African Journal of Biotechnology Vol. 6 (24), pp. 2740-2745, 17 December 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Antioxidant activity of extract from a brown alga, Sargassum boveanum

Rastian Zahra¹*, Mehranian Mehrnaz², Vahabzadeh Farzaneh² and Sartavi Kohzad³

¹Research C enter of Bushehr University of Medical Science, Bushehr, Iran.

²Food Process Engineering and Biotechnology research center - Chemical Engineering Department, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran.

³Agricultural and Natural Resources Research Center of Bushehr, Iran.

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

Accepted 15 November, 2007

Water and ethanol extracts (WE and EE) from the dried sample of brown alga (Sargassum boveanum) were prepared and examined for its phenolic compounds. Amount of total phenolic compounds in WE was about 17 ± 0.492 mg catechin equivalent (CE)/g of dry sample, using Folin-Ciocalteu method. The antioxidant activity (AOA) of WE was high at about 90% inhibition of peroxidation of linoleic acid with 7 mg dry sample/ml solvent. The IC₅₀ of the WE sample and catechin which was used as the positive control with the hemoglobin catalyzed linoleic acid peroxidation method, were (mg/ml): 3.82 and 0.0713, respectively. The IC₅₀ of the WE sample in terms of CE was 18.76 mg CE/g dry sample. The WE sample exhibited noticeable scavenging effects in DPPH free radical scavenging assay. The radical scavenging activity (RSA) was about 94% at 3 mg dry sample/ml solvent. The phenolic constituent appears to be responsible at least in part, for the observed AOA of the algal extract. The results suggest that this alga could be a potential source of natural antioxidant.

Key words: Antioxidant activity, brown algae, Sargassum boveanum, polyphenols, radical scavenging activity, linoleic acid peroxidation.