ANTIOXIDANT ACTIVITIES AND ANTIOXIDANT COMPOUNDS OF METHANOL EXTRACTS OBTAINED FROM MORPHOLOGICAL FRACTIONS OF BLACK RICE

摘要

Rice is the main staple food in Korea and many countries in Asia. With growing concerns regarding national health and the expanding markets of health foods, researches in the industrial use of bioactive compounds from diverse crops have been extensively increased. Pigmented rice is broadly known as enriched rice with improved healthy properties (Oki et al 2002). It is likely to have a greater antioxidant capacity than white rice. Particularly black rice, an economically important special rice species, derives its name from the rich natural anthocyanin compounds such as cyanidin-3-glucoside and peonidin-3-glucoside. The previous investigations have shown that black rice has relatively strong free-radical scavenging and antioxidative effect and is animportant source for natural antioxidants (Ling et al 2002). Free radicals produced by radiation, chemical reactions and several redox reactions of various compounds may contribute to DNA damage, lipid peroxidation in living tissues and cells (Morrisseyet al 1998). This oxidative stress may be related to many disorders such as cancer, atherosclerosis, and diabetes (Halliwell et al 1984). The beneficial components of black rice include anthocyanin, polyphenolics, flavonoids, tocopherols, tocotrienols and y-oryzanol. These antioxidative compounds effectively eliminate reactive oxygen species (ROS) including lipid peroxide, superoxide anion radical, hydroxy 1 radical and singlet oxygen, and decrease incidence of nitric oxide that occurs an inflammation.The purposes of this study were to determine the antioxidant compounds and to evaluate antioxidant activities of the methanolic extracts from milling fractions and whole grains of two black rice cultivars.