A. M. Maskouki, A. Mortazavi,
Volume 8, Issue 2 (7-2004)
Abstract
The inhibitory effects of thyme and ajowan oils on growth of A. parasiticus on pear during cold storage were studied. The main components of the two essential oils are phenolic compounds such as thymol and carvacrol with antimicrobial properties. Pear samples were inoculated by suspension ( 106 spor/ml) of A. parasitcus spores and sprayed by thyme (200 p.p.m) and ajowan (300p.p.m) separately and kept in cold storage (0 ±10C and relative humidity of 85%). Organoleptic test for evaluating oil odor residue was studied after 3 months. The amount of spoilage and contamination of pear fruit in 1st, 2nd, and 3nd month after cold storage was determined and were data the statistically analyzed. The results showed that in spite of the higher thymol content in ajowan oil constituent, which is well known as an antimicrobial agent Stronger than thyme oil, thyme oil at 200 p.p.m was more effective than ajowan oil in controlling and preventing, A.parasiticus growth in pear. It seems this is due to synergistic effects of other phenolic compounds such as carvacrol which does not exist in ajowan oil. The results of organoleptic test showed that the samples treated with ajowan oil have more acceptance than those treated with thyme oil thie applied even to the control sample. According to the results, thyme and ajowan oils are good promising natural antifungal agents without any hazardous effects on human health and can be successfully use as chemical fungicides.
J. Shakarami, E. Bazgir, M. Feizian,
Volume 10, Issue 3 (10-2006)
Abstract
To search for reproducible and environment-friendly antifungal agents, essential oils of five plant species including Myrtus communis, Mentha aquatica, Vitex agnus-castus, Thymus daenensis and Artemisia aucheri were studied for their inhibition effects on the mycelial growth of plant pathogenic fungi including Fusarium oxysporum, Pythium ultimum, Rhizoctonia solani and Gaeumannomyces graminis. The experiment was conducted using a completely randomized design of factorial experiment including three essential oil concentrations and three replications at 25±2 ºC on PDA. Results revealed that R. solani with 48.83 and P.ultimum with 89.62% mean of mycelial growth inhibition were the most resistant and the most susceptible fungi to the essential oils, respectively. The essential oil of M. aquatica and T. daenensis with 93.70 and 92.74% mean of mycelial growth inhibition showed the most inhibition effect and V. agnus-castus with 33.88% was the least mycelial growth inhibitor. The essential oil of M. aquatica and T. daenensis at 20 µl/petri plate (9 cm. in diameter) completely inhibited the mycelial growth of the tested fungi. Considering the high antifungal effect, and low human and environmental hazard of essential oils, it seems that the essential oils may be used for the control of plant pathogenic fungi, or at least they may be adopted as a model for the synthesis of new antifungal agents.
