Antioxidant potential of meso-zeaxanthin a semi synthetic carotenoid

Semi synthetic carotenoid meso-zeaxanthin was evaluated for its antioxidant potential in vitro and in vivo. Meso-zeaxanthin was found to scavenge superoxide radicals, hydroxyl radicals and inhibited in vitro lipid peroxidation. Concentrations needed for 50% inhibition (IC₅₀) were 27.0, 3.5 and 3.2 μg/ml, respectively. It scavenged 2,2-azobis-3-ethylbenzthiozoline-6-sulphonic acid and 2,2-diphenyl-1-picryl hydrazyl radicals and IC₅₀ were 46.5, 6.25 μg/ml, respectively. It also scavenged nitric oxide radicals and IC₅₀ was found to be 2.2 μg/ml. Oral administration of meso-zeaxanthin inhibited superoxide radicals generated in macrophages by 25.2%, 50.1% and 67.2% at doses of 50, 100 and 250 mg/kg b.wt., respectively. One month oral administration of meso-zeaxanthin to mice significantly increased catalase, superoxide dismutase, glutathione and glutathione reductase levels in blood and liver. Levels of glutathione peroxidase and glutathione-S-transferase were also found to be increased in the liver, in a dose dependent manner. These results showed that meso-zeaxanthin has significant antioxidant activity in vitro and in vivo.