Phytochemical Tests, Assessment of Antioxidant Properties and Isolation of Two Compounds of Ethyl Acetate Extract of Chadian Propolis: Case of Bebotho (Southern Chad)

Abstract

The present work deals with the research of chemical constituents and evaluation of antioxidant properties of Bebotho propolis. From the ethyl acetate extract, we isolated, using various chromatographic techniques, a mixture of two identical compounds (isomers) indexed PBy4a and PByb. The structures of these compounds were elucidated by means of spectroscopic analysis techniques (MS, IR, 1 H-NMR, 13 C-NMR, HMBC and HSQC) and by comparison of the spectral data with those described in the literature. Thus, these compounds were identified to a mixture of two chromones namely 5,7-dihydroxy-2-methylchromone-6-C- α -D-glucopyranoside and 5,7-dihydroxy-2-methylchromone-8-C- β -D-glucopyranoside, first reported in propolis. The study of the antiradical power, chelating power and the quantification of phenolic compound of these same extracts, showed interesting properties that propolis extracts have to scavenge free radicals.