Long-term effects of dietary fiber supplementation on serum glucose and lipoprotein levels in diabetic rats fed a high cholesterol diet

Phytochemical Analysis of Anacamptis coriophora Plant Cultivated Using Ex Vitro Symbiotic Propagation

This study aims to investigate the functional groups and phytochemical profile of Anacamptis coriophora seeds, tubers, and flowers. Symbiotic seedlings produced using the ex vitro method were transferred to their natural habitat and grown to analyze the functional groups and phytochemical profiles of tubers and flowers. The life cycles of the transferred seedlings were monitored, and tubers and flowers were harvested for analysis. ATR-FTIR spectroscopy revealed the presence of functional groups such as polysaccharides, lignin, and proteins in both tubers and flowers. Differences in spectral frequencies between first-year and second-year tubers were observed. Fatty acid analysis identified 30 different compounds in seeds, flowers, and tubers, with linoleic acid being the most abundant (27 % in seeds, 33 % in tubers), and palmitic acid present in flowers (24 %). GC-MS analysis of ethanol extracts from these components highlighted the presence of 32 compounds, including hydroxyacetic acid, hydrazide, cytidine (Z)-7-hexadecenal, 2,2-dimethoxyethane, 2,5,6-trimethyldecane, and butanamide, 4-amino-N-hydroxy. A. coriophora's tubers, flowers, and seeds may contain active metabolites with therapeutic potential. These results are valuable for the commercial cultivation of the plant.

Konjac Glucomannan Attenuated Triglyceride Metabolism during Rice Gruel Tolerance Test

In a recent study, we showed that konjac glucomannan (KGM) inhibits rice gruel-induced postprandial increases in plasma glucose and insulin levels. To extend this research, we investigated the effects of KGM addition to rice gruel on pre- and postprandial concentrations of circulating lipoprotein lipase (LPL), glycosylphosphatidylinositol-anchored high-density lipoprotein-binding protein 1 (GPIHBP1), hepatic triglyceride lipase (HTGL), free fatty acids (FFA), and triglycerides (TG). A total of 13 Japanese men, without diabetes, dyslipidemia, or gastrointestinal diseases, interchangeably ingested rice gruel containing no KGM (0%G), rice gruel supplemented with 0.4% KGM (0.4%G), and rice gruel supplemented with 0.8% KGM (0.8%G), every Sunday for 3 weeks. Blood samples were obtained at baseline and at 30, 60, and 120 min after ingestion to measure the abovementioned lipid parameters. Lipid parameters showed small, but significant, changes. Significant reductions were found in circulating FFA levels among all participants. Circulating TG levels significantly declined at 30 min and then remained nearly constant in the 0.8%G group but exhibited no significant difference in the 0%G and 0.4%G groups. Although circulating levels of LPL and GPIHBP1 significantly decreased in the 0%G and 0.4%G groups, they increased at 120 min in the 0.8%G group. Participants in the 0%G and 0.4%G groups showed significant decreases in circulating HTGL levels, which was not observed in the 0.8%G group. Our results demonstrate the novel pleiotropic effects of KGM. Supplementation of rice gruel with KGM powder led to TG reduction accompanied by LPL and GPIHBP1 elevation and HTGL stabilization, thereby attenuating TG metabolism.

Health-promoting effects of konjac glucomannan and its practical applications: A critical review

Konjac glucomannan (KGM) is a dietary fiber hydrocolloidal polysaccharide isolated from the tubers of Amorphophallus konjac. Over the last few decades, the purified KGM has been offered as a food additive as well as a dietary supplement in many countries. Also, a diet containing konjac flour or KGM is considered as healthier, and these foods are popular in many Asian and European markets. Further, due to the adhesive property of KGM, it can form a defensive covering on the surface of the intestine. Additionally, KGM can reduce the levels of glucose, cholesterol, triglycerides, and blood pressure and can enable weight loss. Its wide-ranging effects prevent many chronic diseases through the regulation of metabolism. In this review, the recent studies on the health benefits such as anti-diabetic, anti-obesity, laxative, prebiotic, and anti-inflammatory activities of KGM were discussed. Also, this review deals with the applications of KGM and its derivatives in bio-technical, pharmaceutical, tissue engineering, fine chemical fields, etc.

Effects of liquid konjac on parameters related to obesity in diet-induced obese mice

Konjac-mannan has been suggested to exert a protective effect against visceral obesity. However, there is little knowledge about the effects of liquid konjac (LK) that is partially alkali gelled. The purpose of the present work was to evaluate the potential beneficial effects of a LK powder on obesity in mice. Male C57BL/6J mice were fed a high-fat diet supplemented with either 2.5 or 5% LK powder for 80 days. Growth parameters, abdominal fat content, serum biochemical markers, and hepatic lipid accumulations were measured. Dietary supplementation with LK resulted in decreased body weight gain and abdominal fat accumulation. Dose-dependent decreases were observed in accumulation of hepatic lipids and serum total cholesterol, leptin, insulin concentrations. The study findings indicated that LK had preventing effect against obesity, including the reduction of abdominal and hepatic lipid accumulation and serum parameters related to obesity.

One-pot synthesis of biocompatible superparamagnetic iron oxide nanoparticles/hydrogel based on salep: characterization and drug delivery

This work describes synthesis of biocompatible magnetic iron oxide nanoparticles/hydrogel based on salep (MION-salep hydrogel) by a facile one-pot strategy. The prepared sample was characterized by techniques like scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDAX), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), thermal gravimetric analysis (TGA), and vibrating sample magnetometer (VSM). The obtained MION had an 8 nm diameter with a narrow size distribution and was superparamagnetic with large saturation magnetization at room temperature. The most attractive feature of the obtained sample was its swelling properties under external magnetic field (EMF), different temperatures, and pHs. Moreover, MION-salep hydrogel showed ability to deferasirox release at pH=7 with non-Fickian diffusion mechanism. An in vitro cytotoxicity study implied that the as-synthesized sample is nontoxic.

Effects of dietary fibers on weight gain, carbohydrate metabolism, and gastric ghrelin gene expression in mice fed a high-fat diet

Diets that are high in dietary fiber are reported to have substantial health benefits. We sought to compare the metabolic effects of 3 types of dietary fibers -- sugarcane fiber (SCF), psyllium (PSY), and cellulose (CEL) -- on body weight, carbohydrate metabolism, and stomach ghrelin gene expression in a high-fat diet-fed mouse model. Thirty-six male mice (C57BL/6) were randomly divided into 4 groups that consumed high-fat diet alone (HFD) or high-fat diet containing 10% SCF, PSY, and CEL, respectively. After baseline measurements were assessed for body weight, plasma insulin, glucose, leptin, and glucagon-like peptide 1 (GLP-1), animals were treated for 12 weeks. Parameters were reevaluated at the end of study. Whereas there was no difference at the baseline, body weight gains in the PSY and SCF groups were significantly lower than in the CEL group at the end of study. No difference in body weight was observed between the PSY and SCF animals. Body composition analysis demonstrated that fat mass in the SCF group was considerably lower than in the CEL and HFD groups. In addition, fasting plasma glucose and insulin and areas under the curve of intraperitoneal glucose tolerance test were also significantly lower in the SCF and PSY groups than in the CEL and HFD groups. Moreover, fasting plasma concentrations of leptin were significantly lower and GLP-1 level was 2-fold higher in the SCF and PSY mice than in the HFD and CEL mice. Ghrelin messenger RNA levels of stomach in the SCF group were significantly lower than in the CEL and HFD groups as well. These results suggest differences in response to dietary fiber intake in this animal model because high-fat diets incorporating dietary fibers such as SCF and PSY appeared to attenuate weight gain, enhance insulin sensitivity, and modulate leptin and GLP-1 secretion and gastric ghrelin gene expression.

Effects of 2 or 5 consecutive exercise days on adipocyte area and lipid parameters in Wistar rats

Background

Exercise has been prescribed in the treatment and control of dyslipidemias and cholesterolemia, however, lipid responses to different training frequencies in hypercholesterolemic men have been inconsistent. We sought to verify if different frequencies of continuous moderate exercise (2 or 5 days/week, swimming) can, after 8 weeks, promote adaptations in adipocyte area and lipid parameters, as well as body weight and relative weight of tissues in normo and hypercholesterolemic adult male rats.

Methods

Normal cholesterol chow diet or cholesterol-rich diet (1% cholesterol plus 0.25% cholic acid) were freely given during 8 weeks to the rats divided in 6 experimentals groups: sedentary normal cholesterol chow diet (C); sedentary cholesterol-rich diet (H); 5× per week continuous training normal cholesterol chow diet (TC5) and cholesterol-rich diet (TH5); 2× per week continuos traning normal cholesterol chow diet (TC2) and cholesterol-rich diet (TH2).

Results

No changes were observed in lipid profile in normal cholesterol chow diet, but both 2 a 5 days/week exercise improved this profile in cholesterol-rich diet. Body weight gain was lower in exercised rats. Decrease in retroperitoneal and epididymal relative weights as well as reductions in adipocyte areas under all diets types were observed only in 5 days/week, while 2 days/week showed improvements mainly in cholesterol-rich diet rats.

Conclusion

Our results confirm the importance of exercise protocols to control dyslipidemias and obesity in rats. The effects of 5 days/week exercise were more pronounced compared with those of 2 consecutive days/week training.

Isolation and structure analysis of a glucomannan from the seeds of Libyan dates

Polysaccharides extracted from seeds of Libyan dates with hot ethanol 80% (FI) and 0.1 M phosphate solution (FII) were fractionated and purified by ion-exchange and gel-filtration chromatography. According to methylation and hydrolysis analysis, the main chains of FI and FII consisted of (1-->4)-linked glucomannan; only traces of branched sugar residues were detected. This is the first report on the isolation of glucomannan from date seeds.

Alterations in carbohydrate and lipid metabolism induced by a diet rich in coconut oil and cholesterol in a rat model

OBJECTIVE

The type of dietary fat as well as the amount of cholesterol occurring in the diet have been associated with several metabolic disorders. Thus, the aim of the present study was to investigate the influence of a hypercholesterolemic diet enriched with coconut oil and cholesterol on carbohydrate and lipid metabolism in a rat model.

METHODS

Twenty male Wistar rats weighing about 190 g were assigned to two dietary groups. One group received a semipurified control diet and the other was given a diet enriched in coconut oil (25% by weight) and cholesterol (1% by weight) for 26 days.

RESULTS

Our results indicated a significant increase in serum total cholesterol (+285%; p<0.001), low-density lipoproteins (+154%; p<0.01), liver cholesterol (+1509%; p<0.001), as well as a significant increase in liver weight (+46%; p<0.001) in those rats fed the hypercholesterolemia-inducing diet as compared to controls. Moreover, a significant decrease in serum high-density lipoproteins (-67%; p<0.001), triacylglycerols levels (-33%; p<0.05), and abdominal fat weight (-39%; p<0.01) were found. The observed alterations in serum lipid and lipoprotein profile resembled a situation of type IIa hyperlipidemia in humans. Measurement of several enzymes concerned with lipid utilization revealed a significant increase in 3-hydroxy-3-methylglutaryl-CoA reductase activity (+68%; p<0.01) in the liver of animals fed the hypercholesterolemic diet, while a significant reduction in plasma lecithin-cholesterol acyltransferase activity (-66%; p<0.001) was found. The situation of hypoglycemia (-18%; p<0.05) was accompanied by lower levels of serum insulin (-45%; p<0.01) and liver glycogen (-30%; p<0.05) in the hypercholesterolemic rats. Furthermore, glucose utilization was altered since lower glucose-6-Pase (-33%; p<0.05) and increased glucokinase (+212%; p<0.001) activities in the liver were found in the rat model of hypercholesterolemia.

CONCLUSION

These results provide new evidence that a diet-induced hypercholesterolemia in rats is associated with several adaptative changes in carbohydrate metabolism. These findings may be of importance not only considering the role of western diets on cholesterogenesis, but also in other metabolic disturbances involving lipid and carbohydrate metabolism.