L-Fucose Suppresses Lipid Accumulation via the AMPK Pathway in 3T3-L1 Adipocytes.

L-fucose (Fuc), a monosaccharide with different biological functions in various organisms, exhibits potent anti-obesity effects in obese mice. However, the mechanisms underlying its anti-obesity effects remain largely unknown. In this study, we aimed to investigate the effects of Fuc on lipid metabolism and insulin signaling in 3T3-L1 adipocytes. We found that Fuc treatment suppressed lipid accumulation during adipocyte differentiation. Additionally, Fuc treatment enhanced the phosphorylation of AMP-activated kinase (AMPK) and its downstream pathways, responsible for the regulation of fatty acid oxidation and lipolysis. Furthermore, Fuc-induced activation of the AMPK pathway was diminished by the AMPK inhibitor Compound C, and Fuc treatment considerably promoted glucose uptake via Akt activation in an insulin-resistant state. These findings provide a basis for elucidating the mechanism underlying the anti-obesity effect of Fuc, which may, in the future, be considered as a therapeutic compound for treating obesity and related diseases.

The Effects of Brown Algae-Derived Monosaccharide L-Fucose on Lipid Metabolism in C57BL/6J Obese Mice.

Obesity is a global public health problem and a risk factor for several metabolic disorders as well as cancer. In this study, we investigated the effects of L-fucose on lipid metabolism through chronic and acute in vivo experiments in mice. In the chronic test, mice were fed a high-calorie diet (HCD) containing 0.0001%, 0.001%, 0.01%, and 0.1% L-fucose for one month. The L-fucose supplementation inhibited body weight and visceral fat mass gain in HCD-fed mice. The results of the acute test showed that L-fucose increased the ratio of serum high molecular weight adiponectin and enhanced glucose and lipid catabolism. Furthermore, L-fucose also decreased the expression of adipogenic genes (peroxisome proliferator-activated receptor γ and cluster of differentiation 36). In conclusion, this study provides a new approach to combat obesity and the related diseases.

Effect of oral theaflavin administration on body weight, fat, and muscle in healthy subjects: a randomized pilot study.

Theaflavins are reddish-colored polyphenols in black tea. To test the efficacy of theaflavin administration on body fat and muscle, we performed a randomized, double-blind, placebo-controlled study and investigated the effect of theaflavins administration on the body composition using of healthy subjects. In this study, 30 male and female Japanese were enrolled and participants were randomly allocated to receive placebo, theaflavin (50 or 100 mg/day), or catechin (400 mg/ml) for 10 weeks. The effects were evaluated using body weight, body fat percentage, subcutaneous fat percentage, and skeletal muscle percentage. Theaflavin administration significantly improved body fat percentage, subcutaneous fat percentage, and skeletal muscle percentage when compared to with the placebo. In contrast, there was no significant difference in all measured outcomes between the catechin and the placebo groups. The results indicate that oral administration of theaflavin had a beneficial effect on body fat and muscle in healthy individuals.

Alkyldihydropyrones, new polyketides synthesized by a type III polyketide synthase from Streptomyces reveromyceticus.

Genome sequencing allows a rapid and efficient identification of novel catalysts that produce novel secondary metabolites. Here we describe the catalytic properties of dihydropyrone synthase A (DpyA), a novel type III polyketide synthase encoded in a linear plasmid of Streptomyces reveromyceticus. Heterologous expression of dpyA led to the accumulation of alkyldihydropyrones A (1), B (2), C (3) and D (4), which are novel dihydropyran compounds that exhibit weak cytotoxicity against the leukemia cell line HL-60. DpyA catalyzes the condensation of ß-hydroxyl acid thioester and methylmalonyl-CoA to yield a triketide intermediate that then undergoes lactonization of a secondary alcohol and a thioester to give alkyldihydropyrone.