Thymus vulgaris essential oil and thymol against Alternaria alternata (Fr.) Keissler: effects on growth, viability, early infection and cellular mode of action.

Abstract

BACKGROUND:

In initial assays, Thymus vulgaris essential oil (TEO) has demonstrated activity against several plant-pathogenic fungi and has reduced the fungal diseases to levels comparable with commercial fungicides. Thus, the goal of this work was to identify the mode of action in fungi of TEO and its major compound thymol (TOH) at the cellular level using an ultrastructure approach.

RESULTS:

TEO from leaves and TOH had minimum inhibitory concentrations (MICs) of 500 and 250 µg mL(-1) respectively against A. alternata; under the same conditions, MIC for a commercial fungicide was 1250 µg mL(-1) . Ultrastructure analysis showed that TOH phenolic substance prevented fungal growth, reduced fungal viability and prevented the penetration in fruits by a cell wall/plasma membrane interference mode of action with organelles targeted for destruction in the cytoplasm. Such mode of action differs from protective and preventive-curative commercial fungicides used as pattern control.

CONCLUSION:

These findings suggest that TOH was responsible for the antifungal activity of TEO. Therefore, both the essential oil and its major substance have potential for use in the development of new phenolic structures and analogues to control Alternaria brown spot disease caused by Alternaria alternata.

• Authors: Fabiano J Perina, Douglas C Amaral, Rafael S Fernandes, Claudia Rg Labory, Glauco A Teixeira, Eduardo Alves
• Journal: Pest management science (Pest Manag Sci) Vol. 71 Issue 10 Pg. 1371-8 (Oct 2015) ISSN: 1526-4998 [Electronic] England
• PMID: 25354766 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2014 Society of Chemical Industry.

Chemical References

• Fungicides, Industrial
• Oils, Volatile
• Thymol

Topics

• Alternaria (drug effects, growth & development, physiology)
• Citrus (microbiology)
• Fungicides, Industrial (pharmacology)
• Microbial Sensitivity Tests
• Microbial Viability (drug effects)
• Oils, Volatile (pharmacology)
• Plant Diseases (microbiology)
• Thymol (pharmacology)
• Thymus Plant (chemistry)