The phytochemical constituents and antibacterial activity of methanolic and ethanolic leaf and stem extracts of Eucalyptus torelliana, Nigeria

Christiana Jesumirhewe Christiana Jesumirhewe,Oluwasegun Adedokun Oluwasegun Adedokun,Adaobi Sandra Okoro Adaobi Sandra Okoro

doi:10.30574/gscbps.2021.16.2.0246

Christiana Jesumirhewe Christiana Jesumirhewe, Oluwasegun Adedokun Oluwasegun Adedokun + Show 1 more

Open Access

https://doi.org/10.30574/gscbps.2021.16.2.0246

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Abstract

The use of traditional medicines has been observed to increase globally. The search for new antimicrobial agents has increased as a result of increase in microbial infections as well as antimicrobial resistance. The phytochemical and antibacterial activities of ethanolic and methanolic extract of leaves and stem of Eucalyptus torelliana was investigated to detect the presence of secondary metabolites and also evaluate their antibacterial potential. The phytochemical constituents of the powdered leaves and stem of Eucalyptus torelliana were determined using standard methods. The antibacterial susceptibility of bacteria from different sources to the leaves and stem extract was determined using agar diffusion method. Minimum inhibitory concentrations, MIC of the extracts were also determined. Phytochemical screening of Eucalyptus torelliana yielded glycosides, reducing sugars, condensed tannins and terpenoids in both leaf and stem extract while saponins were found only in the leaves extract. The ethanolic and methanolic extracts of Eucalyptus torelliana had antibacterial activities at 20mg/ml and 10mg/ml especially at 20mg/ml where it showed significant difference in their activity in relation to the negative control. The extracts from the stem were observed to have better antibacterial activity compared to the leaves. Gentamicin was used as a positive control. The ethanolic extracts had MIC range between 10mg/ml->10mg/ml while that of the methanolic extracts was >10mg/ml. The results from this study validate the possible use of Eucalyptus torelliana in the production of new antimicrobial agents.

Highlights

The genus Eucalyptus is a wide genus containing evergreen trees, shrubs and belongs to the order myrtales and family myrtaceae [1]
The results of the phytochemical screening were in line with the results obtained by some other researchers like Adeniyi et al [15] who reported the presence of saponins and tannins in the stem of Eucalyptus torelliana (ET) and anthraquinnone, glycosides in addition to saponins and tannins were reported in the leaves of ET
Results from the study indicated that an increase in the concentration of the plant extracts gives a reciprocal increase in the antibacterial activity of Eucalyptus torelliana

Summary

Introduction

The genus Eucalyptus is a wide genus containing evergreen trees, shrubs and belongs to the order myrtales and family myrtaceae [1]. The genus is native to Australia with only a few species introduced into Nigeria among which is Eucalyptus torelliana [2]. Eucalyptus plant parts have been reported to control several diseases derived from microbial infections [3]. Eucalyptus leaves have been found to be traditionally useful as a powerful antiseptic and is indicated in relieving coughs and colds, sore throats, other respiratory tract infections, wounds, ulcers and urinary tract infections especially caused by bacteria [4, 5, 6]. Aqueous extracts of E. torelliana leaves are reported to be traditionally useful as analgesic, anti-inflammatory and relieves cancer-related symptoms and intestinal challenges [7]

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Results

Conclusion