Scientists at the University of Gothenburg and Chalmers University of Technology have found a bacterial component that serves as a UV filter without causing contact allergies.
"Oxidative Coupling as a Biomimetic Approach to the Synthesis of Scytonemin," was published online as an Organic Letter by the American Chemical Society.
Isabella Karlsson, research student in the department of chemistry at the University of Gothenburg, decided to seek an alternative UV filter based on her finding that some current UV filters, such as 4-tert-butyl-4'-methoxy dibenzoylmethane and octocrylene, can cause contact allergies after sun exposure.
Scytonemin is a UV-absorbing pigment produced more than 300 species of cyanobacteria that live in habitats exposed to strong sunlight. It is said to protect important cellular components in the cyanobacteria against harmful UV radiation. According to the researchers, the pigment has been shown to possess both anti-inflammatory and antiproliferative properties.
Through a collaboration with the Chalmers University of Technology, the University of Gothenburg synthesized an artificial form of the cyanobacterial alkaloid scytonemin. The parent structure, the scytoneman skeleton, was assembled by a ferric chloride induced oxidative coupling of two identical fragments. This tetracyclic fragment was effectively constructed stereospecifically, with respect to the exocyclic double bond, by a tandem Heck–Suzuki–Miyaura cyclization as a key reaction.
The researchers found that the synthetic route is flexible and allows for effective synthesis of numerous scytonemin analogues. Karlsson and her team plan to conduct more research on the material before they test it as part of a sunscreen formulation; however, they are hopeful that their research will lead to an effective, allergen-free UV filter. They find that the pigment could also be developed into an anti-inflammatory or anticancer drug.