Abstract

Hibiscus sabdariffa is a plant of the Malvaceae family, commonly found in tropical and subtropical regions of Africa, Asia, and the Americas. Its leaves, seeds, and calyxes are utilized in both human and animal nutrition. The objective of this study was to evaluate the antioxidant activity of phenolic compounds in leaves and calyxes harvested from H. sabdariffa plants that were fertilized with chicken manure in Congo. The total polyphenol, flavonoid, and anthocyanin contents of each extract were determined using a UV-visible spectrophotometer.  Whereas, the antioxidant activities were assessed using the 2, 2-diphenyl-1-picrylhydrazyl free radical scavenging assay. The highest contents of total polyphenols, flavonoids and anthocyanins observed in leaf extracts were 364, 91 and 134.6 mg EC3G/g MS, respectively. While the calyx extracts, showed for the same compounds from H. sabdariffa plants fertilized with chicken droppings, were 362, 322, and 162 mg EC3G/g MS, respectively. The IC50 mean values from leaves and calyxes were 0.64 and 1.01 mg/ml, respectively. This demonstrated that the leaves and fruits of H. sabdariffa cultivars from Congo are rich in phenolic compounds and can be used as a source of natural antioxidants which are essential in human and other mammalian foods.

Key words: Calyxes, chicken manures, leaves, polyphenols, flavonoids, anthocyanins, Hibiscus sabdariffa.