Terminalia Chebulanin Attenuates Psoriatic Skin Lesion via Regulation of Heme Oxygenase-1

Background/Aims: Psoriasis is one of the most common inflammatory skin disorders, affecting 3% of the general population. Terminalia chebulanin (TC) is a polyphenolic compound that possesses antioxidant and anti-inflammatory activities. The current study was designed to investigate the effect of TC on psoriatic lesions. Methods: We examined the protective effect of TC against psoriatic lesions in mice and keratinocyte proliferation in HaCaT cells. Results: We found that TC exhibited potent anti-psoriatic activities, as evidenced by improvement of erythema and scaling scores, decrease of epidermal, ear and skinfold thickening, decrease of tumor necrosis factor α (TNFα), interleukin (IL)-17A, IL-23 and matrix metalloproteinase (MMP)-9 expression, and decrease of TBARS content and increase of GSH content in IMQ-treated mice, and decrease of keratinocyte proliferation, TNFα, IL-17A and IL-23 expression, and ROS level in M5-treated cells. All those effects induced by TC were inhibited by zinc protoporphyrin IX (ZnPP), an inhibitor of heme oxygenase (HO)-1, indicating that HO-1 was responsible the anti-psoriatic effect of TC. Moreover, TC inhibited the upregulation of p65 NF-κB under in vitro psoriatic condition. ZnPP suppressed TC-induced inhibition of p65 NF-κB expression. Overexpression of p65 NF-κB significantly suppressed TC-induced decrease of TNFα, IL-17A and IL-23 expression and keratinocyte proliferation, indicating that HO-1-mediated downregulation of NF-κB was involved in the anti-psoriatic effect of TC. Conclusions: The data demonstrate that TC may serve as a potential therapeutic option for psoriatic patients.