Antioxidant and Antifungal Effects of <i>Lavandula stoechas</i> Aqueous Extract Against <i>Aspergillus niger</i> and <i>Fusarium oxysporum</i> as a Potential Natural Preservative and Crop Protection Agent in the Agrifood Sector

The antioxidant and antifungal activities of (Lavandula stoechas) L. stoechas aqueous extract were studied to examine their potential application against food and crop spoilage. Total phenolic (TPC) and flavonoids (TFC) contents were quantified and individual polyphenols were analyzed by high-performance liquid chromatography (HPLC). In vitro antioxidant assays including DPPH, ABTS, and Galvinoxyl radical scavenging, β-carotene bleaching assay, reducing power, CUPRAC, and phenanthroline were applied. The antifungal effect of the extract was evaluated against the two plant pathogenic fungi Aspergillus niger and Fusarium oxysporum using the agar diffusion method. High TPC (197.23 ± 0.12 µg GAE/mg) and TFC (166.93 ± 1.15 µg QE/mg) contents were recorded with the extract. In total, 36 compounds were identified by HPLC, of which 35 are phenolic compounds, with rosmarinic acid (25.2%), p-coumaric acid (7.7%) and luteolin-7-O-glucoside (7.6%) being the representative phenolic compounds. L. stoechas demonstrated strong antioxidant activity in all the methods used. The extract completely inhibited (100% inhibition) the growth of A. niger at a concentration of 5%, while at the same concentration the extract inhibited F. oxysporum with a percentage of 89.62%. These preliminary results suggest the possible use of L. stoechas extract as a potential alternative for preventing plant diseases, reducing post-harvest losses and for food preservation.