Full Length Research Paper

Antioxidant activity of plants methanolic extracts containing phenolic compounds

Huda-Faujan, N.^1,3, Noriham, A.^2*, Norrakiah, A. S.³ and Babji, A. S.³

¹Food Biotechnology Programme, Faculty of Science and Technology, University of Sains Islam Malaysia, Bandar Baru Nilai, 71800 Nilai, Malaysia.

²Food Technology Programme, Faculty of Applied Science, University of Technology MARA, 40450 Shah Alam, Malaysia.

³Food Science Programme, School of Chemical Sciences and Food Technology, Faculty of Science and Technology, University of Kebangsaan, Malaysia, 43600 Bangi, Malaysia.

*Corresponding author. E-mail: noriham2002@yahoo.com.

Accepted 28 November, 2007

The presence of natural antioxidant in plants is well known. This paper reports the antioxidative activities of some methanolic plant extracts namely ‘ulam raja’ (Cosmos caudatus), ‘kesum’ (Polygonum minus), ‘selom’ (Oenanthe javanica), ‘pegaga’ (Centella asiatica) and ‘curry leaf’ (Murraya koenigii). The analysis carried out was total phenolic content, ferric reducing power, ferric thiocyanate (FTC) and thiobarbituric acid (TBA) tests. From the analyses, M. koenigii had the highest yield extraction (1.65%), highest total phenolic content (38.60 mg TAE/ 100 g fresh weight) and antioxidant activity (70.60%) using FTC method. Increasing the concentration of the extracts resulted in increased ferric reducing antioxidant power for all methanolic extracts tested. TBA analysis showed that C. caudatus extract had the highest antioxidant effect. Total phenolic content had positive correlation with antioxidant capacity (r = 0.451). This shows that the plants, especially M. koeniigi, may be potent source of natural antioxidants.

Key words: Antioxidative activities, plants, total phenolic content, reducing power, thiobarbituric acid.