Abstract

The nutrient and antinutrient compositions of the seed of Persea americana were determined prior to the determination of antimicrobial activities of the seed extracts. The seeds were treated to provide the hot water, cold water, methanol and ethanol extracts, which were tested on susceptible micro-organisms such as Eschericha coli, Pseudomonas aeruginosa,Staphylococcus aureus and Klebsiella pneumoniae. Proximate analysis revealed the presence of the following constituents: moisture 12.70±1.00%; crude fat 18.63±0.20%; crude protein 18.44±0.10%; carbohydrate 48.10±0.10 %; ash 2.50±0.00% and crude fiber 3.25±0.20%. Phytochemical screening revealed the presence of tannins (21.26±0.10%); saponins (51.00±0.00%); flavonoids (21.00±0.00%); alkaloids (9.43±0.10%) and cyanogenic glycosides (4.86±0.10 mg/100 g). Antimicrobial activity of the extracts on various micro-organisms showed that the hot water and methanol extracts exhibited the highest antimicrobial function followed by the cold water and the ethanol extracts by comparing their zones of inhibition. The activity of the methanol extract was more pronounced against P. aeruginosa (30 mm) and St. aureus (20 mm); while the hot water extract exhibited effective antimicrobial effect on P. aeruginosa (20 mm) and E. coli (14 mm). All the four extracts were more effective on P. aeruginosa than on other microbes. The antimicrobial activity of the extracts when compared with other standard antimicrobial did not show any statistical difference at p < 0.05. The antimicrobial activities of the methanol and hot water extracts were more than those of ciprofloxacin (CPX) and perflaxin (PRX), but similar to that of ofloxacin (OFL). These extracts exhibited wide spectra of antimicrobial activity, which implies that, P. americana seed extracts can be used therapeutically in the treatment of many bacterial diseases to which the bacterium is sensitive. There is no doubt that such disease conditions like sepsis, pneumonia, boils and abscess can be managed with the extracts; equally, the extracts can be used to supplement orthodox drugs especially in rural areas where incomes are very low and effective medical facilities are defective and inadequate.

Key words: Antimicrobials, extracts, anti-nutrients, proximate analysis, avocado pear seed.