PHARMACOGNOSTIC AND ANTIBACTERIAL STUDIES OF ACACIA SIEBERIANA VAR WOODII (FABACEAE) STEM BARK, A RESEARCH PROJECT TOPIC ON MICROBIOLOGY
ABSTRACT
Acacia sieberiana var. Woodii (Fabaceae) is traditionally used as a remedy for stomach aches and ulcers among some localities in Northern Nigeria. The plant was investigated sequel to the reports of its ethnomedicine uses in the management of stomach ache and ulcers. Anatomical and physical constants studies were carried out using standard procedures. Phytochemical (preliminary studies, thin layer and column chromatography) were also carried out on the hexane and methanol extracts. Toxicity and antibacterial studies of the hexane and methanol extracts, and the isolated compound were investigated. The microscopical studies revealed the presence of cellulose cell wall, lignified and suberized cell walls, tannins and calcium crystals. Anatomical features identified in the stem bark consist of epidermis, phellogen, phelloderm, and cortex. The percentage moisture content and ash values were observed to be 9.0% and 10.5% respectively. Water extractive value was 1.2% while ethanol extractive value was 1.6%.The preliminary phytochemical studies as well as the TLC chromatogram of the hexane extract revealed the presence of steroids and triterpenes while the methanol extract contains tannins, flavonoids, alkaloids, steroids and triterpenes. Fraction AS1 collected through column chromatography was suggested to be a hydrocarbon on the basis of its colourless and oily nature. The acute toxicity study carried out indicated that the hexane extract was slightly toxic while the methanol extract was moderately toxic. Antibacterial studies of the stem bark carried out showed zones of inhibition between 16 to 27 mm for the hexane and methanol extracts against Helicobacter pylori, Escherichia coli, Salmonella typhi and
Shigella dysenteriae. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were between the range of 2.5 and 10 mg/ml and 5.0 to 20 mg/ml respectively. Fraction AS1 exerted a dimension of zones of inhibition between 26 to 30 mm against all the bacterial strains except S. typhi. It was also able to exert MIC and MBC against E. coli and H. pylori at 12.5 and 25µg/ml respectively, while it had MIC and MBC at the lowest concentrations of 6.25 and 12.5 µg/ml against S. dysenteriae. Results of the present studies had shown that A. sieberiana and fraction AS1 collected from this plant have wide antibacterial property.
CHAPTER ONE
1.0Â Â Â INTRODUCTION
1.1Â Â Â Traditional Medicine
Traditional medicine can be said to be a comprehensive knowledge system that encompasses the utilization of substances, dosages and practices based on socio-cultural norms and religious beliefs as well as witnessed experiences and observations of a specific group (Tom et al., 2008). The practice is used in various therapies by the indigenous population all over the world. It has been documented that about 80% of the people in developing countries rely on traditional medicines for their primary health care need, which can be attributed to increased poverty, ignorance as well as unavailability of modern health facilities (Omonike, 2010; Christiana et al., 2012).
