Daily Intake of Smallanthus sonchifolius (Yacon) Roots Reduces the Progression of Non-alcoholic Fatty Liver in Rats Fed a High Fructose Diet

Effects of yacon on carbohydrates and lipid metabolism, oxidative-nitrative stress markers changes in rats with experimental metabolic syndrome

Background and aim

Smallanthus sonchifolius (Poepp. and Hendl.) H. Robinson, commonly known as yacon, is a medicinal species recognized for its therapeutic properties. The hypoglycemic and hypolipidemic effects of yacon root tubers have been well-documented across various models of metabolic syndrome. However, research on the effects of biologically active compounds derived from yacon leaves remains limited. The aim of the study was to evaluate the hypoglycemic, hypolipidemic and antioxidant effects of an aqueous extract of yacon leaves under the fructose-induced experimental metabolic syndrome.

Experimental procedure

In the study were used male Wistar white rats, in which metabolic syndrome was induced by consuming a 10 % fructose solution. Animals were given an aqueous extract of yacon leaves at a dose of 500 mg per kilogram of body weight for seven and fourteen days following the establishment of metabolic syndrome. Hypoglycemic (glucose and glycosylate hemoglobin concentrations) and hypolipidemic (plasma cholesterol, triglycerides, low-density lipoproteins and high-density lipoproteins levels) effects and antioxidant activity (activity of superoxide dismutase, catalase, glutathione peroxidase, NO-synthase, the content of nitrite anion (NO₂‾) and nitrate anion (NO₃‾), content of carbonyl groups and thiobarbituric acid reactive substances) of extract were then evaluated.

Results

The 14 days use of aqueous extract of yacon for the treatment of fructose-induced metabolic syndrome leads to a decrease of animals' body weight (59.94 %), glucose concentration (10.33 %), glycosylated hemoglobin content (61.58 %), blood plasma triglycerides (50.35 %), cholesterol (24.46 %), low-density lipoproteins (21.56 %), as well as to increase in high-density lipoproteins concentration (29.29 %), paraoxonase activity (56.03 %). In animals with experimental MetS yacon cause oxidative-nitrative stress indicators normalization: increase in SOD (47.85 %) and GPO activity (16.55 %); decrease in TBARS content (23.77 %) and proteins oxidative modification products of neutral character (52.56 %); decrease in NOS activity (12.30 %), which was accompanied by a decrease in nitrate content (10.44 %).

Conclusions

The aqueous extract of yacon demonstrates significant hypoglycemic and hypolipidemic effects in a fructose-induced model of experimental metabolic syndrome, contributing to the normalization of both prooxidant and antioxidant states in rat erythrocytes.

Effects of Smallanthus sonchifolius Flour on Metabolic Parameters: A Systematic Review

Smallanthus sonchifolius, popularly known as yacon, is a member of the Asteraceae family. Due to its medicinal and edible value, yacon is consumed by different populations. Yacon is unique due to its high fructo-oligosaccharide and inulin content, as well as flavonoids, sesquiterpene lactones, and phenolic acids. Roots can be used to produce flour, which is less perishable and can be applied in various industrial products. This systematic review focuses on the effects of yacon flour on metabolic parameters. PubMed, Cochrane, Embase, Science Direct, Scopus, Web of Science, and Google Scholar databases were consulted, and PRISMA guidelines were followed in the selection of the studies. In total, 526 articles were found in the databases, and of these, only 28 full texts were eligible for inclusion. After applying the inclusion and exclusion criteria, seven studies were finally included. The results showed that the use of yacon flour can reduce glycemia, HbA1c, advanced glycation ends, plasma lipids, body fat mass, body weight, and waist circumference and improve intestinal microbiota and the antioxidant status. Further exploration of the effects of yacon flour is warranted, and additional clinical trials are necessary to determine the optimal daily consumption levels required to assist in improving metabolic parameters.

Process and quality parameters of convective dried yacon: Influence of ethanol treatment

Yacon is a highly perishable tuberous root, rich in fructooligosaccharides (FOS). Convective drying preceded by ethanol treatment (ET) is an alternative for increasing shelf life in a shorter process. The aim of this study was to investigate the impact of ET and temperature (50 °C and 70 °C) on quality parameters (fructan retention, total phenolic content, antioxidant capacity, shrinkage, color and microstructural parameters) and process parameters (drying time, drying kinetics, and energy consumption) in the convective drying of yacon slices. The ET induced structural alterations in the tissues and cells that aids in the reduction of drying time up to 28.00 %. ET resulted in an increase in effective diffusivity and leaded to noteworthy reduction in energy consumption (up to 22.72 %). The quality parameters such as color, shrinkage, and total phenolic content showed no significant differences among the treatments. The use of ethanol promoted highest preservation of antioxidant activity; however, it caused degradation of FOS. The ethanol pretreated drying at 50 °C was the better condition for lower consumption and preservation of quality parameters as total phenolic content, antioxidant capacity and fructan retention, but the samples dried at 50 °C were the ones with the highest fructan retention (55.11 ± 2.19 %).

Alterations in Oxidative Stress Markers and Na,K-ATPase Enzyme Properties in Kidney after Fructose Intake and Quercetin Intervention in Rats

The study aimed to characterize the consequences of a 15-week intake of 10% fructose on the kidney, with the focus on oxidative stress markers and properties of the Na,K-ATPase enzyme. Various antioxidants naturally occurring in common food were demonstrated to be protective against fructose-induced deterioration of kidneys. Therefore, we also aimed to observe the effect of 6-week quercetin administration (20 mg/kg/day) that was initiated following the 9-week period of higher fructose intake, by determining the concentration of sodium, potassium, creatinine, urea, and glucose in blood plasma and oxidative status directly in the renal tissue. Kinetic studies of renal Na,K-ATPase were utilized for a deeper insight into the molecular principles of expected changes in this enzyme activity under conditions of presumed fructose-induced renal injury. Fructose intake led to increase in body weight gain, plasma glucose and sodium levels, and deterioration of kidney properties, although some compensatory mechanisms were observable. Quercetin administration improved glycemic control in rats exposed to fructose overload. However, an increase in plasma creatinine, a decrease in GSH/GSSG ratio in renal tissue homogenate, and a controversial effect on renal Na,K-ATPase enzyme suggest that quercetin treatment may not be beneficial in the condition of pre-existing renal pathology.