Immunomudulatory effects of hydroalcoholic extract of Hypericum perforatum

Abstract

Objective: Hypericum perforatum (St. John's Wort) has long been used in traditional medicine to treat a variety of internal and external ailments. The present study was done to evaluate the immumodulatory potentials of the hydroalcoholic extract of H. perforatum.

Materials and methods: Twenty male BALB/c-mice were randomly allocated in two equal groups and immunized with sheep red blood cells (SRBCs) and complete Freund's adjuvant. Mice in the treatment group orally received hydroalcoholic extract of H. perforatum (110 mg/Kg daily) from the beginning of the study which continued for 2 weeks.

Results: The data indicated a significant increase in the level of anti-SRBC antibody and simultaneously a significant decrease in the level of cellular immunity, an enhancement in foot pad thickness, in treatment group compared to control group. The level of the respiratory burst in phagocytic cells and the level of lymphocyte proliferation in splenocytes were significantly decreased in the treatment group compared to control group. Moreover, extract caused a significant reduction in the production of pro-inflammatory IL-17 as well as IFN-γ, parallel to increasing the level of IL-6.

Conclusions: The hydroalcoholic extract of H. perforatum may be used as a natural source for treatment of immunopathologic conditions.

Keywords: Cellularimmunity; Humoralimmunity; Hypericumperforatum; Lymphocyteresponse.

Figure 1

Cytokines production assay after treatment with hydroalcoholic extract of Hypericum perforatum. Spleen cells isolated from immunized mice with SRBC were cultured with 50 µl of PHA (1 mg/ml) for 72 h. The levels of IFN-γ, IL-17, and IL-10 in culture supernatants were determined after 72 h by ELISA. The results were shown as mean±SD. (* p < 0.001, versus control mice).

Figure 2

Effects of hydroalcoholic extract of Hypericum perforatum administration on lymphocytes proliferation and respiratory burst in phagocytic cells. Splenocytes were isolated from sensitized mice with SRBC. A) Splenocytes cultured with 50 μL PHA solution (1 mg/ml) for 72 h. Then, lymphocytes proliferation were evaluated by MTT test. B) Splenocytes with S. aureus suspension and NBT were mixed and incubated for 30 min as detailed under materials and methods. The reduced dye was extracted in dioxan and quantitated at 520 nm. The values were presented as mean ± SD. (*p<0.01, ** p<0.001 versus control mice).