SUN PROTECTIVE FORMULATION FROM CAROTENOIDS EXTRACTED FROM THERMOTOLERANT GENERA SYNECHOCYSTIS PEVALEKII

Naturally occurring safe and broad spectrum UV blockers are required now- a- days to protect oneself from the onslaught of UV radiations that are known to cause many skin related ailments. The commercial inorganic sunblockers like Zinc oxide and titanium di oxide and organic sunblockers like Avobenzone and Benzophenone are known to be unstable and also their safety is doubted. Aim of the present communication was to study the secondary carotenoids like Zeaxanthin / Canthaxanthin / b– carotene extracted from thermotolerant genera Synechocystis pevalekii is screen for its role in skin protection against UV radiations. Solvents like Petroleum ether, Hexane, acetone, ethyl acetate, ethanol and methanol were used for extraction. Out of all these, freeze – thaw technique in 100% methanol proved to be the best solvent for extraction of carotenoids. The crude extract thus obtained was fractionated by silica gel open column chromatography and the resultant fractions were analyzed by HPLC. The HPLC analysis showed the presence of carotenoids like Zeaxanthin, Canthaxanthin and b- carotene. The next part of the study was to determine the role of zeaxanthin in skin protection against UV radiations. The crude extract and the zeaxanthin fraction were incorporated in a gel based sun protective formulation and analysed for the SPF and boot star rating. It was found that the incorporation of the crude extract as well as the fractions did not result in SPF increase but gave a 5 star boot star rating proving it to be a potential UV A radiation absorber. Also the synergistic effect of the Zeaxanthin fraction with commercial sunblockers like Octyl methyl cinnamate and Avobenzone was studied. It was found that the incorporation of Zeaxanthin not only enhanced the boot star rating, UV A/ UV B ratio but also protected Avobenzone from degradation. Thus Zeaxanthin from Synechocystis pevalekii can be used a natural component for sunscreens and as a stabilizing agent for chemical sunblockers like Avobenzone.