Crystal Structure Characterization of Natural Allantoin from Edible Lichen Umbilicaria esculenta

In China, Korea, and Japan, Umbilicaria esculenta is considered as both food and medicinal resources from lichen. In the current study, a prismatic crystal was first isolated from edible lichen U. esculenta via solvent fractionation. The structure of the crystalline compound was elucidated as allantoin using single-crystal X-ray crystallographic and spectroscopic techniques. In light of the wide use of synthesized allantoin in cosmetic industry as a skin protectant, the biological origin of the allantoin isolated from natural food stuff edible lichen has great potential to be developed into functional cosmetics. Current findings also provided useful information for ecologists to further explore the role of lichen and allantoin in nitrogen metabolism.