Multi-Target Anti-Psoriatic Effects of Melissa officinalis: Phytochemical, Redox, Immunological, and Histological Evidence from an In Vivo Study

Psoriasis is a chronic inflammatory skin disease linked to immune dysregulation and oxidative stress. Due to the limitations and side effects of conventional therapies, natural compounds are gaining increasing attention. The aim of this study was to evaluate the therapeutic potential of Melissa officinalis extract in psoriasis. HPLC analysis was used to characterize the extract, while its antioxidant activity was assessed by DPPH, ABTS, and FRAP assays. An in vivo study was conducted on 18 male Wistar albino rats divided into control (CTRL), psoriasis (PSORI), and psoriasis treated with M. officinalis (PSORI+MO) groups. Psoriasis was induced by daily topical application of 5% imiquimod cream on the shaved back skin of rats for seven constitutive days. The PSORI+MO group received M. officinalis extract orally at a dose of 200 mg/kg during seven days. Redox and inflammatory cytokine analysis were performed. Isolated skin was fixed and stained with H/E and immunohistochemical staining. Morphometric and histological analyses revealed reduced inflammation, keratinocyte proliferation, and epidermal thickness. Systemic and tissue redox status showed decreased oxidative stress biomarkers and enhanced antioxidant defense. Inflammatory cytokines (IL-17A, IL-22, IL-23, IL-1β, and IL-6) were significantly reduced. Our findings suggest that Melissa officinalis extract exerts anti-psoriatic effects through antioxidant, anti-inflammatory, and antiproliferative mechanisms.