Comparative Studies On The Phytochemical Screening And In Vitro Antioxidant Activities Of Aqueous Extracts Of Garcinia Kola Stem And Root Barks

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.