Anti-Inflammatory Activity of Sulfur-Containing Compounds from Garlic

We identified four anti-inflammatory sulfur-containing compounds from garlic, and their chemical structures were identified as Z- and E-ajoene and oxidized sulfonyl derivatives of ajoene. The sulfur compounds inhibited the production of nitric oxide (NO) and prostaglandin E-2 (PGE(2)) and the expression of the pro-inflammatory cytokines tumor necrosis factor-alpha, interleukin-1 beta, and interleukin-6 in lipopolysaccharide (LPS)-activated macrophages. Western blotting and reverse transcription- polymerase chain reaction analysis demonstrated that these sulfur compounds attenuated the LPS-induced expression of the inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins and mRNA. Moreover, these sulfur-containing compounds suppressed the nuclear factor-kappa B (NF-kappa B) transcriptional activity and the degradation of inhibitory-kappa B alpha in LPS-activated macrophages. Furthermore, we observed that they markedly inhibited the LPS-induced phosphorylations of p38 mitogen-activated protein kinases and extracellular signal-regulated kinases (ERK) at 20 mu M. These data demonstrate that the sulfur compounds from garlic, (Z, E)-ajoene and their sulfonyl analogs, can suppress the LPS-induced production of NO/PGE(2) and the expression of iNOS/COX-2 genes by inhibiting the NF-kappa B activation and the phosphorylations of p38 and ERK. Taken together, these data show that Z- and E-ajoene and their sulfonyl analogs from garlic might have anti-inflammatory therapeutic potential.