Anti-inflammatory and anti-cancer activity of mulberry (Morus alba L.) root bark

Background: Root bark of mulberry (Morus alba L.) has been used in herbal medicine as anti-phlogistic, liver protective, kidney protective, hypotensive, diuretic, anti-cough and analgesic agent. However, the anti-cancer activity and the potential anti-cancer mechanisms of mulberry root bark have not been elucidated. We performed in vitro study to investigate whether mulberry root bark extract (MRBE) shows anti-inflammatory and anti-cancer activity. Methods: In anti-inflammatory activity, NO was measured using the griess method. iNOS and proteins regulating NF-kappa B and ERK1/2 signaling were analyzed by Western blot. In anti-cancer activity, cell growth was measured by MTT assay. Cleaved PARP, ATF3 and cyclin D1 were analyzed by Western blot. Results: In anti-inflammatory effect, MRBE blocked NO production via suppressing iNOS over-expression in LPS-stimulated RAW264.7 cells. In addition, MRBE inhibited NF-kappa B activation through p65 nuclear translocation via blocking I kappa B-alpha degradation and ERK1/2 activation via its hyper-phosphorylation. In anti-cancer activity, MRBE deos-dependently induced cell growth arrest and apoptosis in human colorectal cancer cells, SW480. MRBE treatment to SW480 cells activated ATF3 expression and down-regulated cyclin D1 level. We also observed that MRBE-induced ATF3 expression was dependent on ROS and GSK3 beta. Moreover, MRBE-induced cyclin D1 down-regulation was mediated from cyclin D1 proteasomal degradation, which was dependent on ROS. Conclusions: These findings suggest that mulberry root bark exerts anti-inflammatory and anti-cancer activity.