Phytochemical Screening and In-Vitro Antioxidant Activity of Selected Medicinal Plants from Edo State Rainforest

Phytochemical Screening and In-Vitro Antioxidant Activity of Selected Medicinal Plants from Edo State Rainforest

Abstract

Medicinal plants are vital sources of natural compounds that help prevent and manage diseases. This research investigates the phytochemical composition and antioxidant activity of selected medicinal plants from the Edo State rainforest. Fresh plant materials were collected, dried, and extracted using ethanol and methanol solvents. Phytochemical screening identified the presence of alkaloids, flavonoids, tannins, saponins, phenols, and terpenoids.

To assess antioxidant capacity, the study employed DPPH (2,2-diphenyl-1-picrylhydrazyl) and FRAP (Ferric Reducing Antioxidant Power) assays. The results showed that extracts with high concentrations of phenols and flavonoids had stronger antioxidant activities. Therefore, these plants may serve as potential natural sources of free radical scavengers.

In conclusion, this study highlights the therapeutic potential of Edo rainforest plants. It also supports further exploration into their bioactive compounds for the development of plant-based antioxidants and natural pharmaceuticals.

CHAPTER ONE

1.0 Introduction

Medicinal plants play a crucial role in traditional healthcare and modern pharmacology. Their importance lies in their ability to produce bioactive compounds capable of treating and preventing diseases. In recent years, increasing evidence has shown that plant-derived antioxidants can protect cells from oxidative stress, which often leads to conditions such as cancer, diabetes, and cardiovascular diseases.

The Edo State rainforest in southern Nigeria contains numerous plant species used in folk medicine. However, the biochemical properties of many of these plants remain unverified. Scientific studies that identify and quantify their phytochemical and antioxidant components are essential. They not only validate traditional knowledge but also promote sustainable use of local natural resources.

1.1 Background of the Study

The human body continuously produces free radicals during metabolic processes. When these radicals exceed the body’s defense capacity, oxidative stress occurs. This condition damages lipids, proteins, and DNA, increasing the risk of chronic diseases. To reduce such damage, antioxidants neutralize free radicals and maintain cellular balance.

Synthetic antioxidants, although effective, may cause harmful side effects. Consequently, scientists now focus on identifying safe, plant-based antioxidants. Many medicinal plants contain flavonoids, phenols, and tannins, which act as natural antioxidants. They donate electrons to neutralize free radicals and protect biological systems from oxidative harm.

Edo State’s rainforest hosts several of these plants. Despite their popularity in traditional medicine, limited data exist on their phytochemical contents and antioxidant efficiency. This study, therefore, aims to analyze selected medicinal plants from the region and provide biochemical evidence of their medicinal value.

1.2 Statement of the Problem

Many indigenous plants in Edo State are widely used for treating diseases, yet their biochemical effectiveness remains unverified. The absence of scientific evaluation restricts their inclusion in modern medicine. Additionally, oxidative stress–related illnesses continue to rise due to poor diet, pollution, and unhealthy lifestyles. There is a pressing need to identify natural antioxidant sources that can mitigate these effects. This research addresses that gap by studying the phytochemical profiles and antioxidant activities of local rainforest plants.

1.3 Aim and Objectives of the Study

Aim:
To examine the phytochemical composition and in-vitro antioxidant activity of selected medicinal plants from Edo State rainforest.

Objectives:

1. Identify and quantify phytochemical constituents in the selected plants.

2. Evaluate their antioxidant potential using DPPH and FRAP assays.

3. Compare antioxidant capacities among different plant species and solvents.

4. Determine the relationship between phytochemical content and antioxidant activity.

5. Provide biochemical evidence supporting traditional medicinal use.

1.4 Significance of the Study

This study contributes to scientific understanding of local medicinal plants. By validating their antioxidant properties, it supports the development of safe, natural alternatives to synthetic antioxidants. Furthermore, the findings promote the conservation of rainforest biodiversity and encourage the sustainable use of Nigeria’s medicinal resources. It also strengthens the connection between traditional medicine and biochemistry, bridging cultural knowledge with modern science.

1.5 Scope of the Study

The study focuses on medicinal plants found within the Edo State rainforest. Fresh plant samples were collected and analyzed for their phytochemical composition and antioxidant potential using standardized laboratory methods. Other pharmacological evaluations such as antimicrobial and anti-inflammatory tests were not included in this research.

1.6 Definition of Key Terms

• Phytochemicals: Bioactive chemical compounds naturally present in plants.

• Antioxidants: Substances that prevent oxidative damage by neutralizing free radicals.

• DPPH Assay: A method used to measure free radical scavenging ability.

• FRAP Assay: A test used to assess the reducing power of antioxidant compounds.

• Rainforest Ecosystem: A dense tropical forest characterized by high biodiversity and rainfall.