ABSTRACT

Ethanol, methanol and chloroform leaf extracts of Senna alata and Breynia nivosa were used for evaluation of antimicrobial activity against seven clinical isolates of pathogenic bacteria and one pathogenic fungus. These include Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, Pseudomonas areuginosa, Proteus mirabilis, Streptococcus pneumoniae. Staphylococcus aureus and Candida albican. The leaf extracts were used for acute toxicity study, phytochemical screening and antimicrobial assay using disc diffusion method. The results of the quantitative analysis of Senna alata and Breynia nivosa shows the following parameters to be higher in Senna alata; alkaloids(8 205%). phenols (5.030%),Steroid (2.457%),Saponins (7.696%), flavonoids (2.636%), other parameters including tannins were however higher in Breynia nivosa. The essential minerals were also present such as potassium 687.80 and 525.00mg/100g. sodium 0.504 and 0.651mg/100g, magnesium 153.510 and 192.5I0mg/100g, nitrogen 2.357and 1.362 mg/100g, zinc 0.616 and 0.536 mg/lOOg, phosphorus 162.110 andl45.550 mg/lOOg, calcium 166.180 and 152.950 mg/lOOg. The vitamin content showed the following, thiamine 64.320±0.565 and 52.034±0.103 mg/lOOg, niacin 25.535±0.106 and 26.785±0.092mg/100g, riboflavin47.950±0.495 and 47.130±0.297mg/100g, retinol 11.424±0.198 andl3.565±0.081mg/100g and ascorbic acid 107.510±4.681 and 98.685±0.621mg/100g. In antimicrobial screening, methanol, ethanol leaf extracts of Senna alata and Breynia nivosa were more active against Escherichia coli, Salmonella typhi, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Streptococcus pneurnoniue, Staphylococcus aureus and Candida albican but chloroform leaf extracts of Senna alata and Breynia nivosa were not as active as the former. Methanol leaf extracts of Breynia nivosa were against Proteus mirabilis (4.700) and lower a Candida albican (1.533), the ethanol leaf extract ofBreynia nivosa were against Salmonella typhi (3.100) and low activity on Streptococcus pneumoniae (1.800). Chloroform leaf extract of Breynia nivosa were against Proteus mirabilis (3.767) the lowest activity was against Streptococcus pneumoniae (2.133). Ethanol leaf extract of Senna alata was higher against Proteus mirabilis (4.033) and lower against Candida albican (2.600). Methanol leaf extracts of Senna alata were higher against Klebsiella pneumoniae (2.900) and lower against Candida albican (1.767). The chloroform leaf extract of Senna alata showed maximum activity against Candida albican (1.100) however there was no antimicrobial activity against the Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa. The Minimum inhibitory concentration for ethanol, methanol leaf extract of Senna alata and Breynia nivosa ranged from 62.5mg and 125mg where as in chloroform leaf of Senna alata and Breynia nivosa ranged from 62.5mg and lOOOmg. The result of acute toxicity test revealed that the LD50 of the ethanol leaf extract of Senna alata was 707mg/kg whereas in Breynia nivosa it was 354mg/kg. This study showed that ethanol, methanol and chloroform leaf extract of Senna alata and Breynia nivosa contained some secondary metabolites that may be responsible for the observed antimicrobial activity and thus supports the traditional use of tiie plants in the management ofdiseases caused by susceptible organisms