The impact of topical Saint John's Wort (Hypericum perforatum) treatment on tissue tumor necrosis factor-alpha levels in plaque-type psoriasis: A pilot study.

BACKGROUND

Psoriasis is an inflammatory disorder, formed by inappropriate interaction of T lymphocytes with keratinocytes, and consequent eruption of immune responses. High concentrations of tumor necrosis factor-alpha (TNFα) are found in the skin lesions and plasma of patients with psoriasis. Hypericum perforatum, a phytomedicine that has both anti-inflammatory and antiproliferative properties, has been recently reported to be clinically helpful for improvement of psoriatic lesions.

OBJECTIVE

The aim of the present study was to investigate the effects of topical H. perforatum on TNFα levels in psoriatic lesions for possible identification of the mechanism by which Hypericum reduces inflammation and modulates the disease in patients with plaque-type psoriasis.

METHODS

A double-blind, placebo-controlled, pilot study with intraindividual comparison was conducted on twenty patients with mild to moderate plaque-type psoriasis.

METHODS

TNFα levels in tissue samples were measured with immunohistochemistry method. Moreover, Psoriasis Area Severity Index (PASI) scores and histological and clinical changes were investigated after topical application of Hypericum extract.

METHODS

The Wilcoxon signed-rank test was used to evaluate the possible differences between the drug and placebo group.

RESULTS

TNFα concentrations in dermis (p= 0.025), endothelial cells (p=0.033), and dendrite cells (p=0.014) were significantly reduced in lesions treated with drug and the reduction observed in epidermis was superior to placebo (p=0.046). Results of PASI scores showed that erythema, scaling, and thickness were significantly lower where the ointment had been applied compared to application of placebo (p=0.014, p=0.004, p=0.003, respectively). Moreover, significant improvement in clinical and histological features of treated lesions in comparison with untreated lesions was observed (P < 0.05).

CONCLUSIONS

H. perforatum ointment can help decrease PASI scores and TNFα levels in psoriatic tissue. Its efficacy is probably related to its effect on lowering cytokines including TNFα.