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

Abstract

Jatropha dioica 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 Pseudomonas syringae, Botrytis cinerea and Fusarium oxysporum using hydroalcoholic extracts of J. dioica 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 B. cinerea, 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 F. oxysporum, 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 P. syringae 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 J. dioica as an alternative to biopesticides that minimize agrochemical applications and generate pathogen resistance. These advances contribute to the revaluation and conservation of the species.

Keywords: antimicrobial; biological control; postharvest; revalorization; secondary metabolites.

Figure 1

Percentage value of growth inhibition of Botrytis cinerea with hydroalcoholic extracts (ethanol and methanol) evaluated for five days. (a) evaluation at 24 h; (b) at 48 h; (c) at 72 h; (d) at 96 h; (e) at 120 h; at concentrations of 500, 1000, 1500, 2000 and 4000 µg mL⁻¹. C (-): negative control. C (+): positive control with commercial fungicide Ridomil Gold. EB (Botrytis ethanol). MB (Botrytis methanol). Average values ± standard error. ANOVA, Tukey (p ≤ 0.05). Equal letters for each factor are significantly different.

Figure 2

Percentage value of Fusarium oxysporum with the hydroalcoholic extracts evaluated for five days. (a) evaluation at 24 h; (b) at 48 h; (c) at 72 h; (d) at 96 h; (e) at 120 h; at concentrations of 500, 1000, 1500, 2000 and 4000 µg mL⁻¹. C (-): negative control. C (+): positive control with commercial fungicide Ridomil Gold. EF (Fusarium ethanol). MF (Fusarium methanol). Average values ± standard error. ANOVA, Tukey (p ≤ 0.05). Equal letters for each factor are significantly different.

Figure 3

Average value of inhibition halo of Pseudomonas Syringae treated with hydroalcoholic extracts of Jatropha dioica Sessé root at doses of 1000 to 20,000 µg mL⁻¹. EP1 (ethanol 1000); MP1 (methanol 1000); EP2.5 (ethanol 2500); MP2.5 (methanol 2500); EP7.5 (ethanol 7500); MP7.5 (7500); EP10 (ethanol 10,000); MP10 (methanol 10,000); EP20 (ethanol 20,000); MP20 (20,000). Average values ± standard error. ANOVA, Tukey (p ≤ 0.05). Equal letters for each factor are significantly different.