Comparing the Photoprotection Capabilities of the Phytochemical Anthocyanin to the Chemical Oxybenzone

2019-2020

Oxybenzone is an active photoprotective chemical commonly used in commercial sunscreen. While the chemical absorbs UVB and UVA II radiation and thus provides a chemical shield for the skin, the chemical is hazardous to the marine ecosystem. Oxybenzone is particularly harmful for the coral reef population for the chemical catalyzes hydrogen peroxide, a known bleach agent. A small amount is sufficient to cause corals to bleach and become more susceptible to viral infections. The Hawaiian government, recognizing the ramifications of the chemical, recently signed a bill that would ban all sunscreens containing oxybenzone. Furthermore, oxybenzone is a known endocrine disruptor and is identified to be the cause of various reproductive issues and hormonal diseases. Thus, the ban and the health hazard raise the necessity for an alternate photoprotective chemical that is both eco-friendly and safe for human application. One potential alternative is anthocyanins, which are water soluble pigments found in plants. By having numerous double bonds and oxygen lone pairs in its molecular structure, anthocyanins are able to absorb large amounts of UV radiation, and thus provide protection for plants from intense UV radiation that otherwise may degrade important photolabile molecules. This property makes anthocyanins a potential photoprotection chemical alternative to oxybenzone. The overall purpose of this project is to exploit the potential of the phytochemical anthocyanin as an alternative for oxybenzone in commercial sunscreen. Anthocyanins were extracted from red cabbages and a hexane partition was performed on the solution for further isolation and purification. The concentration of anthocyanin of the solution was then calculated using the pH differential method. Pure oxybenzone was diluted in ethanol to the same concentration. In order to compare the photoprotective capabilities of the two chemicals, the survival rate of E.coli under exposure to UV radiation was compared between a bacterial group that was protected with the anthocyanin solution, a bacterial group that was protected with the oxybenzone solution and a control group that received no protection. Results supported the hypothesis that the bacterial groups protected by anthocyanins and protected by oxybenzone demonstrate similar rates of survival. Furthermore, the bacterial groups that received protection by anthocyanins and oxybenzone demonstrated significantly higher survival rates compared to control groups that did not receive any protection. Thus, it can be concluded that anthocyanin has photoprotective properties that function outside the plant body and is viable to replace oxybenzone in commercial sunscreen.