chemical composition and antifungal activity of trachyspermum copticum essential oil against alternaria alternata (in-vitro study)

background: alternaria alternata (aa) is a fungus that has wide range of plant host and can cause diseases in humans and produces a number of mycotoxins. exposure to high numbers of aa spores can trigger severe asthma exacerbations. resistance to antifungal drug has been shown in this species. trachyspermum copticum (ajowan) is an annual herbaceous essential oil )eo) bearing plant . the ripening seeds of this plant contain 2- 4% essential oil that is rich in monoterpenes like thymol and is mainly used as an antiseptic agent as well as a drug component in medicine . anti alternaria agents can be used in agriculture products or food preservatives, homes and industrial disinfectants and use in infection treatment. objective: in the present study, chemical composition of trachyspermum copticum essential oil were analyzed and examined for antifungal activity against alternaria alternata. methods: the eo was extracted by distillation method.gc- ms analysis was performed using gas chromatograph with a hp-5ms column. gc analyses were carried out on a system equipped with a hp-5 column. six isolated alternaria alternata and standard strain atcc6663 were cultured on to sabouraud’s dextrose slant agar and condia harvested. the mic and mfc values of eo for alternaria alternata isolates were determined by the broth micro dilution and macro dilution methods according the m38-a2 clsi method (this process was repeated three times for all isolated). results: of number 11 compounds representing 94.48 % of eo were identified. the major constituents of ajowan oil were thymol (46.19%) and, γ-terpinene (18.26%), and ρ-cymene (25.53%). mic value in five isolate was 0.09 mg/ml and in two isloted was 0.19 mg/ml. range of mfc was 0.19- 0.78 mg/ml. conclusion: this study confirms that ajowan essential oil possess in vitro antifungal activity against alternaria alternata.