Antioxidant Activities of Methanol Extract and Solvent Fractions of Marine Macroalga, &lt;i&gt;Avrainvillea erecta&lt;/i&gt; (Berkeley) A. Gepp and E.S. Gepp (Dichotomosiphonaceae)

T-T Chai,M-T Kwek,M Ismail,Jls Ooi,Y-C Law,F-C Wong,Ay Amri,Fa Manan

doi:10.4314/tjpr.v14i3.20

Abstract

Purpose: To determine the antioxidant activity of methanol extract (ME) and solvent fractions of Avrainvillea erecta as well as their total phenolic and flavonoid contents.Methods: The antioxidant activities of ME as well as its chloroform, butanol, and aqueous fractions (CF, BF and WF, respectively) of A. erecta were evaluated via 2,2-diphenyl-1-picrylhydrazyl (DPPH), nitric oxide (NO) and hydrogen peroxide (H2O2) scavenging assays as well as ferric reducing antioxidant power (FRAP) assay. Total phenolic and flavonoid contents were determined spectrophotometrically.Results: CF and BF possessed equally high DPPH scavenging activity with half-maximal effective concentration (EC50) of 535 and 532 mg/ml, respectively. CF had stronger NO scavenging activity (EC50 743 μg/mL) than ME and BF, although weaker compared with quercetin (EC50 279 μg/ml). CF also produced the highest FRAP value (451 μmol Fe2+/g) among all samples examined. Notably, H2O2 scavenging activity was only found in CF (EC50 387 μg/ml), which was as strong (p > 0.05) as that of gallic acid (EC50 456 μg/mL). BF had the highest total phenolic content while CF had the highest total flavonoid content.Conclusion: CF of A. erecta, which has the highest flavonoid content of all the extracts evaluated, is a potential source of natural antioxidants, especially hydrogen peroxide scavengers.Keywords: Antioxidant, Avrainvillea erecta, Flavonoid, Macroalga, Phenolic

Highlights

Marine macroalgae, known as seaweeds, are consumed as foods in many countries
Owing to limited sample yields, we have begun our investigation with a preliminary assessment of the antioxidant activity of methanol extract (ME), chloroform fraction (CF), butanol fraction (BF) and water fraction (WF) at the sample concentration of 1 mg/ml
The strongest nitric oxide (NO) scavenging activity was found in CF, followed by BF, ME and WF

Summary

Introduction

Known as seaweeds, are consumed as foods in many countries. Traditionally, some macroalgae are used as gelling agent and stabilisers for the food and pharmaceutical industries [1]. There is great interest worldwide to discover bioactive metabolites from macroalgae with the goals of using them as active ingredients in functional food/nutraceutical and pharmaceuticals production [3]. The search for potent natural antioxidants to be used as alternatives to synthetic antioxidants has intensified over the past decades due to concerns for the toxicity of synthetic antioxidants [6] In this context, the exploration of macroalgae for natural antioxidants is relevant to current research interest and need of society. The green seaweeds have the greatest phenolic contents and antioxidant activities among the three macroalgae groups [1]. Antioxidant activities have been discovered from extracts of other green macroalgae [9]. 7hydroxycymopol and avrainvilleol are examples of antioxidant compounds isolated from green seaweeds [10]

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