Immunomodulatory effects of Tinospora crispa extract and its major compounds on the immune functions of RAW 264.7 macrophages

The in vivo immunomodulatory activities of Tinospora crispa have been reported but its molecular mechanisms underlying its immunomodulatory properties remains obscure and the active constituents contributing to the activities have not been identified. The present study was aimed to investigate the immunomodulatory effects of T. crispa extract (TCE) and its chemical constituents on RAW 264.7 macrophages. Six known compounds including magnoflorine and syringin were isolated by various chromatographic techniques from TCE and their structures were determined spectroscopically. A validated HPLC method was used to quantify magnoflorine and syringin in the extract. The immunomodulatory effects of TCE and its isolated compounds on chemotaxis, phagocytosis, production of inflammatory mediators including reactive oxygen species (ROS), nitric oxide (NO), prostaglandin E2 (PGE2) and pro-inflammatory cytokines which include tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and monocyte chemoattractant protein-1 (MCP-1) on macrophages were assessed. TCE increased the chemotaxis and phagocytic activity of macrophages and significantly enhanced the production of ROS, NO and pro-inflammatory cytokines. All alkaloids isolated, specifically magnoflorine showed remarkable inducing effects on the chemotaxis, phagocytic activity, ROS and NO productions and the secretions of IL-1β, TNF-α, IL6, PGE2 and MCP-1. In contrast, syringin potently reduced the chemotaxis, phagocytic activity, ROS and NO productions and secretions of IL-1β, TNF-α, IL6, PGE2 and MCP-1. TCE showed strong immunostimulant effects on various components of the immune system and these activities were possibly contributed mainly by the alkaloids specifically magnoflorine. TCE has potential to be developed as an effective natural immunostimulant for improvement of immune-related disorders.