Bioassay-guided fractionation networking for discovery of biofungicides from cultivated Salvia canariensis

Abstract

Considering the detrimental impacts of the current pesticides on the biotic components of the biosphere, the development of novel pesticides is vital. Plant-derived biopesticides have emerged as popular alternatives to create a safer and more sustainable agriculture model. This study aims to validate the previous bioguided fractionation of endemic Canary Islands sage, Salvia canariensis, as a potential source of botanical pesticides using a cultivation process. Accordingly, the bioassay-guided fractionation of the ethanolic extract of the leaves of cultivated S. canariensis on the phytopathogenic fungal mycelia of Botrytis cinerea, Fusarium oxysporum, and Alternaria alternata yielded six known terpenoids. Their abietane diterpenoid-type (1–5) and sesquiterpenoid (6) structures were established based on spectroscopic and spectrometric analysis. This strategy identified one abietane diterpenoid, salviol (5), as a potential candidate for the future development of biofungicides with similar potency towards the assayed phytopathogenic fungi to commercial fungicides. Salviol worked in a concentration-dependent manner. Overall, this study reinforces the potential of abietane-type diterpenoids as promising agrochemical lead compounds against infectious diseases caused by phytopathogenic fungi and validates the cultivation of S. canariensis as a potential source of plant-derived biopesticides.