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)

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.