Royalactin is a possible marker for quality of royal jelly.

摘要

The relationship between the composition, physiological activity and the freshness of royal jelly (RJ) was investigated to identify a marker that can be used to evaluate the quality of RJ. The change in the composition of RJ during storage was investigated to find a marker for freshness. The bioactive component of RJ, 10-hydroxy-2-decenoic acid, and the vitamin content did not change during storage at 40鳦 for 7 days. The specific protein of RJ, designated royal jelly protein-1 (RJP-1), was gradually degraded during storage under various conditions (from 4鳦 to 50鳦 for up to 7 days). The specific degradation of RJP-1 was proportional to both storage temperature and storage period. RJP-1 was purified to homogeneity and characterized as a monomericglycoprotein with a molecular mass of 57 kDa. The antifatigue effect of RJ on male Std ddY mice was investigated. All mice were forced to swim for 15 minutes once and maximum swimming time to fatigue was measured after a rest period. The swimming endurance of the RJ group significantly increased compared with those of the other groups. The mice in RJ group showed significantly decreased accumulation of serum lactate and serum ammonia and decreased depletion of muscle glycogen after swimming compared with the other groups, whereas there were no significant difference between the 40-7 d RJ (RJ stored at 40?for 7 days) group and the control group in these parameters after swimming. These results suggest that RJ can ameliorate the physical fatigue afterexercise and this anti-fatigue effect of RJ in mice seems to be associated with the freshness of RJ, possibly with the content of 57-kDa protein. Further, 57-kDa protein stimulates hepatocyte DNA synthesis, prolongs the proliferation of hepatocytes and increases albumin production. Therefore, the 57-kDA protein can be a suitable marker of RJ quality. The 57-kDa protein was named royalactin (royal jelly-derived, hepatocyte-activating protein).