Effect of Australian propolis from stingless bees (Tetragonula carbonaria) on pre-contracted human and porcine isolated arteries

• Published in: PloS one Vol. 8; no. 11; p. e81297
• Main Authors: Massaro, Flavia C, Brooks, Peter R, Wallace, Helen M, Nsengiyumva, Vianne, Narokai, Lorraine, Russell, Fraser D
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 15-11-2013; Public Library of Science (PLoS)
• Subjects: Animals; Arteries; Australia; Bees; Bees - physiology; Biological activity; Blood vessels; Calcium - metabolism; Calcium channels; Calcium channels (voltage-gated); Calcium Channels - metabolism; Calcium ions; Cell Membrane - drug effects; Chlorides; Coronary artery; Coronary Vessels - drug effects; Coronary Vessels - physiology; Denudation; Endothelial cells; European honeybee; Female; Human Umbilical Vein Endothelial Cells - cytology; Human Umbilical Vein Endothelial Cells - drug effects; Human Umbilical Vein Endothelial Cells - metabolism; Humans; Isotonic Solutions; Kinases; Mitochondria; Mitochondria - drug effects; Mitochondria - metabolism; Muscle contraction; Muscle Contraction - drug effects; Muscle, Smooth, Vascular - drug effects; Muscles; Potassium chloride; Potassium Chloride - pharmacology; Propolis; Propolis - pharmacology; Resins; Rodents; Secretions; Smooth muscle; Swine; Tetragonula carbonaria; Tissue Culture Techniques; Umbilical Arteries - drug effects; Umbilical Arteries - physiology; Umbilical vein; Vasoconstriction - drug effects; Vasodilation - drug effects; Veins & arteries; Viguiera; Washout; Australia; New Zealand; Queensland Australia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0081297

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 Ca(2+) in vessels that were depolarised with 60 mM KCl, in Ca(2+)-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 6 h 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 Ca(2+) 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.