Novel ultraviolet absorbers derived from cashew nut shell liquid: spectrophotometric, in silico and in vitro assays

Abstract

The use of sunscreens prevents erythema, photodamage and skin cancer. Natural products have been studied as ultraviolet (UV) absorbers due to their structural similarity to organic UV filters and their lower cost. The cashew nut shell liquid (CNSL) constituents were isolated by our group leading to four mixtures and seventeen pure compounds, which had chromophoric groups similar to organic UV filters. In addition, C15 and C8 CNSL-derivatives molecules were rationally planned as UV absorbers. The aim of this work was to evaluate the potential of CNSL’s constituents and its derivatives as new UV absorbers using spectrophotometric methods, study their physical-chemical properties and toxicity using in silico method, and perform in vitro assays. Mixtures and isolated CNSL compounds were demonstrated to be non-phototoxic when evaluated in a phototoxicity assay using the yeast Saccharomyces cerevisiae. Considering the absorption values on the UV range, 6 compounds showed appropriate SPF values regarding the spectrophotometric test. Additionally, in silico and in vitro evaluations were performed, showing non-oral bioavailability, as well as non-mutagenic, non-genotoxic and non-phototoxic properties for the tested compounds. These results contribute favorably to the aimed use of the compounds under analysis as novel organic UV absorbers that have as precursor the phenolic lipid component of CNSL, a waste product obtained as the by-product of cashew nut food processing.