Antimicrobial and Phytotoxic Activity of <i>Origanum heracleoticum</i> and <i>O. majorana</i> Essential Oils Growing in Cilento (Southern Italy)

• Main Authors: Teresa Della Pepa, Hazem S. Elshafie, Raffaele Capasso, Vincenzo De Feo, Ippolito Camele, Filomena Nazzaro, Maria Rosa Scognamiglio, Lucia Caputo
• Format: Article
• Language: English
• Published: MDPI AG 2019-07-01
• Series: Molecules
• Subjects: <i>Origanum heracleoticum</i>; <i>Origanum majorana</i>; antimicrobial activity; phytotoxic activity; spore germination; minimum inhibitory concentration
• Online Access: https://www.mdpi.com/1420-3049/24/14/2576

There is a growing interest in a potential use of essential oils (EOs) as a replacement for traditional pesticides and herbicides. The aims of this study were to: (i) Identify the chemical composition of the two EOs derived from <i>Origanum heracleoticum</i> L. and <i>O. majorana</i> L., (ii) evaluate the in vitro antifungal activity of the EOs against some postharvest phytopathogens (<i>Botrytis cinerea</i>, <i>Penicillium expansum</i>, <i>Aspergillus niger</i> and <i>Monilinia fructicola</i>), (iii) evaluate the in vitro antibacterial activity against <i>Bacillus megaterium</i>, <i>Clavibacter michiganensis</i>, <i>Xanthomonas campestris</i>, <i>Pseudomonas fluorescens</i> and <i>P. syringae</i> pv. <i>phaseolicola</i>, (iv) evaluate the effect of both studied EOs on the spore germination percentage and their minimum inhibitory concentration (MIC) against <i>M. fructicola</i>, and (v) study the possible phytotoxicity of the two EOs and their major constituents, carvacrol for <i>O. heracleoticum</i> and terpinen-4-ol for <i>O. majorana</i>, against tha germination and initial radicle growth of radish, lettuce, garden cress and tomato. The two EOs demonstrated promising in vitro antimicrobial and antifungal activities against all tested microorganisms. EOs showed high inhibition of spore germination percentage at the minimal inhibitory concentration of 500 and 2000 &#181;g/mL, respectively. Moreover, both germination and radical elongation of selected plant species were sensitive to the oils.