Isolation of Positive Modulator of Glucagon-like Peptide-1 Signaling from Trigonella foenum-graecum (Fenugreek) Seed.

The glucagon-like peptide-1 receptor (GLP-1R) is expressed in many tissues and has been implicated in diverse physiological functions, such as energy homeostasis and cognition. GLP-1 analogs are approved for treatment of type 2 diabetes and are undergoing clinical trials for other disorders, including neurodegenerative diseases. GLP-1 analog therapies maintain chronically high plasma levels of the analog and can lead to loss of spatiotemporal control of GLP-1R activation. To avoid adverse effects associated with current therapies, we characterized positive modulators of GLP-1R signaling. We screened extracts from edible plants using an intracellular cAMP biosensor and GLP-1R endocytosis assays. Ethanol extracts from fenugreek seeds enhanced GLP-1 signaling. These seeds have previously been found to reduce glucose and glycated hemoglobin levels in humans. An active compound (N55) with a new N-linoleoyl-2-amino-γ-butyrolactone structure was purified from fenugreek seeds. N55 promoted GLP-1-dependent cAMP production and GLP-1R endocytosis in a dose-dependent and saturable manner. N55 specifically enhanced GLP-1 potency more than 40-fold, but not that of exendin 4, to stimulate cAMP production. In contrast to the current allosteric modulators that bind to GLP-1R, N55 binds to GLP-1 peptide and facilitates trypsin-mediated GLP-1 inactivation. These findings identify a new class of modulators of GLP-1R signaling and suggest that GLP-1 might be a viable target for drug discovery. Our results also highlight a feasible approach for screening bioactive activity of plant extracts.

Effect of glycosides based standardized fenugreek seed extract in bleomycin-induced pulmonary fibrosis in rats: Decisive role of Bax, Nrf2, NF-κB, Muc5ac, TNF-α and IL-1ß.

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is a chronic progressive multifactorial disease with limited therapeutic options. Glycosides based standardized fenugreek seed extract (SFSE-G) possesses potent anti-inflammatory and anti-oxidant property. AIM: To evaluate the efficacy of SFSE-G against bleomycin (BLM) induced pulmonary fibrosis by assessing behavioral, biochemical, molecular and ultrastructural changes in the laboratory rats. MATERIALS AND METHODS: IPF was induced in male Sprague-Dawley rats by single intratracheal BLM (6IU/kg) injection followed by SFSE-G (5, 10, 20 and 40mg/kg, p.o.) or methylprednisolone (10mg/kg, p.o.) treatment for 28day. Various parameters were analyzed in lung and bronchoalveolar lavage fluid (BALF) after 14 and 28days of the drug treatment. RESULTS: SFSE-G (20 and 40mg/kg, p.o.) administration significantly prevented the BLM induced alteration in body weight, lung index, lung function test and hematology. The altered total and differential cell count in BALF and blood was significantly prevented by SFSE-G treatment. The decreased peripheral blood oxygen content after BLM instillation was significantly increased by SFSE-G treatment. SFSE-G significantly enhanced the BALF and lung antioxidant status, through modulating the SOD, GSH, T-AOC, MDA, NO level and Nrf2, HO-1 mRNA expression. There was a significant reduction in lung 5-HT level by SFSE-G treatment. The altered mRNA expression of biomarkers of lung inflammation (TNF-α, IL-1ß, IL-6 and IL-8), fibrosis (TGF-ß, collagen-1, ET-1, Muc5ac, NF-κB, VEGF, Smad-3) and apoptosis (Bax, Bcl-2 and Caspase-3) were significantly prevented by SFSE-G treatment. BLM induced histological inflammatory and fibrotic insult in the lung were reduced by SFSE-G treatment. It also ameliorated BLM induced lung ultrastructural changes as observed by transmission electron microscopic studies. However, administration of SFSE-G (5mg/kg, p.o.) failed to show any protective effect against BLM-induced PF whereas SFSE-G (10mg/kg, p.o.) showed significant amelioration in BLM-induced PF except lung function test, BALF and lung antioxidant level. CONCLUSION: SFSE-G showed anti-fibrotic efficacy executed through induction of Nrf2, which in turn may modulate anti-inflammatory molecules, inhibit fibrogenic molecules and decreased apoptosis to ameliorate BLM induced pulmonary fibrosis.

Safety, efficacy and toxicological evaluation of a novel, patented anti-diabetic extract of Trigonella Foenum-Graecum seed extract (Fenfuro).

Safety and anti-diabetic efficacy of a novel, proprietary Trigonella foenum-graecum seed extract [novel fenugreek extract (FE), Fenfuro™, CR0010810) enriched in furostanolic saponins (>60% w/w, HPLC) were assessed. Concerning safety, we undertook studies dealing with acute oral toxicity, 28-d sub-chronic toxicity and Ames' bacterial reverse mutation assay that revealed no toxicity. Concerning efficacy, we examined beneficial effects of the extract on rats with type 2 diabetes (T2D). Male Sprague-Dawley rats received a high-fat diet for 2 weeks followed by streptozotocin (STZ, 35 mg/kg i.p.) to produce T2D. Seven days post-STZ, rats showing ≥300 mg/dl fasting plasma glucose level (PGL) were included in the study. FE (150- or 450- mg/kg p.o.) and glipizide (5 mg/kg p.o.) were administered once daily for 20 d and then twice daily for another 10 d (total 30 d). Blood samples were collected at 0, 10, 20 and 30 d of treatment and estimated for fasting plasma triglyceride (PTG), total cholesterol and insulin levels. After 30 d, FE and glipizide-treated diabetic animals were treated in combination with or without metformin (100 mg/kg) twice daily for another 10 d. FE did not influence body weight, feed and water intake. FE (150 mg/kg p.o.) reduced PTG levels in T2D rats by 22%, 24.6% and 29% at 10, 20 and 30 d of treatment, respectively, while glipizide (5 mg/kg p.o.) reduced the PTG levels by 57.4%, 46.2% and 39.4% at these time points. FE (450 mg/kg) treatment in STZ-induced diabetic rats produced significant hypoglycemic activity (approximately 31.5%) as compared to insulin (48.2% with 1 U/kg i.p.). FE (150 mg/kg p.o.) and metformin (100 mg/kg p.o.) combined produced significant reduction (20.7%) of PGL in T2D rats. No adverse effects were observed. We conclude after extensive in vitro and in vivo safety and efficacy studies that FE is safe and effective in treating T2D.

Alkaloid and flavonoid rich fractions of fenugreek seeds (Trigonella foenum-graecum L.) with antinociceptive and anti-inflammatory effects.

The seeds of fenugreek (Trigonella foenum-graecum L.) have medicinal uses as hypoglycemic, antinociceptive and anti-inflammatory agents. We aimed to evaluate the antinociceptive and anti-inflammatory effects of the major fractions of fenugreek seeds. The methanolic extract of the plant seeds was partitioned using a liquid-liquid extraction procedure to give six major fractions. Following phytochemical screening of isolated fractions, the total extract and each fraction were evaluated for their antinociception and anti-inflammatory effects using formalin and carrageenan-induced paw edema tests respectively. The methanolic extract exhibited both antinociceptive and anti-inflammatory effects at a dose of 100mg/kg. Among the tested fractions, alkaline chloroform fraction (AKC), which was alkaloid positive in screening tests, showed the most anti-nociceptive effect in a dose-dependent manner. AKC fraction was as effective as morphine (5mg/kg) in this regard. Both aqueous and acidified chloroform fractions (ACC) could significantly inhibit paw edema at a different dose. The latter fraction dose-dependently inhibited carrageenan-induced paw edema. The results of phytochemical screening tests confirmed the presence of flavonoids in both ACC and aqueous fractions. It can be concluded that the alkaloid and flavonoid content of fenugreek seeds can be responsible for antinociception and anti-inflammatory effects of the plant respectively.

Deep EST profiling of developing fenugreek endosperm to investigate galactomannan biosynthesis and its regulation.

Galactomannans are hemicellulosic polysaccharides composed of a (1 â†’ 4)-linked ß-D-mannan backbone substituted with single-unit (1 â†’ 6)-α-linked D-galactosyl residues. Developing fenugreek (Trigonella foenum-graecum) seeds are known to accumulate large quantities of galactomannans in the endosperm, and were thus used here as a model system to better understand galactomannan biosynthesis and its regulation. We first verified the specific deposition of galactomannans in developing endosperms and determined that active accumulation occurred from 25 to 38 days post anthesis (DPA) under our growth conditions. We then examined the expression levels during seed development of ManS and GMGT, two genes encoding backbone and side chain synthetic enzymes. Based on transcript accumulation dynamics for ManS and GMGT, cDNA libraries were constructed using RNA isolated from endosperms at four ages corresponding to before, at the beginning of, and during active galactomannan deposition. DNA from these libraries was sequenced using the 454 sequencing technology to yield a total of 1.5 million expressed sequence tags (ESTs). Through analysis of the EST profiling data, we identified genes known to be involved in galactomannan biosynthesis, as well as new genes that may be involved in this process, and proposed a model for the flow of carbon from sucrose to galactomannans. Measurement of in vitro ManS and GMGT activities and analysis of sugar phosphate and nucleotide sugar levels in the endosperms of developing fenugreek seeds provided data consistent with this model. In vitro enzymatic assays also revealed that the ManS enzyme from fenugreek endosperm preferentially used GDP-mannose as the substrate for the backbone synthesis.

Prophylaxis effect of Trigonella foenum graecum L. seeds on renal stone formation in rats.

Despite considerable progress in medical therapy, there is no satisfactory drug to treat kidney stones. Therefore, the current study aimed to look for an alternative by using Trigonella foenum graecum (Tfg) on nephrolithiasic rats as a preventive agent against the development of kidney stones, which is commonly used in Morocco as a phytotherapeutic agent. The inhibitory effect of the aqueous extract of Tfg seeds was examined on the formation of calcium oxalate renal stones induced by ethylene glycol (EG) with ammonium chloride. At the end of the experiment all kidneys were removed and examined microscopically for possible crystal/stone locations and the total calcium amount in the renal tissue was evaluated. The blood was recovered to determine the levels of calcium, phosphorus, creatinine and urea. The results showed that the amount of calcification in the kidneys and the total calcium amount of the renal tissue in rats treated with Tfg were significantly reduced compared with the untreated group. Consequently, Tfg may be a useful agent in the treatment of patients with calcic urolithiasis.

Effects of sodium-orthovanadate and Trigonella foenum-graecum seeds on hepatic and renal lipogenic enzymes and lipid profile during alloxan diabetes.

Sodium-orthovanadate (SOV) and seed powder of Trigonella foenum graecum Linn. (common name: fenugreek, family: Fabaceae) (TSP) besides being potential hypoglycemic agents have also been shown to ameliorate altered lipid metabolism during diabetes. This study evaluates the short-term effect of oral administration of SOV and TSP separately and in concert (for 21 days) on total lipid profile and lipogenic enzymes in tissues of alloxan diabetic rats. Diabetic rats showed 4-fold increase in blood glucose. The level of total lipids, triglycerides and total cholesterol in blood serum increased significantly during diabetes. During diabetes the level of total lipids increased significantly (P < 0.001) in liver and in kidney by 48% and 55%, respectively, compared to control. Triglycerides level increased by 32% (P < 0.01) in liver and by 51% (P < 0.005) in kidney, respectively, compared to control. Total cholesterol level also increased significantly in both liver and kidney (P < 0.01 and P < 0.001, respectively). The activities of NADP-linked enzymes; namely glucose-6-phosphate dehydrogenase (G6PDH), malic enzyme (ME), isocitrate dehydrogenase (ICDH), and the activities of lipogenic enzymes namely ATP-citrate lyase (ATP-CL) and fatty acid synthase (FAS) were decreased significantly in liver and increased in kidney during diabetes as compared to control. SOV and TSP administration to diabetic animals prevented the development of hyperglycemia and alteration in lipid profile in plasma and tissues and maintained it near normal. Maximum prevention was observed in the combined treatment with lower dose of SOV (0.2%) after 21 days. We are presenting for the first time effectiveness of combined treatment of SOV and TSP in amelioration of altered lipid metabolism during experimental type-I diabetes.