Melinjo (Gnetum gnemon L.) seed extract (MSE) containing trans-resveratrol (3,5,4′-trihydroxy-trans-stilbene) and other derivatives exerts various beneficial effects. However, its mechanism of action in humans remains unknown. In this study, we aimed to investigate beneficial effects of MSE in healthy adult males. In this double-blind, randomized controlled study, 30 males aged 35–70 years with ≤10% flow-mediated dilatation received placebo or 750 mg MSE powder for 8 weeks, and twenty-nine males (45.1 ± 8.8 years old) completed the trial. There was a significant difference in the melinjo and placebo groups. Compared with the placebo control, MSE significantly reduced serum uric acid at 4 weeks and 8 weeks (n = 14 and 15, resp.). HDL cholesterol was significantly increased in the melinjo group. To clarify the mechanism of MSE for reducing uric acid, we investigated xanthine oxidase inhibitory activity, angiotensin II type 1 (AT1) receptor binding inhibition rate, and agonistic activities for PPARα and PPARγ. MSE, trans-resveratrol, and a resveratrol dimer, gnetin C (GC), significantly inhibit AT1 receptor binding and exhibit mild agonistic activities for PPARα and PPARγ. In conclusion, MSE may decrease serum uric acid regardless of insulin resistance and may improve lipid metabolism by increasing HDL cholesterol.

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Although we have found that protease-treated royal jelly (pRJ) benefit for the skeletal muscle mass and strength in the aged animals, the potential beneficial effects have not been evaluated in humans. The aim of this study was to determine whether pRJ intake had beneficial effects on muscle strength in elderly nursing home residents. One hundred and ninety-four subjects enrolled into this multicenter, randomized, double-blind, placebo-controlled study. Subjects received either placebo(Group 1), pRJ 1.2 g/d(Group 2), or 4.8 g/d(Group 3). Data through 1 year are reported for 163 subjects. The primary outcome measure is handgrip strength. Secondary outcomes include several physical performance tests (six-minute walk test, timed up and go test, and standing on one leg with eyes closed). The dropout rate was 16.0%. The means (95% confidence interval) of change in handgrip strength for placebo, low-dose, and high-dose groups are −0.98(−2.04,0.08), 0.50(−0.65,1.65) and 1.03(−0.37,2.44) kg (P = 0.06, P for trend = 0.02), respectively. No significant effects of the interventions were observed for physical performances. These findings suggest that pRJ treatment might not improve, but rather attenuate the progression of decrease in muscle strength in elderly people. In addition, we have not found that pRJ intervention can achieve improvement or attenuating the decrease in physical performance.

Objectives This study aimed to evaluate the effect of Royal Jelly (RJ) at a dose of 800 mg/day on menopausal symptoms in healthy Japanese postmenopausal women with placebo-controlled design. Material and Methods A total of 42 healthy Japanese postmenopausal women have been recruited for this study. The subjects were randomized to oral treatment with either 800 mg of protease-digested lyophilized powder of RJ (enzyme-treated RJ) or placebo (800 mg of dextrin) daily for 12 weeks. The level of menopausal symptoms has been evaluated every 4 weeks, using menopausal symptoms questionnaire of Japanese women. Independent t-test was used to evaluate statistical significance of the treatment effects between the two groups. Results and Conclusion All of the 42 women have completed the trial. There were significant differences related to the anxiety score (P = 0.046) and backache and low back pain score (P = 0.040) between 800 mg/day enzyme-treated RJ and placebo-treated groups after 12 weeks of administration, and no significant differences were found between the two groups in 4 weeks after intervention. No side effects were observed in either group. This study demonstrates that enzyme-treated RJ supplementation with doses of 800 mg/day is effective in relieving menopausal symptoms such as anxiety, backache, and low back pain in Japanese postmenopausal women.

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