| DOI: https://doi.org/10.14456/mujps.2015.8 | Pharm Sci Asia 2015; 42(2), 55-63 |
Effects of Ya-hom on cardiovascular functions after long-term oral administration in ratsN. Nernpermpisooth1, SS. Thirawarapan1*, W. Suvitayavat1, W. Kitpati1, N. Bunyapraphatsara2
1 Department of Physiology, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayudhaya Road, Bangkok 10400, Thailand
2 Department of Pharmacognosy, Faculty of Pharmacy, Mahidol University, 447 Sri-Ayudhaya Road, Bangkok 10400, Thailand
Ya-hom is one of the most popular Thai traditional medicinal preparations that used for the treatment of dizziness and faintness. Ya-hom is also believed to be efficacious as a mild cardiac stimulant and in improving blood circulation. The present study investigated single oral treatment and long-term oral treatment effect of a selected brand of Ya-hom on cardiovascular functions in rats. Single oral-dose of Ya-hom 2.5-5.0 g/kg increased systolic blood pressure (SBP) and heart rate (HR) in a dose-independent manner. The duration of action of increased SBP and onset of increased HR was dose-dependent. After 8 weeks of daily treatment, both control and Ya-hom-treated groups had 8-10 % elevation in SBP. Increased SBP after single Ya-hom administration was observed only in rats who received the highest dose; the stimulatory effect on HR was not apparent. Increased local plantar blood flow (pBF) was also observed after single oral administration of Ya-hom in a dose-dependent manner. Ya-hom at the highest dose (5.0 g/kg BW) increased the pBF over the duration of 90 min. A similar response of increasing pBF was observed at the end of 8 weeks of Ya-hom treatment. After 8 weeks of Ya-hom treatment at 5 g/kg BW/day, responses to both norepinephrine (NE) and Ya-hom, were greater in the aortic rings of Ya-hom-treated groups than in those of the control group. The stimulating effect of Ya-hom was lower than that of NE. Ya-hom also decreased NE-induced contraction when Ya-hom and NE were simultaneously applied to aortic rings of both control and Ya-hom-treated groups. These results demonstrate that Ya-hom effectuated an elevation in blood pressure, due to stimulatory effects on the large artery and heart. This increase in blood pressure accelerated blood distribution through the microcirculatory system. In long-term use, Ya-hom demonstrated no persistent cardiovascular stimulation, but tended to increase the vascular response to vasoconstrictor. This study confirmed the stimulatory effect of this brand of Ya-hom on cardiovascular functions, in support of its claimed efficacy in the treatment of dizziness and faintness.
Keyword:
Ya-hom, blood pressure, heart rate, peripheral blood flow, aortic ring, cardiovascular effects
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