Phytochemical and Pharmacological Properties of Crude Extracts and Pure Compounds from Leaves of Vernonia galamensis and Croton macrostachyus
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Date
2014-07
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Addis Ababa Universty
Abstract
Human beings rely on medicinal plants to combat infections since long time ago. Vernonia galamensis and Croton macrostachyus are used in different parts of Ethiopia to treat wound and/or intestinal worms traditionally. The main objective of this research was to proof the traditional uses of these plants through testing the effect of their leaf extracts on selected pathogenic bacteria and on the contractility of ileum muscle. Crude extraction was done by subsequent method using n-hexane, acetone/ethylacetate, ethanol and methanol. Bioactive compounds were isolated using column chromatography, NMR and MS. Crude extracts were tested against Escherichia coli, Salmonella typhi, Shigella boydii and Staphylococcus aureus at load of 3mg/disk, 6mg/disk and 9mg/disk followed by testing the isolated compounds using disk diffusion method. The effect of six crude extracts on ACh induced guinea pig ileum contractility was tested at concentrations of 80μg/ml, 160μg/ml and 320μg/ml in a dose dependent manner. Acute toxicity tests were done for each crude extract on albino mice. Each crude extract showed antibacterial activities at loads of 6mg/disk (200mg/ml) and 9mg/disk (300mg/ml) with MIC of 125mg/ml. At a load of 9mg/disk both extracts showed strong activity against S. aureus and S. boydii. Vernolide (C-I), vernoguinoside (C-II), vernodalin (C-III), compound IV (C-IV) from VAE, methyl laurate (C-VI) and creptoxide (C-VII) from CEaE were isolated. C-I and C-II were not reported from V. galamensis so far. C-II and C-IV showed strong antibacterial activities against S. typhi and S. boydii (P=0.69; 0.89) while C-VI and C-VII showed moderate to strong activity without significant differences with the respective standards against all tested bacteria. CEaE and VAE significantly increased the ACh induced contraction of guinea pig ileum in a dose dependent manner while CME and VME reduced it (P<0.00). All extracts showed no toxicity at all tested doses. Results showed that these plants possess antibacterial and intestinal muscle contractile properties, which might validate their traditional uses. However, further studies must be carried out on their mechanism of actions.
Key Words: Phytochemicals, Antibacterial, Contractility, Vernonia galamensis, Croton macrostachyus
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Keywords
Phytochemicals, Antibacterial, Contractility, Vernonia galamensis, Croton macrostachyus