Immunochemical approach to detection of adulteration in honey: physiologically active royal jelly protein stimulating TNF-alpha release is a regular component of honey

The presence of royal jelly (RJ) proteins in honey collected from nectars of different plants, origin, and regions and in honeybee's pollen was detected by Western-blot analysis using polyclonal antibodies raised against water-soluble RJ-proteins. The most abundant RJ-protein in honeybee products corresponded to a 55 kDa protein. The N-terminal amino acid sequence of 55 kDa protein was N-I-L-R-G-E. This sequence is identical to the apalbumin-1, the most abundant protein of RJ. Apalbumin-1 is a regular component of honeybee products and thus is a suitable marker tool for proving adulteration of honey by means of immunochemical detection. Its presence in all tested samples of honeys and honeybee pollen was confirmed also by Western-blot analysis using polyclonal antibodies raised against recombinant apalbumin-1. It has been found that major RJ-proteins, apalbumin-1, and apalbumin-2, stimulate mouse macrophages to release TNF-alpha, which demonstrates that physiologically active proteins of honey could be used for its biological valuation.