Antioxidant properties of royal jelly associated with larval age and time of harvest.

This study aimed to evaluate the antioxidant properties of royal jelly (RJ) collected from larvae of different ages that were transferred in artificial bee queen cells for 24, 48, and 72 h. RJ harvested from the 1 day old larvae 24 h after the graft displayed predominant antioxidant properties, including scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, inhibition of linoleic acid peroxidation, and reducing power. Regardless of the initial larval age, lower antioxidant activities were observed in the RJ harvested later than 24 h except for the activity of superoxide dismutase. In addition, higher contents of proteins and polyphenolic compounds were determined in the RJ harvested 24 h than that harvested 48 or 72 h after the graft. It implied that the polyphenolic compounds may be the major component for giving the antioxidant activities in RJ. In summary, the time of harvest and the initial larval age did affect the antioxidant potencies in RJ, and RJ collected 24 h after the larval transfer showed the most substantial antioxidant activities.