Background: Artemisia diffusa contains a new type of sesquiterpene lactone with an endoperoxide group (Tehranolide).
Objective: Due to the existing similarity between the structures of Tehranolide and Artemisinin, it was hypothesized that Tehranolide would have similar effects as Artemisinin. In this study, the immunotherapeutic effec-tiveness of Tehranolide was investigated by direct intra-tumoral injection.
Methods: Tehranolide was purified from Artemisia diffusa, and its effect on the tumor volume was investigated. The splenocyte proliferation, shifting of cytokine profile, and the presence of naturally-occurring CD4+CD25+Foxp3+ Treg cells were assessed to describe the anti-tumor immune response.
Results: Analysis of immune response showed that, intra-tumoral injection of Tehranolide decreased the rate of tumor growth compared to control group. Furthermore, the proliferative response of mice treated with Tehranolide was en-hanced. In comparison with the control group, production of both IL-4 and IFN-γ was in-duced (p<0.05). The results indicated a decrease in tumor CD4+CD25+Foxp3+ T lym-phocytes in the Tehranolide-treated group compared to the control group.
Conclusion: Treatment of tumors with Tehranolide attenuated CD4+CD25+Foxp3+ Treg cell-mediated immune suppression and elicited a persistent anti-tumor immunity against can-cer.