Ethanolic Extract of Tubtim-Chumphae Rice Bran Decreases Insulin Resistance and Intrahepatic Fat Accumulation in High-Fat-High-Fructose Diet Fed Rats

Abstract

Objective: Tubtim-chumphae rice is hybrid Thai rice with a red pericarp. This study was aimed to investigate the effect of Tubtim-chumphae rice bran on insulin resistance and intrahepatic fat accumulation in high-fat-high-fructose diet (HFFD) fed rats.Methods: Ethanolic extract of rice bran (ERB) was prepared using a 50% ethanol-water. Male Sprague-Dawley rats were fed HFFD (40% lard, 20% fructose) for 10 weeks, followed by concomitant administrations of distilled water or ERB at 250 or 500 mg/kg/day or pioglitazone at 10 mg/kg/day for a further 4 weeks in treated groups. Normal control rats were fed normal chow and distilled water. At the end of all treatments, fasting blood glucose (FBG), an oral glucose tolerance test (OGTT), serum insulin levels, lipid profiles, and liver fat contents were measured. Liver histological and peroxisome proliferator-activated receptor-α (PPAR-α) gene expression examinations were performed.Results: At week 14, control HFFD rats had significantly (p<0.05) higher FBG, low-density lipoprotein cholesterol, triglycerides, and insulin secretions together with impaired OGTT as compared to normal control rats. These parameters indicated an insulin resistant and dyslipidemic condition in HFFD rats. ERB 250 and 500 mg/kg or pioglitazone 10 mg/kg significantly ameliorated all of these changes. HFFD also caused a significant increase in fat accumulation and a decrease in PPAR-α gene expression in the livers which were significantly decreased by ERB.Conclusions: ERB decreases insulin resistance and intrahepatic fat accumulation possibly through increasing PPAR-α gene expression in HFFD rats. ERB might possibly be a neutraceutical for the metabolic syndrome patients.1. Gauthier MS, Favier R, Lavoie JM. Time course of the development of non-alcoholic hepatic steatosis in response to high-fat diet-induced obesity in rats. Br J Nutr 2006;95:273-81.2. Roberts CK, Hevener AL, Barnard RJ. Metabolic syndrome and insulin resistance: Underlying causes and modification by exercise training. Compr Physiol 2013;3:1-58.3. Grundy SM. Metabolic syndrome update. Trends Cardiovasc Med 2016;26:364-73.4. Fouret G, Gaillet S, Lecomte J, Bonafos B, Djohan F, Barea B, et al. 20-week follow-up of hepatic steatosis installation and liver mitochondrial structure and activity and their interrelation in rats fed a high-fat-high-fructose diet. Br J Nutr 2018;119:368-80.5. Dekker MJ, Su Q, Baker C, Rutledge AC, Adeli K. Fructose: A highly lipogenic nutrient implicated in insulin resistance, hepatic steatosis, and the metabolic syndrome. Am J Physiol Endocrinol Metab 2010;299:E685-94.6. Vichit W, Saewan N. Antioxidant activities and cytotoxicity of thai pigmented rice. Int J Pharm Pharm Sci 2015;7:329-34.7. Settharaksa S, Madaka F, Charkree K, Charoenchai L. The study of anti-inflammatory and antioxidant activity in cold press rice bran oil from rice in Thailand. Int J Pharm Pharm Sci 2014;6:428-31.8. Sukrasno S, Tuty S, Fidrianny I. Antioxidant evaluation and phytochemical content of various rice bran extracts of three varieties rice from Semarang, central Java, Indonesia. Asian J Pharm Clin Res 2017;10:377-82.9. Sabir A, Rafi M, Darusman LK. Discrimination of red and white rice bran from indonesia using HPLC fingerprint analysis combined with chemometrics. Food Chem 2017;221:1717-22.10. Niu Y, Gao B, Slavin M, Zhang X, Yang F, Bao J, et al. Phytochemical compositions, and antioxidant and anti-inflammatory properties of twenty-two red rice samples grown in Zhejiang. LWT Food Sci Technol 2013;54:521-7.11. Boonloh K, Kukongviriyapan V, Kongyingyoes B, Kukongviriyapan U, Thawornchinsombut S, Pannangpetch P, et al. Rice bran protein hydrolysates improve insulin resistance and decrease pro-inflammatory cytokine gene expression in rats fed a high carbohydrate-high fat diet. Nutrients 2015;7:6313-29.12. Peñarrieta JM, Alvarado JA, Akesson B, Bergenståhl B. Total antioxidant capacity and content of flavonoids and other phenolic compounds in canihua (Chenopodium pallidicaule): An andean pseudocereal. Mol Nutr Food Res 2008;52:708-17.13. Mungkhunthod S, Senggunprai L, Tangsucharit P, Sripui J, Kukongviriyapan U, Pannangpetch P. Antidesma thwaitesianum pomace extract improves insulin sensitivity via upregulation of PPAR-γ in high fat diet/streptozotocin-induced Type 2 diabetic rats. Asia Pac J Sci Technol 2016;21:63-76.14. Matthews DR, Hosker JP, Rudenski AS, Naylor BA, Treacher DF, Turner RC, et al. Homeostasis model assessment: Insulin resistance and beta-cell function from fasting plasma glucose and insulin concentrations in man. Diabetologia 1985;28:412-9.15. Naowaboot J, Wannasiri S. Anti-lipogenic effect of Senna alata leaf extract in high-fat diet-induced obese mice. Asian Pac J Trop Biomed 2016;6:232-8.16. Couturier K, Qin B, Batandier C, Awada M, Hininger-Favier I, Canini F, et al. Cinnamon increases liver glycogen in an animal model of insulin

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