LK5 herbal complex attenuates psoriatic-like skin lesions and suppresses melanogenesis

Psoriasis is a chronic inflammatory skin disorder characterized by Th1/Th17 immune activation and keratinocyte hyperproliferation.Phototherapy can effectively improve psoriatic lesions through localized application; however, excessive or prolonged exposure may induce pigmentary abnormalities, such as post-inflammatory hyperpigmentation.These clinical observations highlight the interplay between immune dysregulation and melanogenesis, emphasizing the need for therapeutic strategies that simultaneously control inflammation and pigmentary changes.This study evaluated the effects of LK5 herbal complex, composed of Scutellaria baicalensis, Sophora flavescens, Dictamnus dasycarpus, Liriope platyphylla, and Phellodendron amurense, on psoriaticlike lesions in vivo and melanogenesis in vitro.Oral administration of LK5 herbal complex (12.5, 25, and 50 mg/kg for six consecutive days) in IMQ-induced C57BL/6 mice reduced Psoriasis Area and Severity Index scores, decreased epidermal thickness, and lowered the number of Ki67-positive keratinocytes.In α-MSH and L-tyrosine-stimulated B16F10 melanoma cells, LK5 herbal complex suppressed intracellular and extracellular melanin production, inhibited tyrosinase activity, and downregulated Microphthalmiaassociated transcription factor, tyrosinase, and TYRP1 mRNA expression without affecting cell viability.These results demonstrate that LK5 herbal complex modulates immune responses and melanogenesis, supporting its potential as a natural candidate for managing chronic skin disorders with inflammation or pigmentary abnormalities.Its dual actions suggest that LK5 herbal complex could serve as a safe and integrative therapeutic approach for complex dermatological conditions.