Extraction of essential oil from Lavandula angustifolia flowers for the green synthesis of AgNPs and evaluation of their antifungal activity

Abstract

The growing need for sustainable agricultural practices has spurred interest in green-synthesized nanomaterials as alternatives to synthetic fungicides like benomyl, which face challenges of resistance development and environmental toxicity. This study demonstrates the dual potential of Lavandula angustifolia (lavender) as a source of bioactive compounds and a platform for eco-friendly silver nanoparticle (AgNP) synthesis. AgNPs were biosynthesized using lavender extract and characterized by UV-Vis spectroscopy, SEM, FT-IR, and XRD, revealing spherical nanoparticles (46–52 nm) stabilized by plant metabolites. While lavender’s ethyl acetate and methanolic extracts showed limited antifungal activity against pathogens (Alternaria alternata, Colletotrichum musae, Aspergillus niger, Penicillium digitatum, Fusarium proliferatum, and Bipolaris sorokiniana), its essential oil exhibited good inhibition (72–75 % at 2000–4000 ppm). In contrast, the lavender-synthesized AgNPs displayed remarkable broad-spectrum efficacy, achieving 90 % inhibition of C. musae at 1000 ppm and 96 % inhibition of A. alternata at 1000 ppm—surpassing both lavender extracts and conventional benomyl in persistence and penetration ability in PDA media. The nanoparticles’ superior performance is suggested to be due to their green synthesis-derived biocompatible capping agents and potential multimodal antifungal mechanisms, as supported by the literature, including cell wall disruption and oxidative stress induction. This work underscores lavender-based AgNPs as a sustainable, resistance-proof alternative to chemical fungicides, aligning with green chemistry principles by minimizing synthetic inputs and environmental impact while enhancing crop protection.