Interprofessional Journal of Health Sciences. Vol.20 No.2 , July - December 2022.

ANTIOXIDANT AND ANTIBACTERIAL PROPERTIES OF HYDROALCOHOLIC RICEBERRY RICE EXTRACT
 

Mallika Pongsathit, Verisa Chowjarean, Preeyaporn Plaimee Phiboonchaiyanan, Kamala Sadabpod, and Saraporn Harikarnpakdee

Abstract

This study was designed to investigate the optimum extraction condition by UAE of Riceberry rice, and determined its total phenolic and flavonoid contents, antioxidant activity and antibacterial activity. Riceberry rice was extracted in various ethanolic concentrations (50 - 90%) and various extraction time (20 - 60 min). Riceberry rice extract obtained from 50% ethanolic concentration at 50 min of extraction time showed the highest values of total phenolic (438.94 mg GAE/g extract) and flavonoid (129.02 mg QE/g extract) contents. The major phenolic acids of Riceberry rice, measured by using HPLC, were protocatechuic acid and vanillic acid. Antioxidant activities of extract prepared with optimum condition were the IC₅₀ of 72.49 mg/ml for DPPH radical assay and 767.02 mg/ml for ABTS radical cation assay. The potential antibacterial activity of this extract revealed that the inhibition zone was observed for only Staphylococcus aureus by agar disc diffusion assay, and the MIC must be equal or greater than 100 mg/ml to inhibit the growth of Staphylococcus aureus. This result suggested the optimum extraction on condition as standard method for Riceberry rice extraction. Our findings provide valuable information on phenolic and flavonoid compounds, antioxidant activity and antibacterial activity of Riceberry rice for further medicinal application.

Keywords: Riceberry rice, antioxidant activity, antibacterial activity

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