A Standardized Extract Prepared from Red Orange and Lemon Wastes Blocks High-Fat Diet-Induced Hyperglycemia and Hyperlipidemia in Mice

Abstract

Citrus fruits are a rich source of high-value bioactive compounds and their consumption has been associated with beneficial effects on human health. Red (blood) oranges (Citrus sinensis L. Osbeck) are particularly rich in anthocyanins (95% of which are represented by cyanidin-3-glucoside and cyanidin-3-6″-malonyl-glucoside), flavanones (hesperidin, narirutin, and didymin), and hydroxycinnamic acids (caffeic acid, coumaric acid, sinapic, and ferulic acid). Lemon fruit (Citrus limon) is also rich in flavanones (eriocitrin, hesperidin, and diosmin) and other polyphenols. All of these compounds are believed to play a very important role as dietary antioxidants due to their ability to scavenge free radicals. A standardized powder extract, red orange and lemon extract (RLE), was obtained by properly mixing anthocyanins and other polyphenols recovered from red orange processing waste with eriocitrin and other flavanones recovered from lemon peel by a patented extraction process. RLE was used for in vivo assays aimed at testing a potential beneficial effect on glucose and lipid metabolism. In vivo experiments performed on male CD1 mice fed with a high-fat diet showed that an 8-week treatment with RLE was able to induce a significant reduction in glucose, cholesterol and triglycerides levels in the blood, with positive effects on regulation of hyperglycemia and lipid metabolism, thus suggesting a potential use of this new phytoextract for nutraceutical purposes.

Keywords: citrus fruits; high-fat diet; hyperglycemia; hyperlipidemia; phytoextract.

Figure 1

Eight weeks of RLE diet supplementation reduce glucose blood concentration in HFD-mice. RLE diet supplementation was able to block blood glucose level increase in CD1 mice fed on a high-fat diet (HFD-mice) after eight weeks of treatment. No significant differences were observed after four weeks of treatment with RLE. Data are means ± SEM of 9 to 12 mice per group. Two-way ANOVA followed by Bonferroni post-test. * p < 0.5 vs vehicle HFD-mice basal group; °° p < 0.1 vs vehicle HFD-mice 8 weeks group.

Figure 2

Eight weeks of RLE diet supplementation reduce cholesterol blood concentration in HFD-mice. RLE diet supplementation was able to block blood cholesterol increase in CD1 mice fed on a high-fat diet (HFD-mice) after four and eight weeks of treatment. Data are means ± SEM of 9 to 12 mice per group. Two-way ANOVA followed by Bonferroni post-test. * p < 0.5 vs. vehicle HFD-mice basal group; ° p < 0.5 vs vehicle HFD-mice 8 weeks group.

Figure 3

Eight weeks of RLE diet supplementation reduce triglycerides blood concentration in HFD-mice. RLE diet supplementation was able to block blood triglycerides increase in CD1 mice fed on a high-fat diet (HFD-mice) after four and eight weeks of treatment. Data are means ± SEM of 9 to 12 mice per group. Two-way ANOVA followed by Bonferroni post-test. * p < 0.5; ** p < 0.1 vs vehicle HFD-mice basal group; ° p < 0.5; °° p < 0.5 vs vehicle HFD-mice 8 weeks group.

Figure 4

Effect of RLE diet supplementation on body weight increment in HFD-mice. RLE diet supplementation did not significantly reduce body weight increment in HFD-mice over the eight-week treatment. Data are means ± SEM of 9 to 12 mice per group.