Composition and antifungal effects of aqueous extracts of Cymbopogon citratus, Laurus nobilis and Santolina chamaecyparissus on the growth of Fusarium oxysporum f. sp. lentis

Abstract

Aqueous extracts of three aromatic and medicinal plants, viz. lemongrass (Cymbopogon citratus), laurel (Laurus nobilis) and cotton-lavender (Santolina chamaecyparissus) were tested against the growth of Fusarium oxysporum f. sp. lentis. The aqueous extracts concentrations were evaluated from 0.05 to 20 mg/mL. Ultra-High-Performance Liquid Chromatography (UHPLC)-Quadrupole-Time-of-Flight-Mass Spectrometer and UHPLC-potato dextrose agar were used to identify and quantify the major phenolic compounds. Lemongrass extract revealed the best antifungal activity; a concentration of 0.05 mg/mL inhibited 67% of conidial germination and 77% sporulation, 5 mg/mL restrain 70% of mycelial growth and 20 mg/mL stopped almost completely the pathogen. The extracts of laurel and cotton-lavender exhibited a moderate inhibition on conidial germination and mycelial growth even at 20 mg/mL, while laurel extracts inhibited 75% of sporulation at 0.05 mg/mL. Four phenolic acids and 16 flavonoids were identified and quantified in the three aqueous extracts. Luteolin derivatives represent 96% of the phenolic compounds identified in lemongrass while procyanidin and caffeic acid derivatives represent 76% and 96% in laurel and cotton-lavender, respectively. Our investigation demonstrates that lemongrass was an actual source of aqueous extract with a biomolecule content that could effectively be used for the control of lentil Fusarium wilt.