Curcumin is a polyphenolic bioactive compound in turmeric. We examined if antioxidant effects of curcumin are associated with lifespan extension in Drosophila. In this experiment, females and males of Drosophila were fed diets either containing no curcumin (C0) or supplemented with curcumin at 0.5 (C1) and 1.0 (C2) mg/g of diet. The levels of malondialdehyde (MDA), enzyme activity of superoxide dismutase AGE (2013) (SOD), and expression of seven age-related genes in females and males were analyzed. We found that C1 and C2 increased mean lifespan by 6.2 % and 25.8 % in females, and by 15.5 % and 12.6 % in males, respectively. Meanwhile, C1 and C2 significantly decreased MDA levels and increased SOD activity in both genders. Diets C1 in females and C2 in males are effective in extending mean lifespan and improving levels of two physiological and biochemical measures related to aging in Drosophila. Lifespan extension of curcumin in Drosophila was associated with the up-regulation of Mn-SOD and CuZn-SOD genes, and the downregulation of dInR, ATTD, Def, CecB, and DptB genes. The present results suggest that curcumin increases mean lifespan of Drosophila via regulating gene expression of the key enzyme SOD and reducing accumulation of MDA and lipid peroxidation. This study provided new insights for understanding the anti-aging mechanism of curcumin in Drosophila.

The major royal-jelly proteins (MRJPs) are the main constituents responsible for the specific physiological role of royal jelly (RJ) in honeybees. Male and female Drosophila flies were fed diets containing either no MRJPs (A) or casein (B) at 1.25% (w/w) of diet or MRJPs at 1.25% (C), 2.50% (D), or 5.00% (E). Diets B, C, D, and E increased mean lifespan by 4.3%, 9.0%, 12.4%, and 13.9% in males and by 5.8%, 9.7%, 20.0%, and 11.8% in females in comparison to results from diet A, respectively. The diet supplemented with 2.50% MRJPs seems to have the optimal dose to improve both physiological and biochemical measures related to aging in both sexes. Interestingly, lifespan extension by MRJPs in Drosophila was positively associated with feeding and fecundity and up-regulation of copper and zinc-superoxide dismutase (CuZn-SOD) and the Egfr-mediated signaling pathway. This study provides strong evidence that MRJPs are important components of RJ for prolonging lifespan in Drosophila.

Major royal jelly protein 1 (MRJP1), designated apalbumin 1, has been regarded as a freshness marker of royal jelly (RJ). A MRJP1-specific peptide (IKEALPHVPIFD) identified by bioinformatics analysis of homologous members of the major royal protein family was synthesized and used to raise polyclonal anti-MRJP1 antibody (anti-SP-MRJP1 antibody). Western blot analysis showed that anti-SP-MRJP1 antibody only reacted with MRJP1 in RJ. In contrast, the previously reported antibody against recombinant MRJP1 (anti-R-MRJP1 antibody) reacted with other members of MRJP family in RJ. Enzyme-linked immunosorbent assay (ELISA) using anti-SP-MRJP1 antibody demonstrated that MRJP1 content in RJ stored at 40 °C significantly degraded by 37.3%, 55.9%, 58.0%, 60.6%, 65.7%, 72.7%, and 73.1% at 7, 14, 21, 28, 35, 42, and 49 d, respectively, when compared with MRJP1 content in fresh RJ (0 d). Optical density analysis of MRJP bands from sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) profiles demonstrated that the degradation of MRJP1, MRJP2, MRJP3, and MRJP5 in RJ was strongly and positively correlated with the period of storage (P<0.0001). Our results indicated anti-SP-MRJP1 antibody was highly specific for MRJP1, and ELISA using the antibody is a sensitive and easy-to-use method to determine the freshness and authenticity of RJ.