Antibacterial activities and phytochemical screening of crude extract of &lt;i&gt;Carica papaya&lt;/i&gt; leaf against selected pathogens

R.A. Olawoyin,A.E. Ajiboye

doi:10.4314/gjpas.v26i2.8

Abstract

Carica papaya commonly known as paw paw belongs to the family of Curcubitaceae and commonly grown in tropical regions. It possesses antimicrobial, antihelmintic and antioxidant properties. The study assessed the antibacterial potency of Carica papaya against Escherichia coli, Klebsiella pneumoniae and Staphylococcus aureus. Acetone and aqueous extracts of the leaves of Carica papaya were obtained using standard methods. The antibacterial activity of the extracts was done using agar well diffusion methods. The Minimum inhibitory and Minimum bactericidal concentrations were done using standard procedures. The antibacterial activities of the crude extracts of Carica papaya against the test organisms revealed that acetone extract showed maximum zone of inhibition on Staphylococcus aureus with a diameter of 17.90±0.10mm at 500 mg/ml and the lowest inhibitory effect on Klebsiella pneumoniae with a zone of 6.50±0.50mm at 100 mg/ml, the aqueous extract showed maximum zone of inhibition on Staphylococcus aureus with a diameter of 15.50±0.50mm at 500 mg/ml and the lowest zone of inhibition was on Staphylococcus aureus with a diameter of 6.50±0.50mm at 100 g/ml. The Minimum Inhibitory Concentration of acetone and aqueous extract was 40 mg/ml and 50mg/ml against Klebsiella pneumoniae respectively. The Minimum Bactericidal Concentration of the extracts ranges from 40-60mg/ml. The qualitative phytochemical screening result revealed the presence of tannins, saponnin, alkaloids and steroid. The quantitative phytochemicals revealed 0.70% of flavonoids, 0.48% of alkaloids, 1.02% of tannin, 0.11% of steroids and 1.08% of glycoside. The result obtained revealed that crude extracts of Carica papaya leaves has antibacterial activities against the test organisms. Keywords: Carica papaya, Phytochemical screening, Pathogens, Antibacterial activity

Highlights

The activities of plant extracts against bacteria have been studied for years, but with more emphasis in the last three decades
The three organisms exhibited varying degrees of antibacterial activities using the aqueous extract with Staphylococcus aureus having the highest activity with a diameter of zone of inhibition 15.50±0.50mm at 500 mg/ml concentration and the lowest activity was seen in Staphylococcus aureus with a diameter of zone of inhibition 6.50±0.50 at 100 mg/ml
The minimum inhibitory concentration for the acetone and aqueous extracts for S. aureus ranged from 40-50 mg/ml, E. coli ranged from 50-60 mg/ml while K. pneumoniae ranged from 40-50 mg/ml

Summary

Introduction

The activities of plant extracts against bacteria have been studied for years, but with more emphasis in the last three decades. Over these years, numerous antimicrobial activities and screening evaluations have been published based on the traditional use of Chinese, African and Asian plant-based drugs (Suffredin et al 2004). The use and history of herbs dates to the time of early man, who had the crudest tools as his implements and used stones to start his fire. They used herbs in their raw and cooked forms to keep fit.

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