Abstract

ANALYSIS OF ANTIBACTERIAL ACTIVITY OF THE LEAVES OF GOSSYPIUM HIRSUTUM ON SELECTED BACTERIA

Nwobodo H. A.*

Abstract

Antibacterial and phytochemical analysis of the leaves of Gossypiumhirsutum was carried out using selected bacteria; Salmonella typhi,Staphylococcus aureus, Proteus mirabilis and Escherichia coli. Theleaves were collected, identified, washed and air dried at roomtemperature and milled into powder. Forty (40) g of the powder wasmacerated in extracting solvents (methanol and ethanol) used. Thecrude extract was concentrated by evaporation at variousconcentrations (100mg/ml, 300mg/ml, and 500mg/ml) prepared using5% DMSO. Phytochemical analysis showed that Saponin (+++),Tannin (+++), Alkaloids (+++), and Flavonoids (+) were present.Methanol and ethanol yielded 220mg (0.55%) and 150mg (0.38%)crude extracts respectively. Methanol extract at 500mg/ml exhibitedinhibition zones of 28 mm, 28 mm, 26 mm, and 20 mm against Escherichia coli, Salmonellatyphi, Proteus mirabilis and Staphylococcus aureus respectively while ethanolic extractshowed inhibition zones of 20 mm, 17 mm, 17 mm, and 7 mm against Escherichia coli,Salmonella typhi, Proteus mirabilis and Staphylococcus aureus. Both extracts showedactivity against all the test bacteria except Staphylococcus that was less susceptible toethanolic extract. This study therefore suggests that methanolic and ethanolic extracts ofGossypium hirsutum have activity against certain bacteria since they exhibited comparableactivity with the positive control (ciprofloxacin). Further research should be conducted toisolate, purify and characterize bioactive component of the extracts responsible for theobserved antibacterial activity.

Keywords: Antibacterial activity, leaf extract, Gossypium hirsutum, Bacteria.