Some in vitro and in vivo cardiovascular effects of Hypoxis hemerocallidea FischCA Mey (Hypoxidaceae) corm (African potato) aqueous extract in experimental animal models
| Autor: | J A O, Ojewole, D R, Kamadyaapa, C T, Musabayane |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Male
Analysis of Variance Cardiotonic Agents Hypoxis Rats Inbred Dahl Dose-Response Relationship Drug Portal Vein Guinea Pigs Blood Pressure Cardiovascular System Myocardial Contraction Plant Roots Rats Vasodilation Heart Rate Models Animal Animals Heart Atria Plant Preparations Hypotension Rats Wistar Antihypertensive Agents Solanum tuberosum |
| Zdroj: | Cardiovascular journal of South Africa : official journal for Southern Africa Cardiac Society [and] South African Society of Cardiac Practitioners. 17(4) |
| Popis: | This study was undertaken to investigate some cardiovascular effects of Hypoxis hemerocallidea FischCA Mey (Hypoxidaceae) corm (African potato) aqueous extract in experimental animal paradigms. The effect of the corm aqueous extract (APE) on myocardial contractile performance was evaluated on guinea-pig isolated atrial muscle strips in vitro; whereas the antihypertensive (hypotensive) effect of the plant extract was examined in hypertensive Dahl salt-sensitive rats in vivo. APE (25-400 mg/ml) produced concentration-dependent, significant (p0.05-0.001) negative inotropic and negative chronotropic effects on guinea-pig isolated electrically driven left, and spontaneously beating right atrial muscle preparations, respectively. Moreover, APE reduced or abolished, in a concentrationdependent manner, the positive inotropic and chronotropic responses of guinea-pig isolated atrial muscle strips induced by noradrenaline (NA, 1-100 microM) and calcium (Ca2+, 5-40 mM). The negative inotropic and chronotropic effects of APE on guinea-pig atrial muscle strips were not modified by exogenous administration of atropine (ATR, 7.5 x 10(-7)-2.5 - 10(-6) M) to the bath fluid. APE also significantly reduced (p0.05-0.001) or abolished in a concentration-dependent manner, the rhythmic, spontaneous, myogenic contractions of portal veins isolated from rats. Furthermore, APE caused dose-related transient but significant (p0.05-0.001) reductions in the systemic arterial blood pressure and heart rates of the hypertensive rats used. Although the exact mechanisms of the cardiodepressant and the transient hypotensive (antihypertensive) actions of APE could not be established in the present study, we exclude the involvement of the cholinergic system; since the extract's cardiovascular effects were resistant to atropine pretreatment. However, the results of this laboratory animal study indicated that APE caused bradycardia and brief hypotension in the mammalian experimental models used. These observations tend to suggest that the herb may be used as a natural supplementary remedy in some cases of cardiac dysfunctions and in essential hypertension. The findings of this experimental animal study lend pharmacological support to the folkloric, anecdotal uses of the African potato in the management and/or control of certain cardiac dysfunctions and essential hypertension in some rural communities of southern Africa. |
| Databáze: | OpenAIRE |
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