抄録
1. Riboflavin 2′, 3′, 4′, 5′-tetranicotinate (B2-Nic) showed vitamin effect on rat, although its effect was somewhat lower than that of free riboflavin (FR). This compound was also found to be somewhat inferior to FR for the maintenance of the hepatic and the renal flavin levels. However, by increasing the dose of its administration, flavin levels of these organs can be elevated.
2. The rate of excretion of flavin into urine of animals administered with B2-Nic was found to be considerably lower than that of animals administered with FR, suggesting that B2-Nic was more accumulative in living body than FR. Moreover, it was found that B2-Nic was superior to FR in keeping blood flavin level higher than the normal for a long time. It is, therefore, suggested that this compound could be beneficially used as deposit-type riboflavin.
3. In acute toxicity test of B2-Nic, mice and rats were administered orally with 1.0g/kg body weight and 5.0g/kg body weight of this compound, respectively, but no death was found after 72 hours of administration. No difference was found in appearance and in appetite, between animals tested and those of control. In chronic toxicity test, rats were administered compulsorily with 230mg/day/kg body weight of this compound. The body weight gains of the rats tested were the same with those of control rats. After 6 months' feeding, the measurement of the weight of each organ, hematological examination on blood, and histological investigation of organs and tissues were made. No difference was found between the rats fed on B2-Nic and those of control, indicating that this compound has no chronic toxicity up to the dose of 230mg/day/kg.
