An Anacardiaceae preparation reduces the expression of inflammation-related genes in murine macrophages

This study investigated the effects of an aqueous extract of the stem bark of Mangifera indica L. (Anacardiaceae; Vimang), which contains a defined mixture of components including polyphenols (principally mangiferin, MA), triterpenes, phytosteroids, fatty acids and microelements, on expression of inflammation mediators in inflammatory murine macrophages after stimulation in vitro with lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma). In vitro treatment with Vimang at 4 microg/ml reduced levels of NOS-2 mRNA and NOS-2, while treatment at 40 microg/ml also reduced levels of COX-2 mRNA, COX-2, and prostaglandin E2 (PGE2). Results suggested that MA is involved in these effects. In vitro treatment with Vimang at 40 microg/ml also inhibited mRNA levels of the proinflammatory cytokines interleukin 1beta (IL-1beta), tumor necrosis factor alpha (TNF-alpha) and colony-stimulating factor (GM-CSF), but did not affect mRNA levels of IL-6 or tumor growth factor-beta (TGF-beta). Extracellular release of TNF-alpha by inflammatory macrophages was inhibited by in vitro treatment with Vimang at the same concentrations that showed inhibition of TNF-alpha mRNA levels. The inhibition of TNF-alpha production appears to be at least partially attributable to MA. Vimang at 4 microg/ml decreased mRNA levels of nuclear factor-kappaB (NF-kappaB) but did not affect expression of the NF-kappaB inhibitor (IkappaB). These data indicate that the potent anti-inflammatory effects of Vimang are due to selective modulation of the expression of inflammation-related genes, leading to attenuation of macrophage activation.