Phytochemicals are natural chemicals of plant origin that have implicated in anti-disease mechanism. Antioxidant are insulator of the process of the oxidation even at relatively small concentration and this have diverse physiological role in the body. They are naturally occurring in the medicinal plants, vegetables, leaves and roots that have defense mechanism and protect from various diseases as well inhibit, or delay the oxidation of other molecules by inhibiting the initiation or propagation of oxidizing chain reaction. Garcinia kola is a tropical flowering plant grown mainly in West and Central Africa. Garcinia kola is known for its anti-inflammatory and antioxidant properties. Therefore, comparative studies on the phytochemical screening and in vitro antioxidant activity on aqueous extracts of stem and root of Garcinia kola were investigated to assess their antioxidant properties in different antioxidant property determination assays. Aqueous extracts of Garcinia kola stem and root bark revealed the presence of tannins, resin, saponins, flavonoids, phenols, carbohydrates and alkaloids. In addition, the aqueous root bark extract of the plant contained phlobatanins and sterols while its stem bark aqueous extract contained terpenoids. The IC50 (μg/ml) values of the stem bark extract were 108.35 ± 7.70, 122.81 ± 3.98, 0.20 ± 0.01, 0.16 ± 0.01 and 0.43 ±0.01 for total antioxidant capacity (AAE), ferric reducing antioxidant activity (AAE), diphenyl picryl hydrazyl (DPPH) assay, nitric oxide (NO) scavenging activity and metal chelating activity respectively. On the other hand, the IC50 (μg/ml) values of the root bark extract were 31.54 ± 2.72, 30.50 ± 0.96, 2.26 ± 0.13, 4.36 ± 0.52 and 0.75 ± 0.04 for total antioxidant capacity (AAE), ferric reducing antioxidant activity (AAE), diphenyl picryl hydrazyl (DPPH) assay, nitric oxide (NO) scavenging activity and metal chelating activity respectively. Consequently, both the stem bark and root bark extracts generally exhibited remarkable in vitro antioxidant properties with respect to the parameters investigated.

This study sought to probe into the health significance of two (white and yellow) species of Dioscorea dumetorum (bitter yam) based on their chemical composition and phytochemicals. Matured tubers were analyzed for proximate composition, mineral contents and phytochemicals, using standard analytical procedures. Significant differences (p<0.05) were observed between the means of some of the compositions in the two species. The results showed moisture contents of 71.45±0.15 and 75.55±1.20 g% wet weight for white and yellow species respectively. Others in g% dry weight included: crude protein (white, 5.20±0.27; yellow, 5.70±0.35), crude ash (white, 4.75±0.16; yellow, 4.05±0.09), crude fat (white, 0.70±0.20; yellow, 0.72±0.01), crude fibre (white, 15.90±0.75; yellow, 14.95±0.070) and carbohydrate (white, 81.86±0.17; yellow, 75.95±0.05). The most predominant minerals were potassium (white, 680±0.20; yellow, 767.85±1.35), phosphorus (white, 270.00±2.10, yellow, 277.25±3.45), sodium (white, 70.35±1.40; yellow, 76.45±0.05) and magnesium (white, 47.10±0.25; yellow, 67.40±0.05). The yellow species showed significantly higher concentrations over the white. The phytochemical screening revealed much presence of glycosides and alkaloids, but little presence of flavonoids, oxalates, phytates and  tannins. The results justify the medicinal use of the tuber and could serve as a synergy to man and animal nutrition.

Phytochemicals are plant-derived chemicals, which are beneficial to human health and disease. They are naturally occurring in the medicinal plants, vegetables, leaves and roots that have defense mechanism and protect from various diseases as well inhibit, or delay the oxidation of other molecules by inhibiting the initiation or propagation of oxidizing chain reaction. Cashew (Anacardium occidentale) is one of the most important nut-bearing trees. Therefore comparative studies on the phytochemical screening and in vitro antioxidant activities on aqueous extracts of leaves and nuts of Anacardium occidentale were investigated to assess their antioxidant properties in different antioxidant property determination assays. Aqueous extracts of the Anacardium occidentale leaves and nuts revealed the presence of resin, flavonoids, phenols, carbohydrates, alkaloids and terpenoids. In addition, the aqueous leaf extract of the plant contained tannins, saponins, phlobatanins and steroids. The IC50 (µg/ml) values of the leaves’ extract were  36.77 ± 1.11, 1.71 ± 0.10, 1.01 ± 0.07, 0.11 ± 0.002 and 0.99 ±0.22 for total antioxidant capacity (AAE), ferric reducing antioxidant activity (AAE), diphenyl picryl hydrazyl (DPPH) assay, nitric oxide (NO) scavenging activity and metal chelating activity respectively. On the other hand, the IC50 (µg/ml) values of the nuts’ extract were  34.85 ± 0.27, 1.37 ± 0.02, 4.65 ± 0.19, 8.65 ± 0.09 and 3.54 ±0.05 for total antioxidant capacity (AAE), ferric reducing antioxidant activity (AAE), diphenyl picryl hydrazyl (DPPH) assay, nitric oxide (NO) scavenging activity and metal chelating activity respectively. Consequently, even though both extracts exhibited remarkable in vitro antioxidant properties, the leaf extract seemed to have better performance with respect to the parameters investigated.

Blighia sapida is a plant belonging to the family of Sapindaceae. In this study we aimed to carry out the phytochemical screening of hydro-ethanolic (15%) extract of Blighia sapida stem bark and evaluate its in vitro antioxidant activity. It was found that the hydro-ethanolic extract of Blighia sapida stem bark showed the presence of saponin, flavonoid, alkaloid, phenols and ascorbic acid. It also contains trace elements zinc and selenium. Furthermore it showed some scavenging activity but not as such could be compared with the various standards used except for nitric oxide scavenging activity.

Liver is a vital organ present in vertebrates, which has a wide range of functions including aiding of digestion, detoxification and protein biosynthesis. But the ability of the liver to perform these functions can be compromised by numerous substances it is daily exposed to, including certain medicinal agents which when taken in over doses. Liver damage, just like many other diseased conditions can lead to oxidative stress, especially when the body’s antioxidant system is overwhelmed by the free radicals thus generated. A major component of this antioxidant system are the natural antioxidant enzymes superoxide dismutase and catalase manufactured in the body, which provide an important defense against free radicals usually generated in diseased conditions. Most synthetic anti-hepatotoxicity drugs available present serious side effects and are generally out of reach of the common man. Consequently, the effect of administration of aqueous extract of Anacardium occidentale stem bark on the activities of superoxide dismutase and catalase in some tissues of acetaminophen-induced hepatotoxic rats was investigated. There was a significant (p < 0.05) reduction in the activities of superoxide dismutase and catalase in the serum, liver, kidney and heart of the hepatotoxic rats. However, treatment of hepatotoxic rats with aqueous extract of Anacardium occidentale stem bark led to a significant (p < 0.05) increase in the activities of superoxide dismutase and catalase in the serum, liver, kidney and heart of acetaminophen-induced hepatotoxic rats.