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Global interest in phytogenic feed additives as alternatives to antibiotics in feed has been spurred by the banning of antibiotic growth promoters by several countries. Suitable plant extracts for development of phytogenic feed additives should have therapeutic value and should also be safe.The aim of this study was to evaluate the antibacterial, antioxidant and anti-lipoxygenase activities as well as cytotoxicity of selected plant species used in poultry ethnomedicine in Zimbabwe.Antibacterial activity was determined against three ATCC strains (Staphylococcus aureus, Escherichia coli, Salmonella Enteritidis) and two clinical strains isolated from chickens (Escherichia coli and Salmonella Gallinarum) using a two-fold serial microdilution assay. Qualitative antibacterial bioautography was also carried out using the ATCC strains. Antioxidant activities of crude acetone and methanol extracts were determined using free radical scavenging assays whilst anti-lipoxygenase activity was evaluated using a ferrous oxidation-xylenol orange (FOX) assay. Cytotoxicity was evaluated using a tetrazolium-based colorimetric assay (MTT assay) on Vero monkey kidney cells.Erythrina abyssinica had the best antibacterial activity against both ATCC strains and clinical strains with minimum inhibitory concentration (MIC) values ranging from 0.02 to 0.156 mg/ml. Aloe greatheadii, Adenia gummifera (leaves), Senna singueana and Aloe chabaudii had moderate activity against the poultry pathogens. Bioautography showed that all ten plant species have antibacterial activity against the tested microorganisms with E. abyssinica and S. singueana having prominent bands of inhibition against both Gram-negative and Gram-positive bacteria. The acetone extract of S. singueana and the methanol extract of Euphorbia matabelensis had the most powerful antioxidant activities with mean ICThis study showed that S. singueana had a cocktail of therapeutic activity and supports further investigation of this plant species for development of phytogenic poultry feed additives. Other plant species with noteworthy biological activities include B. madagascariensis, E. abyssinica, A. greatheadii, T. bicaudata and E. matabelensis.

Cissampelos mucronata A. Rich., a perennial climber belonging to the family Menispermaceae, has been used traditionally to treat parasites and tuberculosis-related symptoms. Co-infection of helminth parasites and tuberculosis-causing pathogens heightens the risk of developing active tuberculosis.The aim was to isolate and characterize antimycobacterial compounds from Cissampelos mucronata and to investigate their antibiofilm and anthelmintic efficacy as well as cytotoxicity.The acetone extract of C. mucronata leaves and stems was fractionated by vacuum liquid chromatography using hexane, ethyl acetate, acetone and methanol:chloroform (3:7). Separation of the active ethyl acetate fraction by column and preparative thin layer chromatography led to the isolation and identification of five compounds using NMR and LC-MS, as well as GC-MS for non-polar compounds. The anthelmintic, antimycobacterial, antibiofilm, antioxidant and anti-inflammatory effects as well as cytotoxicity of the fractions and compounds were determined.The ethyl acetate fraction had the best antimycobacterial activity (MIC = 0.015-0.08 mg/ml). The fractions were relatively non-toxic to Vero cells (0.03-0.79 mg/ml) and had good anti-inflammatory and antibiofilm effects. Five compounds were identified as stigmasterol, hentriacontane, simiarenol, nonacosene and carbonic acid. Nonacosene had moderate anthelmintic effects but poor antimycobacterial activity (MIC = 0.375 mg/ml). Nonacosene and hentriacontane had good biofilm inhibitory effect (90-100%).This study reveals that C. mucronata is a potential source of promising compounds with a range of useful bioactivities that support its use in traditional medicine. Development of plant-based remedies may assist in reducing the impact of co-infections with helminth parasites and tuberculosis-causing mycobacteria.

Antioxidant activity of the solvent fractions obtained from a 20% aqueous methanol dried leaf extract of Leucaena leucocephala was evaluated using a 1, 1-diphenyl-2-picrylhydrazyl (DPPH) TLC assay. The more polar fractions ethyl acetate and butanol fractions demonstrated strong activity. A DPPH activity-guided fractionation procedure was used to isolate the antioxidant constituents of these active fractions. Separate fractionation of the fractions led to the isolation of epicatechin-3-O-gallate (1) along with two quercetin glycosides: quercetin-3-O-arabinofuranoside (2) and quercetin-3-O-rhamnoside (3) together with apigenin (4). The structures of the isolated compounds were elucidated using spectroscopic techniques NMR (1D and 2D) and mass spectrometry. Compounds 1 and 4 are reported for the first time from this species. In the qualitative antioxidant TLC assay, isolated compounds instantly bleached the DPPH (0.2% in MeOH) purple colour indicating strong antioxidant activity. The antioxidant quercetin glycosides were not cytotoxic at the highest concentration tested (200 ig/ml), and apigenin was not isolated in sufficient quantity to test for cytotoxicity. Epicatechin-3-O-gallate showed slight cytotoxicity against Vero cells (LC 50 = 92 μg/ml). Keywords : Leucaena leucocephala , Fabaceae, antioxidant, DPPH, cytotoxicity.