ABSTRACT

The antimicrobial properties of Citrus aurantfolia and Bryophyllum pinnatum on some selected microorganisms were investigated. The various concentrations of the extracts were prepared by double dilution method, while the ability of the various extracts to inhibit the growth of the pathogenic organisms was determined using the agar well technique. The methanol and aqueous soluble plant extracts were active against all the test isolates but methanol extract of Bryophyllum pinnatum demonstrated greater antimicrobial activity on Staphylococcus aureus, Escherichia coli, Streptococcus species at the range of 12.5mglml each, while the lime juice extracts demonstrated greater antimicrobial activity on Escherichia coli at 12.5mg/ml each. The minimum bactericidal concentration revealed that the methanol soluble extracts of Bryophyllum pinnatum showed greater activity against Staphylococcus aureus, Streptococcus species and Klebsiella species at lOOmg/ml, when compared to the aqueous plant extract. The lime juice extracts were active against Staphylococcus aureus, Streptococcus species, and Kiebsiella species at 200mg/ml. The highest in-vitro antimicrobial activity of methanolic extract of Bryophyllum pinnatum at the highest concentration of 200mglml against Kiebsiella pneumonia was (13 .Oa±2.83amm) while the least antimicrobial activity was (10.Od±O.Oemm) exhibited at the concentration of 200mg/ml against Candida albicans. The highest in-vitro antimicrobial activity of (9 o±14 lemm) was also exhibited by the aqueous extract of Bryophyllum pinnatum at the highest concentration of 200mg/ml against Aspergillus niger, while the least antimicrobial activity (6.Oa±0.00cmm) was exhibited at the concentration of 200mg/mi against Staphylococcus aureus. The lime juice extracts had the highest in-vitro antimicrobial activity of (11.Ob±0.00cmm), at the concentration of 200mg/mi against Staphylococcus aureus, while the least antimicrobial activity is (8.Oa±O.Ocmm) was exhibited at the concentration of 200mg/mi against Candida albicans and Aspergillüs niger. Therefore, methanolic and aqueous extracts of Bryophyllum pinnatum as well as lime juice extracts have broad-spectrum antimicrobial activity when compared to the standard antibiotics used in this study, hence can serve as natural therapeutic agent against some enteric pathogens.