St. John’s wort and its component hyperforin alleviate experimental autoimmune encephalomyelitis through expansion of regulatory T-cells

Abstract

Multiple sclerosis (MS) is a central nervous system disorder mainly characterized by inflammation, demyelination and axonal injury. Anti-inflammatory agents can be used to ameliorate the disease process. Hypericum perforatum L or St. John’s wort is widely used as an anti-depressant and anti-inflammatory remedy in traditional and herbal medicine. Based on St. John’s wort properties, the therapeutic potentials of an H. perforatum extract (HPE) and a single component, hyperforin were evaluated for effectiveness against MOG_35–55-induced experimental autoimmune encephalomyelitis (EAE), an animal model for human multiple sclerosis. Female C57BL/6 mice were immunized with specific antigen MOG_35–55 and then administered different doses of hyperforin or HPE post-immunization. Clinical symptoms/other relevant parameters were assessed daily. Histological analysis of the spinal cord was performed. T-cell proliferative activity was also evaluated using a BrdU assay. The effect of hyperforin on regulatory T-cells (T_reg cells) was assessed using flow cytometry. The results indicate hyperforin and HPE reduced the incidence and severity of EAE, an outcome that closely correlated with an inhibition of pathological features (leukocyte infiltration and demyelination) and antigen-specific T-cell proliferation. The study also showed that hyperforin caused increased T_reg cell levels in the spleen. These results indicated that hyperforin and HPE could attenuate EAE autoimmune responses by inhibiting immune cell infiltration and expansion of T_reg cell and could eventually be considered as a potential candidate for use in the treatment of MS.

Keywords:

• Experimental autoimmune encephalomyelitis (EAE)
• Hypericum perforatum L
• hyperforin
• multiple sclerosis
• myelin oligodendrocyte glycoprotein (MOG)

Acknowledgements

The authors wish to thank the authorities in the Research Council of Mashhad University of Medical Sciences (MUMS) for financial support (Grant #910234).

Disclosure statement

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.