ANTIBACTERIAL ACTIVITIES OF THE ESSENTIAL OIL OF VIETNAMESE HOLY BASIL (Ocimum sanctum L.) AGAINST FOOD-BORNE BACTERIA AND FUNGI SPECIES

Abstract

Antimicrobial activities of essential oil (EO) of Vietnamese holy basil (Ocimum sanctum L.) were screened against several food-borne bacteria and fungi species. The main volatile components detected in the holy basil EO were eugenol (53.61%), (E)-caryophyllene (25.37%), (β)-elemene (15.86%), germacrene A (2.03%). A significant growth inhibition of this EO with some different concentrations against Escherichia coli ATCC® 25922™ (E. coli), Staphylococcus aureus ATCC ® 25923 ™ (S. aureus), Bacillus subtilis ATCC® 11774™ (B.subtilis), Bacillus cereus ATCC® 13061™ (B.cereus) and Candida albicans ATCC 10231, Rhizoctonia solani, Fusarium oxysporum were observed by the standard disc diffusion method. The inhibition zone for each isolate by holy basil EO obtained from 5 µl and 10 µl of EO ranged from 15.3 - 16.4 mm and 16.7 – 18.4 mm in diameter, respectively. The minimum inhibitory concentration (MIC) of holy basil EO was 0.78 µl/ml determined by a micro-dilution method in MHB liquid medium. The bactericidal concentrations (MBC) was 1.56 µl/ml in all isolates tested. The antifungal properties of the holy basil EO were also determined in this study against three important pathogenic fungi such as Candida albicans, Rhizoctonia solani and Fusarium oxysporum with the inhibition zone ranges from 20 to 30 mm. The results suggested that holy basil EO can be applied in food industries as natural flavoring preservatives/additives to control food spoilage and food-borne pathogenic bacteria and fungi causing severe destruction in food.