Search

The objective of the present work was to evaluate the effect of minor glycosides on the QUICKI index as a marker of insulin resistance, triglycerides (TG), and antioxidant capacity in Wistar rats induced with diabetes mellitus type 2 (DM2). DM2 was induced in male Wistar rats (n = 35) through streptozotocin-nicotinamide. Hyperglycaemia was confirmed two weeks later, the subjects were divided into seven experimental groups, and each group was treated as follows: (1-5) dulcoside A, steviolbioside, rebaudioside B, C, and D (20 mg/kg, respectively); (6) metformin (180 mg/kg); and (7) standard diet, orally for four weeks. Blood sample was obtained from the tail before and after the treatment. The serum was separated after clotting by centrifugation. The included parameters namely serum triglycerides (TG) and superoxide dismutase (SOD) activity were measured before and after the treatments, then the changes were determined; and at the end of the treatment, the QUICKI index was determined. The analysis of one-way variance (ANOVA) was performed considering p < 0.05. No statistically significant differences were found in any of the three variables (p > 0.05); however, the rebaudioside group B had the highest QUICKI index, while the reduction of triglycerides was greater in rebaudioside D. SOD activity increased in all groups, but was higher in rebaudioside D and steviolbioside. Minor glycosides at the dose and time evaluated had no significant effects on QUICKI index, antioxidant capacity, and triglycerides concentration. [ABSTRACT FROM AUTHOR]

Peptide fractions from marine animal hydrolysates can have biological activity. Red lionfish (Pterois volitans L.) is an invasive fish species in the tropical Atlantic, and harvest is a proposed control mechanism. With the aim of identifying possible bioactivity in peptides from red lionfish, an evaluation was done for the antioxidant, Cu2+ and Fe2+chelating, and angiotensin- converting enzyme inhibitory (ACE-I) activities of ultra-filtered peptide fractions derived from lionfish muscle enzymatically hydrolysed with the commercial enzyme Alcalase®. Hydrolysates were generated at 0, 30, 60, and 90 min, and the degree of hydrolysis (DH) were determined. The 30-min hydrolysate yielded the highest DH (30.78 ± 1.57%). This hydrolysate was ultra-filtered using four cut-offs (10, 5, 3, and 1 kDa), and the resulting polypeptides were analysed to generate their amino acids profile and estimated molecular weight (EMW). The F 5-3, F 3-1, and F < 1 kDa peptide fractions yielded the highest copper-chelating activity with values of approximately 88%. Fractions F > 10 and F 10-5 kDa yielded the highest iron-chelating activity with values of approximately 18.8%. The β-carotene bleaching test showed that the F 10-5, F 5-3, F 3-1, and F < 1 kDa fractions to have high antioxidant capacity, inhibiting more than 80% of β-carotene discoloration versus the control. The F 5-3 kDa fraction exhibited the highest ACE inhibition (34.57%), possibly due to the presence of amino acids such as Gly, Leu, Phe, Tyr, and Pro. Polypeptides with an EMW of 6.51 to 3.49 kDa were identified in F > 10, and 2.17 kDa in F 5-3. Peptide fractions from hydrolysed red lionfish muscle exhibit in vitro activities, and could serve as potential source of functional ingredients. [ABSTRACT FROM AUTHOR]

Objective: To determine the risk of cardiovascular diseases and differences by sex in adolescents in a highly-marginalized locality in Yucatan., Methods: The study was carried out with high school students (n = 170). Weight, height, age, waist circumference, and blood pressure were recorded; the indicators height/age, body mass index (BMI)/age, waist circumference/height, and systolic blood pressure/height were calculated. Descriptive statistics and chi-square tests were calculated., Results: Concerning height/age, only 44.1% of the adolescents had normal height, while 55.2% had low or severely low height. Concerning waist circumference/height, 26% presented a cardiovascular risk, more frequently in women (p&lt;.05) than in men; of the adolescents, 8.8% registered prehypertension/hypertension., Conclusions: Risk factors found in the population, confer susceptibility to health risks due to age, poverty, and social marginalization. It is necessary to carry out intervention programs for adolescents from highly-marginalized communities.

Many studies describe different pharmacological effects of flavonoids on experimental animals and humans. Nevertheless, few ones are confirming the safety of these compounds for therapeutic purposes. This study aimed to investigate the preclinical safety of naringenin, naringin, hesperidin, and quercetin by in vivo, in vitro, and in silico approaches. For this, an MTT-based cytotoxicity assay in VERO and MDCK cell lines was performed. In addition, acute toxicity was evaluated on Wistar rats by OECD Guidelines for the Testing of Chemicals (Test No. 423: Acute Oral Toxicity-Class Method). Furthermore, we used the ACD/Tox Suite to predict toxicological parameters such as hERG channel blockade, CYP450 inhibition, and acute toxicity in animals. The results showed that quercetin was slightly more cytotoxic on cell lines (IC 50 of 219.44 ± 7.22 mM and 465.41 ± 7.44 mM, respectively) than the other citroflavonoids. All flavonoids exhibited an LD 50 value > 2000 mg/kg, which classifies them as low-risk substances as OECD guidelines established. Similarly, predicted LD 50 was LD 50 > 300 to 2000 mg/kg for all flavonoids as acute toxicity assay estimated. Data suggests that all these flavonoids did not show significant toxicological effects, and they were classified as low-risk, useful substances for drug development.

Steviol glycosides are a family of compounds found in Stevia rebaudiana Bertoni that are responsible for sweetness capacity. The antihyperglycemic effect of the two major steviol glycosides, Rebaudioside A and Stevioside, has been studied and it has been found that despite having the same common structure, only Stevioside exerts an antihyperglycemic effect. Although other steviol derivatives are found in smaller amounts (minor steviol glycosides) in S. rebaudiana, whether or not they possess antihyperglycemic activity has not been evaluated. The aim of this study was to evaluate the antihyperglycemic effect of minor steviol glycosides in normoglycemic and diabetic (streptozotocin/nicotinamide) Wistar rats. Rats were subjected to an intraperitoneal glucose tolerance test (IPGTT) both before and after chronic treatment (28 days). After 6 h of fasting, IPGTT was conducted in pentobarbital-anesthetized rats using 1 g/kg of glucose plus 20 mg/kg of the minor glycoside (Dulcoside A, Rebaudioside B, C, D, or Steviolbioside) or control treatment (distilled water, glibenclamide, or metformin); the blood of the tip of the tail was collected at time 0, 15, 30, 60, and 120 min.; and blood glucose was measured, and its net area under the curve (AUCnet) was calculated. After 28-day chronic oral administration, IPGTT was again performed. Differences were considered significant at P < .05 by one-way ANOVA. Acute intraperitoneal or chronic oral administration of 20 mg/kg of minor steviol glycosides had no antihyperglycemic effect in normoglycemic or induced-diabetic Wistar rats. Considering the dose tested, it is unlikely that these glycosides have an effect on glucose in diabetic or normoglycemic humans.

Leaves of Stevia rebaudiana contain glycosides with sweetness and biological activity. However besides the major glycosides, there are other glycosides within extracts that may contribute to its activity, and therefore it is important to quantify them. In this work, an isocratic HPLC method was validated for determination of dulcoside A, steviolbioside, rebaudioside C and rebaudioside B. An HPLC method was performed using a C18 column (250 × 4.6 mm, particle size 5 µm) and a UV detector set at 210 nm. The mobile phase consisted of a 32:68 (v/v) mixture of acetonitrile and sodium phosphate buffer (10 mmol/L, pH 2.6), set to a flow rate of 1.0 mL/min. The calculated parameters were: sensitivity, linearity, limit of detection (LOD), limit of quantification (LOQ), accuracy and precision. The calibration curves were linear over the working range 25-150 µg/mL, with coefficient of correlation of ≥0.99 and coefficient of determination of ≥0.98. The LOD was 5.68-8.81 µg/mL, while the LOQ was 17.21-26.69 µg/mL. The percentage recoveries of fortified samples were 100 ± 10% and precision, relative standard deviation, was <10%. The method validation showed accuracy, linearity and precision; therefore this method can be applied for quantitative analysis of minor steviol glycosides in S. rebaudiana leaves., (Copyright © 2014 John Wiley & Sons, Ltd.)