Potential Preventive Effects of Curcuma longa Gel Against Ultraviolet-Induced Actinic Keratosis in Balb/c Mice

Abstract

Actinic keratosis (AK), is a precancerous lesion formed on sun-exposed skin of individuals exposed to long-term ultraviolet (UV) light and may eventually progress to squamous cell carcinoma in the absence of treatment. In this study, the researchers examined the protective action of Curcuma longa gel from UVB-induced AK in Balb/c mice. Fifteen mice were first treated with three (3) different concentrations of gel (0.1%, 0.5%, 1.1%) and a positive and a negative control before being irradiated with UVB light from a 311nm UV lamp for four (4) hours on the first session, a 30-minute break, and another 4 hours for the second session, everyday. After fourteen (14) days of irradiation, the mice were subjected to histopathological analysis using 3 parameters namely, presence of cellular atypia, stratum corneum morphology, and epidermal thickness. The phytochemical analysis showed the presence of phenols, glycosides, reducing sugars, and quinones. The dermatological testing of the different concentrations to the 3 guinea pigs showed no erythema and edema, confirming it is safe for application. The preventive effects of Curcuma longa gel showed a dose-dependent effect, wherein the 1.1% of Curcuma longa gel was the most effective in preventing the presence of cellular atypia, the hallmark of AK, and also in preventing epidermal thickness, alongside 0.5% Curcuma long gel, making it the most effective concentration. Kruskal-Wallis and Dunn’s post hoc analysis indicated that the most effective concentration (1.1%) was similar to the positive control for all analyzed parameters, and significantly better than the negative control. The 1.1% Curcuma longa gel’s physicochemical properties were also evaluated. Having a deep yellow color, smooth texture, pH 5-6 along with a good spreadability and a viscosity of 4,970 cP. Based on this, it can be concluded that 1.1% of Curcuma longa gel is a good topical photoprotective formulation in the prevention of UVB-induced AK.