Effect of Australian Propolis from Stingless Bees Tetragonula carbonaria on Pre-Contracted Human and Porcine Isolated ArteriesReport as inadecuate




Effect of Australian Propolis from Stingless Bees Tetragonula carbonaria on Pre-Contracted Human and Porcine Isolated Arteries - Download this document for free, or read online. Document in PDF available to download.

Bee propolis is a mixture of plant resins and bee secretions. While bioactivity of honeybee propolis has been reported previously, information is limited on propolis from Australian stingless bees Tetragonula carbonaria. The aim of this study was to investigate possible vasomodulatory effects of propolis in KCl-precontracted porcine coronary arteries using an ex vivo tissue bath assay. Polar extracts of propolis produced a dose-dependent relaxant response EC50=44.7±7.0 μg-ml, which was unaffected by endothelial denudation, suggesting a direct effect on smooth muscle. Propolis markedly attenuated a contractile response to Ca2+ in vessels that were depolarised with 60 mM KCl, in Ca2+-free Krebs solution. Propolis 160 µg-ml reduced vascular tone in KCl pre-contracted vessels to near-baseline levels over 90 min, and this effect was partially reversible with 6h washout. Some loss in membrane integrity, but no loss in mitochondrial function was detected after 90 min exposure of human cultured umbilical vein endothelial cells to 160 µg-ml propolis. We conclude that Australian stingless bee T. carbonaria propolis relaxes porcine coronary artery in an endothelial-independent manner that involves inhibition of voltage-gated Ca2+ channels. This effect is partially and slowly reversible upon washout. Further studies are required to determine the therapeutic potential of Australian stingless bee propolis for conditions in which vascular supply is compromised.



Author: Flavia C. Massaro, Peter R. Brooks, Helen M. Wallace, Vianne Nsengiyumva, Lorraine Narokai, Fraser D. Russell

Source: http://plos.srce.hr/



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