The effects of royal jelly protein on bone mineral density and strength in ovariectomized female rats

[Purpose] Sex hormones deficiency leads to dramatically bone loss in particular postmenopausal women. Royal jelly has anti-osteoporosis effect due to maintain bone volume in that condition. We hypothesized that royal jelly protein (RJP, a latent residue after extracting royal jelly) also prevents bone deficient in ovariectomized (OVX) female rats, the animal model of postmenopausal women. [Methods] Female Sprague-Dawley rats (n = 30, 6 weeks age old) were sham operated (Sham; sham operated group, n = 7), OVX control group (OC, n = 7), OVX with low RJP intake group (ORL, n = 8), and OVX with high RJP intake group (ORH, n = 8) during 8 weeks experimental periods. In the end point of this experiment, the bone samples (lumbar spine, tibia, and femur) were surgically removed under anesthesia. These bone samples were evaluated bone mineral density (BMD) and bone strength.[Results] BMD of lumbar spine in RJP intake groups (ORL, ORH) were higher than that in OC group (p < 0.05 and p < 0.01) in RJP intake volume dependent manner. BMD of tibial proximal metaphysis and diaphysis in RJP intake groups were also higher than these in OC group (p < 0.01 and p < 0.01 / p < 0.05 and p < 0.001). In addition, breaking force of femur in RJP intake groups were significantly increase compared with that in OC group (p < 0.001 respectively). [Conclusion] These findings indicate that RJP contribute to prevent sex hormone related bone abnormality

The Bioactive Compound Contents and Potential Protective Effects of Royal Jelly Protein Hydrolysates against DNA Oxidative Damage and LDL Oxidation

In this study, the inhibition of DNA oxidative damage and low-density lipoprotein (LDL) oxidation of royal jelly protein (RJP) hydrolysates obtained from two commercial proteases were investigated. The results showed that the inhibition of DNA oxidative damage induced by the Fenton reaction, RJP, RJPs hydrolyzed by alcalase (RJP-A), RJPs hydrolyzed by flavourzyme (RPJ-F) and RJP two-stage hydrolysates (RPJ-AF) all had the effect of inhibiting deoxyribose oxidative damage. The inhibition effect of RJP, RJP-A, RJP-F and RJP-AF (1.0 mg/mL) were 47.06%, 33.70%, 24.19% and 43.09%, respectively. In addition, studies have also found that both RJP and RJP hydrolysates can reduce the production of 8-OH-2′-dG and the order of its inhibitory ability is RJP-AF ≒ RJP-A > RJP-F > RJP. The inhibition of DNA damage induced by bleomycin-Fe3+/ascorbic acid (Asc) with the addition of RJP, RJP-A, RPJ-F and RPJ-AF were 17.16%, 30.88%, 25.00% and 37.25%, respectively. The results of LDL oxidation inhibition showed that RJP-AF (1 mg/mL) not only had the most effective inhibitory Cu2+-induced LDL oxidation to produce a thiobarbituric acid reactive substance (TBARS) but also extended the lag time of conjugated diene formation to 300 min, which was 3.3 times that of the control group.

The Effects of Sub-lethal dose of Insecticides on Honeybee Behavior and Transcriptome

Exposure to insecticides is the main cause of honeybee (Apis mellifera) population decline. At sub-lethal doses, these chemicals have been shown to negatively affect honeybee physiological development and behavior. Previously, we found the insecticide imidacloprid and deltamethrin significant reduced honeybee dancing and foraging efficiency. As a follow up, we performed a deep RNA-seq analysis to reveal the gene regulatory mechanisms underlying the altered foraging behavior. Genes involved in detoxification were up-regulated in both imidacloprid and deltamethrin treatment groups. Gene members in immune pathways, odorant receptors and major royal jelly protein families showed significant up or down regulation in treatment groups compared with controls. This fluctuating gene expression profile reflects that multifaceted aspects of honeybee physiology were affected by the two insecticides, leading to inaccurate communication and impaired learning and memory. Our findings reveal candidate molecular mechanisms under impaired dance performance in honeybees exposed to insecticides.

Mechanistic Insight into Royal Protein Inhibiting the Gram-Positive Bacteria

Royal jelly (RJ), a natural honeybee product, has a wide range of antibacterial activities. N-glycosylated major royal jelly protein 2 (N-MRJP2), purified from RJ, can inhibit the growth of Paenibacillus larvae (P. larvae, Gram-positive), a contagious etiological agent of the American foulbrood disease of honeybees. However, the inhibitory mechanism is largely unknown. Antibacterial assay and membrane proteome were conducted to investigate the inhibition capacity of RJ from different instar larvae and P. larvae treated by N-MRJP2, respectively. The similar antibacterial efficiency of RJ from different larval instar indicates that RJ is vital for the adaptive immune defense of small larvae. The killing of P. larvae by N-MRJP2 is achieved by disturbing the cell wall biosynthesis, increasing the permeability of cell membrane, hindering aerobic respiration, restraining cell division and inducing cell death. This demonstrates that RJ is critical for the passive immunity of immature larvae and N-MRJP2 can be used as natural antibiotic substance to resist P. larvae, even for other gram-positive bacteria. This constitutes solid evidence that RJ and N-MRJP2 have potentials as novel antibacterial agents.

Dermatan sulfate and chondroitin sulfate from Lophius litulon alleviate the allergy sensitized by Major royal jelly protein 1

The objective of the present study was to explore the desensitization effect of dermatan sulfate (DS) and chondroitin sulfate (CS) from Lophius litulon (Ll) in mice sensitized by major royal...