# Extracts of Argemone mexicana L. Contain Antifungal Compounds for the In Vitro Control of Monilinia fructicola, Colletotrichum gloeosporioides, Fusarium oxysporum, and Sclerotinia sclerotiorum: Preliminary Evidence for Field Application

## TL;DR

This study shows that extracts from the plant Argemone mexicana have antifungal properties that could be used to control harmful fungi in crops.

## Contribution

The study identifies specific antifungal compounds in A. mexicana extracts and evaluates their effectiveness against multiple phytopathogenic fungi.

## Key findings

- Hexanic extract showed fungistatic activity against four fungi, while methanolic extract was fungicidal against two.
- GC-MS analysis identified 14 and 11 compounds in hexane and methanol extracts, respectively.
- Extracts demonstrated variable EC50 and EC90 values, suggesting potential as natural antifungal agents.

## Abstract

Argemone mexicana L. is considered a weed; however, it contains secondary metabolites that can control phytopathogenic fungi in vitro, with the potential to adapt its effectiveness in the field. In the present study, leaf extracts of A. mexicana (hexane and methanol) were prepared, and their chemical profiles were analyzed using gas chromatography–mass spectrometry (GC-MS). The in vitro antifungal activity of each extract was evaluated at different concentrations (500, 1000, 2000, 4000, and 8000 mg L−1) against phytopathogens such as Monilinia fructicola, Colletotrichum gloeosporioides, Fusarium oxysporum, and Sclerotinia sclerotiorum. Based on their chemical profiles, 14 compounds were identified in the hexanic extract, and 11 compounds were identified in the methanolic extract. These compounds included those with antifungal activity, such as Benzene; 1.3-bis(1.1-dimethylethyl)-; pentanoic acid; 5-hydroxy-, 2,4-di-1-butylphenyl esters; 1,2,4-Triazol-4-amine; and N-(2-thienylmethyl). The hexanic extract demonstrated fungistatic activity on the four fungi tested, while the methanolic extract exhibited fungicidal activity against C. gloeosporioides and F. oxysporum. The results of the Probit analysis showed variations in the sensitivity of phytopathogenic fungi to the treatments evaluated. In M. fructicola, the hexane extract presented an EC50 of 317,146 mg L−1 and an EC90 of 400,796 mg L−1. For C. gloeosporioides, the EC50 was 2676 mg L−1 and the EC90 was 888,177 mg L−1, while in F. oxysporum an EC50 of 34,274 mg L−1 and an EC90 of 1528 mg L−1 were estimated. In the case of S. sclerotiorum, an EC50 of 560 mg L−1 and an EC90 of 7776 mg L−1 were obtained. Finally, for the commercial fungicide Captan®, an EC50 of 1.19 mg L−1 and an EC90 of 1.67 mg L−1. These results suggest that extracts from A. mexicana could provide a natural alternative for the control of phytopathogenic fungi.