Quercetin handles cellular oxidant/antioxidant systems and mitigates immunosenescence hallmarks in human PBMCs: An in vitro study

Immunosenescence, oxidative stress, and low vaccine efficacy are important symptoms of aging. The goal of our study was to test if quercetin had antiaging and stimulating effects on peripheral blood mononuclear cell (PBMC) immune cells in vitro in the presence of concanavalin a, PBMCs were isolated from healthy elderly and young people and cultured in a complete Roswell Park Memorial Institute 1640 medium supplemented with quercetin. Cell proliferation was assessed using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide colorimetric assay after a 48-h incubation period. Spectrophotometric assays were used to assess oxidative biomarkers (proteins carbonyl PC], malondialdehydes MDA], and reduced glutathione GSH]). The enzyme-linked immunosorbent assay method was used to determine the amount of interleukin (IL)-2 released. A Griess reagent was used to investigate inducible nitrite oxide synthase (iNOS) activity. When compared to young control cells, aged PBMCs had lower proliferation potency, lower IL-2 and NO release, and higher MDA and PC levels. Importantly, quercetin-treated aged PBMCs have a high proliferative response comparable to young cells, restored iNOS activity, and increased levels of GSH antioxidant defences. In comparison to untreated aged PBMCs, treated PBMCs have lower lipo-oxidative damage but higher PC levels. Quercetin may be used as a promising dietary vaccinal adjuvant in the elderly, it has significant effects in reducing immunosenescence hallmarks, as well as mitigating the lipo-oxidative stress in PBMCs cells.