Lichens--photophysical studies of potential new sunscreens.
Fundamental photophysical properties have been obtained for six polyaromatics, calycine, usnic acid, vicanicine, 1-Cl-pannerine and epiphorelic acids I and II, extracted from Antarctic lichens--potential future sunscreens. None of the lichen compounds produced a measurable amount of triplet states and the singlet oxygen quantum yield was also very low ranging from 0.003 to 0.06. However, three exhibited triplet energy levels which may be above that of thymine. The radical cations of calycine and usnic acid were generated via pulse radiolysis and were observed to be quenched by vitamin C, vitamin E and Trolox.
Boehm
Fritz
F
Department of Dermatology, Humboldt University, 10117 Berlin, Germany.
Clarke
Kristy
K
Edge
Ruth
R
Fernandez
Ernesto
E
Navaratnam
Suppiah
S
Quilhot
Wanda
W
Rancan
Fiorenza
F
Truscott
T George
TG
D001572:Benzofurans / Q000737:chemistry* / Q000302:isolation & purification / Q000528:radiation effects; D005609:Free Radicals / Q000737:chemistry / Q000528:radiation effects; D008011:Lichens / Q000737:chemistry*; D010782:Photolysis; D011675:Pulse Radiolysis; D011789:Quantum Theory; D026082:Singlet Oxygen / Q000378:metabolism; D013056:Spectrophotometry, Ultraviolet; D013473:Sunscreening Agents / Q000737:chemistry* / Q000302:isolation & purification / Q000528:radiation effects
D001572:Benzofurans; D005609:Free Radicals; D013473:Sunscreening Agents; D026082:Singlet Oxygen