Hypericum perforatum Alleviates Ovalbumin-Induced Asthma through Downregulating TH2 and Upregulating TH1 Related Parameters in BALB/C Mice

Background: Allergic asthma is a chronic and inflammatory disease of the respiratory tract, which is characterized by inflammation, airway obstruction and swelling. Anti-inflammatory compounds can be used to improve the disease severity. Hypericum perforatum (HP)/ St. John’s wort has been used in the treatment of many diseases due to its anti-inflammatory effects. Therefore, this study was performed to investigate the effects of HP on TH1 and TH2 parameters in an animal model of allergic asthma. Methods: Thirty BALB/c mice were sensitized with subcutaneous injection and inhalation of ovalbumin and then administered different doses of HP post-sensitization. Histological analysis of the lungs was performed. The effects of HP on mRNA expression of T-bet and GATA3 (TH1 and TH2 transcription factors, respectively), IFN-γ, IL-4 and IL-10 in the spleen were determined by real-time PCR. The protein levels of IFN-γ, IL-4 and IL-10 cytokines were also determined by ELISA technique in the serum of mice. Results: HP extract (HPE) reduced the clinical severity in asthma-induced mice, and a reduction in the inflammatory cell infiltration in the lung. Furthermore, treatment with HPE inhibited asthma-related mediators as well as increased the anti-inflammatory parameters compared to the control. The study also showed that treatment with HPE significantly increased IFN-γ, IL-10 and T-bet, while decreasing the level of IL-4 and GATA3 in mice treated with HPE. Conclusion: The data indicated that HPE can attenuate allergic asthma autoimmune responses by inhibiting infiltration of immune cell in the lung and TH2-related parameters. It is reasonable to assume that HPE has significant effects in the treatment of allergic asthma.