ANTIMICROBIAL EFFECT OF ETHANOLIC EXTRACT OF THE STEM OF GLIRICIDIA PLANT

ANTIMICROBIAL EFFECT OF ETHANOLIC EXTRACT OF THE STEM OF GLIRICIDIA PLANT

ANTIMICROBIAL EFFECT OF ETHANOLIC EXTRACT OF THE STEM OF GLIRICIDIA PLANT

ABSTRACT

The ethanolic extract of the stem of Gliricidia sepium (Agunimaniye plant) demonstrated potent antimicrobial activity against a spectrum of pathogenic microorganisms. In this study, the extract exhibited significant inhibition zones ranging from 24 to 32 mm when tested against various bacteria, including Bacillus cereus, Enterobacter faecalis, Salmonella paratyphi, Staphylococcus aureus, Escherichia coli, Streptococcus faecalis, Proteus vulgaris, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Serratia marcescens. Comparative analysis with standard antibiotics revealed that the ethanolic extract from Gliricidia sepium flowers at a concentration of 1mg/ml exhibited superior activity against Enterobacter faecalis compared to 10μg of tobramycin and ciprofloxacin. Moreover, the methanol extract of the flowers showed remarkable antimicrobial activity against Staphylococcus aureus and Serratia marcescens, surpassing the effectiveness of all antibiotics tested. The findings of this study are particularly significant, as even the crude extract of the Gliricidia sepium plant demonstrated remarkable activity against various pathogenic bacteria, filling a gap where modern therapy has often fallen short. The varying susceptibility of the tested microorganisms may be attributed to inherent properties linked to the permeability of their cell surfaces to the plant extracts. In conclusion, the ethanolic extracts from the stem of Gliricidia sepium plant exhibit comparable antimicrobial activity to standard antibiotics, suggesting their potential use as external antiseptics in the prevention and treatment of bacterial infections. The incorporation of these extracts into drug formulations is recommended, further highlighting their promising role in the field of antimicrobial therapy.

CHAPTER ONE

1.1 Introduction

Medicinal properties of plants always have interested people since ancient times. Different cultures around the world have a variety of medicinal traditions that include the use of plants and other plant products in curing different diseases (WHO, 2019). A report of the World Health Organization tells that 80% of the world population mainly rely on traditional therapies which involve the use of plant extracts or their active substances (Ahmad, 2018). Plant products remain the principal source of pharmaceutical drugs and agents used in traditional medicine (Cunha, 2021). With about half a million plants around the world, medicinal plants have a promising future (Vemani and Garg, 2022). Medicinal plants are considered as a rich resource of ingredients which can be used in drug development including pharmacopoeial, non- pharmacopoeial, or synthetic drugs (Delizo and Del , 2017). The modern pharmaceutical industry itself still relies largely on the diversity of secondary metabolites in plants and secondary metabolites, of which at least 12,000 have been isolated; a number estimated to be less than 10% of the total (Vemani and Garg, 2022). Through the Department of Science and Technology (DOST), the Philippine government is now addressing the need to assess scientifically the use of medicinal plants in the country (Asolkar et al, 2016).

In the Nigeria setting, the use of herbal medicine has been a part of its rich culture and tradition. Even during the early times, Nigerians prepared medicines to treat some illnesses out of the plants available in their backyards. An example of these plants is Angunmaniye plan (G. sepium) which has folkloric uses such as wound healing, skin itching, or dermatitis (Berger et al, 2018). Gliricidia, a native of the seasonally dry Pacific Coast of Central America, has long been cultivated and is naturalized in tropical Mexico, Central America, and northern South America. It was also introduced to the Caribbean and later to West Africa. It is also used as a poison for rodents and in fact, the Latin name Gliricidia means rodent poison (Sharma et al., , 2018).

Entire parts of this plant- leaves, barks, roots, etc. have been reported to have ethno-medicinal properties (Ahmad, 2018). It has been used as a folk remedy for alopecia, boils, bruises, burns, colds, cough, debility, erupti ons, erysipelas, fever, fractures, gangrene, headache, itch, prickly heat, rheumatism, skin tumors, ulcers, urticarial, and wounds (Manner and Jurd, 2019). In Panama, the decoction of G. sepium (Jacq.) Walp leaves is used in urticaria, rash and also in burns and erysipelas. In Guatemala and Costa Rica, bark decoction is used against bacterial and protozoal infections (Sharma et al., , 2018). The traditional use of branches and leaves of G. sepium is against pruritic ailments, fever, and is frequently used plant for skin infections (Rastrelli et al., 2019). This is served as the basis for the antimicrobial evaluation in this study.

Branches of Gliricidia sepium is used to reduce fever in children and adults. It has also been used to treat infections produced by Microsporum canis, Trychophyton mentagrophytes and Neisseria gonorrohae. Sharma and Qadry investigated the larvicidal activity of the crude ethanol extract of Gliricidia sepium bark and leaves. Various phytochemicals like flavanoids, triterpenoid saponins, stigmastanol glucoside, rhamnogalactoside of kaempferol, coumarin, coumaric acid and melilotic acid have been isolated and characterised from various parts of this plant. Allelochemicals from Gliricidia sepium leaves were extracted, identified and quantified using HPLC15. Rastrelli isolated a new a‐hydroxy rotenoids from the methanolic extract of Gliricidia sepium bark. In the present study antimicrobial effect of Ethanolic extract of the stem of Angunmaniye plant is investigated for the aim of discovering the medicinal potential of these plant extracts.

1.2 Statement of the Problem:

In recent years, there has been growing concern about the emergence of antibiotic-resistant microorganisms, which poses a significant threat to global public health. As a result, researchers are continuously exploring alternative sources of antimicrobial agents to combat these drug-resistant pathogens. One such source of interest is the Gliricidia plant, known for its traditional medicinal uses and the potential antimicrobial properties of its extracts. This study aims to investigate the antimicrobial effect of the ethanolic extract of the stem of the Gliricidia plant.

1.3 Aim of the Study

The aim of this study is to investigate the antimicrobial effect of ethanolic extract of the stem agunmaniye (Gliricidia sepium) plant

1.4 Objectives of the study

i. To determine the antimicrobial activity of the ethanolic extract of Gliricidia sepium plant stem against a broad spectrum of microorganisms, including bacteria and fungi.

ii. To evaluate the minimum inhibitory concentration (MIC) and minimum bactericidal/fungicidal concentration (MBC/MFC) of the extract against selected microorganisms.

iii. To compare the antimicrobial efficacy of the ethanolic extract of Gliricidia sepium plant stem with that of standard antibiotics or antifungal agents.

1.5 Significance of the Study:

This research is of paramount importance for several reasons:

1. Public Health: In the era of antibiotic resistance, finding new sources of antimicrobial agents is crucial to combat infectious diseases effectively.

2. Conservation: Investigating the medicinal properties of Gliricidia plant could promote its conservation and sustainable use.

3. Pharmaceutical Development: The study may lead to the development of novel antimicrobial drugs or natural alternatives to conventional antibiotics.

4. Knowledge Enrichment: The research contributes to our understanding of the potential applications of plant extracts in healthcare.

5. Economic Potential: If the Gliricidia plant proves to be a potent source of antimicrobial agents, it could have economic