Research Journal of Food Science and Nutrition Volume 1(1), pages 28-34, June 2016 https://doi.org/10.31248/RJFSN2016.011 ISSN 2536-7080. Copyright © 2016 Article Number: D37B80564 http://integrityresjournals.org/journal/RJFSN Full Length Research Comparative studies of physico-chemical composition and antibacterial activities of essential oil extracted from medicinal plants of scent leaves (Ocimum basilicum Lamiaceae and Ocimum gratissimum Lamiaceae) Aladekoyi, Gbenga* and Orungbemi O. O. Food science & Technology Department, Rufus Giwa Polytechnic, Owo, Ondo State, Nigeria. *Corresponding author. Email: gbengu7@yahoo.com. Tel: +2348034651804, +2348036267170 Copyright © 2016 Aladekoyi and Orungbemi. This article remains permanently open access under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Received 29th February, 2016; Accepted 26th May, 2016 ABSTRACT: A comparative study was conducted on essential oil extracted from sweet basil ( Ocimum basilicum L.) and Africa basil (Ocimum gratissimum L.) using standard methods (AOAC, 2000, Pelczer and Black, 1993), for their physico- chemical composition and antibacterial activities. The comparison between the two scent leaves was necessary to indicate the one with high potency in terms of their physical, chemical and antibacterial activities for Industrial and medicinal purposes. The experimental result obtained from essential oil extracted from Ocimum basilicum L. and Ocimum gratissimum L. revealed some physiological properties like a viscosity of 1.342 ± 0.01 and 1.299 ± 0.01, Specific gravity 0.9026 ± 0.02 and 0.9032 ± 0.02, Refractive index 1.672 ± 0.20 and 1.660 ± 0.10 respectively, and the chemical compounds of Saponification(mg/g) 19.074 ± 0.10 and 13.464 ± 0.20, Iodine(g/100g) 34.7706 ± 0.30 and 35.2782 ± 0.30, Free fatty acid(oleic)(g/100g) 0.949 ± 0.10 and 1.267 ± 0.10, Peroxide value(mg/g) 0.923 ± 0.01 and 0.945 ± 0.02 and Acid value(g/100g) 3.366 ± 0.10 and 4.488 ± 0.10 for Ocimum basilicum L. and Ocimum gratissimum L. respectively. The antibacterial activities revealed that the zone of inhibition between the pathogenic organism under test for Ocimum basilicum L. and Ocimum gratissimum L. were; Staphylococcus spp. 3.00 ± 0.01 mm and 5.00 ± 0.01 mm, pseudomonas spp. revealed no zone for both essential oil and E. coli spp. had 3.00 ± 0.01 mm and 4.00 ± 0.02 mm respectively. Klebsiella spp. had 4.00 ± 0.02 mm and 4.00 ± 0.02 mm, Proteus also indicated no zone for both oil samples. An observable trend was that Pseudomonas and Proteus spp. showed resistance to both oil samples while Staphylococcus spp., E. coli spp., Klebsiella spp. were susceptible with the highest of value of 5.00 ± 0.01 mm Staphylococcus spp. essential oil from Ocimum gratissimum L. Keywords: Physic-chemical, antibacterial activity, essential oil, pathogenic bacteria. INTRODUCTION The genus of Ocimum belonging to family of Lamiaceae is widely distributed in tropical and warm temperate regions of the world wide (Wangner et al., 1999). It is usually named as sweet basil and is an annual plant, with extraordinary medicinal properties and contains several antioxidant compounds. In traditional medicine, Ocimum basilicum has been used as an antiseptic, preservative, sedative, digestive regulator and diuretic (Effraim et al., 2003). It has also been recommended for the treatment of headaches, cough, infections of upper respiratory tract, kidney malfunction and to eliminate toxins. Both Ocimum oil and its extracts were shown to exhibit antibacterial activities against gram positive and gram negative bacteria by various experimental researches. Ocimum basilicum L. commonly called as sweet Basil is a native plant of Indo-Malayan region. It is called the king of herb which contains plenty of phytochemicals with significant nutritional value as well as antioxidant capabili-