A study by Hu et al examined the

A study by Hu et al. [59] examined the effects of combined fucoxanthin and conjugated linoleic niclosamide manufacturer on high-fat diet-induced obesity in rats. The animals were fed a high-fat diet (control), supplemented with two doses of fucoxanthin or low-dose fucoxanthin plus conjugated linoleic acid for 52 days. In comparison to the control group, body weight and white adipose tissue weight were reduced in the combined group, white adipose tissue weight was decreased in the two fucoxanthin groups. Serum total cholesterol level, triacylglycerol and leptin levels were reduced in the fucoxanthin groups. Furthermore, the mRNA expression of adiponectin, adipose triacylglycerol lipase, carnitine palmitoyltransferase 1A was up-regulated in all fucoxanthin groups. These findings indicate that fucoxanthin administered alone or in combination with conjugated linoleic acid decreases serum levels of triacylglycerol and leptin, and fucoxanthin may exert anti-obesity effects by regulating mRNA expression of enzymes related to lipid metabolism in white adipose tissue weight of rats with diet-induced obesity [59]. Wu et al. [60] attempted to elucidate the mechanism of how fucoxanthin reduces adipose accumulation and studied the effects of fucoxanthin on metabolic rate and expressions of genes related to thermogenesis, mitochondria biogenesis and homeostasis. Mice were fed high sucrose or high-fat diets supplemented with or without 0.2% fucoxanthin. Fucoxanthin increased oxygen consumption and carbon dioxide production and reduced white adipose tissue mass. Dietary fucoxanthin enhanced the metabolic rate and lowered adipose mass irrespective of the diet. These effects were associated with upregulated genes of, among others, mitochondrial fusion in inguinal and epididymal white adipose tissue [60]. Ha and Kim [61] investigated the effects of fucoxanthin on gene expressions related to lipid metabolism in rats on a high-fat diet. The findings of this study indicate that fucoxanthin consumption decreases lipid accumulation in the liver of rats fed a high fat diet. A fucoxanthin-enriched diet also suppressed mRNA expression of transcription factors and enzymes involved in hepatic lipogenesis. In addition, fucoxanthin consumption increased expression of enzymes that stimulate fatty acid oxidation and decreased expression of cholesterol synthesizing enzyme [61]. Fucoxanthin appears therefore to be effective in improving lipid metabolism in rats with a high fat diet. The peptidyl prolyl cis/trans isomerase Pin1 has been shown to increase the uptake of triglycerides and the differentiation of fibroblasts into adipose cells in response to insulin stimulation. A down-regulation of Pin1 may therefore be a novel approach to prevent and treat obesity-related disorders [62]. The Pin1 inhibitor 974-B, a phlorotannin isolated from the seaweed Ecklonia kurome, was able to inhibit the differentiation of mouse embryonic fibroblasts into adipose cells, suggesting that this compound could be a potential drug for obesity-related disorders [62]. The promising findings of animal experiments need to be confirmed in humans. Abidov et al. [63] have assessed the effectiveness of dietary fucoxanthin supplementation for weight loss in humans. These authors investigated the effects of xanthigen (brown marine algae fucoxanthin plus pomegranate seed oil) on body weight, body fat, liver lipids, and blood biochemistry in the weight management of 151 non-diabetic, obese premenopausal women (113 with non-alcoholic fatty liver disease and 38 with normal liver fat) in a 16-week, double-blind, randomized, placebo-controlled study. The administration of xanthigen-600/2.4mg (300mg pomegranate seed oil+300mg brown seaweed extract containing 2.4mg fucoxanthin) resulted in a statistically significant reduction of body weight, waist circumference, body and liver fat content, liver enzymes, serum triglycerides and C-reactive protein. Fucoxanthin (>2.4mg) and xanthigen-400/1.6mg (200mg pomegranate seed oil+200mg brown seaweed extract containing 1.6mg fucoxanthin) significantly increased resting energy expenditure in participants with non-alcoholic fatty liver disease compared to placebo [63]. The decrease in body weight following the administration of xanthigen may be caused by the stimulation of resting energy expenditure and by anti-inflammatory and metabolism normalizing mechanisms.