cells (VSMCs) in vitro. The methanol extract of taheebo was separated into five sub-fractions using n-hexane, chloroform, ethyl acetate, butanol and water. Sub-fractions were investigated for inhibitory effects on platelet aggregation and VSMC proliferation. n-Hexane, chloroform, and ethyl acetate sub-fractions showed marked and selective inhibition of platelet aggregation induced by collagen and arachidonic acid (AA) in a dose-dependent manner. These fractions also significantly suppressed AA liberation induced by collagen in [3H]AA-labeled rabbit platelets. Effects of sub-fractions on cell proliferation and DNA synthesis in rat aortic VSMCs were also tested using [3H]-thymidine incorporation. The sub-fractions, especially chloroform sub-fraction, potently inhibited cell proliferation and DNA synthesis induced by platelet derived growth factor (PDGF)-BB, and inhibited the levels of phosphorylated extracellular signal regulated kinase (ERK1/2) mitogen activated protein kinase (MAPK) stimulated by PDGF-BB, in the same concentration range that inhibits VSMC proliferation and DNA synthesis. These results suggest that the chloroform sub-fraction of taheebo methanolic extract may be useful as a lead material and new agent for the preventing or treating of cardiovascular diseases such as thrombosis and atherosclerosis.