Eugenol-loaded lipid nanoparticles-derived hydrogels ameliorate psoriasis-like skin lesions by lowering oxidative stress and modulating inflammation

Abstract

Psoriasis is a chronic T-cell-mediated autoimmune skin disorder characterized by excessive epidermal thickening, overproliferation of keratinocyte, disruption of epidermal cell differentiation, and increased blood vessel growth in the dermal layer. Despite the common use of corticosteroids in psoriasis treatment, their limited efficacy and numerous side effects pose significant challenges. This research introduces a promising alternative approach by encapsulating eugenol (EU) in soya phosphatidylcholine (SPC) nanoparticles (EUNPs) which showed spherical shape nanoparticles with a hydrodynamic size of approximately 200 nm, polydispersity index 0.23, encapsulation efficiency of 85% having good colloidal stability indicated by ζ-potential of −27 mV. Later on, these EUNPs were formulated into a topical hydrogel system by using Carbopol 974P (EUNPGel), which exhibited superior drug loading, enhanced release kinetics for 48 h, long-term stability, and the ability to scavenge reactive oxygen species (ROS). Furthermore, EUNPs inhibited keratinocyte proliferation, induced apoptosis, and augmented the uptake of IL-6-mediated inflammation in human keratinocyte cells. Application of EUNPs-loaded gels (EUNPGel) to imiquimod-induced psoriatic lesions demonstrated effective dermal penetration, suppressed keratinocyte hyperplasia and restored epidermal growth. This led to a remarkable reduction in the Psoriasis Area and Severity Index (PASI) score from 3.75 to 0.5 within 5 days. This novel approach enhances ROS scavenging capacity, improves cellular uptake, facilitates skin penetration and retention, reduces the activity of hyperactive immune cells, and suggests potential applications for treating other immune-related disorders such as acne and atopic dermatitis.