Researchers in the School of Pharmacy

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Browsing by Author "Green, Ivan"

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    Cardiovascular effects of the alkaloid hippadine on the isolated perfused rat heart
    (Open Access Science Research Publisher, 2012) Mugabo, Pierre; Obikeze, Kenechukwu; Njagi, Angela; Burger, Andries; Dietrich, Danielle; Green, Ivan
    Crinum macowanii has been used extensively in traditional medicines for treatment of various illnesses such as oedema and ‘heart disease’. Previous studies of the crude bulb extracts on Langendorff perfused isolated rat hearts indicated a positive inotropic effect. The aim of this study was to isolate and characterize compound(s) from C. macowanii with cardiovascular effects similar to that observed with the crude extracts of the plant. The methanol extract of dried bulbs was extracted for alkaloids, and structural elucidation of the isolated alkaloid identified it as hippadine. The cardiovascular effects of hippadine was evaluated in vitro in isolated perfused rat hearts using the “double sided” working heart system. Perfusion with 0.5 μg/ml and 5.0 μg/ml hippadine in Krebs-Hanseleit buffer led to significant decreases in coronary flow, aortic output, cardiac output, systolic pressure, and heart rate, accompanied by increases in diastolic pressure. Hippadine exhibited a negative chronotropic and inotropic effect on the isolated rat heart and is responsible either partly or fully for the cardiovascular effects of C. macowanii.
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    Characterization and Cradiovascular Effects of (13S)-9α,13α-epoxylabda-6β(19),15(14)diol dilactone, a Diterpenoid Isolated from Leonotis leonurus
    (South African Chemical Institute, 2008) Obikezea, Kene C.; McKenzieb, Jean M.; Green, Ivan; Mugabo, Pierre
    A new diterpenoid, (13S)-9 ,13 -epoxylabda-6 (19),15(14)diol dilactone (1), was isolated from Leonotis leonurus and the structure determined via NMR analysis. The compound causes significant changes in blood pressure of anaesthetized normotensive rats and exhibits a negative chronotropic effect.
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    Inorganic ions in leonotis leonurus extract do not explain changes in isolated Wistar rat heart function
    (Open Access Science Research Publisher, 2011) Burger, Andries; Mugabo, Pierre; Henkel, Ralf; Green, Ivan
    Leonotis leonurus (L. leonurus) R. Br (Lamiaceae) is used by healers in South Africa. The present study was conducted to determine if the L. leonurus effect on isolated rat heart is due to ionic changes in the perfusion fluid.