Abstract: This study seeks to determine the antioxidant properties and the ability of polyphenol extracts from Ocimum gratissimum (OGP) and Ocimum canum (OCP) leaves (commonly used Spices in Tropical Africa, Asia and South America) to inhibit some pro-oxidants (Fe2+ and sodium nitroprusside) induced lipid peroxidation in rat`s brain homogenates-in vitro. The free soluble polyphenols were extracted with 80% acetone; thereafter the ability of the extracts to inhibit 25 μM FeSO4 and 7.0 μM sodium nitroprusside induced lipid peroxidation in isolated rat`s brain was determined. The antioxidant properties of the extracts as typified by their total phenol content, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging ability, reducing power and Fe (II) chelating ability were also determined. The results of the study revealed that both pro-oxidants [Fe2+ (256%) and sodium nitroprusside (160%)] caused a significant increase (p<0.05) in the malondialdehyde (MDA) content of the brain. However, polyphenol extracts (0.4-1.6 μg mL-1) from both species of Ocimum caused a dose-dependent significant decrease (p<0.05) in the malondialdehyde (MDA) contents of the brain. However, polyphenol from Ocimum canum had a significantly higher (p<0.05) inhibitory effect on both Fe (II) and sodium nitroprusside induced lipid peroxidation in the rat`s brain homogenates than that of Ocimum gratissimum. This higher inhibitory effect of Ocimum canum could be attributed to its significantly higher (p<0.05) total phenol content, Fe (II) chelating ability, reducing power and free radical scavenging ability. Therefore, Fe (II) and sodium nitroprusside induced oxidative stress in the brain could be potentially prevented/ managed by dietary intake of Ocimum gratissimum (OGP) and Ocimum canum (OCP) leaves, however Ocimum canum (OCP) leaf extract is more active. These antioxidant properties of the Ocimum spp. polyphenol may have contributed to the use of the leaves in the treatment of mental illness in folk medicine.