Investigation of morin-induced insulin secretion in cultured pancreatic cells.

Morin is a flavonoid contained in guava that is known to reduce hyperglycemia in diabetes. Insulin secretion has been demonstrated to increase following the administration of morin. The present study is designed to investigate the potential mechanism(s) of morin-induced insulin secretion in the MIN6 cell line. First, we identified that morin induced a dose-dependent increase in insulin secretion and intracellular calcium content in MIN6 cells. Morin potentiated glucose-stimulated insulin secretion (GSIS). Additionally, we used siRNA for the ablation of imidazoline receptor protein (NISCH) expression in MIN6 cells. Interestingly, the effects of increased insulin secretion by morin and canavanine were markedly reduced in Si-NISCH cells. Moreover, we used KU14R to block imidazoline I3 receptor (I-3R) that is known to enhance insulin release from the pancreatic ß-cells. Without influence on the basal insulin secretion, KU14R dose-dependently inhibited the increased insulin secretion induced by morin or efaroxan in MIN6 cells. Additionally, effects of increased insulin secretion by morin or efaroxan were reduced by diazoxide at the dose sufficient to open KATP channels and attenuated by nifedipine at the dose used to inhibit L-type calcium channels. Otherwise, phospholipase C (PLC) is introduced to couple with imidazoline receptor (I-R). The PLC inhibitor dose-dependently inhibited the effects of morin in MIN6 cells. Similar blockade was also observed in protein kinase C (PKC) inhibitor-treated cells. Taken together, we found that morin increases insulin secretion via the activation of I-R in pancreatic cells. Therefore, morin would be useful to develop in the research and treatment of diabetic disorders.

Effects of Davallia formosana Hayata Water and Alcohol Extracts on Osteoblastic MC3T3-E1 Cells.

The Taiwanese native fern Davallia formosana Hayata (DFH) is used to treat bone diseases in classical Chinese medicine. We analyzed MC3T3E1 osteoblasts treated with different concentrations of water and ethanol extracts (10, 25, and 50 [both], and 100 µg/mL [DFE only]) using cell viability, expression of osteoblast differentiation markers [bone morphogenetic protein 2 (BMP-2), collagen 1 (CoL-1), alkaline phosphatase (ALP), and Runt-related transcription factor 2 (Runx 2)], and mineralization. These were significantly increased by DFW or DFE after 24-h incubation compared with the untreated controls. Compared with other treatments, DFW 50 and DFE 100 µg/mL significantly increased MC3T3E1 cell survival. DFW 25 and 50 µg/mL increased bone BMP-2, CoL-1, ALP, and Runx2 protein expression, ALP activity, and mineralization more than DFE did. Repeated chromatographic separation of DFW yielded compound (-)-epicatechin-3-O-d-allipyranoside (ECAP), which was characterized using 1 H and 13 C nuclear magnetic resonance spectroscopy. (-)-Epicatechin-3-O-d-allipyranoside (0.01 µg/mL) significantly increased cell survival (118.9%) and mineralization (218.7%) compared with that of the control treatment. We inferred that ECAP could mediate the main activity of DFW in bone formation, likely through BMP-2-induced Runx2 transcription, which increased bone cell differentiation factors ALP and CoL-1 and promoted mineralization. (-)-Epicatechin-3-O-d-allipyranoside could be an anti-osteoporotic agent. Copyright © 2017 John Wiley & Sons, Ltd.

Butterfly Pea Flower as a Novel Ingredient to Produce Antioxidant-Enriched Yellow Pea-Based Breakfast Cereals.

Butterfly pea flower (BP) is a rich source of bioactive components and can potentially be utilized to produce appealing, wholesome foods. Antioxidant and dietary fiber-enriched breakfast cereals were produced by extrusion cooking using blends of BP and yellow pea flour (YP). BP was added to YP at 0%, 5% and 10% levels (w/w), respectively, and extruded at two temperature profiles with die temperatures of 130 and 150 °C. Incorporation of BP significantly (p < 0.05) improved the total phenolics content, antioxidant properties, and insoluble and total dietary fiber content of the extrudates, with 10% BP extrudates showing the highest values. At a die temperature of 150 °C, the extrudates had a higher expansion ratio, a lower dry hardness, and a higher dry crispiness as compared to those at 130 °C. The color of BP-incorporated extrudates was darker and bluer as compared to the no-BP extrudates. The 10% BP extrudates retained relatively more of their hardness, crispiness, and crunchiness after soaking, indicating a better bowl-life and, therefore, better suitability of this blend formula for breakfast cereal production. Overall, this research shows that healthier breakfast cereals with appealing color and relatively longer bowl-life can be produced using BP, making BP a potential novel ingredient for extrusion formulations.

Retrogradation and Digestibility of Rice Starch Gels: The Joint Effect of Degree of Gelatinization and Storage.

Retrogradation affects acceptability of starchy foods; however, it is preferred in some products such as rice noodles. Amylose content, gelatinization temperature, and storage condition were reported to affect retrogradation but with disputed data. The joint effects of these parameters were interested in this study. Rice starch was gelatinized using different temperatures (77, 81, 95, and 121 °C) and stored isothermally with temperature cycles for 10 days. Results showed that the most important parameter that affected retrogradation was storage time followed by storage condition and gelatinization temperature. The recrystallization rate constant (k) and Avrami exponent (n) of retrograded starches stored under temperature cycle were higher than isothermal storage. All samples showed similar polymorphs of a mixture of B and V types. High-temperature gelatinized starch gel stored under temperature cycle condition produced higher yield of resistant starch. The study provided useful information on how to apply these parameters to control the retrogradation of starchy foods, especially rice noodle. PRACTICAL APPLICATION: Retrogradation is found to be more prominent at higher gelatinization temperature and longer storage time. Resistant starch produced from retrograded starch depended largely on storage time than storage condition. This finding can be applied to improve rice noodle qualities (by increasing retrogradation) with lower digestibility (by producing higher resistant starch).

Safety and tolerability of prescription omega-3 fatty acids: A systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Omega-3 fatty acids [eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA)] are widely recommended for health promotion. Over the last decade, prescription omega-3 fatty acid products (RxOME3FAs) have been approved for medical indications. Nonetheless, there is no comprehensive analysis of safety and tolerability of RxOME3FAs so far. METHODS: A systematic review of randomized controlled trials (RCTs) was carried out based on searches in six electronic databases. The studies involving marketed RxOME3FA products were included, and adverse-effect data were extracted for meta-analysis. Subgroup analysis and meta-regression were conducted to explore the sources of potential heterogeneity. RESULTS: Among the 21 included RCTs (total 24,460 participants; 12,750 from RxOME3FA treatment cohort and 11,710 from control cohort), there was no definite evidence of any RxOME3FA-emerging serious adverse event. Compared with the control group, RxOME3FAs were associated with more treatment-related dysgeusia (fishy taste; p = 0.011) and skin abnormalities (eruption, itching, exanthema, or eczema; p < 0.001). Besides, RxOME3FAs had mild adverse effects upon some non-lipid laboratory measurements [elevated fasting blood sugar (p = 0.005); elevated alanine transaminase (p = 0.022); elevated blood urea nitrogen (p = 0.047); decreased hemoglobin (p = 0.002); decreased hematocrit (p = 0.009)]. Subgroup analysis revealed that EPA/DHA combination products were associated with more treatment-related gastrointestinal adverse events [eructation (belching; p = 0.010); nausea (p = 0.044)] and low-density lipoprotein cholesterol elevation (p = 0.009; difference in means = 4.106mg/dL). CONCLUSION: RxOME3FAs are generally safe and well tolerated but not free of adverse effects. Post-marketing surveillance and observational studies are still necessary to identify long-term adverse effects and to confirm the safety and tolerability profiles of RxOME3FAs.

Identification of morin as an agonist of imidazoline I-3 receptor for insulin secretion in diabetic rats.

Morin is a flavonoid contained in guava that is known to reduce hyperglycemia in diabetics. Morin has been demonstrated to increase plasma insulin. However, the mechanism(s) remains unknown. The present study is designed to investigate the effect of morin on the imidazoline receptor (I-R) that regulates insulin secretion. We used Chinese hamster ovary (CHO) cells transfected with an I-R expression construct (NISCH-CHO-K1 cells) to identify the direct effect of morin on the I-R. Moreover, the imidazoline I3 receptor (I-3R) is known to be present in pancreatic ß cells and involved in insulin secretion. Therefore, we applied a specific antagonist (KU14R) to block I-3R in diabetic rats. Additionally, the effect of morin on insulin secretion was characterized in isolated pancreatic islets. Morin decreased blood glucose levels by increasing plasma insulin levels in diabetic rats. In CHO cells expressing an I-R, morin increased calcium influx in a dose-dependent manner. Additionally, KU14R dose-dependently inhibited the morin-induced effects, including hypoglycemia and the increase in insulin secretion and plasma C-peptide levels, in diabetic rats. Furthermore, morin enhanced insulin secretion from isolated pancreatic islets, and this effect was also dose-dependently inhibited by KU14R. Phospholipase C (PLC) is known to couple with the I-R, and a PLC inhibitor dose-dependently attenuated the insulin secretion induced by morin in isolated pancreatic islets. Taken together, these data suggest that morin can activate I-3R to enhance insulin secretion. Therefore, it would be useful to develop morin into a treatment for diabetic disorders.

Variable classifications of glycemic index determined by glucose meters.

THE STUDY EVALUATED AND COMPARED THE DIFFERENCES OF GLUCOSE RESPONSES, INCREMENTAL AREA UNDER CURVE (IAUC), GLYCEMIC INDEX (GI) AND THE CLASSIFICATION OF GI VALUES BETWEEN MEASURED BY BIOCHEMICAL ANALYZER (FUJI AUTOMATIC BIOCHEMISTRY ANALYZER (FAA)) AND THREE GLUCOSE METERS: Accue Chek Advantage (AGM), BREEZE 2 (BGM), and Optimum Xceed (OGM). Ten healthy subjects were recruited for the study. The results showed OGM yield highest postprandial glucose responses of 119.6 +/- 1.5, followed by FAA, 118.4 +/- 1.2, BGM, 117.4 +/- 1.4 and AGM, 112.6 +/- 1.3 mg/dl respectively. FAA reached highest mean IAUC of 4156 +/- 208 mg x min/dl, followed by OGM (3835 +/- 270 mg x min/dl), BGM (3730 +/- 241 mg x min/dl) and AGM (3394 +/- 253 mg x min/dl). Among four methods, OGM produced highest mean GI value than FAA (87 +/- 5) than FAA, followed by BGM and AGM (77 +/- 1, 68 +/- 4 and 63 +/- 5, p<0.05). The results suggested that the AGM, BGM and OGM are more variable methods to determine IAUC, GI and rank GI value of food than FAA. The present result does not necessarily apply to other glucose meters. The performance of glucose meter to determine GI value of food should be evaluated and calibrated before use.

Glycemic index, glycemic load and insulinemic index of Chinese starchy foods.

AIM: To determine the glycemic index (GI), glycemic load (GL) and insulinemic index (II) of five starchy foods that are commonly used in Chinese diets. METHODS: Ten healthy subjects aged between 20-30 years were recruited. Each subject was asked to consume 50 g of available carbohydrate portions of test foods and reference food. Finger capillary blood samples were collected at the start of eating and 15, 30, 45, 60, 90 and 120 min after consumption. The GI and II of foods were calculated from the ratio of incremental area under the glucose/insulin response curves of test and reference foods. The GL for each test food was determined from its GI value and carbohydrate content. RESULTS: The results showed that brown rice elicited the highest postprandial glucose and insulin responses, followed by taro, adlay, yam and mung bean noodles, which produced the lowest. Among the five starchy foods, brown rice evoked the highest GI and GL at 82 ± 0.2 and 18 ± 0.2, followed by taro (69 ± 0.4, 12 ± 0.2), adlay (55 ± 0.4, 10 ± 0.2), yam (52 ± 0.3, 9 ± 0.0) and mung bean noodles (28 ± 0.5, 7 ± 0.2), respectively. The II values of the test foods corresponded with GI values. Similarly, brown rice gave the highest II at 81 ± 0.1, followed by taro (73 ± 0.3), adlay (67 ± 0.3), yam (64 ± 0.5) and mung bean noodles (38 ± 0.3). All five starchy foods had lower GI, GL and II than reference bread (P < 0.05). CONCLUSION: The GI, GL and II values of starchy foods provide important information for the public to manage their diet and could be useful for the prevention of lifestyle-related diseases such as diabetes mellitus.