Abstract

The study is aimed at investigating the antioxidant properties of the free and bound phenols of the leaves of Jatropha tanjorensis. Antioxidant properties of the leaves were determined by various assays. Results showed that the free (FP) and bound phenols (BP) content were 294 and 432 mg/g (GAE), respectively while the flavonoid content of (FP) and (BP) were 32.72 ± 1.37 and 77.24 ± 4.45 mg/g (QE), respectively. Further results show that both FP and BP demonstrated potent but dose-dependent free radical scavenging activity against both hydroxyl and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals. Moreover, both phenolic extracts displayed significant (P < 0.05) Fe(II)-chelating and ferric reducing properties even at the least dose used. Finally, both extracts demonstrated a significant (P < 0.05) inhibitory effect against lipid peroxidation intentionally induced by Fe²⁺ in rat’s brain and liver. From the foregoing, it is rational to attribute the wide usage of the leaves of J. tanjorensis in folkloric medicine to its high phenolic content. Hence, information from this study could be exploited in the global fight against degenerative diseases, whose etiology has been linked to oxidative stress.

Key words: Free phenols, bound phenol, antioxidant, free radical, oxidative stress.