A Comparative Study on the Antifungal Activity of Aqueous Extracts from Different Parts of Wild Lettuce (Lactuca serriola) Against Selected Phytopathogenic Fungi

Abstract

Wild lettuce (Lactuca serriola L.) is a medicinal plant traditionally used to treat various ailments. This study evaluated the antifungal activity of cold and hot aqueous extracts from different plant parts (roots, stems, and leaves) against three phytopathogenic fungi: Aspergillus niger, Aspergillus flavus, and Fusarium oxysporum. Plant materials were collected from Misurata, Libya, air dried, and ground into powder. Extracts were prepared using cold maceration and hot water extraction methods and incorporated into Sabouraud Dextrose by adding 2 mL of extract to Agar at 15 mL of medium (final concentration: 11.8% v/v). Fungal growth inhibition was assessed by measuring radial growth after 7 days of incubation at 25±2°C. Compared to the control (9.00 cm radial growth), the cold root extract reduced A. flavus growth to 1.60 cm (80.12% inhibition), while the hot root extract only reduced it to 7.00 cm (22.22% inhibition). A similar trend was observed for F. oxysporum and A. niger, where cold extracts also produced much higher inhibition than hot extracts, particularly in root treatments, respectively. Fourier Transform Infrared Spectroscopy (FTIR) analysis revealed the presence of hydroxyl (-OH), carbonyl (C=O), and alkene (C=C) functional groups, indicating bioactive compounds. These findings suggest that L. serriola aqueous extracts, particularly from roots, possess significant antifungal properties may have potential as natural antifungal agents and ecofriendly alternatives to synthetic fungicides in sustainable agriculture.