Quantitation of tocotrienol and tocopherol in various rice brans.
Rice bran is abundant in bioactive compounds including tocotrienol (T3, unsaturated vitamin E). T3 has been reported about its potential functionalities (i.e., antiangiogenic effect), so much attention has been paid on usability of rice bran T3. Hence, we developed a rapid screening method for T3-rich rice bran by one-step equilibrium direct solvent extraction followed by normal phase high-performance liquid chromatography (HPLC). The method gave high-extraction rate of rice bran T3 and tocopherol (above 90%), and the determination of vitamin E by HPLC was completed within 15 min. Using the method, an average of total T3 content in 109 kinds of rice bran samples was 830 mug/g dry wt. Kouchi-Akamai, Joushuu, and Wataribune were found as the T3-rich rice bran varieties (1350-1430 microg T3/g dry wt). According to T3 ratio against total vitamin E (wt %), the average ratio was 61%. Hirayama, Moritawase, and Kaneko were found as the varieties having the highest T3 ratio (80-86%). Since T3 content in Koshihikari rice bran (the leading variety in Japan) was a little above the average, we cross-fertilized Koshihikari with T3-rich varieties and found that T3 content or ratio in F1 was improved compared with Koshihikari. The varieties found rich in T3 could be used for nutraceutical purpose.
Sookwong
Phumon
P
Food & Biodynamic Chemistry Laboratory, Graduate School of Agricultural Science, Tohoku University, Sendai 981-8555, Japan.
Nakagawa
Kiyotaka
K
Murata
Kazamasa
K
Kojima
Yoichiro
Y
Miyazawa
Teruo
T
D000383:Agriculture / Q000379:methods; D002851:Chromatography, High Pressure Liquid; D012275:Oryza / Q000737:chemistry* / Q000254:growth & development; D012639:Seeds / Q000737:chemistry*; D024505:Tocopherols / Q000032:analysis*; D024508:Tocotrienols / Q000032:analysis*; D014815:Vitamins / Q000032:analysis*
D024508:Tocotrienols; D014815:Vitamins; D024505:Tocopherols