Chemical characterization of essential oil constituents of three selected botanicals and their antimicrobial activity against postharvest rot pathogens of tomato (Solanum lycopersicum L.)

Abstract

This study investigated chemical constituents of essential oils (EOs) of Thaumatococcus daniellii, Hyptis suaveolens and Hildegardia barteri and their bioactivity against three tomato fruit rot pathogens, Aspergillus terreus, Fusarium oxysporum and Geotrichum candidum. The EOs were extracted using hydro distillation, and their chemical composition was determined by gas chromatography and mass spectrometry, while inhibition was determined by Agar diffusion method. Sesquiterpene hydrocarbons were the major constituents of the EOs of T. daniellii (38.7%), H. suaveolens (49.48%) and H. barteri (48.1%). Caryophyllene, guaiol and β-cubebene were the most predominant constituents of T. daniellii, H. suaveolens and H. barteri EOs, respectively. The EOs effectively inhibited radial growth of the pathogens in the in vitro bioassay and their efficacy was significantly higher than mancozeb. This study has shown the prospects of the EOs and sets the pace for further research in the management of postharvest tomato fruit rot under field conditions.

Keywords:

• Essential oils
• fruit rot
• mass spectrometry
• postharvest
• sesquiterpene hydrocarbons

Acknowledgement

Authors are grateful to Mr. Alfred Ossai, a Plant Taxonomist at the Department of Forest Resources Management, University of Ibadan, Nigeria who assisted in the identification of botanicals used in this study and Mr Henry Ade of Hydrochrom Resources Laboratory, Lagos state, Nigeria for his guidance in the gas chromatography, mass spectrometry protocol.

Disclosure statement

The authors declare that they have no competing interests.