Melinjo (Gnetum gnemon L.) Seed Extract Decreases Serum Uric Acid Levels in Nonobese Japanese Males: A Randomized Controlled Study.
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 PPAR α and PPAR γ . MSE, trans-resveratrol, and a resveratrol dimer, gnetin C (GC), significantly inhibit AT1 receptor binding and exhibit mild agonistic activities for PPAR α and PPAR γ . In conclusion, MSE may decrease serum uric acid regardless of insulin resistance and may improve lipid metabolism by increasing HDL cholesterol.
Department of Aging Control Medicine, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-0033, Japan.
Hiroyuki
H
Konno
Department of Aging Control Medicine, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-0033, Japan.
Yoshiaki
Y
Kanai
Department of Aging Control Medicine, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-0033, Japan.
Mikiyuki
M
Katagiri
Institute for Bee Products & Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino-cho, Okayama 708-0393, Japan.
Tami
T
Watanabe
Institute for Bee Products & Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino-cho, Okayama 708-0393, Japan.
Akemi
A
Mori
Institute for Bee Products & Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino-cho, Okayama 708-0393, Japan.
Tomoki
T
Ikuta
Institute for Bee Products & Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino-cho, Okayama 708-0393, Japan.
Hiroko
H
Tani
Institute for Bee Products & Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino-cho, Okayama 708-0393, Japan.
Shinobu
S
Fukushima
Institute for Bee Products & Health Science, Yamada Bee Company, Inc., 194 Ichiba, Kagamino-cho, Okayama 708-0393, Japan.
Tomoki
T
Tatefuji
Department of Aging Control Medicine, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-0033, Japan.
Takuji
T
Shirasawa