Background: Ultraviolet (UV) radiation induces oxidative stress, inflammation, and structural skin damage. Bougainvillea glabra (BG) leaves are rich in flavonoids and phenolic compounds with reported antioxidant and anti-inflammatory properties.
Aim: The aim of this study was to formulate and evaluate hydroalcoholic extract gel of BG leaves and assess its protective effect against UV-induced skin inflammation.
Materials and Methods: Hydroalcoholic extract (ethanol: water, 70:30) was prepared by maceration and subjected to preliminary phytochemical screening. Carbopol 940-based gels containing 1% and 5% w/w extract were formulated and evaluated for physicochemical properties, drug content, and stability. Anti-inflammatory activity was assessed in UV-irradiated Wistar rats by evaluating erythema, edema, body weight, catalase (CAT), lipid peroxidation (LPO), tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and histopathological changes.
Results: The extract showed an 8% yield and contained flavonoids, alkaloids, tannins, phenolic compounds, carbohydrates, and saponins. The optimized F2 formulation exhibited acceptable pH, viscosity, spreadability, drug content, and stability. UV irradiation significantly increased oxidative stress and inflammatory markers, whereas BG gel reduced LPO, TNF-α, and IL-6 while restoring CAT activity. The 5% gel showed superior efficacy, comparable to hydrocortisone cream, and markedly improved skin histopathology.
Conclusion: The 5% BG hydroalcoholic gel demonstrated significant antioxidant and anti-inflammatory effects, indicating its potential as a natural topical therapy for UV-induced inflammatory skin disorders.
Keywords: Bougainvillea glabra, hydroalcoholic extract, skin inflammation, topical gel, ultraviolet irradiation