Secondary metabolites and antioxidant activity of <i>Theobroma cacao</i> (cocoa) stem bark

Abstract

Background: The phytochemical composition and antioxidant activity of extracts obtained from Theobroma cacao stem bark were investigated. Materials and Methods: Dried T. cacao stem bark was extracted with methanol to obtain a crude extract. The crude extract was subjected to solvent-solvent extraction/fractionation using solvents of increasing polarities to obtain several fractions. Results: Phytochemical screening revealed the presence of several metabolites such as saponins, flavonoids, phenols, tannins, anthraquinones, and alkaloids in various fractions. Total phenolic and flavonoid contents were highest in the petroleum ether fraction and lowest in the chloroform fraction. DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity used to access the antioxidant potential of the extracts revealed that the petroleum ether fraction had the best free radical scavenging activity (IC50 value of 134.67 ± 2.08 μg/ml) compared to the other fractions with higher IC50 values. Similarly, petroleum ether fraction had the highest ferric reducing antioxidant potential followed by the crude extract, while chloroform extract exhibited the least ferric reducing antioxidant potential. Conclusion: We conclude that Theobroma cacao stem bark extracts contain phytochemicals with antioxidant activities that may be beneficial to health.