Comparative Antibacterial Studies On The Root, Stem Bark And Leaf Extracts Of Parkia Clappertoniana.

摘要

The research on medicinal plants is gradually gaining popularity due to millions of people depending on the use of different parts of these materials for various ailments.The antibacterial activity of hot and cold water and ethanolic extracts of the root, stem and leaf of Parkia clappertonia against Escherichia coli ATCC 11775, Pseudomonas aeruginosa ATCC10145, Staphylococcus aureus ATCC 12600 was evaluated using agar-well diffusion and agar dilution methods. All the organisms were susceptible to all the extracts with the diameter of zones of inhibition ranging between 14 mm – 27 mm for hot water extracts, 12 mm – 22 mm for cold water extracts and 12 mm – 25 mm for ethanolic extracts. The Minimum Inhibitory Concentrations ranged between 2.5 mg/ml – 20.0 mg/ml. The rate of kill of the test bacterial species by hot water extract was concentration dependent. Saponin, flavonoids, tannin, glycoside, alkaloid and anthraquinone were the phytochemical constituents detected from the Parkia clapatoniana root, stem and leaf extracts. The implications of these findings in the medicinal use of Parkia clapertoniana are discussed. Introduction Parkia clappertoniana (Keay) which is commonly known as West African Locust beans belongs to family Leguminosae-Mimosaceae which has about 236 genera1. The common species of the Parkia genus are Parkia biglobosa, P. filicoidea and P. clappertoniana. Parkia clappertoniana is a tree of about 18meters high and 3.6meters in width with spreading branches. The plant tends to occur in the savanna country and has been recorded from Gold Coast (Ghana), Togoland (Ghana and Togo), Dahomey (Benin) and Northern Nigeria1. Parkia species have been reportedly used in folk medicine for the treatment of various diseases especially infections2, 3. The roots and leaves of Parkia clappertoniana are pounded with water and used as an eye wash; the roots and the leaves were also reported to be active against dental caries, conjunctivitis4. It was also reported that an infusion of the stem bark was successfully used for the treatment of many infectious diseases such as diarrhoea, orchitis, dental caries, pneumonia, bronchitis, violent stomachaches, severe cough, infected wounds, otitis, dermatosis, amoebiasis, bilharziosis, leprosis, ankylosis, tracheitis, and conjunctivitis4.Many phytochemical constituents have isolated from Parkia species. Lemmich et al., 5 isolated 5- deoxyflavones from Parkia clappertoniana and phenolics were also isolated from Parkia biglobosa 2.Bacterial genera such as Staphylococci, Escherichia and Pseudomonads have been implicated in the above mentioned infectious diseases6. Staphylococcus aureus occur harmlessly as a normal flora of the skin and mucous membrane and it is one of the commonest bacterial pathogens encountered in the community causing severe food poisoning or minor skin infections to severe life threatening infections6. Escherichia coli are known as part of normal flora but incidentally may cause diseases: urinary tract infection, diarrhoea and hemorrhagic colitis; blood stream sepsis when the normal host defenses are inadequate7. Pseudomonas aeruginosa are wide spread in soil, water and sewage and this can be considered as an indication of their involvement in the natural process of mineralization of organic matter. It has long been a troublesome cause of secondary infections of wound, especially burns, giving rise to blue-green pus. It produces meningitis, when introduced by lumber puncture and urinary tract infection when introduced by catheters and instruments or irrigating solutions7. Bacterial resistance to antibacterial drugs used in the treatment of some of the earlier mentioned infections has become a menace, therefore causing untold health challenges to patients. The aim of our study is to check the antibacterial effects of the root, stem and leaf of Parkia clappertoniana against the above mentioned pathogens in order to determine which of the plant parts would be the most activ