Fungistatic and Bactericidal Activity of Hydroalcoholic Extracts of Root of Jatropha dioica Sessé

<i>Jatropha dioica</i> Sessé (JD) is a plant from arid and semiarid zones of Mexico related to local therapeutic uses and possible use in food and agriculture as a control agent of pest organisms that helps to reduce impacts on the environment, human health and resistance by phytopathogens. In vitro bactericidal activity was evaluated with the well diffusion method in doses of 1000, 2500, 5000, 7500, 10,000 and 20,000 µg mL^-1, and fungistatic activity was evaluated with the agar dilution method (500, 1000, 1500, 2000 and 4000 µg mL^-1) in <i>Pseudomonas syringae</i>, <i>Botrytis cinerea</i> and <i>Fusarium oxysporum</i> using hydroalcoholic extracts of <i>J. dioica</i> root in a completely randomized design with five replications. Total phenol and flavonoid contents were recorded by the Folin-Ciocalteu and aluminum chloride methods. Ethanol and methanol extracts showed fungistatic activity on <i>B. cinerea</i>, inhibiting from 42.27 ± 1.09 to 46.68 ± 0.98 mg mL^-1, with an IC₅₀ of 5.04 mg mL^-1, with no differences by solvent type. In <i>F. oxysporum</i>, inhibition ranged from 14.77 ± 1.08 to 29.19 ± 0.89 mg mL^-1, and the methanol extract was more efficient, generating a stress response to the ethanol extract. The bactericidal activity on <i>P. syringae</i> recorded inhibition zones of 17.66 ± 0.33 and 16.66 ± 0.33 mg mL^-1, with ethanol being more efficient. The phenol content ranged from 8.92 ± 0.25 to 12.10 ± 0.34 mg EAG g^-1 and flavonoid content ranged from 20.49 ± 0.33 to 28.21 ± 0.73 mg QE g^-1 of sample dry weight. The results highlight the biological activity of <i>J. dioica</i> as an alternative to biopesticides that minimize agrochemical applications and generate pathogen resistance. These advances contribute to the revaluation and conservation of the species.