Clinacanthus nutans is widely used as a traditional medicine in Thailand and other countries in Southeast Asia. Although its effectiveness is well documented, its therapeutic use is limited to the treatment of only a few diseases; mostly it is used as an anti-viral agent against varicella-zoster and herpes simplex virus infections. Herein, we demonstrate the therapeutic activity of C. nutans extracts in lowering inflammation in a model of bovine mastitis caused by bacterial infection. Lipopolysaccharide (LPS), a gram-negative bacterial component, caused inflammation activation in bovine endothelial cells (CPAE) through the upregulation of proinflammatory cytokines (IL6 and IL1β) and chemokines (CXCL3 and CXCL8) gene expression, partially leading to cell death. Treatment with C. nutans crude extract significantly diminished these responses in a dose-dependent manner. The solvent fractionation of C. nutans extract revealed that the ethyl acetate (C4H8O2) fractions had a high potential to protect against cell death and diminished IL1β, IL6, CXCL3, and CXCL8 levels to less than 0.45 folds relative to the LPS-treated control. Glyceryl 1,3-distearate (C39H76O5) was identified as a bioactive compound responsible for the anti-inflammation activity but not the anti-cell death activity of C. nutans extract. This study highlighted the efficiency of C. nutans extracts as an alternative therapeutic option for the natural-product sustainable development of bovine mastitis treatment.
Keywords: Clinacanthus nutans; LPS-induced cell death; anti-inflammatory activity; bovine mastitis; plant extracts.