Effects of jujube fruit extract on peripheral blood mononuclear cell proliferation, cytokine productions and intracellular hydrogen peroxide level

Abstract

Background: Ziziphus genus (jujube) is a fruit, which is commonly found and used in Eastern traditional medicine for various conditions. Immunomodulation and anti-oxidant activities of jujube fruit extract are reported. This study aimed to observe immunomodulation effects of green (unripe) and ripe jujube fruit extract on peripheral blood mononuclear cell (PBMC) proliferation by carboxyfluorescein diacetate (CFSE) fluorescence, cytokine profiling by enzyme-linked immunosorbent assay (ELISA), and intracellular H2O2 level by dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence. Results: Treatments of PBMC with both green and ripe pulp extracts resulted in non-significant increases, about 1.01 - 1.15 times, in PBMC proliferation compared to the untreated group (p > 0.05). The pro-inflammatory cytokine (IL-1β) and regulatory Th2 cytokine (IL-10) levels were significantly higher in PBMC treated with ripe jujube fruit extract than in the cells stimulated with green jujube extract (p < 0.05). Th1 cytokine (IFN-γ) level was not significantly different between the ripe and green jujube extract. A higher percentage of intracellular H2O2 reduction was observed in PBMC treated with the green pulp extract compared to the ripe pulp extract (p < 0.05). Conclusions: This study provides practical information about an effect of jujube staging on some cytokine inductions. The reduction of intracellular oxidative stress seems to involve these cytokine induction phenomena.