Chemical compounds in natural medicines that affct macropharges and adipocyte cells

Abstract

Macrophages play major roles in infiammation, immunity and host defense mechanisms. Once activated they produce and release cytokines, oxygen and nitrogen species, and eicosanoids. The best characterized stimuli to induce the transcription of genes encoding pro-infiammatory proteins in macrophages in vitro is bacterial lipopolysaccharide (LPS). LPS could be used alone or in combination with recombinant mouse interferon-γ (IFN-γ). Such stimulation results in cytokine release and the synthesis of enzymes such as cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS). The nitric oxide (NO) radical is known to play a central role in infiammatory and immune reactions for self-protection. However, the excessive production of NO may lead to tissue damage. In infiammatory diseases such as rheumatoid arthritis, excessive NO production by activated macrophages has been observed. Adipose tissue is composed of various cell types such as mature adipocytes, preadipocytes, fibroblasts, endothelial cells, vascular cells, and macrophages. Recent studies indicate that obesity is associated with low-grade chronic infiammation of adipose tissues, and that such infiammation is one of the potential mechanisms leading to the insulin resistance. It has been demonstrated that obese adipose tissue is characterized by the increased infiltration of macrophages. Therefore, we attempted to identify natural anti-infiammatory compounds that not only inhibit the secretion of NO from RAW 264.7 cells, but also inhibit triglyceride accumulation in 3T3-L1 adipocytes. This review describes the NO prpduction inhibitory activity or the TG accumulation inhibitory activity of the compounds obtained from 18 plants and a fungi that have been used as traditional medicines.