Immunomodulatory Effects of Anacardium occidentale Leaves Extract on RAW 264.7 Mouse Macrophage Cell Lines

Abstract

Macrophages are specialist cells in immune system that recognize, engulf, and eliminate pathogens. Furthermore, they have the ability to present antigens to T cells and start an inflammatory response by producing cytokines that stimulate other cells. Macrophage play a major role in innate immunity. Altered immune system may lead to numerous immune-related diseases. Unfortunately, synthetically produced drugs may cause long-term adverse or side effects when consumed such as liver cirrhosis and kidney failure. Due to this, it is essential for researcher to find or develop alternative medicine that able to give immunomodulatory effects without causing adverse or side effects. Based on community believe, Anacardium occidentale has the potential to be an immunomodulatory agent. However, there is still lack of scientific prove to support the statement. Hence, the in vitro was done to determine the immunomodulatory effects of A. occidentale on innate immunity of RAW 264.7 mouse macrophage cell lines. The normal model of the macrophages was cultured and treated with three different treatments for 24 hours. These treatments include different concentration of A. occidentale methanolic extract as treated cells, LPS-induced macrophages as positive control and 0.05% of dimethyl sulfoxide as untreated cells. The cytotoxicity effects on the macrophages were observed through MTT assay (viability percentage) and morphological changes. The results indicate that there were no cytotoxicity effects because no significant different of viability percentage for A. occidentale methanolic extract treated cells when compared to untreated cells. Additionally, treatment of 100 µg/mL, 25 µg/mL and 6.25 µg/mL significantly improve rate of migration and wound closure as compared to the untreated macrophages. As a nutshell, this plant has the potential as immunostimulant agent to prevent infectious diseases.