Antiinflammatory effect of Oldenlandia diffusa and its constituent, hentriacontane, through suppression of caspase-1 activation in mouse peritoneal macrophages.

Oldenlandia diffusa (OD) has been used as a natural drug for the treatment of cancer in Asia and specifically in Korea. However, the antiinflammatory mechanisms employed by OD have yet to be completely understood. This study attempted to determine the effects of OD and hentriacontane, one of the constituent compounds of OD, on lipopolysaccharide (LPS)-induced inflammatory responses in mouse peritoneal macrophages. The findings of this study showed that OD inhibited the production of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and prostaglandin E(2) (PGE(2)). The OD inhibited the enhanced levels of cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) induced by LPS. It was shown that the antiinflammatory effect of OD occurs via the regulation of the activation of nuclear factor (NF)-κB and caspase-1. Moreover, hentriacontane was shown to ameliorate the expression of inflammatory mediators (TNF-α, IL-6, PGE(2), COX-2 and iNOS) and the activation of NF-κB and caspase-1 in LPS-stimulated peritoneal macrophages. These results provide novel insights into the pharmacological actions of OD as a potential candidate for the development of new drugs for the treatment of inflammatory diseases.