Comparison of different climatic seasons of Brazil in the value of phenolic compounds, oleuropein, and antioxidant capacity in olive leaves of three cultivars

Resumo

This study evaluated the effects of different Olive leaves cultivars harvested in the different climatic seasons on the total polyphenolic content (TPC), oleuropein content and antioxidant capacity. Arbosana presented higher TPC in summer and Koroneiki and Arbequina in spring. Oleuropein content presented a similar profile. DPPH had its best values for Arbosana and Koroneiki in the spring, followed by Arbequina in the summer. FRAP had the highest values in summer for all cultivars, with Arbosana presenting the higher value. ORAC had the highest values in winter for all cultivars, with Koroneiki presenting the higher value. Autumn had the worst results considering all the analysis. DPPH was the method more indicated to predict the antioxidant capacity of oleuropein according to statistical correlation. The results highlighted that the different harvest periods for Brazilian production and the different cultivars strongly influenced TPC, oleuropein content and the antioxidant capacity of olive leaf extracts.