RESUMO
Obesity and its comorbidities are a severe public health problem worldwide. The use of bioactive compounds found in some foods has been demonstrated to ameliorate the metabolic abnormalities associated with obesity. The purpose of this study was to assess whether the bioactive compounds present in aguamiel concentrate (AC) from Agave salmiana could attenuate glucose intolerance and hepatic steatosis in mice fed a high fat (HF) diet. HPLC-ELSD analysis showed that AC contained several saponins. The consumption of an AC extract rich in saponins reduced weight gain and fat mass and lowered serum glucose, insulin and LDL-cholesterol levels in mice fed a HF diet. Additionally, mice fed the saponin extract exhibited a reduced HOMA index and hepatic lipid levels and increased expression of genes involved in fatty acid oxidation. Saponins increased white adipose tissue browning, AMPK phosphorylation, fatty acid oxidation, and mitochondrial activity in skeletal muscle and energy expenditure in mice fed the HF diet. These metabolic changes were accompanied by an increase in the abundance of Akkermansia muciniphila in the gut microbiota. Therefore, Agave salmiana saponins can be an alternative to attenuate the metabolic changes that accompany obesity.
RESUMO
Nopal is a plant used in traditional Mexican medicine to treat diabetes. However, there is insufficient scientific evidence to demonstrate whether nopal can regulate postprandial glucose. The purpose for conducting this study was to evaluate the glycemic index, insulinemic index, glucose-dependent insulinotropic peptide (GIP) index, and the glucagon-like peptide 1 (GLP-1) index, and the effect of nopal on patients with type 2 diabetes after consumption of a high-carbohydrate breakfast (HCB) or high-soy-protein breakfast (HSPB) on the postprandial response of glucose, insulin, GIP, GLP-1, and antioxidant activity. In study 1, the glycemic index, insulinemic index, GIP index, and GLP-1 index were calculated for seven healthy participants who consumed 50 g of available carbohydrates from glucose or dehydrated nopal. In study 2, 14 patients with type 2 diabetes consumed nopal in HCB or HSPB with or without 300 g steamed nopal. The glycemic index of nopal was 32.5±4, insulinemic index was 36.1±6, GIP index was 6.5±3.0, and GLP-1 index was 25.9±18. For those patients with type 2 diabetes who consumed the HCB+nopal, there was significantly lower area under the curve for glucose (287±30) than for those who consumed the HCB only (443±49), and lower incremental area under the curve for insulin (5,952±833 vs 7,313±1,090), and those patients with type 2 diabetes who consumed the HSPB avoided postprandial blood glucose peaks. Consumption of the HSPB+nopal significantly reduced the postprandial peaks of GIP concentration at 30 and 45 minutes and increased the antioxidant activity after 2 hours measured by the 2,2-diphenyl-1-picrilhidracyl method. These findings suggest that nopal could reduce postprandial blood glucose, serum insulin, and plasma GIP peaks, as well as increase antioxidant activity in healthy people and patients with type 2 diabetes.
Assuntos
Antioxidantes/análise , Desjejum , Diabetes Mellitus Tipo 2/dietoterapia , Polipeptídeo Inibidor Gástrico/sangue , Hiperglicemia/prevenção & controle , Hiperinsulinismo/prevenção & controle , Opuntia , Adulto , Diabetes Mellitus Tipo 2/sangue , Feminino , Alimentos em Conserva/análise , Alimento Funcional/análise , Índice Glicêmico , Humanos , Incretinas/sangue , Masculino , Medicina Tradicional , México , Pessoa de Meia-Idade , Opuntia/química , Componentes Aéreos da Planta/química , Proteínas de Vegetais Comestíveis/uso terapêutico , Período Pós-Prandial , Proteínas de Soja/uso terapêuticoRESUMO
Nonalcoholic fatty liver disease (NAFLD) is associated with multiple factors such as obesity, insulin resistance, and oxidative stress. Nopal, a cactus plant widely consumed in the Mexican diet, is considered a functional food because of its antioxidant activity and ability to improve biomarkers of metabolic syndrome. The aim of this study was to assess the effect of nopal consumption on the development of hepatic steatosis and hepatic oxidative stress and on the regulation of genes involved in hepatic lipid metabolism. Obese Zucker (fa/fa) rats were fed a control diet or a diet containing 4% nopal for 7 wk. Rats fed the nopal-containing diet had â¼50% lower hepatic TG than the control group as well as a reduction in hepatomegaly and biomarkers of hepatocyte injury such as alanine and aspartate aminotransferases. Attenuation of hepatic steatosis by nopal consumption was accompanied by a higher serum concentration of adiponectin and a greater abundance of mRNA for genes involved in lipid oxidation and lipid export and production of carnitine palmitoyltransferase-1 and microsomal TG transfer proteins in liver. Hepatic reactive oxygen species and lipid peroxidation biomarkers were significantly lower in rats fed nopal compared with the control rats. Furthermore, rats fed the nopal diet had a lower postprandial serum insulin concentration and a greater liver phosphorylated protein kinase B (pAKT):AKT ratio in the postprandial state. This study suggests that nopal consumption attenuates hepatic steatosis by increasing fatty acid oxidation and VLDL synthesis, decreasing oxidative stress, and improving liver insulin signaling in obese Zucker (fa/fa) rats.