In vitro Immunostimulatory Activity of Bok Choy (Brassica campestris var. chinensis) Sprouts in RAW264.7 Macrophage Cells

Bok choy is one of Brassica vegetables widely consumed worldwide. Brassica vegetables have been reported to exert various pharmacological activities such as antioxidant, anti-cancer and cardioprotective activity. However, studies on immunostimulatory activity of bok choy sprout have not been conducted properly. Thus, in this study, we investigated in vitro immunostimulatory activity of bok choy sprout extract (BCS) using mouse macrophage RAW264.7 cells. Our results showed that BCS increased the production of immunomodulators such as NO, iNOS, IL-1β, IL-6, IL-12, TNF-α and MCP-1, and phagocytic activity in RAW264.7 cells. BCS activated MAPK, NF-κB and PI3K/AKT signaling pathways. However, BCS-mediated production of immunomodulators was dependent on JNK, NF-κB and PI3K/AKT signaling pathways. the mRNA expression of TLR2 were significantly increased by BCS, TLR2 inhibition by anti-TLR2 dramatically suppressed the production of immunomodulators by BCS. In addition, TLR2 inhibition by anti-TLR2 significantly reduced BCS-mediated phosphorylation level of AKT, JNK and NF-κB. From these results, BCS may have immunostimulatory activity via TLR2-MAPK, NF-κB and PI3K/AKT signaling pathways. Therefore, BCS expected to be used as a potential immune-enhancing agent.