Effect of Australian Propolis from Stingless Bees
(Tetragonula carbonaria) on Pre-Contracted Human and Porcine Isolated Arteries
PLOS One, Nov. 15, 2013
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.
No comments:
Post a Comment