Immunomodulatory effects of Curcuma longa L. and Carthamus tinctorius L. on RAW 264.7 macrophages and cyclophosphamide-induced immunosuppression C57BL/6 mouse models

Abstract

• First, the anti-inflammatory effect of the two natural products is due to curcumin and luteolin, the active ingredients of these two natural products. • Second, cotreatment with CLE and CTE exerted anti-inflammatory activities by suppressing the activation of ERK 1/2 and p38 pathways. • Third, both natural products can regulate innate immunity by regulating the activation of NK cells. The present study investigated the immunomodulatory effects of extracts of Curcuma longa L. (CLE) and Carthamus tinctorius L. (CTE) on inflamed macrophages and immunosuppressed mouse models. RAW 264.7 Macrophage cells were treated with various concentrations of CLE, CTE, and CLE + CTE to observe cell viability and nitric oxide (NO) production. Results showed that all treatments inhibited NO production, with the CLE + CTE treatment showing the strongest inhibitory effect. Furthermore, expression levels of iNOS and COX-2 were more strongly downregulated by treatment with CLE + CTE via regulation of ERK 1/2 and p38 activation. Moreover, CLE + CTE significantly upregulated the viability of peritoneal cavity cells, natural killer (NK) cell activity, and NK cell-related cytokines expression. All treatments (CLE, CTE, CLE + CTE) upregulated body weights and NK cell activity. Taken together, our results provide scientific evidence for the synergic effect between CLE and CTE as a co-treatment for anti-inflammatory and immunomodulatory effects.