THE ACTIVITY OF PROPOLIS IN THE SCAVENGING OF VITAMIN B2-PHOTOGENERATED ROS

MARIELA GONZALEZ; MARÍA L. TERESCHUK; SUSANA CRIADO; EUGENIA REYNOSO; CECILIA CHALLIER; MARÍA B. AGUERO; LORENA C. LUNA; GABRIELA FERRARI; MARÍA P. MONTAÑA; NORMAN A GARCÍA

REDOX REPORT

MANEY PUBLISHING

Lugar: London; Año: 2015 vol. 20 p. 246 - 253

1351-0002

Objectives: The study was focused on the activity of propolis from Amaicha del Valle,Argentina (ProAV) as a promoter and scavenger of Riboflavin (Rf) -photogenerated reactive oxygen species (ROS).Methods: Through a kinetic and mechanistic study, employing stationary and timeresolved photochemical and electrochemical techniques, the protecting activity of ProAV was investigated.Results: In the absence of light and Rf, ProAV exerted a relatively efficient inhibitory effect on DPPH radicals and acts as a protector of artificially-promoted linoleic acid oxidation. Under aerobic visible-light-irradiation conditions, in the presence of Rf as the only light-absorber species, a complex picture of competitive processes takes place, starting with the quenching of singlet and triplet electronically excited states of Rf by ProAV. The species O2(1g), O2.- , H2O2 and OH. are generated and interact with ProAV.Discussion: ProAV behaves as an efficient ROS scavenger. It is scarcelyphotooxidized by interaction with the mentioned ROS. Quantitative results indicate that ProAV is even more resistant to photooxidation than the recognized antioxidant trolox. Two dihydroxychalcones, mostly present in the ProAV composition, are responsible for the protecting activity of the propolis.