Oregano Essential Oil Interactions with Photogenerated Singlet Molecular Oxygen

DIMARCO PALENCIA, FRIDA C. D.; MUÑOZ, VANESA A.; POSADAZ, ARIANA C.; CIFUENTE, DIEGO A.; MISKOSKI, SANDRA; FERRARI, GABRIELA V.; GARCÍA, NORMAN A.; MONTAÑA, MARÍA P.

PHOTOCHEMISTRY AND PHOTOBIOLOGY

WILEY-BLACKWELL PUBLISHING, INC

Año: 2020

0031-8655

Essential oils are a mixture of volatile compounds, products of the secondary metabolism ofplants. Once extracted, they can be deteriorated losing their organoleptic and therapeuticproperties due to various environmental factors, being light exposure in aerobic conditions themain cause. In this work the oregano essential oil extraction and characterization from Origanumvulgare plants grown in the experimental field of the FTU-UNSL and its photodegradation inMeOH:H2O 60:40 v/v solvent were studied. Characterization by EIMS and NIST MassSpectrometry indicates the main compounds of oregano essential oil, quantified in the extracted oilby GC-MS, are carvacrol (7.14%) and thymol (47.37%). Degradation of essential oil and its twomajor components can be caused by reactive oxygen species photogenerated from endogenoussensitizers as riboflavin. Our results suggest degradation occurs involving singlet molecularoxygen. Interaction of carvacrol and thymol with singlet oxygen is mainly a physical process,while essential oil has an important reactive component, which indicates there might be otherconstituents which could contribute to reactive photoprotection.The effect of simultaneouspresence of oregano essential oil and tryptophan aminoacid used as a photooxidizable modelunder riboflavin- photosensitizing conditions was studied in order to evaluate the possiblephotoprotection exerted by the essential oil.