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.     

Localization of metallothioneins-I & -II and -III in the brain of aged dog.

Localization of metallothionein (MT) -I & -II and MT-III and its significance in the brain aging in dogs were examined using immunohistological and molecular pathological techniques. MT-I & -II immunohistochemistry showed positive staining in the hypertrophic astrocytes throughout the aged dog brains; these MT-I & -II immunoreactive astrocytes were predominant in the cerebral cortex and around the blood vessels in the brain. These findings dominated in the brain regions with severe age-related morphological changes. In situ hybridization using MT-I mRNA riboprobes also demonstrated signals for MT-I mRNA in these hypertrophic astrocytes. Immunohistochemistry using a guinea pig antiserum against a synthetic polypeptide of canine MT-III demonstrated positive MT-III immunoreactivity predominantly in neurons in the Zn-rich regions such as hippocampus and parahippocampus. The findings were supported by in situ hybridization using MT-III mRNA riboprobes. Both MT-III immunoreactivity and signals for MT-III mRNA were demonstrated in neurons in the brain regardless of the intensity of the age-related changes. These results suggest, first, MT-I & -II may be induced in relation to the progress of the age-related morphological changes in the brain, playing an important role in the protection of the brain tissue from the toxic insults responsible for the brain aging, and second, MT-III may play a role in maintenance of Zn-related essential functions of the brain.