The Verbesina gender represents the second most diverse group from the Asteraceae family in Mexico; Verbesina sphaerocephala is one of the most distributed species along the Mexican territory. This species has been poorly studied, reporting the presence of some bioactive compounds with antioxidant and antibacterial activity. In this study, phenolic and flavonoid contents and composition, antioxidant and antifungal activities of aqueous extracts of the stem of V. sphaerocephala and its fractions were determined. The results showed that the highest antifungal activity against Botrytis cinerea was shown by the aqueous extract (IC₅₀: 0.10 mg/mL) and the ethyl acetate fraction (IC₅₀: 14.8 mg/mL). In addition, the aqueous extract and the ethyl acetate fraction exhibited the highest phenolic (21.40 and 21.26 mg gallic acid equivalents per gram of dry extract, respectively) and flavonoid contents (11.53 and 3.71 mg rutin equivalents, respectively) and high antioxidant activity determined by the Total Antioxidant Capacity (20.62 and 40.21 mg ascorbic acid equivalents per gram of dry extract, respectively), Ferric Reducing Power (74.76 and 129.57 mg gallic acid equivalents per gram of dry extract, respectively), DPPH (IC₅₀: 12.38 and 7.36 mg/mL, respectively), and ABTS (IC₅₀: 5.60 and 7.76 mg/mL, respectively) methods. Twelve phenolic compounds were detected in the aqueous extract using UPLC-MS analysis, of which the major ones were protocatechuic, vanillic, and hydroxybenzoic acid, while in the ethyl acetate fraction, the presence of 18 phenolic compounds were identified, of which the majority were vanillin, rutin, and hydroxybenzoic acid. The results of this research demonstrate that the aqueous extract of V. sphaerocephala stems has phenolic compounds with antifungal and antioxidant activity.

Verbesina sphaerocephala A. Gray (Asteraceae) is an endemic plant species with wide distribution in Mexico. This plant is used in traditional medicine and mainly has antioxidant and antifungal activity, due to its phenolic composition. The present study aimed to analyze the antifungal activity and perform a phytochemical screening of aqueous, methanol, ethyl acetate, and chloroform extracts of the inflorescences, leaves, stems, and roots of V. sphaerocephala. Antifungal activity was evaluated using the well diffusion method against two phytopathogenic fungi: Botrytis cinerea and Fusarium oxysporum. Phytochemical screening was performed for phenolic compounds, flavonoids, coumarins, quinones, saponins, and terpenes. Aqueous stem extract exhibited the highest antifungal activity, resulting in a 100% reduction in the mycelial growth of the two fungi at 10 mg/mL. This study revealed that aqueous stem extract suppressed the growth of B. cinerea at a concentration of 1 mg/mL and that this extract contains a high content (++) of phenolics, coumarins and quinones, with and flavonoids and terpenes slightly present (+). Our study showed that the aqueous stem extract of V. sphaerocephala contains phytochemical compounds with fungicidal properties, mainly against B. cinerea.