Insight into Antioxidant and Photo-protective Properties of Natural Compounds from Marine Fungus

This computational and experimental work aims to elucidate physicochemical and photo-physical natures of free radical scavenging and ultraviolet radiation (UVR) filtering activities of five terpenoids available in the extract of marine fungus. The antioxidant activities of ochraceopone F (C1), aspertetranone D (C2), cycloechinulin (C3), wasabidienone E (C4) and mactanamide (C5) are evaluated by using density functional theory (DFT) at the M05-2X/6-311++G(d,p) level of theory in the gas phase, water and pentyl ethanoate (PEA). Double antioxidant mechanisms allowing the second (H+/e–) donation such as double hydrogen atom transfer (dHAT), double single electron transfer  proton transfer (dSET-PT) and double sequential proton loss  electron transfer (dSPL-ET) are considered. Reaction enthalpies (rH0), standard Gibbs free energies (rG0) and potential energy surfaces of reactions towards HOO• radical are then established to evaluate the hydrogen transfer (HT) and radical adduct formation (RAF) mechanisms. ...