Determination of the chemical composition and evaluation of the antimicrobial and antioxidant potential of the essential oil from Cryptocarya ovalifolia van der Werff leaves (Lauraceae)

Abstract

The present work aims to evaluate the chemical composition, the antimicrobial and antioxidant properties of the essential oil from Cryptocarya ovalifolia van der Werff (COEO) leaves collected in Mandraka forest. COEO was extracted by steam distillation from fresh leaves, with a yield of 0.7%. COEO appeared as a clear liquid, yellow, with a pleasant odour and relative density of 0.8943 at 20 °C, a refractive index of 1.4746, an optical rotation of – 31°13, an acid index of 0.638 and an ester index of 6.375. A total of 31 constituents accounting for 99.98% of the total essential oil content were identified by gas chromatography/mass spectrometry. The main component was sabinene (30.65%) and the major components (>5%) were limonene (17.33%), methyleugenol (14%) and α-pinene (8.33%). The antibacterial activity was tested on nine pathogenic microorganisms including four Gram positive bacteria, four Gram negative bacteria and one yeast using the disk diffusion and the microdilution assays. COEO was active on 4 strains with inhibition zone diameter (IZD) ranging from 8.7 mm (Bacillus cereus) to 12.7 mm (Clostridium perfringens). Minimum Inhibitory Concentration (MIC) varied from 1.12 to 2.23 mg/ml and Minimum Bactericidal Concentration (MBC) was 8.93 mg/ml for all strains. COEO had bacteriostatic action on Streptococcus pneumoniae, Clostridium perfringens, Bacillus cereus and Candida albicans (MBC/MIC>4) and bactericidal action on Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Salmonella typhi and Vibrio fischeri (MBC/MIC≤4). COEO exhibited radical scavenging activity against DPPH with an IC50 of 123.29 mg/ml. By oral route, its LD50 was 1.9/Kg body weight.