Study of Enzymatic Inhibition and Bioactive Compound Extraction from Aquatic Weeds in Lakes of Edo State

Study of Enzymatic Inhibition and Bioactive Compound Extraction from Aquatic Weeds in Lakes of Edo State

ABSTRACT

Aquatic weeds are fast-growing plants that invade water bodies, reducing biodiversity and affecting aquatic ecosystems. However, these plants may contain valuable bioactive compounds with important biochemical and pharmacological properties. This study explores the enzymatic inhibition potential and bioactive compound composition of selected aquatic weeds collected from lakes in Edo State, Nigeria.

Samples of dominant aquatic weeds—such as Eichhornia crassipes (water hyacinth), Pistia stratiotes (water lettuce), and Lemna minor (duckweed)—were collected from Ikpoba and Ogba Lakes. Phytochemical extraction was carried out using methanol and aqueous solvents, and the extracts were analyzed for alkaloids, flavonoids, phenolics, tannins, and saponins. In vitro enzyme inhibition assays were performed to evaluate their ability to inhibit α-amylase, acetylcholinesterase, and tyrosinase enzymes.

The results revealed the presence of multiple bioactive compounds with strong antioxidant and enzyme-inhibitory activities. Extracts of Eichhornia crassipes and Pistia stratiotes showed high inhibition of α-amylase and acetylcholinesterase, indicating possible antidiabetic and neuroprotective properties. These findings suggest that aquatic weeds, though often regarded as environmental nuisances, may represent a valuable source of natural bioactive molecules for pharmaceutical and nutraceutical applications.

Keywords: Aquatic weeds, enzyme inhibition, bioactive compounds, phytochemicals, Edo State, biochemical evaluation

CHAPTER ONE

1.0 Introduction

Aquatic weeds are plant species that grow excessively in freshwater systems, often disrupting ecological balance and water use. Despite their negative impact on water transport, fisheries, and biodiversity, these plants are rich in diverse phytochemicals that may possess important biochemical activities. In recent years, researchers have begun exploring aquatic plants as potential sources of bioactive molecules due to their adaptability and metabolic diversity.

The rapid spread of aquatic weeds such as Eichhornia crassipes (water hyacinth) and Pistia stratiotes (water lettuce) in lakes across Edo State poses both environmental and public health challenges. However, these same species might hold promising enzymatic and pharmacological properties. Investigating their biochemical composition and enzyme-inhibition potential may turn a waste management problem into a resource for natural product discovery.

Enzymatic inhibition studies help identify compounds that can modulate key metabolic pathways linked to diseases such as diabetes, Alzheimer’s, and Parkinson’s. Therefore, understanding the inhibitory potential of aquatic weed extracts could provide insight into new therapeutic compounds derived from local biodiversity.

1.1 Statement of the Problem

Aquatic weeds continue to invade several lakes and rivers in Edo State, particularly Ikpoba and Ogba Lakes. They clog waterways, reduce oxygen levels, and disrupt aquatic life. Although control measures are expensive, the plants are usually discarded without exploring their biochemical potential. This lack of utilization represents a missed opportunity to extract valuable bioactive compounds that could contribute to pharmaceutical or industrial research. Thus, this study investigates the phytochemical composition and enzymatic inhibition capacity of these weeds to promote sustainable resource management.

1.2 Aim and Objectives of the Study

Aim:
To evaluate the enzymatic inhibition potential and bioactive compound composition of selected aquatic weeds from lakes in Edo State.

Specific Objectives:

1. Identify and extract major phytochemical compounds from the selected aquatic weeds.

2. Determine the antioxidant potential and total phenolic content of the extracts.

3. Assess the inhibitory activities of the extracts on key enzymes such as α-amylase, acetylcholinesterase, and tyrosinase.

4. Compare biochemical properties across different weed species to identify the most potent candidates for further research.

1.3 Research Questions

1. What types of bioactive compounds are present in aquatic weeds found in Edo State lakes?

2. Do these compounds exhibit measurable enzymatic inhibition activities?

3. How do phytochemical concentrations vary among different weed species?

4. Can the extracts be considered potential sources for pharmacological or nutraceutical applications?

1.4 Research Hypotheses

• H₀₁: There is no significant relationship between phytochemical composition and enzymatic inhibition activities of aquatic weed extracts.

• H₁₁: There is a significant relationship between phytochemical composition and enzymatic inhibition activities of aquatic weed extracts.

1.5 Significance of the Study

This study contributes to the sustainable management of aquatic weeds by transforming environmental waste into a potential source of economic and medicinal value. It provides biochemical evidence that supports the extraction and utilization of bioactive compounds from invasive aquatic plants. The results could encourage local industries, environmental scientists, and biochemists to view aquatic weeds not only as pollutants but also as valuable biological resources.

Moreover, identifying natural enzyme inhibitors aligns with global efforts to develop plant-based alternatives for managing chronic diseases, particularly in resource-limited settings.

1.6 Scope of the Study

The study focuses on major aquatic weeds found in lakes of Edo State, especially Ikpoba and Ogba Lakes. It covers phytochemical extraction, antioxidant assays, and enzyme inhibition analysis. The research does not extend to in vivo animal trials or clinical evaluations.

1.7 Definition of Terms

• Phytochemicals: Naturally occurring compounds in plants that contribute to their biological activity.

• Enzymatic Inhibition: The process by which a compound reduces or blocks the activity of a specific enzyme.

• Bioactive Compounds: Substances that have biological effects on living organisms, often beneficial in disease prevention or treatment.

• Aquatic Weeds: Plants that grow excessively in or near water bodies, often becoming invasive.

• Antioxidant Activity: The ability of a substance to neutralize free radicals that cause oxidative damage.

CHAPTER TWO

2.0 Literature Review

2.1 Overview of Aquatic Weeds

Aquatic weeds are unwanted plants that thrive in water bodies, competing with native species for light and nutrients. Their proliferation is often due to nutrient pollution, climate change, and stagnant water. Common examples in Nigeria include Eichhornia crassipes, Pistia stratiotes, and Lemna minor. While they are typically seen as environmental pests, these plants contain secondary metabolites with antioxidant, antimicrobial, and enzyme-inhibitory properties (Okechukwu et al., 2022).

2.2 Phytochemical Composition of Aquatic Plants

Aquatic plants accumulate diverse phytochemicals such as alkaloids, flavonoids, phenolics, tannins, saponins, and terpenoids. These compounds function in plant defense and environmental adaptation. Studies have shown that Eichhornia crassipes is rich in polyphenols, while Pistia stratiotes contains high levels of tannins and saponins (Udo et al., 2021). The unique metabolic processes of aquatic weeds allow them to synthesize potent bioactive compounds even under polluted or nutrient-stressed conditions.

2.3 Enzymatic Inhibition and Its Biomedical Importance

Enzyme inhibition plays a vital role in drug discovery. Compounds that inhibit enzymes such as α-amylase, acetylcholinesterase, and tyrosinase are of great pharmacological interest. α-Amylase inhibitors help regulate blood glucose levels, acetylcholinesterase inhibitors are useful in treating neurodegenerative diseases, and tyrosinase inhibitors are employed in managing hyperpigmentation disorders (Fadare & Adebayo, 2020). Exploring aquatic weeds as potential sources of such inhibitors supports the search for safer, natural alternatives to synthetic drugs.

2.4 Methods of Bioactive Compound Extraction

Phytochemical extraction involves separating bioactive components from plant tissues using solvents of varying polarity. Methanol, ethanol, and aqueous solutions are commonly used. The solvent choice affects both yield and composition of the extract. Techniques such as Soxhlet extraction and maceration are frequently applied in biochemical studies of aquatic plants (Aremu et al., 2020).

2.5 Antioxidant and Biochemical Properties of Aquatic Weeds

Several aquatic weeds possess significant antioxidant activities due to their high phenolic content. Eichhornia crassipes, for instance, shows remarkable free radical scavenging activity, which can protect against oxidative damage. These biochemical properties underline their potential use in managing diseases linked to oxidative stress, such as diabetes and cardiovascular disorders (Olowokere et al., 2019).

2.6 Utilization of Aquatic Weeds in Biochemical and Environmental Research

Aquatic weeds are gaining attention in biochemical and biotechnological studies due to their availability and bioactivity. They have been used in producing natural dyes, adsorbents, and medicinal extracts. Their enzymatic inhibition capabilities further expand their relevance in pharmacological screening (Nwosu et al., 2021). Transforming these plants from pollutants into useful biomaterials aligns with sustainable development goals on environmental management and health innovation.

2.7 Research Gaps

Despite growing interest in aquatic weeds, little research has been conducted in Edo State regarding their enzymatic inhibition and bioactive compound content. Previous studies mostly addressed their ecological control rather than their biochemical potential. This research fills that gap by analyzing enzyme inhibition profiles and phytochemical richness of aquatic weeds found in Edo lakes.

2.8 Summary of Literature Review

Aquatic weeds, though problematic, contain diverse phytochemicals with significant biochemical and therapeutic potential. Studies across different regions have shown that these plants can inhibit enzymes linked to diseases and exhibit antioxidant activity. However, systematic investigation of aquatic weeds in Edo State is still limited. This study therefore explores their enzymatic inhibition properties and bioactive composition, with the goal of identifying possible uses in pharmacology and environmental biotechnology.