World Applied Sciences Journal 16 (4): 523-530, 2012 ISSN 1818-4952 © IDOSI Publications, 2012 Corresponding Author: F.C. Akharaiyi, Department of Microbiology, Federal University of Technology, Akure, Ondo State, Nigeria. 523 Antibacterial, Phytochemical and Antioxidant Activities of the Leaf Extracts of Gliricidia sepium and Spathodea campanulata F.C. Akharaiyi, B. Boboye and F.C. Adetuyi Department of Microbiology, Federal University of Technology, Akure, Ondo State, Nigeria Abstract: The methanol, ethanol and petroleum ether soluble crude and fractions extract of Gliricidia sepium and Spathodea campanulata leaf were examined for antibacterial activities, phytochemicals and possible sources of antioxidant. The antibacterial activity of the crude and fractions were carried out against nine clinical bacteria isolates using the agar well and disc diffusion methods respectively. S. campanulata crude and fractions extract possessed higher inhibitory potencies than G. sepium extracts. The antioxidant DPPH test was performed where appreciable level of both ferric reducing antioxidant properties and free radical scavenging activities were of better expression in S. campanulata than G. sepium. However, G. sepium extract has the highest concentration of phenol with a value of 1.7mg/ml and flavonoid content with a value of 0.46mg/ml. The highest phenol and flavonoids contents in S. campanulata were 1.2mg/ml and 0.56mg/ml respectively. The phytochemical compounds of the extracts such as phenols, alkaloids and saponin could have shown the high value in antibacterial assay. The crude ethanol extracts of the two plants was more potent in inhibiting the organisms, followed by the methanol extract and was least with the petroleum ether extract. G. sepium fractions extract inhibited the organisms with halos between 0-48.7mm while S. campanulata inhibited the organisms with halos between 0-49.3mm. Key words: Antibacterial Clinical Antioxidant Plant extracts Phytochemical Nigeria INTRODUCTION important in recent years due to the development of Medicinal plant is defined as any plant with one or undesirable side effect of some antibiotics [4, 5]. With the more of its organs containing substance that can be used recent advent of ever-increasing resistant bacteria, there for therapeutic purpose or which can be used as has been a corresponding rise in the universal demand for precursors for the synthesis of antimicrobial drugs [1] natural antibacterial therapeutics [6]. Although antioxidant, anti-infectious and anti-tumor activities [2]. pharmacological industries and researchers have Plants are presently the sources of medicines for many produced a good number of antibiotics in the last three people of different age in many countries of the world, decade, resistance to these drugs by microorganisms is where diseases are treated primarily with traditional increasingly high. medicines obtained from plants. The modern Herbal medicines have been widely used and form an pharmaceutical industry itself still relies largely on the integral part of primary health care of many countries [7- diversity of secondary metabolites in plants and 11] and may constitute a reservoir of new antimicrobial secondary metabolites of which at least 12,000 have been substances to be discovered. However, the last few years isolated; a number estimated to be less than 10% of the have seen a major increase in their use in the developed total [3]. world [12, 13]. Nearly all culture and civilizations from The synthesized aromatic substances (metabolites) ancient times to the present day have depended fully are used by plants as defensive weapon against predation or partially on herbal medicines because of their by microorganisms, insects and herbivores. The search effectiveness, affordability, low toxicity and acceptability for plants with antimicrobial has gained increasing antimicrobial drug resistance and often the occurrence of [14]. Antioxidant is a molecule capable of inhibiting the