_____________________________________________________________________________________________________ *Corresponding author: E-mail: dakinpel@yahoo.com; Journal of Pharmaceutical Research International 20(5): 1-17, 2017; Article no.JPRI.38749 ISSN: 2456-9119 (Past name: British Journal of Pharmaceutical Research, Past ISSN: 2231-2919, NLM ID: 101631759) Investigations into Antibacterial, Phytochemical and Antioxidant Properties of Vitellaria paradoxa (Gaertn.) Stem Bark Extracts Oluwaseun Oyetunji Olasunkanmi 1 , David Ayinde Akinpelu 1,2* , Paul Opeyemi Adeniyi 1 , Oludare Femi Ajayi 1 , Joseph Omololu-Aso 1 and Felix Oluwasola Olorunmola 3 1 Department of Microbiology, Obafemi Awolowo University, Ile Ife, Osun State, Nigeria. 2 Department of Plant Science, University of The Free State, Qwaqwa Campus, South Africa. 3 Drug Research and Production Unit, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Osun State, Nigeria. Authors’ contributions This work was carried out in collaboration between all authors. Author OOO was involved in microbiological aspect of the experiments which include mode of action of the plant extract. Author DAA designed the project and proof read the manuscript. Author POA carried out the chemistry aspect of the experiment. Author OFA collected the plant sample and prepared it for extraction of the biological components. Author JOA carried out the preparation of media and other chemicals used for the experiments. Author FOO assisted in the microbiological analysis of the plant extract. All authors read and approved the final manuscript. Article Information DOI: 10.9734/JPRI/2017/38749 Editor(s): (1) Triveni Krishnan, National Institute of Cholera and Enteric Diseases, India. Reviewers: (1) Mohini Chetan Kuchekar, Pune University, India. (2) Victor Y. A. Barku, University of Cape Coast, Ghana. Complete Peer review History: http://www.sciencedomain.org/review-history/22774 Received 11 th December 2017 Accepted 30 th December 2017 Published 17 th January 2018 ABSTRACT This study investigated the antibacterial potentials and mechanisms of action of crude extract and fractions from stem bark of Vitellaria paradoxa on susceptible bacterial isolates. It also assessed the phytochemical constituents and antioxidant properties of the plant. This was with a view to tackling problem of multidrug resistance development by microorganisms. The stem bark of V. paradoxa was harvested from Ijagbo, Kwara State, Nigeria, in the month of April, 2016. The plant sample was oven dried at 40°C using hot-air oven and ground into fine Original Research Article