Essential oil of four medicinal plants and protective properties in plum fruits against the spoilage bacteria and fungi

Abstract

There are limited studies available regarding the chemical composition of essential oils and their activities against fruit spoilage bacteria and fungi. In this study, chemical composition of essential oils from medicinal plants namely Acorus calamus, Allium sativum, Mucuna pruriens, and Sesamum indicum L showed invitro antibacterial and antifungal properties against fruits spoilage microbes were evaluated. Gas Chromatograph-Mass Spectrometry analysis confirmed the presence of major metabolites namely Hydroxylamine (98.26%), 1,2,4 - trimethoxy-5-1-propenyl (93.07%), Dodecanoic acid, 1,2,3-propanetriyl ester (92.64) and 2-diisoprophylphosphinnoethane (67.97%) from the studied plants. The minimum inhibitory concentration of the essential oils against bacteria were ranged from 11.3 ± 2.3 to 617 ± 4.9 μg/ml and fungi were ranged from 1.1 ± 0.4 to 292 ± 3.2 μg/ml, respectively. Among the essential oil, Allium sativum showed significant antibacterial activity with least minimum inhibitory concentration and minimum bactericidal concentrations (11.3 ± 2.3 μg/ml and 24 ± 1.6 μg/ml) while Sesamum indicum oil showed the least activity with high minimum inhibitory concentration and minimum bactericidal concentrations values (460 ± 11.9 μg/ml and 940 ± 12.8 μg/ml). Interestingly, Allium sativum documented the highest antifungal activity against Penicillium notatum and also significantly inhibited the growth of other tested fungal species such as, Aspergillus niger, Aspergillus flavus and Rhizopus microsporus. Among all tested essential oils, in combination of studied antibiotics, essential oils from Allium sativum showed excellent synergistic activity against seven out of nine spoilage microbes. Two-way analysis of variance showed significant depletion of pathogenic microorganism due to the effect of essential oils (p < 0.05). In addition, essential oil from Allium sativum significantly reduced the growth of Aspertillus flavus and Aspergillus niger on plum fruit. Results revealed the application of essential oil from Allium sativum counter Aspergillus flavus growth and prevented deterioration of plum fruit.