Quantitative Analysis of Apisin, a Major Protein Unique to Royal Jelly

Apisin, a protein that is unique to royal jelly (RJ), is known to compose the greater part of the RJ proteins and to exist as a heterooligomer containing major royal jelly protein 1 and apisimin. However, few reports on the methods for quantifying apisin have been published. Thus, we attempted to quantify apisin using HPLC, a widely used analytical technique, as described below. Isoelectric precipitation and size-exclusion chromatography were used to obtain the purified protein, which was identified as apisin by SDS-PAGE and LC-MS analyses. The purified apisin was lyophilized and then used to generate a calibration curve to quantify apisin in RJ. The apisin content was fairly constant (i.e., 3.93 to 4.67 w/w%) in natural RJ. This study is the first to describe a simple, standardized method for quantifying apisin using HPLC and suggests that apisin can be used as a benchmark for future evaluations of RJ quality

Studies of royal jelly and associated cross-reactive allergens in atopic dermatitis patients.

Royal jelly (RJ), a creamy substance secreted by honeybees, is the exclusive diet for queen bee differentiation and life maintenance. RJ has been used in cosmetics, beverages, medicines, and supplements worldwide. However, allergy is a concerning issue for RJ, especially in atopic dermatitis (AD) and asthma patients. In some cases, allergic reactions are seen after the first intake of RJ, suggesting the existence of allergens cross-reactive with RJ. Information about the cross-reactive allergens is very important for the safe application of RJ; however, study of this cross-reactivity is quite limited. In this study, we attempted to identify allergens cross-reactive with RJ by using serum samples from 30 AD patients who had never been exposed to RJ. In an enzyme-linked immunosorbent assay (ELISA) experiment, RJ-binding IgE antibodies were detected in the serum of 10 out of 30 patients, and their antibody titers ranged from 4- to 2,048-fold dilution ratios. Additionally, 3 AD patients were determined to be positive in a skin-prick test (SPT) with an RJ solution. Significant correlations were observed between the anti-RJ antibody titer and nonspecific IgE and between the anti-RJ antibody titer and the Eczema Area and Severity Index score. We further examined the cross-reactivity between RJ and 14 typical allergens by using an ELISA-inhibition assay and demonstrated that the following 6 allergens showed cross-reactivity with RJ: the European house dust mite (HDM) (Dermatophagoides pteronyssinus), American HDM (Dermatophagoides farinae), snow crab (Chionocetes spp.), edible crab (Cancer pagurus), German cockroach (Blatella germanica), and honeybee venom (Apis mellifera). In conclusion, people with a history of allergic diseases, including AD, asthma, and allergic rhinitis, should be cautioned against consuming RJ products because of the potential for cross-reactive responses to ensure the safe and successful use of RJ supplements