Characterization of two unique carotenoid fatty acid esters from Pterosperma cristatum (Prasinophyceae, Chlorophyta)

Carotenoid composition and spectroscopic characteristics were analyzed for Pterosperma cristatum Schiller, one of the most primitive known members of green algae. This alga contained a substantial amount of carotenoid esters, siphonaxanthin C14:1 trans-Delta2 ester and 6'-OH siphonaxanthin C14:1 trans-Delta2 ester, but lacked lutein. This is the first report of carotenoid C14:1 trans-Delta2 esters from phototrophic organisms. In vivo absorption spectra and excitation spectra of the cells revealed that these carotenoids absorbed blue-green light and could transfer energy to chl a. These carotenoids were concluded to function as antenna pigments in P. cristatum.