Original Articles
Geetha Surendran, Mackenzie Mc
Abstract
There is a need to identify non-toxic UV filters of natural origin for use in sunscreen products due to concerns about potential health and environmental toxicity of synthetic UV filters. Hydroxycinnamic acids (HCAs) are plant metabolites that exhibit excellent antioxidant properties, and absorb efficiently solar UV radiation. A comparative UV spectroscopy analysis of HCAs was performed to determine the feasibility of their use as multifunctional UV filters with simultaneous antioxidant capacities. Sun protection factor (SPF) values were calculated using the Mansur equation. The UVA/UVB ratio and critical λ, which are indicators of sunscreen ability to offer broadband UVB/UVA protection, were calculated from UV spectra. Our analysis indicates that each of HCAs, specifically caffeic acid, ferulic acid, and sinapic acid absorb efficiently and simultaneously in multiple regions of UV solar radiation, specifically UVB (290 nm-320 nm), UVA II (320 nm-340 nm), and to some extent in the UVA I (340 nm-400 nm) region. We concluded that HCAs incorporating at least one catechol moiety, such as sinapic acid, caffeic acid, and ferulic acid, could provide broadband UVB/UVA screening comparable or superior to commercial UV filters, in addition to antioxidative capabilities. Thus, HCAs, if properly modified to ensure emulsification into sunscreens, have the potential to provide an alternative to multiple current UV filters suspected of health and environmental toxicity.