Hypertensive and Sympathomimetic Effects of the Methanol and Aqueous Extracts of Scoparia Dulcis in Anaesthetized Male Wistar Rats
C. O. Esume1, A. O. Opajobi2*, A. Osasuyi3, O. O. Ebong4 and A. K. Osakwe41Department of Pharmacology, Delta State University, Abraka, (Nigeria).
2Department of Medical Biochemistry, Delta State University , Abraka (Nigeria).
3Department of Nursing Science, Delta State University, Abraka, (Nigeria).
4Department of Pharmacology, University of Port-Harcourt (Nigeria).
Abstract: Objective Scoparia dulcis, a widely used medicinal plant is believed to have antihypertensive effects among traditional medical healers. This study investigates the efficacy of Scoparia dulcis as an antihypertensive agent in Wister rats. Methods Plant specimens were collected from local gardens in Portharcourt and identified in Department of plant Science, University of Portharcourt. Methanol and aqueous extracts were made from the leaves of the plant. Phytochemical screening was done using conventional methods and acute toxicity studies carried out to determine the LD50 using the Arithmetic method of Karber. Rats were anaesthesized using urethane, and endotracheally-intubated. The rats were then cannulated via the jugular vein and carotid artery. The carotid artery was connected to a pre- calibrated Ugo Basile double channel pen recorder. Adrenaline (0.5µg/kg), Acetylcholine (1.5µg/kg), and 20, 40, 80 and 160mg/kg of the aqueous and methanol extracts were administered through the jugular vein and their effects on the blood pressure (BP) and heart rate (HR) recorded. The mean arterial pressure (MAP) was calculated. This was repeated in four series for each extract and the mean of all experiment ± standard error of mean calculated. Results were analyzed statistically using Kruskal-Wallis, Dunn’s and Tukey-Kramer multiple comparisons test and Friedman nonparametric test. Results The phytochemical analysis reveals the presence of Tannins, Phlobatannins, Steroids, Terpenoids, Flavonoids and Cardiac glycosides in the leaves of Scoparia dulcis. There were no Saponins. The LD50 was 450 and 650mg/kg for the methanol and aqueous respectively. There was significant (P<0.05) hypertensive and sympathomimetic effects at 40, 80 and 160mg/kg dose levels for both extracts. Discussion Though, Scoparia dulcis plant is used traditionally in the treatment of hypertension, scientific research has not demonstrated this property but rather has shown this plant to increase the BP, MAP and HR as revealed by the above results. The plant contains catecholamines which accounts for these effects after parenteral administration. In the traditional medicine system, there are no scientific means of diagnosis of hypertension such as measurement of BP, other than perceived symptoms such as headache, insomnia and malaise. Extracts of Scoparia dulcis plant are reported to have analgesic, anti-inflammatory and sedative effects and it is likely that the improvement in the above symptoms in hypertensive patients that is erroneously believed to be the BP lowering effects among traditional medical healers.
Keywords: Hypertensive and Sympathomimetic effects; Ethanol; Aqueous extracts Back to TOC