Sclareol Reduces CD4+ CD25+ FoxP3+ T-reg Cells in a Breast Cancer Model in Vivo

Background: Sclareol is a phytochemical used in people's diet in Southeast Asia. Objective: To investigate the immunotherapeutic effectiveness of Sclareol against breast cancer by direct intraperitoneal injection. Methods: Sclareol was isolated and purified from Salvia sclarea. Effect of Sclareol on cell growth inhibition was evaluated by MTT assay. Intraperitoneally injected Sclareol effects on reducing the tumor volume and shifting the cytokine profile were investigated. We also assessed if intraperitoneally injected Sclareol could improve the outcome of cancer therapy through suppressing the regulatory T cells. Results: The results confirmed a significant decrease in the tumor size. Furthermore, a significant decrease in the level of IL-4 and an increase in the level of IFN-γ were noticed in the intraperitoneally injected Sclareol group (p