In vitro Antioxidant and Antibacterial Activities of Extracts from Annatto (Bixa orellana L.) Leaves and Seeds

摘要

The aim of this work was to determine (1) the total phenolic compound (TPC), total flavonoid compound (TFC) and bixin and norbixin content of polar extracts of leaves (ALE) and seed (ASE) from annatto (Bixa orellana L.); (2) the antioxidant activity,the ALE and ASE by means of different antioxidant tests, and (3) the effectiveness of ALE and ASE on the growth inhibition of several bacterial strains. Five different test systems were used to determine the antioxidant activity, while the microdilutionmethod was used to test for antimicrobial activity. ALE presented higher (P<0.05) TPC and TFC than ASE. As regards antioxidant activity, at all the concentrations tested and with all the methods, except the Rancimat test, the ALE samples showed higher (P<0.05) antioxidant activity than ASE samples. As regards antibacterial activity, ASE was a stronger inhibitor (P<0.05) of bacterial growth than ALE. Both ALE and ASE could be used as alternative natural preservatives in food matrices due to mainly theirbroad antioxidant activity and lesser extent of their antibacterial activity.