Etude comparative du profil chimique et de l’activité antioxydante de plusieurs propolis de l’Est algérien et investigation phytochimique de la propolis la plus active.

Abstract

Our study is interested in the investigation of the chemical composition and the biological activities of Algerian propolis. Due to its several biological activities, propolis has been extensively used in folk medicine. In the first part of our study we examined several propolis harvested from north of Algeria in order to compare their antioxydant activity, In addition, the total phenolic and flavonoid contents were evaluated. Propolis of Constantine exhibited the highest antioxydant activity. This result encouraged us to study the anticholinesterase activity of the extracts of this propolis. This first part of our work allowed us to make a first classification of the propolis studied and to select the most active extracts on which we performed an analysis by liquid chromatography coupled to mass spectrophotometry LC-MS for the purpose of studying their chemical profile. The ethyl acetate extract of propolis of Constantine was the most active extract. This extract has the highest levels of caffeic acid, p-coumaric acid, naringenin and kaempferol. Our results suggest that the antioxydant effect is probably due to the presence of these compounds. In the second part of our study we investigated the chemical composition of Algerian propolis. The separation and purification of propolis extracts lead to the identification of 8 compounds, five flavonoids (tectochryin, pinocembrine, pinobksin-3-acetate, chrysin, galangin), one diterpene (cupressic acid) and two derivatives of caffeic acid (3-methyl-3-butenyl (E) -Caffeate and 2-methyl-2 -butenyl (E) -Caffeate). Their structures has been established by spectral analysis including NMR mono (NMR-1H, NMR-13C) and bidimensionelle spectra (HSQC, HMBC) and impact electronic mass spectra.