Hairul, Nuriana Munirah
(2021)
Elucidation of the vasorelaxation
mechanisms induced by
syzygium polyanthum leaves aqueous extract.
Masters thesis, Universiti Sains Malaysia.
Abstract
Previous studies have demonstrated that aqueous extract of Syzygium polyanthum
leaves (AESP) has vasorelaxation activity. However, there is still very little
information on its mechanism of action on direct vasorelaxation activity. Therefore,
the present study was designed to determine endothelium-dependant relaxation of the
AESP and investigated the mechanism of vasorelaxation. The in vitro method was
utilised, mounting the aortic ring into myograph, precontracted with phenylephrine (1
μM) and studied based on the agonist-antagonist inhibition protocols. The
endothelium-dependant was studied on endothelium intact and denuded thoracic
arterial ring isolated from Wistar-Kyoto (WKY) rats. The vasorelaxation mechanisms
of AESP were evaluated on the endothelial-intact aortic rings. This study shown that
the AESP relaxation was endothelium-dependant. The vasorelaxant effect of AESP
was attenuated by L-NAME (endothelial nitric oxide synthase/eNOS inhibitor, 100
μM) and ODQ (soluble guanylate cyclase/sGC inhibitor, 10 μM). However, methylene
blue (cyclic guanosine monophosphate/cGMP lowering agent, 10 μM) and
indomethacin (non-selective COX inhibitor, 10 μM) did not produce significant
inhibition on the AESP relaxation. Taken together, the findings indicated that
vasorelaxation of AESP was endothelium-dependent, through NO/eNOS and sGC
pathways.
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