Blackberry (Rubus sp. var. Loch Ness) Extract Reduces Obesity Induced by a Cafeteria Diet and Affects the Lipophilic Metabolomic Profile in Rats

Abstract

Blackberries (Rubus sp. var. Loch Ness) contain large amounts of anthocyanins and flavonols, which have several health benefits. The present study was designed to determine the effects of a methanolic blackberry extract in rats fed a cafeteria diet. Weaned female rats were assigned to one of three dietary groups: standard pellet diet (SD), cafeteria diet (CD) and cafeteria diet supplemented with Rubus extract (CRD) for 90 days. Plasma metabolites and insulin were analyzed with commercial kits and fatty acid profile was measured by gas chromatography whereas other aliquots were subjected to metabolomics fingerprinting analysis using ultra high efficiency liquid chromatography. Lipoprotein lipase (LPL) activity was determined in fat depots by a radiochemical method. In comparison to the SD group, rats of the CD and CRD groups had increased plasma myristic, palmitic and oleic acids and those of the CD group had increased liver and different adipose tissue weights; the area under the curve of glucose and insulin after oral glucose load and inguinal adipose tissue LPL activity were also increased. Any of these variables were lower in rats of the CRD group, which also showed increased plasma triacylglycerols. However, both the CD and CRD decreased the insulin sensitivity index (ISI). The metabolomic variables showed that most of the acyl-carnitines were up-regulated whereas most of the phosphatidylcholines and lysophosphatidylcholines were down-regulated when comparing rats of the CD group versus those of SD, while when comparing CRD versus CD, oleic acid and lysophosphatidylethanolamines as well as phosphatidylserine and lysophosphatidylserine were up-regulated. In conclusion, besides evidencing the obesogenic and metabolic effects of a cafeteria diet in female rats, results show that such effects are reduced when the same diet is supplemented with this Rubus extract, although it did not modify the decreased ISI values.