In vivo fungicidal properties of Diospyros kaki-isolated compound and its analogues

Jun-Hwan Park,Hoi-Seon Lee

doi:10.1007/s13765-018-0369-1

Abstract

Fungicidal effects of active component purified from Diospyros kaki roots and its analogues against Erysiphe graminis, Botrytis cinerea, Pyricularia grisea, Puccinia recondite, Rhizoctonia solani, and Phytophthora infestans were investigated using a whole-plant method. Active constituents isolated from the chloroform fraction of D. kaki roots were characterized as plumbagin, using various spectroscopic analyses. To establish the structure–activity relationships, the fungicidal effects of plumbagin and its structural analogues were bioassayed against phytopathogenic fungi. At 0.25, 0.125, and 0.0625 g/L, plumbagin had a greater fungicidal effect than p-naphthoquinone, juglone, lawsone, 2-methoxy-p-naphthoquinone, or menadione against P. grisea, B. cinerea, R. solani, and E. graminis. Our results suggest that the methyl and hydroxyl functional groups at the 5′- and 2′-positions of p-naphthoquinone play key roles in its fungicidal effect against six phytopathogenic fungi. Therefore, plumbagin and its analogues may be suitable as antifungal agents to control plant diseases.

Highlights

Plant pathogens, such as bacteria, fungi, nematodes, and viruses, cause several diseases or damages in plants [1]
Synthetic fungicides, such as benzimidazole and difenoconazole, are widely used to control plant diseases caused by phytopathogenic fungi [5, 6]
The extract was filtered over Toyo filter paper No 2 (Tokyo, Japan), and methanol was completely removed from the residual D. kaki roots by evaporation with a rotary vacuum evaporator

Summary

Introduction

Plant pathogens, such as bacteria, fungi, nematodes, and viruses, cause several diseases or damages in plants [1]. Among these plant pathogens, fungi are the major plant pathogen and cause many serious diseases of plants. Synthetic chemicals have been used as fungicidal agents to control plant diseases [4]. Synthetic fungicides, such as benzimidazole and difenoconazole, are widely used to control plant diseases caused by phytopathogenic fungi [5, 6]. One possible answer is to use plant-derived metabolites as sources for the development of fungicidal agents [8, 9]

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