Aqueous and ethanolic extracts of leaves of Spondias mombin* and Alchornea cordifolia were found to inhibit the growth of some Gram-positive and Gram-negative bacteria. The ethanolic extract was found to be more effective than the aqueous extract in inhibiting bacterial growth. * Sometimes incorrectly renderea monbim. Pharmaceutical Biology Downloaded from informahealthcare.com by University of Newcastle on 12/27/14 For personal use only. Pharmaceutical Biology Downloaded from informahealthcare.com by University of Newcastle on 12/27/14 For personal use only.

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Tropolones are of known bioloqical both in the plant and animal world. Their synthesis and physico-chemical properties are therefore of some importance. Tropolone (2-hydroxy-2,4,6-cyclo-heptatriene-l-one), by virtue of its inherent aromatic characteristics, would be expected to underso electrophilic substitution in a facile manner. This is found not to be the case. Substituted tropolones must therefore be produced by new reaction pathways, which necessarily involves more easily accessible intermediates. Such intermediates could possibly be the aminomethyl derivatives of tropolone, which are easily prepared by a simple Mannich condensation. Elaboration of these adducts could lead to more complex tropolones. Nuclear substitution of tropolones Friedel Crafts reactions of tropolones

The interaction of metronidazole with calcium to form a water-soluble complex has been studied by titration with ethylenediaminetetraacetate (EDTA), direct current and pulse polarographic reduction steps of the nitro-group at pH 5 and 7, and by ultraviolet absorption. Stoichiometric calculations, X-ray powder diffraction pattern of the synthesized metronidazole-calcium complex, and molecular ion peak at m/z 381 in the mass spectrum of this product, showed that a 2:1 complex is formed. The interaction of metronidazole with calcium on myocardial contractile performance of guinea-pig electrically-driven isolated left atria in physiological solution was also examined. Metronidazole induced a sustained, concentration-dependent depression of the tension that was reversed by changing the bathing fluid to physiological solution, and/or by adding excess calcium ion. The drug-induced negative inotropic response was antagonized competitively by increasing calcium ion in the bath, whereas noradrenaline antagonized metronidazole-induced negative inotropic responses non-competitively. Addition of the metronidazole-calcium complex to the bath did not affect normal myocardial contractile performance. The results show that metronidazole produces a direct negative inotropic effect on isolated atrial muscles by interfering with Ca2+, and by preventing Ca2+ function in the events leading to contractile activity of atrial muscles.