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 (IC₅₀ = 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.