Immunomodulatory and Metabolic Changes after Gnetin-C Supplementation in Humans.

Abstract

Gnetin-C is a naturally occurring stilbene derived from the seeds of Gnetum gnemon L., an edible plant native to Southeast Asia that is called melinjo. Although the biological properties and safety of G. gnemon extract, which contains nearly 3% Gnetin-C, have been confirmed in various human studies, whether or not pure Gnetin-C is safe for humans is unclear at present. We conducted a randomized, double-blind, placebo-controlled trial. Healthy subjects were randomly divided into two groups. The interventional group (n = 6) was given Gnetin-C, and the control group (n = 6) was provided a placebo, for 14 days. Lipid profiles, biomarkers of oxidative stress and circulating blood cells were assessed before and after the intervention. All subjects completed the study, with no side effects reported across the study duration. Gnetin-C supplementation demonstrated a statistically significant increase in the absolute number of circulating natural killer (NK) cells expressing the activating receptors NKG2D and NKp46. NK cells derived from subjects who received Gnetin-C for two weeks showed higher cytotoxicity against K562 target cells than those before receiving Gnetin-C. In addition, Gnetin-C also resulted in a significant decrease in the absolute neutrophil count in the blood compared with the placebo. Furthermore, Gnetin-C significantly reduced the levels of uric acid, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, total adiponectin, and high-molecular-weight adiponectin. These data indicate that Gnetin-C has biological effects of enhancing the NK activity on circulating human immune cells. The immunomodulatory effects are consistent with a putative improvement in cancer immunosurveillance via the upregulation of the NKG2D receptor. The study was registered with UMIN-CTR, number 000030364, on 12 December 2017.

• Authors: Yuya Nakagami, Susumu Suzuki, J Luis Espinoza, Lam Vu Quang, Megumi Enomoto, Souichi Takasugi, Ayano Nakamura, Takayuki Nakayama, Hiroya Tani, Ichiro Hanamura, Akiyoshi Takami
• Journal: Nutrients (Nutrients) Vol. 11 Issue 6 (Jun 21 2019) ISSN: 2072-6643 [Electronic] Switzerland
• PMID: 31234376 (Publication Type: Journal Article, Randomized Controlled Trial)

Chemical References

• Benzofurans
• Biomarkers
• Immunologic Factors
• KLRK1 protein, human
• Lipids
• NCR1 protein, human
• NK Cell Lectin-Like Receptor Subfamily K
• Natural Cytotoxicity Triggering Receptor 1
• Stilbenes
• gnetin C

Topics

• Adult
• Benzofurans (administration & dosage, adverse effects, pharmacokinetics)
• Biomarkers (blood)
• Coculture Techniques
• Cytotoxicity, Immunologic (drug effects)
• Dietary Supplements (adverse effects)
• Double-Blind Method
• Energy Metabolism (drug effects)
• Female
• Humans
• Immunologic Factors (administration & dosage, adverse effects, pharmacokinetics)
• Japan
• K562 Cells
• Killer Cells, Natural (drug effects, immunology, metabolism)
• Lipids (blood)
• Male
• Middle Aged
• NK Cell Lectin-Like Receptor Subfamily K (blood)
• Natural Cytotoxicity Triggering Receptor 1 (blood)
• Neutrophils (drug effects, immunology)
• Oxidative Stress (drug effects)
• Stilbenes (administration & dosage, adverse effects, pharmacokinetics)
• Time Factors
• Treatment Outcome
• Young Adult