Bioactive potential of Zygophyllum gaetulum Emb. & Maire: Impact of extraction method and plant condition on its antioxidant and antifungal activities

Abstract

Antioxidant and antifungal compounds of plant origin are attracting attention due to concerns about the harmful effects of synthetic agents. This study aims to identify and promote new natural sources with high bioactive potential. It focuses on Zygophyllum goetulum Emb. & Maire, a plant valued in traditional medicine and prepared using an original steaming method. Tests were carried out to evaluate the phytochemical composition and antioxidant and antifungal activity of the plant. The total phenolic compound content was determined using the Folin-Ciocalteu method, and flavonoids were quantified using quercetin. Antioxidant activity was evaluated in vitro using the DPPH. Antifungal activity was tested on Fusarium oxysporum f. sp. lycopersici by measuring the percentage of inhibition after 7 days. Three extraction methods (infusion, decoction, and maceration) were applied to the whole plant in its dried and steamed states. The results revealed a rich phytochemical composition, with the first reported detection of resins and cardiac glycosides in Z. gaetulum. The decoction of the steamed plant has the highest TPC (9.815 ± 0.136 mg GAE · g⁻¹ dry extract) and TFC (4.422 ± 0.171 mg QE · g⁻¹ dry extract), surpassing any type of aqueous extract. DPPH analysis confirms this dominance, with an IC₅₀ of 0.253 mg · ml⁻¹ and an inhibition rate of 80.23%, showing a strong correlation with the presence of polyphenols and flavonoids. In terms of antifungal activity, this same extract was the most effective, with an average inhibition rate of 37.78%, followed by the macerate of the steamed plant (36.39%) and the macerate of the dried plant (31.85%). These results confirm decoction after steaming as the most effective extraction method and Z. goetulum as a promising source of antioxidant and antifungal compounds.