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Photoprotective capacities of lichen metabolites: A joint theoretical and experimental study

Paper ID Volume ID Publish Year Pages File Format Full-Text
29530 44419 2012 10 PDF Available
Title
Photoprotective capacities of lichen metabolites: A joint theoretical and experimental study
Abstract

The adaptative capacity of lichens to UV radiation could be expressed by the production of photo-absorbing secondary metabolites in thalli. A preliminary screening performed on twelve lichen species by high performance thin layer chromatography (HPTLC) revealed five major compounds absorbing in the UVA (315–400 nm) or UVB (280–315 nm) ranges in Diploicia canescens. After phytochemical investigation of this lichen, twelve metabolites have been isolated and characterized. Those obtained in sufficient quantities were evaluated for their photoprotective capacities and compared to three referent sunscreens. Experimental spectra were compared to theoretical spectra as obtained at the TD-DFT level of theory. Different DFT functionals were tested to accurately reproduce the UV/Vis spectra of five depsidones, one diphenylether and two bisxanthones. Results indicate that absorption wavelengths and molecular extinction coefficients (oscillator strengths) obtained for the bisxanthones were similar to those of the UVA referent sunscreen.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► The lichen Diploicia canescens was selected by HPTLC as a source of UV-absorbers. ► In vitro photoprotective data of 5 depsidones and 2 bisxanthones were determined. ► Structure optical property relationship was established using TD-DFT. ► Secalonic acid B appears as a good candidate for UVA sunscreen.

Keywords
Diploicia canescens; Secalonic acid; SPF in vitro; Lichen; TD-DFT
First Page Preview
Photoprotective capacities of lichen metabolites: A joint theoretical and experimental study
Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 111, 4 June 2012, Pages 17–26
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering