Free radicals and oxidative processes are involved in development of some diseases, and the reactive oxygen species (ROS) are considered the most harmful. Antioxidants act inhibiting the formation or the action of free radicals, that’s why there is a search for antioxidants mainly of natural origin, such as phenolic compounds 1.
Coffee (Coffea arabica) is an important source of bioactives and phenolic compounds 2,3. The objective was to evaluate the antioxidant activity (AA) of the aqueous extracts from Coffea arabica beans and its correlation with the total phenolic content compounds.
Extracts of green coffee beans (GCA) and of three different roasting conditions: light roast (LRCA), mean roast (MRCA) and dark roast (DRCA) were prepared with water at 980C by percolation. Total amount of phenolic compounds was determined by Folin-Ciocalteau method 4 and the AA was performed based on the methodologies DPPH 5 and ABTS.+ 6 radicals capture assays. AA was correlated with the total amount phenolic compounds by the test of correlation of Pearson’s.
Extracts LRCA, MRCA and DRCA obtained total content of phenolic compounds similar: 101.70, 94.26 and 93.21 mg/g (mg of gallic acid equivalente for g of extract) respectively, already extract GCA obtained 62.67 mg/g. These extracts at the concentration of 100 μg/mL showed more than 70% inhibition of DPPH radical, and TEAC values (mM of Trolox equivalent to 1000 μg/mL of extract) above 0.7317 μg/ml in ABTS assay.
All extracts showed antioxidant activity in both methodologies used. In the correlation test of AA with phenolic compounds, it was observed that the method of ABTS.+ radical capture has presented a better correlation than the DPPH radical capture assay, indicating that the higher the tenor of phenolic compounds the better AA.

References:
1ARULSELVAN, P. et al. Oxidative Medicine and Cellular Longevity, 15 p., 2016.
2CAMPANA, E.M. et al. Anais do IX Simpósio de Pesquisa dos Cafés do Brasil. Curitiba: 2015.
3KITZBERGER, C.S.G. et al. Food Research International, v. 61, p. 61-66, 2014.
4SWAIN, T.; HILLIS, W.E. Journal of the Science of Food and Agriculture, v. 10, p. 63-68, 1959.
5SINGH, R.P. et al. Journal of Agricultural And Food Chemistry, 50, 81-86, 2002.
6RE, R. et al. Free Radical Biology & Medicine, v. 26, p. 1231-1237, 1999.

This work was supported by FAPEMIG, Rede TOXIFAR/FAPEMIG, CNPq, CAPES and UFOP.