International Journal of Medicinal Plants and Alternative Medicine Vol. 3(2), pp. 018-026, June 2015 ISSN 2327-560X ©2015 Academe Research Journals

Full Length Research Paper

Study on phenolic compounds and their antioxidant activities in Iranian rice varieties

Bahram Ghods¹, Ashraf Haj Hosseini²*, Payman Qajarbeygi³ and Alireza Massiha⁴

¹School of Public Health and Paramedical, Semnan University of Medical Science, Aradan, Semnan, Iran.

²Department of Chemical Engineering, Zanjan University, Iran.

³Department of Health, Qazvin University of Medical Sciences, Iran.

⁴Department of Microbiology, Faculty of Science, Islamic Azad University, Lahijan, Iran.

*Corresponding author. E-mail: payeshmarja@yahoo.com. Tel: ‏982188825999; Fax: ‏982188347783.

Accepted 9 June, 2014

Abstract

The analytical method for the determination of phenolic compounds in Iranian rice varieties was developed. The method consisted of extraction of phenolic compounds from rice before analysis by high performance liquid chromatography (HPLC). Reversed phase HPLC equipped with photodiode array detection was used and the separation condition was optimized. Under the optimum condition, twelve phenolic compounds were separated within 24 min. Pressurized liquid extraction (PLE) was used to extract free phenolic compounds from rice with the optimum extraction condition of 70% methanol and extraction time of 15 min. While bound phenolic compounds were extracted using alkaline hydrolysis for 15 min, six varieties of Iranian rice including pigment and non-pigment rice in their brown and polished forms were investigated. All of the 12 phenolic compounds were detected as free phenolic compounds in all samples. Ferulic acid was the most abundant free phenolic compounds in all samples, while ferulic acid and p-coumaric acid were found as bound phenolic compounds in some samples. The content of phenolic compounds, total flavonoid and antioxidant activity detected in pigment rice and brown form were higher than non-pigment rice and polished form.

Key words: Phenolic compounds, antioxidant activities, rice.