Chemical composition, antibacterial and antioxidant activities of Tunisian garlic (Allium sativum) essential oil and ethanol extract

Abstract

 The aim of the study is to establish some nutritional properties of garlic cultivated in Tunisia and to evaluate the antioxidant and the antimicrobial activites of its essential oil and ethanol extract. Tunisian garlic (Allium sativum) was characterized for moisture, ash and protein contents which were determined as 66%, 1.4% and 5.2% respectively. In addition, Fe (5.90 mg/kg), Cu (1.61 mg/kg), Mg (15 mg/kg) and P (140 mg/kg) were reported such as the major minerals in garlic. The fat profile of tunisian garlic was conducted, the main fatty acids identified were lauric acid (49.3%) and linoleic acid (20.4%). Essential oil obtained from A. sativum was analysed by capillary GCMS. Diallyl disulfide (49.1%) and diallyl trisulfide (30.38%) were the main components of the five identified components. The phenolic content of the ethanol extract are analysed for its phenolic profiles, colorimetric analysis revealed that the total phenols, flavonoids and proanthocyanidins contents were respectively 43.63 mg GA/g, 13.18 mg quercetin/g and 24.24 mg of catechin/g. Antioxidant activity was evaluated by DPPH (2,2-diphenyl-1-picrylhydrazyl) assay, essential oil presented the highest antioxidant activity compared to its ethanol extract. IC50 values observed for the essential oil and ethanol extract were 300 μg/ml and 600 μg/ml respectively. The essential oil and ethanol extract from raw garlic were tested for antimicrobial activity against seven microorganisms. The results showed that ethanol extract was active against all tested strains: Escherichia coli, Salmonella typhi, Staphylococcus aureus, Pseudomonas aeruginosa, Listeria monocytogenes, Yersinia enterocolitica and Bacillus cereus.