Methods for the detection of reactive oxygen species employed in the identification of plant photosensitizers

MAMONE L, DI VENOSA G, SÁENZ D, BATLLE A, CASAS A

METHODS

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2016 vol. 109 p. 73 - 80

1046-2023

Over the past ten years, alternative methods for the rapid screening of PSs have been developed. In thepresent work, a study was undertaken to correlate the phototoxicity of plant extracts on either prokaryoticor eukaryotic cells, with the total oxidation status (TOS) as well as with their ability to produce 1O2.Results demonstrated that the extracts containing PSs that were active either on eukaryotic cells orbacteria increased their TOS after illumination, and that there was a certain degree of positive correlationbetween the extract phototoxic efficacy and TOS levels.The production of 1O2 by the illuminated extracts was indirectly measured by the use of the fluorescenceof ??singlet oxygen sensor green?, which is a method that has proved highly sensitive for such measurement.1O2 was detectable only upon illumination of the most active extracts.In addition, the oxidation of tryptophan and was employed as a method capable of measuring ROS generatedby both type I and II ROS reactions. However, it turned out to be not sensitive enough to detect thespecies generated by plant extracts.Results demonstrated that the TOS method, initially developed to measure the oxidant status inplasma, can be readily applied to plant extracts. Unlike the method used to detect 1O2, the methodemployed for the detection of TOS proved to be accurate, since all the extracts that displayed a high phototoxicactivity on either prokaryotic or eukaryotic cells, presented high TOS levels after illumination.