Antimicrobial Evaluation of Crude Methanolic Leaf Extracts from Selected Medicinal Plants Against Escherichia coli

Hibert Rachuonyo Opinde,Gatheri Gw

doi:10.4172/2155-9597.1000272

Abstract

This study was aimed at determining the antibacterial effects of the selected plant leaf extracts of Tagetes minuta, Aloe secundiflora, Vernonia lasiopus and Bulbine frutescens against clinical isolate of Escherichia coli. The plants materials were obtained from Kenyatta University arboretum and identified by University taxonomist and voucher specimen deposited in the University. Methanol was used as the solvent for the extraction process and the antimicrobial activity test carried out using the disc diffusion method. All the plants extracts analysed had antimicrobial activity against Escherichia coli with Tagetes minuta extract being the most active at low concentrations (8.7 mg/ml). The standard antibiotic used for positive control was ciprofloxacin (5 μg/ml) while distilled water and dimethyl sulphoxide were used as negative control. Screening of phytochemical showed the presence of four phytochemicals; saponins, tannins, alkaloids and flavonoids.

Highlights

Medicinal plants are used by almost 80% of the world’s population for their basic health care because of their low cost and ease in availability [1]
Medicinal plant extracts have shown to have antimicrobial activity against enteropathogenic Escherichia coli found in food material [21]
The plant extract from Tagetes minuta was more active in low concentrations against Escherichia coli as compared to the other extracts

Summary

Introduction

Medicinal plants are used by almost 80% of the world’s population for their basic health care because of their low cost and ease in availability [1]. Herbal drugs made from medicinal plants have been used from ancient times to treat various diseases and their antimicrobial properties make them a rich source of many potent drugs [2]. Extracts from Tagetes minuta leaf flowers and stem extracted using methanol have shown to contain secondary metabolites including terpenes which are thought to be responsible for antibacterial activities [7]. Aloe secundiflora leaf components have been credited for antibacterial, antifungal and antiviral and antihelmintic medicinal properties [10]. Herbalists from the Lake Victoria region have traditionally used Aloe secundiflora to treat ailments including chest problems, polio, malaria and stomach ache [11]. Medicinal plant extracts have shown to have antimicrobial activity against enteropathogenic Escherichia coli found in food material [21]. This study aided in determining whether the plant extracts can be used as an effective antimicrobial agent against Escherichia coli

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Discussion

Conclusion