Comparative Study of Antioxidant Potentials of Methanol Fruit Extracts of Morinda citrifolia and Morinda lucida

lants contain biochemical components that can be extracted and used in the preparation of drug, or used directly as medication. These medicinal plant preparations are administered to man with the hope of promoting health and treating various diseases. Immense benefits have been derived by man from using medicinal herbs in disease management because they are relatively safer, more affordable and sometime offer better therapeutic values than synthetic drugs (Oyewole and Akigbala, 2011). One of these medicinal plants is Morinda. It is in a genus of flowering plants in the madder family, Rubiaceae. Its generic name is derived from the Latin words morus "mulberry", from the appearance of the fruits, and indica, meaning "of India". There are about 80 species of Morinda trees although the species of interest in this work are Morinda citrifolia and Morinda lucida. Morinda citrifolia Linn Rubiaceae is one of the most important traditional Polynesian medicinal plant commercially known as Noni, Indian mulberry, Cheese fruit and indigenously found in open coast region at sea level and in forest areas about 1,300 feet above sea level. It is a small tropical evergreen shrub or tree, three to twelve meters high. It has straight trunk, large green leaves and distinctive grenade like yellow fruit. The size of the fruit is about 12cm due to coalescence of the interior ovaries of many closely packed flowers and it has a foul taste and a soapy smell when ripe. The fruit of this plant has been used as food, drink, P ABSTRACT Herbal preparations of different Morinda plant species had been used as supplements and for therapeutic purposes with less emphasis on the bioactive components. This study is aimed at investigating the in vitro antioxidant potentials of methanol fruit extracts of Morinda citrifolia (MCE) and Morinda lucida. The potent bioactive agents in MCE and MLE were extracted with 90% methanol. Both plants species did not have catalase activity but scavenged 1, 1-diphenl-2picrylhydrazyl radical (DPPH) in concentration dependent manner against percentage inhibition showing effective concentration at 50% inhibition (EC50) of 716.09 μg/ml and 910.24μg/ml for MCE and MLE compared to that of vitamin C standard with the EC50 of 54. 61μg/ml. The MCE and MLE scavenged superoxide (SO) radical in concentration dependent manner with the EC50 of 72. 77μg/ml and 82.43 μg/ml respectively compared to that of vitamin C standard with EC50 of 176. 08μg/ml. Also, MCE and MLE scavenged nitric oxide (NO) radical in concentration dependent manner with the EC50 of 2198. 32μg/ml and 3734. 26μg/ml compared to that of vitamin E standard with EC50 of 1700. 73μg/ml. Both MCE and MLE scavenged hydroxyl (OH) radical in concentration dependent manner with the EC50 of 134. 32μg/ml and 155. 07μg/ml respectively compared to that of vitamin E standard with EC50 of 54. 33μg/ml. These might imply that MCE is a better antioxidant than MLE. The MLE contained more vitamin A (2,438± 0.1i.u) than MCE (1,323± 0.3i.u) while MCE vitamin C (10.80± 0.05i.u) and vitamin E (0.15± 0.2 i.u) contents was higher than that of MLE (vitamin C (7.40± 0.02i.u) and vitamin E (0.14±0.01i.u). These could also imply that MCE had more antioxidant activity and could be preferred in Nigeria folk medicine. Original Research Article