Methyl jasmonate induces the resistance of postharvest blueberry to gray mold caused by Botrytis cinerea.

BACKGROUND: The effects of postharvest methyl jasmonate (MeJA) treatment (50 µmol L-1 ) on the control of gray mold caused by Botrytis cinerea in blueberry fruit were evaluated by analyzing (i) the levels of disease resistance signals; (ii) the activity of enzymes involved in antioxidant system, disease resistance and phenylpropanoid pathway, and (iii) the secondary metabolite content. RESULTS: The results indicated that MeJA treatment significantly restrained the development of gray mold decay in blueberries. The treatment induced a nitric oxide (NO) burst and increased the endogenous hydrogen peroxide (H2 O2 ) content in the earlier period of storage. The enhanced NO and H2 O2 generation by MeJA treatment might serve as a signal to induce resistance against B. cinerea infection. Furthermore, in inoculated fruit, MeJA treatment significantly promoted antioxidant enzymes and defense-related enzyme activity, which included superoxide dismutase, catalase, ascorbate peroxidase, chitinase, and ß-1,3-glucanase, and the degree of membrane lipid peroxidation was reduced. The MeJA treatment enhanced the phenylpropanoid pathway by provoking phenylalanine ammonialyase, cinnamate 4-hydroxylase, and 4-coumarate CoA ligase activity, which was accompanied by elevated levels of phenolics and flavonoids in blueberry fruit. CONCLUSION: These results suggested that MeJA could induce the disease resistance of blueberries against B. cinerea by regulating the antioxidant enzymes, defense-related enzymes, and the phenylpropanoid pathway through the activation of signaling molecules.

Efecto antibacteriano y antioxidante de frutos rojos ecuatorianos sobre streptococcus mutans: estudio in vitro / Antibacterial and antioxidant effect of ecuadorian red fruits on streptococcus mutans: in vitro study

Resumen Objetivo: Evaluar mediante cuantificación de halos de inhibición el efecto antibacteriano de la cáscara y pulpa del capulí (Prunus serotina capulí) y del mortiño (Vaccinium floribundum), sobre cepas de Streptococcus mutans (ATCC 35668) a las 24 y 48 horas, comparado con arándano deshidratado y gluconato de clorhexidina al 0,12%. Materiales y métodos: Estudio experimental transversal in vitro, 15 cajas petri fueron utilizadas para sembrar 20ml de cultivo de cepas de Streptococcus mutans. En cada caja fueron colocados discos de fieltro impregnados con 20 μl de las sustancias evaluadas; mortiño y capulí, en pulpa y en cáscara, arándano deshidratado y gluconato de clorhexidina al 0,12% como control, distribuidos a una distancia equidistante. El análisis del efecto antibacteriano se realizó midiendo la zona de inhibición en un tiempo de 24 y 48 horas de incubación, los datos obtenidos se analizaron estadísticamente en el programa SPSS 22 mediante las pruebas paramétricas y de Kruskal Wallis. Resultados: No existió diferencia estadística significativa entre las variables analizadas, capulí y mortiño tanto en cáscara como en pulpa y clorhexidina empleada como control, en los dos períodos evaluados (p= > 0,05). Conclusiones: Los frutos rojos analizados tienen un efecto antibacteriano a las 24 y 48 horas, lo cual guarda relación con su capacidad antioxidante.

Abstract Objective: To evaluate by quantification of halos of inhibition, the antibacterial effect of the shell and pulp of capulí, (Prunus serotina capuli) and mortiño (Vaccinium floribundum), on strains of Streptococcus mutans (ATCC 35668) at 24 and 48 hours, compared with dehydrated cranberry and chlorhexidine gluconate at 0,12%. Materials and methods: In vitro cross-sectional experimental study, 15 petri dishes were used to plant 20 ul of the evaluated substances were placed in each box, mortiño, and capuli, in pulp and in shell, dehydrated cranberry and 0,12% chlorhexidine gluconate as control, distributed at an equidistant distance. The analysis of the antibacterial effect was performed by measuring the zone of inhibition in a time of 24 and 48 hours of incubation, the dataobtained were statistically analyzed in the SPSS 22 program by parametric and Kruskal Wallis tests. Results: There was no significant statistical difference between the analyzed variables, capuli and mortiño, both in skin and pulp and chlorhexidine used as control, in the two evaluated periods of time (p=>0,05). Conclusions: The red fruits analyzed have an antibacterial effect 24 and 48 hours, which is related to its antioxidant capacity.

Immunomodulatory Effect of Flavonoids of Blueberry (Vaccinium corymbosum L.) Leaves via the NF-κB Signal Pathway in LPS-Stimulated RAW 264.7 Cells.

OBJECTIVE: This study aimed to explore the immunoregulatory effect of flavonoids of blueberry (Vaccinium corymbosum L.) leaves (FBL). METHODS: The flavonoids of blueberry leaves were prepared with 70% ethanol and were identified by ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/Q-Tof-MS). The immunoregulatory effect and possible regulatory mechanisms of FBL were investigated in lipopolysaccharide- (LPS-) induced RAW 264.7 cells. RESULTS: According to the results of UPLC/Q-Tof-MS, nine flavonoids of blueberry leaves were identified. FBL showed a significant reduction in the production of TNF-α in LPS-stimulated RAW 264.7 cells. FBL significantly decreased the expression of NF-κB p65 and P-NF-κB p65 in LPS-induced RAW 264.7 cells in a dose-dependent manner. CONCLUSION: Our study showed the immunoregulatory effect of FBL through the suppression of TNF-α via the NF-κB signal pathway.