Antimicrobial Activities of Leaf Extracts of Guava (Psidium guajavaL.) on Two Gram-Negative and Gram-Positive Bacteria

Bipul Biswas,Dwayne Daniels,Kimberly Rogers,Anand Yadav,Fredrick Mclaughlin

doi:10.1155/2013/746165

Bipul Biswas, Dwayne Daniels + Show 3 more

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https://doi.org/10.1155/2013/746165

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Abstract

Aim. To determine the antimicrobial potential of guava (Psidium guajava) leaf extracts against two gram-negative bacteria (Escherichia coli and Salmonella enteritidis) and two gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) which are some of foodborne and spoilage bacteria. The guava leaves were extracted in four different solvents of increasing polarities (hexane, methanol, ethanol, and water). The efficacy of these extracts was tested against those bacteria through a well-diffusion method employing 50 μL leaf-extract solution per well. According to the findings of the antibacterial assay, the methanol and ethanol extracts of the guava leaves showed inhibitory activity against gram-positive bacteria, whereas the gram-negative bacteria were resistant to all the solvent extracts. The methanol extract had an antibacterial activity with mean zones of inhibition of 8.27 and 12.3 mm, and the ethanol extract had a mean zone of inhibition of 6.11 and 11.0 mm against B. cereus and S. aureus, respectively. On the basis of the present finding, guava leaf-extract might be a good candidate in the search for a natural antimicrobial agent. This study provides scientific understanding to further determine the antimicrobial values and investigate other pharmacological properties.

Highlights

There has been a lot of attention focused on producing medicines and products that are natural
We aim to evaluate the total extracts of P. guajava leaves, growing at Fort Valley State University, using various aqueous and organic solvents to establish if it is effective against killing or inhibiting the growth of foodborne bacterium Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, and Bacillus cereus which can cause foodborne illness and spoilage
The results indicate that ethanol and methanol are better than n-hexane and water for the extraction of the antibacterial properties of guava

Summary

Introduction

There has been a lot of attention focused on producing medicines and products that are natural. Several fruits and fruit extracts, as well as arrowroot tea extract [1] and caffeine [2], have been found to exhibit antimicrobial activity against E. coli O157:H7 This suggests that plants which manifest relatively high levels of antimicrobial action may be sources of compounds that can be used to inhibit the growth of foodborne pathogens. The many parts of the plant have been used in traditional medicine to manage conditions like malaria, gastroenteritis, vomiting, diarrhea, dysentery, wounds, ulcers, toothache, coughs, sore throat, inflamed gums, and a number of other conditions [3,4,5]. We aim to evaluate the total extracts of P. guajava leaves, growing at Fort Valley State University, using various aqueous and organic solvents to establish if it is effective against killing or inhibiting the growth of foodborne bacterium Staphylococcus aureus, Escherichia coli, Salmonella enteritidis, and Bacillus cereus which can cause foodborne illness and spoilage

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