Isolation and Identification of Pennogenin Tetraglycoside from Cestrum nocturnum (Solanaceae) and Its Antifungal Activity against Fusarium kuroshium, Causal Agent of Fusarium Dieback.

Erika Valencia-Mejía,Israel Bonilla-Landa,Yeli Y León-Wilchez,José A Guerrero-Analco,Juan L Monribot-Villanueva,Mónica Ramírez-Vázquez

doi:10.3390/molecules27061860

Erika Valencia-Mejía, Israel Bonilla-Landa + Show 4 more

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https://doi.org/10.3390/molecules27061860

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Abstract

Antifungal assay-guided fractionation of the methanolic crude extract of Cestrum nocturnum (Solanaceae), popular known as ‘lady of the night’, led the isolation and identification of the steroidal saponin named pennogenin tetraglycoside, which was identified for the first time in this plant species by spectroscopic means. The crude extract, fractions and pennogenin tetraglycoside exhibited mycelial growth inhibition of Fusarium solani and F. kuroshium. F. solani is a cosmopolitan fungal phytopathogen that affects several economically important crops. However, we highlight the antifungal activity displayed by pennogenin tetraglycoside against F. kuroshium, since it is the first plant natural product identified as active for this phytopathogen. This fungus along with its insect symbiont known as Kuroshio shot hole borer (Euwallacea kuroshio) are the causal agents of the plant disease Fusarium dieback that affects more than 300 plant species including avocado (Persea americana) among others of ecological relevance. Scanning electron microscopy showed morphological alterations of the fungal hyphae after exposure with the active fractions and 12 phenolic compounds were also identified by mass spectrometry dereplication as part of potential active molecules present in C. nocturnum leaves.

Highlights

Fusarium dieback (FD) is a rapidly spreading plant disease caused by an exotic ambrosia complex made up of a beetle and its symbiotic filamentous fungi
The main objective of the present work was to determine the antifungal activity against F. kuroshium of the methanolic crude extract of C. nocturnum and to identify the active compounds, contributing to the potential development of novel agents of botanical origin useful in the control of emerging pests such those involved in FD
The study highlights the biological importance of including plant species with high presence in the everwet montane cloud forest of Veracruz, Mexico for searching new antifungal natural products

Summary

Introduction

Fusarium dieback (FD) is a rapidly spreading plant disease caused by an exotic ambrosia complex made up of a beetle and its symbiotic filamentous fungi. The fungus colonizes the walls of the gallery, invading the vascular tissue of the tree, blocking water and nutrients transport causing wilting and, in most cases, the death of the tree, a few weeks after the infestation. This fungus-beetle complex uses as hosts more than 300 different plant species, among which are species of the Lauraceae family such as avocado (Persea americana), a species of economic importance for Mexico and worldwide [1–3]. There is no effective method to control the spread of this complex pest, other than pruning (mechanical removal) of infected specimens to reduce beetle populations and the use of conventional synthetic agrochemicals, which causes ecological repercussions such as pollution of aquatic ecosystems, resistance of pest populations, among other undesirable effects [9–12]

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