Optimizing the antifungal effects of Cinnamomum zeylanicum, Zataria multiflora, and Satureja khuzestanica essential oils against the blue mold fungus (Penicillium expansum) using Response Surface Methodology

Utilizing the essential oils (EOs) as natural antifungal agents and alternatives for chemical fungicides has increased the attentions. In this study, chemical components and antifungal activity of Cinnamomum zeylanicum (CEO), Zataria multiflora (ZEO), and Satureja khuzestanica (SEO) plants essential oil (EO) were identified to assess their effect in term of concentration and exposure time on control of Penicillium expansum and also, modeling and optimizing antifungal properties of these EOs via response surface methodology (RSM). The main components of three EOs detected by GC-MS analysis were as follows: Cinnamaldehyde (80.82%) for CEO, Thymol (32.68%), Carvacrol (30.57%), p-Cymene (8.94), and γ-Terpinene (5.96%) for ZEO and Carvacrol (38.43%), γ-Terpinene (21.89%), p-Cymene (16.55%), and α-Terpinene (5.76%) for SEO. Antifungal index (AI) in all EOs increased against the increment of concentration but the effect of time was vice versa; with passage of time, the AI decreased in all EOs. Moreover, based on the optimization results, it was determined that CEO and SEO at concentration of 288.633 and 590.841 μL.L-1 and time of 108.607 and 238.549 h had the highest and lowest inhibitory effect, respectively, on growth of Penicillium expansum. Furthermore, the results of this study showed that the response surface method can be applied to model and optimize the antifungal activity of these EOs as a suitable and accurate method.