Annona muricata belongs to the family Annonaceae, which is rampant in the tropical and subtropical regions of the globe such as North America, Africa, Thailand and Asia. 1 Several pharmacological activities such as anti-inflammation, anti-diabetes, hepatoprotective and countless other benefits have been attributed to the extracts from the plant. [2][3][4][5][6][7] The phytoconstituents residing in the plant exhibit disease preventive properties, though they are not essential nutrients to human health. The plant is a domicile of essential bioactive compounds such as annonaceous acetogenins, polyphenols, tannin and alkaloids. 8 Various parts of the plant including the bark, fruit and seed are said to possess medicinal properties and its bark decoction, root, seed and leaf are vastly used in traditional medicine. 9Lipid peroxidation often involves oxidative damage by free radical assault on the membrane lipids. Lipid peroxidation plays crucial roles in the pathogenesis of numerous diseases such as diabetes, Parkinson disease, silicosis and cancer. Radical oxidation involves the attack on unsaturated fatty acids with multiple bonds by reactive oxygen species (ROS), abstraction of hydrogen atom and eventual generation of lipids radicals which results in the destruction of membrane lipids. Oxidative stress by ROS usually involves a chain of reactions which leads to damage of cell constituents such as proteins, lipid and nucleic acids. 10 Consequent to their preventive role against free radical oxidation which results in emergence of several diseases such as cancer, cardiovascular problems and neurodegenerative diseases such as Parkinson and Alzheimer disease, natural antioxidants from plants have become a subject of attraction and interest in combating and treating diseases, 11 Several experimental guided researches have documented the antioxidant activities of A. muricata, 12,13 but there is dearth of information as regard the antioxidant potential of the plant on several prooxidants. This research is therefore undertaken to investigate the antioxidant potential of ethanol extract of A. muricata against different prooxidants in rat cerebral and hepatic tissues. Methods ChemicalsThiobarbituric acid (TBA) and Tris-HCl were obtained from Sigma Chemical Co., St. Louis, MO, USA. Other chemicals used were obtained from certified suppliers. Animals15 male wistar rats with weight range of 200-250g were kept at room temperature under 12h light/dark cycle with access to water and food. Animals were housed and handled in adherence to Committee on Care and Use of Experimental Animal Resources guideline. Extract preparationFresh leaves of A. muricata were washed with water and dried under shade at room temperature. The dried leaves were grinded with mechanical grinder and 200g of the pulverized leaves was macerated in 600ml absolute ethanol for three days. The extract was then filtered, concentrated in a rotary evaporator and stored at 4 o C for assays.

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Daniellia oliveri is one of the most extensively utilized medicinal plants in Nigeria and some West African countries for the treatment of various ailments. In the present study, the GC-MS profiles and effect of ethanolic extracts of stem bark and leaves of Daniellia oliveri on lipid peroxidation, Na+/K+-ATPase activity and thiols status in H2O2 and Fe2+ (fenton reaction) assaulted cerebral and hepatic tissue homogenates was investigated. The stem bark and leaves were extracted with absolute ethanol for 72hrs and concentrated in a rotary evaporator. Wistar rats were euthanized and the brains and livers were removed, homogenized, centrifuged and the supernatants were used for lipid peroxidation, Na+/K+-ATPase activity, and thiol assays in the presence of prooxidants (1mM H2O2 or 10μM Fe2+ or H2O2 and Fe2+).The results revealed that ethanol extract of both the leaf and stem-bark inhibited lipid peroxidation induced by H2O2, Fe2+ and combination of H2O2 and Fe2+ and this was evident in the reduction of lipid peroxidation adducts formation in rat liver and brain homogenates with the stem-bark possessing more efficacy. Furthermore, the results of  Na+/K+-ATPase and thiol assays revealed that H2O2 and Fe2+ inhibited the activity of cerebral Na+/K+-ATPase, while  H2O2/Fe2+ caused a marked reduction in the levels of both protein and non-protein thiols in the tissues homogenates. However, the ethanolic extract of Daniellia oliveri extirpated this anomaly by increasing the activity of cerebral Na+/K+-ATPase as well as the thiol level in the rat hepatic and cerebral tissues. Finally, GC-MS analysis was carried out on the ethanolic extracts of the stem bark and leaves of Daniellia oliveri and results revealed the presence of 21 compounds including 1,2-Benzisothiazol-3-amine, 1H-Indole-2-carboxylic acid, 2-Ethylacridine, Ethyl 2-(2-chloroacetamido)-3,3,3-trifluoro-2-(3-fluoroanilino) propionate and trans-1-Butyl-2-methylcyclopropane in the stem bark and 10 compounds including Methylthio-acetonitrile, 2-Methyl-Z,Z-3,13-octadecadienol, Desulphosinigrin and 4H-1,2,4-triazole-3,5-diamine in the leaves, justifying the observed biological activities of Daniellia oliveri and the higher potency of the stem bark may be attributed to the presence of more bioactive constituents found in it. This study therefore justifies the medicinal usage of leaves and stem-bark of Daniellia oliveri and suggests its consideration in the treatment and management of degeneration diseases with etiology associated with oxidative stress.

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