Investigating isomer specific photoprotection in a model plant sunscreen.

Sinapate esters are used throughout the plant kingdom, for example in photoprotection from ultraviolet radiation. Sinapate esters are naturally produced in their E-isomeric form; however, upon exposure to ultraviolet radiation, photoisomerization drives Z-isomer formation. To elucidate the photoprotection capacity of E vs. Z forms of sinapate esters, we explore the photochemistry of the model system, Z-ethyl sinapate. Following a novel Z-ethyl sinapate synthesis, we demonstrate that photoprotection is isomer independent. This suggests that, regarding photoprotection, there were no evolutionary pressures for biosynthesis of either isomer.