Bioactive Compounds and their Antioxidant Activities in the Ethanol Extract from Rice Leaves (Oryza sativa L.) of Different Varieties

This article presented a comprehensive analysis of the polyphenol, chlorophyll, tocopherol contents, and antioxidant activities in leaves of three rice varieties (Oryza sativa L. indica), named IR50404, Huyet Rong, and Nang Thom. The study aimed to investigate the potential antioxidant properties of these rice varieties for applications in the pharmaceutical, cosmetic, and food industries. The leaves of three rice varieties harvested at week 5 were collected and then extracted using ethanol as solvent. The results revealed significant variations in the levels of total polyphenols (ranging from 3.04 to 3.90 mg GAE/g of fresh leaf weight), total chlorophyll (1180-1315 µg/g of fresh leaf weight), and tocopherols (40.14 to 187.18 µg/g of fresh leaf weight) among the three varieties. Furthermore, in antioxidant assays, significant variations were observed among rice varieties in terms of their DPPH and ABTS radical scavenging activities, ranging from 19.03 to 21.66 µmol TE/g leaf fresh weight and from 18.77 to 23.33 µmol TE/g leaf fresh weight, respectively. The IR50404 variety was found to exhibit superior potential in terms of bioactive compounds, DPPH, and ABTS radical scavenging activities compared to the other varieties. These findings suggest that certain rice varieties possess considerable antioxidant activity in their leaves, making them promising candidates for applications in the pharmaceutical, cosmetic, and food industries. The identification of these antioxidant-rich rice varieties paved the way for the development of natural antioxidant formulations and functional food products.