Efficacy of Essential Oil and Hydrosol Extract of Marrubium vulgare on Fungi Responsible for Apples Rot

Abstract

Background: The microorganisms such as Penicillium expansum and Botrytis cinerea are wellknown pathogens in apples during postharvest. So, to protect apples from these pathogens, chemical control methods were exercised. Introduction: The main objective of this work was to study the chemical composition and the in-vitro and in-vivo antifungal properties of essential oil and hydrosol extract of Marrubium vulgare. Methods: In this work, the air-dried aerial parts of Marrubium vulgare were hydrodistilled in a Clevengertype apparatus. The essential oil and hydrosol extract isolated were analyzed using Gas Chromatography (GC) and Mass Spectrometry (GC/MS). The in-vitro antifungal activity of the both extracts was investigated against Botrytis cinerea, Penicillium expansum and Alternaria alternata fungi using radial growth technique. The effect of the essential oil and hydrosol extract on disease development of apple caused by Penicillium expansum in the in-vivo conditions was assessed. Results: The essential oil of Marrubium vulgare was characterized principally by E-β-caryophyllene (23.5%), E-β-farnesene (21%), α-humulene (14.8%), β-bisabolene (11.1%), caryophyllene oxide (6.8%) and phytol (3.1%). While, the methyl-eugenol (65.5%), α-Bisabolol (12.5%), linalool (6.5%) and caryophyllene oxide (6.2%) were the major compounds of hydrosol extract. The result of in-vitro antifungal activity of hydrosol extract showed an interesting antifungal inhibition against Botrytis cinerea, Penicillium expansum and Alternaria alternata with percentage inhibition ranging from 77% to 89% at low concentration of 0.15 mL/L. The essential oil was found to inhibit the growth of Penicillium expansum in a dose-dependent manner, with a percentage inhibition of 100% at 30 mL/L. Furthermore, essential oil and hydrosol extract have demonstrated promising in-vivo antifungal activity to control infection of apples by Penicillium expansum up to 25th day of storage, compared with the control. Conclusion: The preventive and protective effects of essential oil and hydrosol extract could be exploited as an ideal alternative to synthetic fungicides for using the protection of stored apples from fungal phytopathogens.