Tomoki Tatefuji

Artepillin C (ARC) in Brazilian Green Propolis Selectively Blocks Oncogenic PAK1 Signaling and Suppresses the Growth of NF Tumors in Mice

There are mainly three types of propolis whose major anticancer ingredients are entirely different: (1) CAPE (caffeic acid phenethyl ester)‐based propolis in Europe, Far East and New Zealand, (2) artepillin C (ARC)‐based Brazilian green propolis and (3) Brazilian red propolis. It was shown previously that NF (neurofibromatosis)‐associated tumors require the kinase PAK1 for their growth, and CAPE‐based propolis extracts such as Bio 30 suppress completely the growth of NF tumors in vivo by blocking PAK1 signaling. Also it was demonstrated that ARC suppresses angiogenesis, suggesting the possibility that ARC also blocks oncogenic PAK1 signaling. Here it is shown for the first time that both ARC and green propolis extract (GPE) indeed block the PAK1 signaling selectively, without affecting another kinase known as AKT. Furthermore, it was confirmed that ARC as well as GPE suppress almost completely the growth of human NF tumor xenografts in mice, as does Bio 30. These results suggest that both CAPE‐based and ARC‐based propolis extracts are natural anti‐PAK1 remedies and could be among the first effective NF therapeutics available on the market. Since more than 70% of human cancers such as breast and prostate cancers require the kinase PAK1 for their growth, it is quite possible that GPE could be potentially useful for the treatment of these cancers, as is Bio 30. Copyright

Resveratrol derivative-rich melinjo (Gnetum gnemon L.) seed extract suppresses multiple angiogenesis-related endothelial cell functions and tumor angiogenesis.

Angiogenesis is a promising target for cancer prevention and treatment. This study aimed to determine the antiangiogenic effects of melinjo (Gnetum gnemon L.) seed extract and its resveratrol derivative components, such as gnetin C (GC), gnetin L (GL), gnemonoside A (GMA), gnemonoside C (GMC), and gnemonoside D (GMD). An ethanol extract of melinjo seeds (EEMS) and the two gnetins markedly inhibited the proliferation and tube formation of human umbilical vein endothelial cells (HUVEC) stimulated with vascular endothelial growth factor and basic fibroblast growth factor. The inhibitory effects of GC and GL were much stronger than those of resveratrol. GMC and GMD inhibited only proliferation, whereas GMA had almost no effect on the two endothelial cell functions. The EEMS and GC also reduced the cell viability of tube-forming HUVEC, with accompanying ERK1/2 inactivation, and suppressed the migration of HUVEC. Furthermore, dietary intake of EEMS significantly inhibited tumor angiogenesis in a mouse dorsal air sac assay. In conclusion, we found that the EEMS and its resveratrol derivatives, particularly GC, suppress multiple angiogenesis-related endothelial cell functions and/or tumor angiogenesis, indicating that the melinjo seeds and the natural resveratrol derivatives may be useful for cancer prevention and treatment.

trans-Resveratrol in Gnetum gnemon protects against oxidative-stress-induced endothelial senescence.

Gnetum gnemon is an arboreal dioecious plant that is cultivated in Indonesia. The seeds of this species mainly contain dimeric stilbenoid compounds [gnetin C (1), gnemonoside A (2), and gnemonoside D (3)] along with trans-resveratrol (4). trans-Resveratrol has been reported to have antiaging, anticancer, and antidiabetic effects, as well as being a calorie restriction mimetic. SIRT1 exerts a protective effect against vascular senescence. In this study, the effects of these four main stilbenoid derivatives of a G. gnemon seed endosperm ethanolic extract on endothelial senescence were investigated. In streptozotocin-induced diabetic mice, administration of the G. gnemon ethanolic extract increased SIRT1 and decreased endothelial senescence. The concentration of 1 in blood plasma was 6-fold higher than 4 in these mice. Next, the in vitro effects of the four main stilbenoid derivatives of G. gnemon seeds were investigated. Senescent human umbilical vein endothelial cells were induced by hydrogen peroxide. Endothelial senescence was inhibited by 4, which increased the expression of endothelial nitric oxide synthase and SIRT1, whereas 1-3 had no effect. These results indicated that the ethanolic extract of G. gnemon seeds inhibits endothelial senescence, suggesting that 4 plays a critical role in the prevention of endothelial senescence.

Inhibitory activity of Brazilian green propolis components and their derivatives on the release of cys-leukotrienes

The effects of Brazilian green propolis ethanol extract on Cry j1-induced cys-leukotrienes and histamine release from peripheral leukocytes of patients with allergic rhinitis were investigated. One of the key mechanisms for the anti-allergic properties of the extract was revealed to be the suppression of cys-LTs release. Furthermore, a series of propolis components and their phenethyl esters were synthesized and evaluated as inhibitors of cys-LTs release. Artepillin C, baccharin, and kaempferide were the major active components of the ethanol extract. The inhibitory activity of artepillin C phenethyl ester was comparable to that of existing LT synthesis inhibitors.

Pharmacokinetics and Safety of Resveratrol Derivatives in Humans after Oral Administration of Melinjo (Gnetum gnemon L.) Seed Extract Powder

Fruits and seeds of melinjo (Gnetum gnemon L.) are resveratrol derivative-rich materials. Pharmacokinetics of resveratrol derivatives in healthy volunteers after oral administration of 1000 mg of melinjo seed extract (MSE) powder were assessed and compared with those after oral dosing of trans-resveratrol (tRV) powder containing 4.8 mg of tRV only, equivalent to the content in 1000 mg MSE powder. Plasma tRV concentrations with enzymatic hydrolysis were maintained over 24 h, with a tmax of 12 h and a mean residence time (MRT) of 14 h, 5 and 2 times higher than those for tRV powder intake, respectively. Gnetin C, a resveratrol dimer, with hydrolysis was maintained in plasma for >96 h with a 36 h MRT. With repeated doses once daily for 28 days, plasma tRV and gnetin C concentrations with hydrolysis were in good agreement with the theoretical curves. MSE powder was well tolerated up to the oral dosing of 5000 mg with no serious adverse events.

Lactobacillus kunkeei YB38 from honeybee products enhances IgA production in healthy adults

To identify lactic acid bacterial isolates, which promote immunoglobulin A (IgA) production in honeybee products and honeybees (Apis mellifera).

Safety assessment of melinjo (Gnetum gnemon L.) seed extract: Acute and subchronic toxicity studies

Melinjo (Gnetum gnemon L.) is widely cultivated in Southeast Asia. Its fruit and seeds are common ingredients in Indonesian foods. The seeds are very rich in resveratrol dimers such as gnetin C and its glucosides, gnemonoside A and gnemonoside D, and also contain trans-resveratrol and its glucoside, trans-piceid. The safety of melinjo seeds is assured, since people in Southeast Asia have consumed them for a long time; however, their safety has not been scientifically verified. In this study, the safety of melinjo seed extract (MSE) powder was assessed in an acute oral toxicity study, a 4-week repeated dose toxicity study, and in a micronucleus test in rats. In the acute and subchronic toxicity studies, the group administered the powder did not show any toxicologically significant MSE-related changes, compared with the control group. The no observed adverse effect level (NOAEL) was determined as 1000 mg/kg/day. A genotoxicity test (rat bone marrow micronucleus test) was negative for MSE powder at levels up to 4000 mg/kg/day. These results might provide supportive evidence of safety of melinjo seeds, which has been used as food ingredients for a long time.

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 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.

Trans-Resveratrol Enhances the Anticoagulant Activity of Warfarin in a Mouse Model

Aim: Resveratrol is a popular ingredient in dietary supplements. Some patients concomitantly use dietary supplements and medicines in Japan. In the present study, we determined whether trans-resveratrol and melinjo (Gnetum gnemon L.) seed extract (MSE), which contains resveratrol dimers, interacted with drugs using a mouse model. Methods: Male C57BL/6J mice were fed experimental diets containing 0.005%, 0.05%, or 0.5% (w/w) trans-resveratrol or MSE for 1 or 12 weeks. The expression of liver cytochrome P-450 (CYP) mRNA and activity of liver microsomal CYP were measured. To determine the influence of resveratrol or MSE on drug efficacy, the anticoagulant activity of warfarin was examined in mice that were fed diets containing trans-resveratrol or MSE for 12 weeks. Results: When the mice were fed experimental diets for 1 week, none of the doses of trans-resveratrol and MSE affected body weight, liver weight, or plasma AST and ALT levels. Trans-resveratrol also did not affect CYP1A1, CYP1A2, CYP2C, or CYP3A activities. In contrast, 0.5% MSE slightly increased CYP1A1 activity. When the mice were fed experimental diets for 12 weeks, 0.05% trans-resveratrol increased CYP1A1, CYP2C, and CYP3A activities, whereas 0.5% MSE suppressed CYP3A activity. Under these conditions, 0.5% trans-resveratrol enhanced the anticoagulant activity of warfarin, although CYP2C activity increased. However, MSE did not affect the anticoagulant activity of warfarin. Conclusion: The 0.05% trans-resveratrol did not interact with warfarin in a mouse model, whereas 0.5% trans-resveratrol may have enhanced the anticoagulant activity of warfarin.

Resveratrol derivative-rich melinjo (Gnetum gnemon L.) seed extract improves obesity and survival of C57BL/6 mice fed a high-fat diet

Melinjo (Gnetum gnemon L.) seed extracts (MSEs) are rich in resveratrol dimers (gnemonoside A, C, D, gnetin C), trans-resveratrol, and other resveratrol derivatives. trans-Resveratrol is a widely studied caloric restriction mimetic. In mice fed a high-fat diet (HFD), trans-resveratrol protects against obesity, type 2 diabetes, and premature death. Here, treatment of HFD-fed mice with 2.0% MSE significantly reduced body weight gain (p < 0.001), blood insulin (p < 0.01), and HOMA-IR (p < 0.05) after 8 weeks compared with untreated HFD-fed mice. Additionally, 0.2% MSE treatment of HFD-fed mice significantly improved physiological activity (p < 0.05) at 18 months of age and reduced risk of death due to HFD by 25% (hazard ratio = 0.75, p = 0.036). These data show that MSE can improve several aspects of metabolic syndrome and survival in mice and may have health benefits as a dietary supplement. Graphical Abstract Resveratrol derivative-rich melinjo (Gnetum gnemon L.) seed extract improves survival of C57BL/6 mice fed a high-fat diet.