Antioxidant and anti‑inflammatory effects of a mixture of propolis, red bean and tomato extracts

The aim of the present study was to investigate the antioxidant and anti‑inflammatory effects of a mixture of propolis, red bean and tomato extracts (PRTE). First, the radical scavenging activities of various combinations of PRTE (1:1:1, M1‑PRTE; 1.5:1:0.5, M2‑PRTE; 1.5:0.5:1, M3‑PRTE; and 1.2:0.9:0.9, M4‑PRTE) were estimated. M2‑PRTE exhibited the optimal 2,2‑diphenyl‑1‑picrylhydrazyl (DPPH) and 2,2'‑azino‑bis (3‑ethylbenzothiazoline‑6‑sulfonic acid) (ABTS) radical scavenging efficacy compared to the other ratios. The DPPH and ABTS radical scavenging activities (IC₅₀) of M2‑PRTE were 192.86±3.34 and 554.28±4.78 µg/ml, respectively. M2‑PRTE also restored the levels of superoxide dismutase, glutathione peroxidase and glutathione which were reduced by fine particulate matter in HaCaT cells. In addition, M2‑PRTE suppressed the levels of inflammatory mediators, such as nitric oxide, inducible nitric oxide synthase, cyclooxygenase‑2 and prostaglandin E2, which were increased by lipopolysaccharide (LPS) stimulation in the RAW264.7 cells, in a dose‑dependent manner. In addition, M2‑PRTE significantly inhibited the production of pro‑inflammatory cytokines, including interleukin (IL)‑1β, tumor necrosis factor‑α and IL‑6, which were increased by LPS stimulation in RAW264.7 cells. On the whole, the findings of the present study suggest that M2‑PRTE is an effective material for alleviating oxidative stress and inflammatory responses caused by environmental pollution, and it has potential for use in health functional foods.