Screening of biological activities present in honeybee (Apis mellifera) royal jelly

Bioactivities present in three honeybee royal jelly (RJ) protein fractions were screened for diverse in vitro model systems. RJCP, a RJ crude protein extract, stimulated cell growth of Tn-5B1-4 insect cells inducing 6.5 population doublings per mg of protein added to culture medium, meanwhile fetal bovine serum, the usual growth supplement, gave rise only to 2.55 population doublings. RJCP, as well as the fractions RJP30 and RJP60 obtained by precipitation with ammonium sulfate, also affected Tn-5B1-4 cell shape and stimulated adhesion of these cells to the substrate. RJP30 also increased the percent of mature adipocytes in cultures of 3T3-F442A murine preadipocytes twofold with respect to insulin treatment, without inducing additional cell growth of confluent preadipocytes. Fractions RJCP and RJP60 showed similar capacity as that of insulin to stimulate the formation of mature 3T3 adipocytes. Fraction RJP30 also was cytotoxic for HeLa human cervicouterine carcinoma cells, diminishing 2.5-fold the initial cell density after seven days of treatment. Our results show the presence of diverse bioactivities in RJ affecting cell growth, cell differentiation and cell survival of insect, murine, and human cancer cells.