© 2019 Odinakachukwu, et al. This is an open access article distributed under the terms of the Creative Commons Attribution License -NonCommercial- ShareAlike Unported License (http://creativecommons.org/licenses/by-nc-sa/3.0/). Antibacterial activity of leaf extract of Chromolaena odorata and the effect of its combination with some conventional antibiotics on Pseudomonas aeruginosa isolated from wounds P. Odinakachukwu Omeke, J. Okechukwu Obi, N. A. Ibuchukwu Orabueze 1,2 , Anthony Chibuogwu Ike 1,3 * 1 Department of Microbiology, University of Nigeria, Nsukka, Nigeria, 2 Department of Medical Microbiology, College of Medicine, University of Nigeria Enugu Campus, Enugu, Nigeria, 3 Department of Biological Sciences, Benue State University, Makurdi, Nigeria ABSTRACT This study was carried out to investigate the in vitro antimicrobial properties of crude methanolic extract of Chromolaena odorata and its interactions with some standard antibiotics (ofloxacin, ciprofloxacin, and gentamicin) on Pseudomonas aeruginosa isolated from wound samples. P. aeruginosa was isolated from wound samples from hospital patients in Enugu State, Nigeria, using standard bacteriological methods. Methanolic extraction of C. odorata was carried out using Soxhlet extractor. The antimicrobial activity and in vitro interactions were evaluated using a combination of agar well diffusion and broth dilution techniques. The findings of this study showed that all the P. aeruginosa isolates were susceptible to the C. odorata methanolic crude extract at high concentrations. There was an enhancement of the potency of the methanolic crude extract when combined with low concentrations of standard antibiotics compared to its potency when tested alone. Our findings give credence to the folkloric use of C. odorata for the treatment of wounds, especially P. aeruginosa-infected wounds. There could be beneficial clinical application of the coadministration of standard antibiotics and the crude extract of C. odorata in the treatment of wound infections caused by P. aeruginosa. 1. INTRODUCTION A wound is a disruption of normal anatomic structure and function of the skin causing breakdown of the protective function of the skin [1]. It constitutes a major cause of physical disability [2]. Wounds provide moist, warm, and nutritious environments which are conducive for microbial colonization and proliferation causing infections which delay wound healing. This can, in turn, cause wound breakdown leading to increased hospital stay, morbidity, and in some cases, even mortality. Infection of wound is the successful invasion and proliferation by one or more species of microorganisms anywhere within the body’s sterile tissues, sometimes resulting in pus formation, and Pseudomonas aeruginosa is one of the species of microorganisms implicated in wound infection [3]. Many traditional medicinal herbs and plant parts (leaves, stem, roots, and bark) have been reported to be effective in providing health- *Corresponding Author: Anthony Chibuogwu Ike, Department of Microbiology, University of Nigeria, Nsukka, Nigeria; Department of Biological Sciences, Benue State University, Makurdi, Nigeria. Email: anthonyc.ike@unn.edu.ng care services to rural dwellers and in the treatment of wounds and combating serious diseases in the world at large [4-6]. Plants contain pharmacologically important phytochemicals such as alkaloids, essential oils, flavonoids, tannins, terpenoids, saponins, and phenolic compounds with essential antimicrobial activities. Chromolaena odorata is one of the plants implicated in wound healing. C. odorata is a fast growing, abundant, and widespread perennial scandent or semi- woody flowering shrub in the sunflower family of Asteraceae [7-10]. This plant is known to have originated from Central and South America but is now distributed throughout Africa and Tropical Asia. C. odorata occupies different types of lands where it forms dense strands that prevent the establishment of other flora as it possesses allelopathic potentials and growth inhibitors [11]. The plant is traditionally used in disinfecting wounds, preventing blood loss from wounds, and treating of open wounds [9]. It is used by traditional medicine practitioners for the treatment of burns, wound healing, skin infections, postnatal wounds, leech bite, soft tissue wounds, and liver diseases [12-17]. The common names of C. odorata include Awolowo weed, Siam weed, Elizabeth weed, Enugu plantation weed [9,18], bitter bush, airplane plant [19], jack in the bush [15], Christmas bush, common floss flower [20], and independence leaf among others. Many commonly used antibiotics have become less effective against certain pathogens, thereby threatening man’s ability to treat wound Journal of Applied Biology & Biotechnology Vol. 7(03), pp. 36-40, May-June, 2019 Available online at http://www.jabonline.in DOI: 10.7324/JABB.2019.70307 ARTICLE INFO Article history: Received on: July 27, 2017 Accepted on: September 23, 2018 Available online: April 05, 2019 Key words: Antibacterial activity, Chromolaena odorata, Crude extracts, Herb-drug combination, Pseudomonas aeruginosa, Standard antibiotics