Background: Fucoxanthin isolated from edible seaweeds and its metabolite fucoxanthinol have been recently found to have anti-obesity effects, but the mechanism is not fully understood.
Aim of study: We investigated the effects of these carotenoids on the absorption of triglycerides in conscious rats implanted with cannulae into a lymph duct and the portal or jugular vein.
Methods: A duodenal infusion of 1 ml of test oil emulsion with or without 2 mg of fucoxanthin or fucoxanthinol was administered in the lymph duct and the portal (Experiment 1) or the jugular vein (Experiment 2) cannulated rats. The test oil contained 10% soybean oil (Experiment 1) and pre-digested 10% soybean oil (Experiment 2). The inhibitory activities of these carotenoids on pancreatic lipase activity were measured in vitro.
Results: Increases in lymphatic and blood triglyceride levels were much lower in the two carotenoid-treated groups than in the carotenoid-free group, indicating that these carotenoids inhibit triglyceride absorption. The total amounts of triglycerides released into the lymph after 4 h in the carotenoid-free, fucoxanthin and fucoxanthinol groups were 113.5, 59.4 and 53.1 micromol, respectively. The inhibitory effects of carotenoids were completely abolished after an infusion of pre-digested soybean oil containing carotenoids. Furthermore, these carotenoids inhibited pancreatic lipase activity in vitro. Regarding absorptive route, we found that fucoxanthinol, but not fucoxanthin, appeared in lymph fluid, whereas neither carotenoid was detected in portal blood.
Conclusion: These results show that these two marine carotenoids inhibit lipase activity in the gastrointestinal lumen and suppress triglyceride absorption, and fucoxanthin was converted to fucoxanthinol in the intestine and released into the lymph.
Suppressive effects of the marine carotenoids, fucoxanthin and fucoxanthinol on triglyceride absorption in lymph duct-cannulated rats, Megumi Matsumoto, Masashi Hosokawa, Noriko Matsukawa, Masahito Hagio, Aki Shinoki, Eur J Nutr . 2010 Jun

Les effets antiobésité de la fucoxanthine ont récemment été démontrés, sans preciser les mécanismes. Les auteurs de cette étude ont mis en évidence que ces effets sont liés à une réduction de l'absorption des triglycérides. L'inhibition de la lipase intestinale, responsable de la formation des triglycérides à partir des lipides alimentaires, est le mécanisme essentiel de cet effet. L'absorption des triglycérides a été réduite de 50 % par 2 mg de fucoxanthine. Son efficacité est donc supérieure à celle de la catéchine de thé, autre molécule d'origine naturelle, mais reste inférieure à celle des actifs pharmaceutiques. Ce point est un avantage, car il permet d'éviter les effets secondaires signalés avec ces actifs. Article en français.
Reduction de l'absorption des triglycérides par la fucoxanthine (CEVA), ALGUES/O5-2011, issu de "Suppressive effects of the marine carotenoids,fucoxanthin and fucoxanthinol on triglyceride absorption in lymph duct-cannulated rats." par Ma Tsumoto M., Hosokawa M., Matsukawa N. (2010). Eur. J. Nutr., 49, (4),243-249.

Abstract :The marine carotenoid fucoxanthin can be found in marine brown seaweeds, the macroalgae, and diatoms, the microalgae, and has remarkable biological properties.
Numerous studies have shown that fucoxanthin has considerable potential and promising applications in human health. In this article, we review the current available scientific literature regarding the metabolism, safety, and bioactivities of fucoxanthin, including its antioxidant, anti-inflammatory, anticancer, anti-obese, antidiabetic, antiangiogenic and antimalarial activities, and its protective effects on the liver, blood vessels of the brain, bones, skin, and eyes. Although some studies have shown the bioavailability of fucoxanthin in brown seaweeds to be low in humans, many studies have suggested that a dietary combination of fucoxanthin and edible oil or lipid could increase the absorption rate of fucoxanthin, and thus it might be a promising marine drug.
Keyword : fucoxanthin; metabolite; bioactivity; brown seaweed; diatom
Fucoxanthin, a Marine Carotenoid Present in Brown Seaweeds and Diatoms: Metabolism and Bioactivities Relevant to Human Health Juan Peng, Jian-Ping Yuan, Chou-Fei Wu and Jiang-Hai Wang - Mar. Drugs 2011, 9, 1806-1828