Abstract

GONZALEZ-ARAUZ, Alexander P. et al. Antioxidant capacity assessment by abts of 9'Z-bixin, 9'Z-norbixin, 9'Z-methylbixin and all e-methylbixin from bixa orellana seeds. Rev. Bol. Quim [online]. 2022, vol.39, n.3, pp.31-38. ISSN 0250-5460.  https://doi.org/10.34098/2078-3949.38.3.3.

The 9´Z-bixin is the major pigment present in the annatto (Bixa orellana L.) seeds. Other carotenoids present in the seeds of annatto are 9´Z-norbixin and 9´Z-methylbixin. Annatto seeds extract is used as a food colorant. In this study, we extracted and isolated 9´Z-bixin from annatto seeds. 9’Z-norbixin was obtained and purified by saponification of annatto seeds extract. Then, 9’Z-methylbixin was obtained by Steglich esterification of 9´Z-bixin with EDC/DMAP. Also, all E-methylbixin was obtained by esterification of 9’Z-bixin in acid conditions with hydrochloric acid in methanol. The antioxidant capacity of 9´Z-bixin and bixin derivatives was measured in ABTS assay to determine their structure-activity relationship. We observed that the esterification of 9´Z-bixin decreases its antioxidant capacity and that the presence of the free carboxyl group is important in the antioxidant capacity of bixin derivatives.

Keywords : 9’Z-Bixin; 9´Z-Norbixin; 9´Z-Methylbixin; All E-methylbixin; Food colorant; Antioxidant activity; structure-activity relationship.

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