Preparation and the functional properties of water extract and alkaline extract of royal jelly

Water extract (WSR) and an alkaline extract (ASR) were prepared from fresh royal jelly from Chinese bees. The yields were about 8.3 and 6.3% on a dry weight basis, respectively. On SDS–PAGE analysis, the protein patterns of the two extracts were very similar, but not identical. Antioxidant activities, in both extracts, increased, depending on the concentration of the sample. The scavenging activities, against superoxide radical of WSR and ASR were high, and the activities at 100 mg/ml were the same as that of 5 mM ascorbic acid. Although the activities of WSR and ASR, at 50 and 100 mg/ml, did not match that of 1 mM tocopherol, the samples scavenged hydroxyl radical to about 50–60%. This shows that the protein fractions in royal jelly have high antioxidative activity and scavenging ability against active oxygen species. Royal jelly seems applicable in both health food and medicine.