IOSR Journal Of Pharmacy And Biological Sciences (IOSR-JPBS) e-ISSN:2278-3008, p-ISSN:2319-7676. Volume 15, Issue 2 Ser. II (Mar –Apr 2020), PP 06-10 www.Iosrjournals.Org DOI: 10.9790/3008-1502020610 www.iosrjournals.org 6 | Page Antimicrobial Activity of Vernonia amygdalina, Justicia betonica, Leonatis nepetaefolium and Mormadica foetildatoStaphylococcus aureus Kiiza Hillary 1 , Kiwanuka Aaron Ssenyondo 2 , Julius Tibyangye 3 , Mivule Kinene 4 , Eyapu Christopher 4 , Kigozi Stephen 5 , Nakiyaga Winnie 6 1 Department of Microbiology/King Ceasor University and Kyambogo University/Uganda 2 Department of Biological sciences/Kyambogo University/Uganda 3 Department of Microbiology/King Ceasor University and Kampala International University/Uganda 4 Department of Anatomy/King Ceasor University/Uganda 4 Department of Microbiology/Soroti University/Uganda 5 Department of Biological sciences/Kyambogo University/Uganda 6 Department of Biological sciences/Kyambogo University/Uganda Abstract Background:Many societies in Africa still apply local medicines against numerous infections(1). Traditional medicine/herbs such as Vernonia amygdalina, Justicia betonica, Leonatis nepetaefolium and Mormadica foetilda possess active compounds that combat these life threatening infections.(2) The rural Africans are ignorant about the best mode of extracting these plant remedies. The aim of this study was to assess the antimicrobial activity of traditionally extracted crude herbal plant remedies of Vernonia amygdalina, Justicia betonica, Leonatis nepetaefolium and Mormadica foetilda on staphylococcus aureus. Methods: 180 fresh and dry uninfected leaves were collected by purposive sampling. 45 leaves for each herb were selected and 15 leaves were used for each method of extraction. Each mode of extraction was tested on two culture plates inoculated with S. aureus. The plant leaves were prepared by sun drying the fresh leaves for 5 days and then pounding to obtain a powder which was then mixed with distilled water, secondly squeezing fresh leaves to obtain an infusion and finally crushing fresh leaves and boiling them in a conical flask to obtain a decoction. The obtained mixture, infusion and decoction were tested for antimicrobial activity against S. aureus inoculated culture plates in an incubator at temperature of 37 o C for 24 hrs. Results: Freshly squeezed leaves produced an infusion which had the highest average diameter of 59.5mm (40%) and dried leaf mixtures followed with an average diameter of 56mm (38%).The extracts obtained from boiled decoction in this study displayed very weak antimicrobial activity with an average of 32mm (22%). Conclusion:S. aureus is susceptible to freshly prepared leaf infusions since they contain all active compounds with antimicrobial activity. Dried leaf mixtures possess some active compounds; however, some are lost during the process of drying. For boiled leaf decoctions, most active compounds are volatile hence evaporate off on heating and others maybe protein in nature hence denatured by heat showing a very weak antimicrobial activity against S. aureus. List of key words: Staphylococcus aureus, Justicia betonica, Leonatis nepetaefolium, Mormadica foetilda, Vernonia amygdalina --------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 12-03-2020 Date of Acceptance: 27-03-2020 --------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Traditional herbal medicines are naturally occurring plant-derived substances with minimal or no industrial processing that have been used to treat illness within local or regional healing practices.(3) The World Health Organization estimates that approximately 80% of the world’s inhabitants rely on traditional or herbal medicines for their primary health care and plants have long formed the basis of sophisticated traditional medicine systems and purportedly provide excellent leads for new drug developments(4, 5) About 70 – 80% of the Ugandan population still relies on traditional healers for day-to-day health care. In some rural areas the percentage is around 90% compared to 80% reported world-wide(6). Many herbal plants have been known to synthesize active secondary metabolites such as phenolic compound found in essential oils with established potent insecticidal and antimicrobial activities against