The addition of antioxidants to biodiesel, as well as the elimination of conditions favoring the initiation of the oxidation reaction, can inhibit or retard the oxidative process. In this work, we present a comparative study of the antioxidant activity of extracts of bilberry (BE), oregano (EO), and basil (BAE), quercetin (QC) and pyrogallol (PY) in biodiesel derived from soybean oil. The oxidation stability of the samples was studied using the Rancimat and PetroOXY methods under 90, 100, 110, 120, 130 and 140 degrees C. Among the extracts, the highest total phenolic contents were found in the oregano extract, followed by the basil and bilberry extracts. The apparent activation energy for the consumption of the antioxidants was determined by the Arrhenius equation. The substrates were ranked in the descending order of PY (81.39 kJ mol(-1) ) > QC (77.73 kJ/mol) > BE (63.85 kJ/mol) > BAE (62.02 kJ/mol) > OE (52.04 kJ/mol) for the Rancimat method and PY (79.64 kJ/mol) > QC (68.92 kJ/ mol) > BE (45.31 kJ/mol) > OE (44.48 kJ/mol) > BAE (41.98 kJ/mol) for the PetroOXY method. Parameters such as enthalpy, entropy, and Gibbs free energy indicated a non-spontaneous endothermic process, as expected for antioxidant samples. The shelf-life of the samples was predicted as: PY > QC > BE > BAE > OE and PY > QC > OE > BE > BAE for Rancimat and PetroOXY methods, respectively. Considering the sensibility and the analysis time, both methods meet the necessary requirements for the stability evaluation of biodiesel samples.