Chemical characterization and biological activities of Simmondsia chinensis (Link) C. K. Schneid seeds oil.

The chemical composition, main physicochemical properties, and biological activities of Simmondsia chinensis (S. chinensis) seeds oil were studied. The results revealed that the physiochemical characteristics of S. chinensis seeds oil were as follows: acid values 1.15 mg KOH/g, peroxide values 8.00 meq O2 Kg-1, iodine values 80.00 g/100 g of oil and saponification values 92.00 mg KOH/g, phenolic content 50.91 mg gallic acid equivalents/g extract. Gas chromatography analysis indicated that eicosenoic (55.50 %), erucic (20.43 %) and oleic (19.01 %) acids were the most abundant, saturated and unsaturated, fatty acids in the oil. Moreover, the evaluation of their antioxidant (DPPH, TAC), antibacterial, antidiabetic and acetylcholinesterase evinced interesting results. Seeds of S. chinensis constitute a substitute source for stable vegetable oil and protein with regard to nutritional and industrial applications.

LC-MS-MS and GC-MS analyses of biologically active extracts and fractions from Tunisian Juniperus phoenice leaves.

CONTEXT: Despite some studies related to Juniperus phoenicea L. (Cupressaceae), phytochemical and biological investigations of this plant remain unexplored. OBJECTIVE: This work is the first report dealing with the identification and characterization of volatile components and flavonoids in hexane and methanol extracts from J. phoenicea leaves Materials and methods: Antioxidant activity of hexane, and methanol extracts from J. phoenicea leaves were determined by DPPH-radical scavenging assay. α-Amylase inhibitory activity was evaluated by enzyme inhibition using in vitro assay (each extract was dissolved in DMSO to give concentrations of 50, 100 and 200 mg/mL). The chemical composition of fractions (Fr1-Fr3) from methanol extract was determined by high-performance liquid chromatography coupled with mass spectroscopy (HPLC-MS) analysis. RESULTS AND DISCUSSION: The hexane extract was analyzed by GC-MS technique which allowed the identification of 32 compounds. The main constituents were α-humulene (16.9%), pentadecane (10.2%) and α-cubebene (9.7%). Fraction Fr 2 exhibited a strong DPPH radical-scavenging activity (IC50 = 20.1 µg/mL) compared to that of BHT as well as the highest α-amylase inhibitory activity (IC50 = 28.4 µg/mL). Three flavonoids were identified in these fractions using HPLC-MS analysis: Quercetin 3-O-glucoside, isoscutellarein 7-O-pentoside and quercetin 3-O-pentoside. In addition, the more active fraction (Fr 2) was purified with semi-preparative HPLC affording one pure compound (amentoflavone) using 1H NMR analysis. This compound exhibited powerful DPPH radical-scavenging (IC50 = 14.1 µg/mL) and α-amylase inhibition (IC50 = 20.4 µg/mL) effects. CONCLUSION: This study provides scientific support to some medicinal uses of J. phoenicea found in North Africa.

Antioxidant and α-amylase inhibitory activities of extract and isolates from Zygogynum pancheri subsp. arrhantum.

One new sesquiterpenoid (5R(*),8R(*),9R(*),10R(*))-cinnamolide (8), and seven known compounds, 5-hydroxy-7-methoxyflavonone (1), 8-hydroxy-3-(4'-hydroxyphenyl)-6,7-(2″,2″-dimethylchromene)-tetralone (2), 8-hydroxy-3-(3',4'-dihydroxyphenyl)-6,7-(2″,2″-dimethylchromene)-tetralone (3), 1ß-E-O-p-methoxycinnamoyl-bemadienolide (4), 1ß-O-(E-cinnamoyl)-6α-hydroxy-9-epi-polygodial (5), 1ß-O-(E-cinnamoyl)-6α-hydroxypolygodial (6), and 1ß-O-E-cinnamoylpolygodial (7) were isolated from the ethyl acetate extract of barks of Zygogynum pancheri subsp. arrhantum (Winteraceae). The structures of these molecules were assigned predominantly based on spectral data. The structure of compound 8 was confirmed by X-ray crystallographic analysis. Compounds 2 and 3 exhibited significant antioxidant activity, whereas compounds 1 and 4-7 showed significant α-amylase inhibitory activity.

The flavonoid resokaempferol improves insulin secretion from healthy and dysfunctional pancreatic ß-cells.

BACKGROUND AND PURPOSE: The pharmacology of flavonoids on ß-cell function is largely undefined especially in the context of defective secretion of insulin. We sought to identify flavonoids that increased the insulin-secreting function of ß-cells and to explore the underlying mechanisms. EXPERIMENTAL APPROACH: INS-1 ß-cells in culture and islets of Langerhans isolated from control and diabetic male rats were used for insulin secretion experiments. Pharmacological and electrophysiological approaches were used for mechanistic studies. KEY RESULTS: Among a set of flavonoids, exposure of INS-1 ß-cells to resokaempferol (ResoK) enhanced glucose-stimulated insulin secretion and therefore we further characterised its activity and its pharmacological mechanism. ResoK glucose-dependently enhanced insulin secretion in INS-1 ß-cells and pancreatic islets isolated from rats. Mechanistically, whole cell patch clamp recordings in INS-1 cells showed that ResoK rapidly and dose-dependently enhanced the L-type Ca2+ current whereas it was inactive towards T-type Ca2+ current. Accordingly, pharmacological inhibition of L-type Ca2+ current but not T-type Ca2+ current blocked the effects of ResoK on glucose-stimulated insulin secretion. ResoK was still active on dysfunctional ß-cells as it ameliorated glucose-stimulated insulin secretion in glucotoxicity-induced dysfunctional INS-1 cells and in pancreatic islets isolated from diabetic rats. CONCLUSION AND IMPLICATIONS: ResoK is a glucose-dependent activator of insulin secretion. Our results indicated that the effects of ResoK on insulin secretion involved its capacity to stimulate L-type Ca2+ currents in cultured ß-cells. As ResoK was also effective on dysfunctional ß-cells, our work provides a new approach to stimulating insulin secretion, using compounds based on the structure of ResoK.

Anti-diabetic and lipid-lowering effects of drimane sesquiterpenoids isolated from Zygogynum pancheri.

Recently, it has been shown that drimane-type sesquiterpenoids isolated from Zygogynum pancheri, a species native to New Caledonia, possessed significant α-amylase inhibitory activities. To further explore their antidiabetic potential, we investigated the effect of 1ß-O-(E-cinnamoyl)-6α-hydroxy-9epi-polygodial (D) and 1ß-E-O-p-methoxycinnamoyl-bemadienolide (L), two of the most active compounds of the series, on diabetic model rats. Compounds D and L (2 mg kg/day) were daily and orally administrated for 30 days to streptozotocin (STZ) (150 mg/kg) induced male diabetic Wistar rats. Animals were allocated into five groups of six rats. Comparatively to diabetic rats, treatments with D and L compounds were able to significantly (P < 0.05) decrease Fasting Blood Glucose (FBG) (70.15%, 71.02%), serum total cholesterol (46.27% and 39.38%), triglycerides (56.60% and 58.15%), creatinine (37.31% and 36.49%) and uric acid levels (67.76% and 69.68%), respectively. Compounds D and L also restored the altered plasma enzyme (aspartate aminotransferase, AST (47.83% and 43.20%), alanine aminotransferase, ALT (49.76% and 48.35%, alkaline phosphatase, ALP (72.78% and 73.21%)) and lactate dehydrogenase, LDH (47.95% and 53.93%) levels to near normal, respectively. Administration of Glymepiride, significantly (p < 0.05) reduced FBG (73.94%) in STZ induced diabetic rats. Additionally, the compounds D and L exhibited inhibitory effects in vivo on lipase activity of diabetic rats (54.83% and 52.25%), respectively. The outcomes of this study suggested that these two drimanes could be considered as efficient hypoglycemic, hypolipidemic and antiobesity agents for diabetes management and its complications.

Anorexic and metabolic effect of jojoba: potential treatment against metabolic syndrome and hepatic complications.

BACKGROUND: Evaluation of the action of various traditional plants to treat metabolic syndrome are strongly studied. In our study, we investigated the effect of the Tunisian jojoba seed on a metabolic syndrome induced in rat by the High Fat diet and High Fructose (HFHF) and its renal and hepatic complications. METHODS: The rats were fed with HFHF or Normal Diet (ND) for a period of 8 weeks. After that, a switch from HFHF to ND or Normal Diet Jojoba (NDJ),(jojoba diet approach) or High Fat and High Fructose and Jojoba diet (HFHFJ) (nutraceutical approach) has been done. Metabolic disorder was evaluated by measuring the fasting body weight, glycemia and C-peptide and leptin. Oxidative stress parameters like ThioBarbituric Acid Reactive Substances (TBARS) and Total Antioxidant Capacity (TAOC) were analyzed in the plasma and renal and hepatic function were determined by the measure of creatinine and alanine transferase (ALT) respectively. Histological analysis was performed on the liver, kidney and pancreas. RESULTS: HFHF diet exhibited characteristics of metabolic syndrome presented by insulin resistance, hyperinsulinemia, hyperleptinemia, fat mass with hepatic steatosis and renal disorder. HFHF diet was associated with oxidative stress (OS) presented by an increase in TBARS and a decrease in TAOC. Adding jojoba seeds to HFHF rat group diet induced a decrease in body weight, fat mass (58 and 41%), insulin resistance (59 and 56%), oxidative stress (60 and 41%), liver steatosis (from a score = 3 to a score = 0) and renal complications (25 and 42%). This effect was emphasized with diet approach. CONCLUSION: The results demonstrated the beneficial effect of jojoba against metabolic syndrome and oxidative stress, suggesting that jojoba could be used in the prevention and treatment of metabolic syndrome.

Metabolic impairments and tissue disorders in alloxan-induced diabetic rats are alleviated by Salvia officinalis L. essential oil.

The current research explored for the first time the effect of Salvia officinalis L. (Sage) essential oil (EO) on Alloxan-induced diabetes in male Wistar rats. Sage EO was extracted by a Clevenger apparatus and analyzed by GC-FID and GC-MS. The most important chemical families identified in this oil were oxygenated monoterpenes (56.32%), hydrocarbon monoterpenes (15.00%) and hydrocarbon sesquiterpenes (14.70%). All treatments were administered orally. In vitro investigation showed that the EO had α-amylase and lipase inhibitory activities with IC50 = 38 µg/mL and IC50 = 52 µg/mL, respectively. In vivo experiments highlighted that the activities of serum α-amylase and lipase were reduced by 46.6% and 32.1%, respectively. Sage EO reduced glycemia by 60% and the level of glycogen stored in the liver by 43.7%. Treatments of diabetes with Sage EO significantly protected the liver function by lowering serum AST (35%), ALT (79%) and LDH (43%) activities. Furthermore, Sage EO was efficient to preserve the kidney function in diabetes by reverting back serum creatinine (47%) and UA (62.5%) concentrations to control values. The obtained results altogether evidenced that Sage EO had hypoglycemic and anti-obesity effects and could be a valuable complement in future diabetes therapy.

Beneficial Effect of Jojoba Seed Extracts on Hyperglycemia-Induced Oxidative Stress in RINm5f Beta Cells.

Hyperglycemia occurs during diabetes and insulin resistance. It causes oxidative stress by increasing reactive oxygen species (ROS) levels, leading to cellular damage. Polyphenols play a central role in defense against oxidative stress. In our study, we investigated the antioxidant properties of simmondsin, a pure molecule present in jojoba seeds, and of the aqueous extract of jojoba seeds on fructose-induced oxidative stress in RINm5f beta cells. The exposure of RINm5f beta cells to fructose triggered the loss of cell viability (-48%, p < 0.001) and disruption of insulin secretion (p < 0.001) associated with of reactive oxygen species (ROS) production and a modulation of pro-oxidant and antioxidant signaling pathway. Cell pre-treatments with extracts considerably increased cell viability (+86% p < 0.001) for simmondsin and +74% (p < 0.001) for aqueous extract and insulin secretion. The extracts also markedly decreased ROS (-69% (p < 0.001) for simmondsin and -59% (p < 0.001) for aqueous extract) and caspase-3 activation and improved antioxidant defense, inhibiting p22phox and increasing nuclear factor (erythroid-derived 2)-like 2 (Nrf2) levels (+70%, p < 0.001) for aqueous extract. Simmondsin had no impact on Nrf2 levels. The richness and diversity of molecules present in jojoba seed extract makes jojoba a powerful agent to prevent the destruction of RINm5f beta cells induced by hyperglycemia.

Effect of Sardina pilchardus oil on alloxan-induced diabetic rats.

The purpose of this study was to prevent or to delay the onset of diabetes-related complications, by using a natural marine resource, Sardina pilchardus oil, administrated to alloxan-induced diabetic rats showing hyperglycemia and hyperlipidemia. Gas chromatography-mass spectrometry analysis of the sardine oil detected 18 constituents. The major ones were n-3 highly unsaturated fatty acids among which are docosahexaenoic acid (25.09%) and eicosapentaenoic acid (19.61%). Sardine oil inhibited the α-amylase activity in rats' sera (26.82%) and thus improved glycemia (54%). The supplement of this oil protected the ß-cells from death and damage, significantly decreased total triglycerides, total cholesterol and LDL-cholesterol concentrations in diabetic rats' sera and increased the HDL-cholesterol level. Gavage administration of this oil to rats protected the liver and kidney functions by reducing the aspartate transaminase, alanine transaminase and phosphatase alkaline activities, and by decreasing creatinine, urea and uric acid levels.

Inhibitory activities of Ulva lactuca polysaccharides on digestive enzymes related to diabetes and obesity.

The aim of this study was to evaluate the effect of alga Ulva lactuca polysaccharides (ULPS) on key enzymes related to diabetes and obesity. This marine natural product, ULPS, exerted potential inhibition on key enzymes related to starch digestion and absorption in both plasma and small intestine mainly α-amylase by 53% and 34% and maltase by 97 and 164% respectively, leading to a significant decrease in blood glucose rate by 297%. Moreover, ULPS potentially inhibited key enzymes of lipid metabolism and absorption as lipase activity in both plasma and small intestine by 235 and 287% respectively, which led to a notable decrease of blood LDL-cholesterol and triglycerides levels, and in the counterpart an increase in HDL-cholesterol level in surviving diabetic rats. Additively, ULPS significantly protected the liver-kidney functions, by decreasing of aspartate transaminase (AST), alanine transaminase (ALT) and gamma-glytamyl transpeptidase (GGT) activities and creatinine, urea and albumin rates in plasma.