INHIBITORY EFFECTS OF ESSENTIAL OIL FROM THE LEAVES OF CINNAMOMUM CASSIA AND CINNAMALDEHYDE ON LPS-STIMULATED MACROPHAGE J774A.1

Abstract

This study investigated and compared the effects of leaf cassia oil from Cinnamomum cassia and cinnamaldehyde on lipopolysaccharide (LPS)-activated macrophage J774A.1 cells. By GC-MS/MS, cinnamaldehyde (78.35 %) was the main component of leaf cassia oil in this study. Cassia oil and cinnamaldehyde at 1-20 µg/ml were markedly inhibited nitric oxide (NO) production in LPS-activated J774A.1 cells in concentration-dependent manner with IC50 value of 6.1±0.25 and 9.97±0.35 µg/ml, respectively. They markedly inhibited phagocytic activity at both 10 and 20 µg/ml. Using RT-PCR, they down-regulated mRNA expression of cytokines and chemokines involve in inflammation in the LPS-activated cells. These mediators included tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and macrophage inflammatory protein-1α (MIP-1α). They also significantly decreased mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), microsomal prostaglandin-E synthase (mPGES-1) determined by RT-PCR and inhibited the production of TNF-α determined by ELISA. In the opposite way, they increased mRNA expression and the production of inhibitory cytokines IL-10 and transforming growth factor (TGF-β). They also up-regulated IL-10 production determined by ELISA. In addition, they promoted the expression of the iron exporter protein ferroportin 1 (Fpn1). The results from this study demonstrated that inhibitory effect of leaf cassia oil from C. cassia came mainly from cinnamaldehyde. This compound not only inhibited inflammatory mediators but also activated anti-inflammatory mediators in LPS activated J774A.1 cells. It may also have effect on iron regulatory proteins in activated macrophages.