Antiinflammatory Effects of Functionally Active Compounds Isolated from Aged Black Garlic

The antiinflammatory effects of functionally active compounds isolated from aged black garlic (AGE‐1 and AGE‐2) were investigated using a lipopolysaccharide‐induced inflammatory response model. To examine the potential antiinflammatory properties of AGE‐1 and AGE‐2, cell viability as well as nitric oxide, prostaglandin E2, and pro‐inflammatory cytokine [interleukin‐6 (IL‐6), TNF‐α, and IL‐1β] levels were measured. The mRNA and protein expression levels of inducible nitric oxide synthase and cyclooxygenase‐2 were detected by reverse transcription polymerase chain reaction and western blotting. The results indicated that AGE‐1 and AGE‐2 were not cytotoxic to macrophages. Nitric oxide and prostaglandin E2 levels decreased significantly with increasing concentration of AGE‐1 (IC 50 = 29.6 and 1.41 µg/mL, respectively), but not AGE‐2. The secretion of IL‐6, TNF‐α, and IL‐1β was also suppressed by AGE‐1 in a dose‐dependent manner, and inducible nitric oxide synthase and cyclooxygenase‐2 mRNA, and protein expression decreased with AGE‐1 treatment. Furthermore, AGE‐1 attenuated the phosphorylation of the extracellular signal‐regulated kinase, p38, and c‐Jun terminal kinase in lipopolysaccharide‐induced RAW264.7 cells. These results suggested that compound AGE‐1 may have significant effects on inflammatory factors and could potentially be used as an antiinflammatory therapeutic agent. Copyright © 2016 John Wiley & Sons, Ltd.