733Cinc. Tecnol. Aliment., Campinas, 32(4): 733-741, out.-dez. 2012
Cincia e Tecnologia de Alimentos ISSN 0101-2061
Received 9/5/2011Accepted 27/6/2012 (005283)1 Department of Biochemistry and Immunology, Institute of Biological Science, Universidade Federal de Minas Gerais UFMG, Av. Antonio Carlos, 6627, CEP 30161-970,
Pampulha, Belo Horizonte, MG, Brazil, e-mail: [email protected] Faculty of Pharmacy, Universidade Federal de Minas Gerais UFMG, Av. Antonio Carlos, 6627, Belo Horizonte, MG, Brazil*Corresponding author
White tea (Camellia sinensis) extract reduces oxidative stress and triacylglycerols in obese miceExtrato de ch branco reduz extresse oxidativo e triacilglicerois em camundongos obesos
Llian Gonalves TEIXEIRA1*, Priscilla Ceci LAGES1, Tatianna Lemos JASCOLKA2, Edenil Costa AGUILAR1, Fabola Lacerda Pires SOARES2, Solange Silveira PEREIRA2, Nathalia Ribeiro Mota BELTRO1, Rafael de Oliveira MATOSO1, Andr Mrcio do NASCIMENTO2, Rachel Oliveira de CASTILHO2, Jacqueline Isaura Alvarez LEITE1
1 IntroductionObesity is a disease involving genetic, endocrine, and
behavioral factors, which include a diet rich in carbohydrate and fat and sedentary lifestyle. Obesity is also associated with increased oxidative stress (FURUKAWAetal., 2004). It has been proposed that hyperglycemia, mitochondrial dysfunction, and enzymatic imbalance of redox system are involved in the cellular production of reactive oxygen species (ROS) in obesity (PARK; CHUNG; KIM, 2007). This disease also induces secretion of pro-inflammatory adipokines, such as leptin, resistin, TNF, IL-6,
MCP-1, and decreases adiponectin secretion. This feature leads to increased pro-inflammatory genes transcription, activates NADPH oxidase dependent reactions, causes oxidation of lipoproteins, enhances insulin resistance, which culminates in atherosclerosis, type 2 diabetes mellitus, and metabolic syndrome. (FURUKAWAetal., 2004).
White tea is an unfermented tea made from young shoot of Camellia sinensis protected from sunlight to avoid the degradation of its polyphenols (ALCAZARetal., 2007). Similarly to green
ResumoO ch branco um ch no fermentando feito a partir de brotos jovens da Camellia sinensis protegidos da luz solar para evitar a degradao de polifenis. Embora os nveis de catequinas sejam mais elevados que os do ch verde (mesma planta), nenhum estudo foi realizado sobre estresse oxidativo relacionado obesidade. Nosso objetivo foi avaliar o efeito do ch verde na obesidade e suas complicaes, usando um modelo de obesidade induzida por dieta. Quarenta camundongos C57BL/6 machos foram alimentados com dieta hiperlipdica para induo da obesidade ou mesma dieta suplementada com 0,5% de extrato de ch branco durante 8 semanas. Foram estudadoso tecido adiposo bem como o perfil lipdico e o estresse oxidativo. A suplementao com ch branco no foi capaz de reduzir a ingesto alimentar, peso corporal ou adiposidade visceral. De forma similar, no foram encontradas diferenas no perfil de lipoprotenas ricas em colesterol. Uma reduo de triacilgliceris sanguneos, associada ao aumento de lipdios cecais, foi observada no grupo suplementado com ch branco. A suplementao tambm reduziu o estresse oxidativo no fgado e tecido adiposo. Em concluso, suplementao com extrato de ch branco (0,5%) no interfere no peso corporal ou adiposidade em camundongos obesos. Seus benefcios so restritos reduo do estresse oxidativo associada obesidade e melhora da hipertrigliceridemia.Palavras-chave: dieta hiperlipdica; obesidade; estresse oxidativo; ch branco; Camellia sinensis.
AbstractWhite tea is an unfermented tea made from young shoots of Camellia sinensis protected from sunlight to avoid polyphenol degradation. Although its levels of catechins are higher than those of green tea (derived from the same plant), there are no studies addressing the relationship between this tea and obesity associated with oxidative stress.The objective of this study was to evaluate the effect of white tea on obesity and its complications using a diet induced obesity model. Forty male C57BL/6 mice were fed a high-fat diet to induce obesity (Obese group) or the same diet supplemented with 0.5% white tea extract (Obese + WTE) for 8 weeks. Adipose tissue, serum lipid profile, and oxidative stress were studied. White tea supplementation was not able to reduce food intake, body weight, or visceral adiposity. Similarly, there were no changes in cholesterol rich lipoprotein profile between the groups. A reduction in blood triacylglycerols associated with increased cecal lipids was observed in the group fed the diet supplemented with white tea. White tea supplementation also reduced oxidative stress in liver and adipose tissue. In conclusion, white tea extract supplementation (0.5%) does not influence body weight or adiposity in obese mice. Its benefits are restricted to the reduction in oxidative stress associated with obesity and improvement of hypertriacylglycerolemia.Keywords: high-fat diet; obesity; oxidative stress; white tea; Camellia sinensis.
Cinc. Tecnol. Aliment., Campinas, 32(4): 733-741, out.-dez. 2012734
White tea effect in obese mice
(HPLC grade, catechin (C), gallocatechin (GC), epigallocatechin (EGC), and epigallocatechin gallate (EGCG)) were accurately weighed in 5 mL volumetric flasks. The standards were dissolved in methanol (3mL) and the volume was adjusted to 5mL with the same solvent. These standard solutions were stored at 3 to 5 C (NASCIMENTO; CASTILHO; VIANNA-SOARES, 2009).
Animals and diet: Male C57BL/6 mice were kept in collective cages (five animals per cage) with free access to diet and water with a controlled dark/dark cycle in a temperature controlled room. The project was approved by the Ethics Committee of Animal Experiments of Federal University of Minas Gerais (protocol 116/2009). The diet induced obesity model had been previously confirmed by a pilot experiment in which animals were fed chow or high-fat diet, as suggested by Akagiri (AKAGIRIetal., 2008).
The animals were allocated into Obese group (n = 20), receiving high-fat diet and white tea obese group (Obese + WTE; n = 20), receiving the same high-fat diet supplemented with 0.5% of WTE for 8 weeks. Body weight and food and water intake were determined weekly. After 8 experimental weeks and fasting for 12 hours, all animals were anesthetized and euthanized by exsangination and cervical dislocation.
Perigonadal adipose tissue analysis. Perigonadal adipose tissue was removed, dried in filter paper, weighed, and used for the determination of visceral adiposity, which was calculated as follows: perigonadal adipose tissue (g)/final body weight (g) 100.
For histological analysis, a sample of perigonadal adipose tissue was washed in PBS, fixed in Bouins solution and ethanol, and included in paraffin. Samples of 7 m-thick were obtained in microtome, stained with hematoxylin-eosin, and analyzed using an ImageProPlus software (Image-Pro Plus Software, Bethesda Maryland-USA). The area of adipocytes of each animal was determined by the mean of 100 adipocyte areas.
The sections of adipose tissue were also used for the counting of crown-like structures. The result was expressed as the mean of structures seen in 10 fields per mouse. Macrophage infiltration in adipose tissue was measured indirectly by measuring the activity of the enzyme N-acetyl-glucosaminidase (NAG), as previously described (BAILEY, 1988).
Blood measurements: Samples of blood were collected during the sacrifice without anticoagulant for lipid profile determination or using glucose determination specific anticoagulant (EDTA, 6 g.L1 and potassium fluoride, 12 g.L1, Glistab, Labtest). After that, serum and plasma were obtained after centrifugation at 6.000 rpm for 5 minutes. Total cholesterol, HDL cholesterol (HDL-c), and triacylglycerols as well as plasma glucose concentration were determined by enzymatic colorimetric tests (Labtest, Brazil) in a 96-well microplate, as previously described (FAZIO et al., 1997). The non-HDL cholesterol fraction was calculated by the difference between total cholesterol and HDL-c. The oral glucose tolerance and insulin sensitivity tests were performed as previously described (SANTOSetal., 2008).
tea, white tea has been used to reduce oxidative stress and to treat obesity and associated diseases. However, most studies using white tea investigated its composition (ALCAZARetal., 2007; MALINOWSKAetal., 2008; UNACHUKWUetal., 2010; VAN DER HOOFT et al., 2012), its antitumorigenic effect (ANGER; PETRE; CRANKSHAW, 2005; KUMARetal., 2012; WANGetal., 2008), or its antioxidant action (ALMAJANO; VILA; GINES, 2011; CALZUOLA; GIANFRANCESCHI; MARSILI, 2006; KOUTELIDAKISetal., 2009; LOPEZ; CALVO, 2011; PEREZ-JIMENEZ et al., 2011; 2012; SEERAM et al., 2008; THRING; HILI; NAUGHTON, 2009, 2011). Nonetheless, despite its popular use, there are no in vivo studies relating white tea and obesity associated with oxidative stress. Thus, the effect of the white tea extract (WTE) supplementation on the development of obesity was evaluated using a high-fat diet induced obesity model.
2 Materials and methodsPreparation of the white tea extract: white tea extract was
prepared by Nanjing Wellchem Enterprise Co. LTDA as follows: the sprouts of the Camellia sinensis leaves were dried under room temperature (25-35 C) by natural ventilation and processed to obtain flakes of 40-60 mesh. The flakes were mixed in water, and the extract filtered and submitted to Vacuum Decompression Concentration. After filtration, the extract was mixed with ethyl acetate and washed with water. The ethyl acetate extract was recovered and again submitted to vacuum concentration following by sterilization at high temperatures. Finally, the ex