Synthesis of corn-derived carbohydrate derivatives as effective multifunctional sunscreen

The eighty-years-old sunscreen industry is sustained by the growing incidence of skin cancer and the continual exploration of skin aging. From the UVB-induced erythema to the UVA-induced persistent pigment darkening, scientists have used versatile methods to reveal that not only does UVB damage skin but also that longer wavelengths such as UVAIL (290nm ~ 340nm) and UVAL rays (340nm ~ 400nm) trigger skin cancer, premature skin aging and immunosuppression. To meet a significant demand for improved photoprotection, a broad-spectrum sunscreen with a high extinction coefficient has been desired. As part of our ongoing studies on isosorbide-cinnamate derivatives, this work have found they have great promise as multifunctional sunscreens, based on the isosorbide molecule as a carrier and the cinnamate group’s UV absorption. In this study, a series of isosorbide derived UVB and UVA sunscreens of high extinction coefficient have been successfully synthesized. The combination of these two types of sunscreens covers the full UV-spectrum from 290 to 400nm. The high absorbance in the long wavelength UVA region of these synthetic UVA sunscreens magnifies their improved photoprotective properties, which is the deficient for most commercial sunscreens. Furthermore, these UVA sunscreens are highly photostable under UVA radiation, which benefits their properties as UV stabilizers in cosmetic and pharmaceutical formulations. The work described in this thesis also covers the synthesis of isosorbide-derived antioxidants and an isosorbide-derived single compound which functions as both UVB sunscreen and plasticizer. This compound can also increase the flow properties of polymers especially polyvinyl chloride (PVC) etc. Based on the different reactivities of the two -OH groups on the isosorbide, this work have demonstrated two synthetic routes to multifunctional single compounds such as a UV absorbing antioxidant. Continuing this idea, a full spectrum UV absorber, a UV absorbing thermal stabilizer and other multiple combinations could be made using the same synthetic route in the future