Cellular antioxidant and cytotoxic activity of astaxanthin and ellagic acid on UV irradiated skin melanoma cells and gel formulation

Abstract

Ultraviolet radiation accounts for most non-melanoma skin cancers (carcinoma of basal and squamous cells) and melanoma skin cancers. Hence, UV radiation is considered one of the most potent physical carcinogens. Radiation exposure leads to water hydrolysis and heightens free radical production. The free radicals, in turn, react with macromolecules such as proteins, DNA, RNA, and lipids and alters their structure. Antioxidants protect the cells against radiation-induced cell death and DNA damage. It was also attributed to the reduction in ROS induced by UV radiation. Both ellagic acid and astaxanthin has antioxidant property. In addition to the antioxidant property, these compounds possess inflammatory, anti-proliferative, and wound-healing properties. The study aims to evaluate the ROS scavenging potential of ellagic acid and astaxanthin in Skin melanoma (SK-Mel-28) cells and formulate a gel that can treat radiation dermatitis. The spectral characterization of ellagic acid and astaxanthin was carried out using UV–Vis spectroscopy and FTIR. The antioxidant potential of astaxanthin and ellagic acid was measured using probe 2′, 7′-dichlorofluorescein-diacetate in UV-treated skin melanoma cells. These antioxidants attenuated the intracellular ROS in UV-treated SK-Mel-28 cells, evident at 25 μg/ml and 50 μg/ml. Comparative fluorescent intensity profile analyzed using ImageJ also showed that both astaxanthin and ellagic acid exhibit high ROS scavenging potential without prooxidant capacity. The ellagic acid extract and astaxanthin decreasedSK-Mel-28 cell viability with a median inhibitory concentration IC50 of 47.23 μg/ml and 41.39 μg/ml. The ellagic acid enhanced thiobarbituric acid reactive substance level, an indicator of lipid peroxidation with a median stimulatory concentration EC50 of 53.7 μg/ml in SK-Mel-28 cells. This substantiated that ellagic acid potentiates the antitumor effect through lipid peroxidation. It was proposed that the astaxanthin-ellagic acid gel formulation produced better results in reducing UV-induced skin cancers due to positive synergism.