Osmolytes
Osmolytes are organic solutes whose chief function is
to maintain cell volume. However, they also appear to
protect cells against harmful agents, such as reactive
oxygen species. Both UV-A and UV-B radiation stimulated
the uptake of specific osmolytes by keratinocytes,
and pretreatment of cultured keratinocytes with
the osmolyte taurine inhibited the synthesis of
tumor necrosis factor-a and interleukin-10.70 Topical
application of the bacterial osmolyte ectoin following
exposure to UV-B radiation prevents depletion of
Langerhans cells and the formation of sunburn cells.71
The results of in vitro studies have demonstrated
that ectoin reduces UV-induced DNA mutations in
fibroblasts. Based on these findings, osmolytes could
prove to be a very interesting ingredient in future
photoprotective products.