Variation in phytochemical content and antifungal activity of Trigonella foenum-graecum L. with plant developmental stage and ploidy level

Abstract

The present study was conducted to assess in vitro antifungal activity of diploid and mixoploid Trigonella foenum-graecum L. aqueous extracts, harvested at three developmental stages (vegetative, flowering and fruiting) against Fusarium oxysporum f. sp. radicis-lycopersici (FORL) and Fusarium oxysporum f. sp. lycopersici (FOL). All tested extracts inhibited FORL and FOL mycelial growth. The aqueous extracts of diploid plants were shown to be less toxic than mixoploid ones. FORL seemed to be more sensitive to fenugreek extracts compared to FOL and this toxicity varied with the plant developmental stages. The mixoploids were most toxic against the two pathogens at the flowering stage. Diploids were more toxic at vegetative stage for FOL and at flowering one for FORL. The total phenolics, flavonoids, flavonols and flavones, alkaloids and proanthocyanidins contents in the aqueous extracts were higher in vegetative stage in comparison with the two others. Knowing the plant development stage that gives the richest material would counteract the difficulties of the allelochemical production in very small quantities. Moreover, it seems that mixoploidy induction is an effective tool, to increase the secondary metabolite production, since extract toxicity of diploid and mixoploid plants was different.