Suppressive effects of the marine carotenoids, fucoxanthin and fucoxanthinol on triglyceride absorption in lymph duct-cannulated rats.
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.


OBJECTIVE
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.


CONCLUSIONS
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.
Matsumoto
Megumi
M
Creative Research Initiative Sousei (CRIS), Hokkaido University, Kita-21, Nishi-10, Kita-ku, Sapporo, Hokkaido, 001-0021, Japan. matsumeg@cris.hokudai.ac.jp
Hosokawa
Masashi
M
Matsukawa
Noriko
N
Hagio
Masahito
M
Shinoki
Aki
A
Nishimukai
Megumi
M
Miyashita
Kazuo
K
Yajima
Takaji
T
Hara
Hiroshi
H
D000818:Animals; D002338:Carotenoids / Q000378:metabolism / Q000494:pharmacology; D007408:Intestinal Absorption / Q000187:drug effects*; D007601:Jugular Veins; D008049:Lipase / Q000037:antagonists & inhibitors / Q000378:metabolism; D008196:Lymph / Q000378:metabolism*; D008297:Male; D010179:Pancreas / Q000201:enzymology; D011169:Portal Vein; D011897:Random Allocation; D051381:Rats; D017208:Rats, Wistar; D012624:Seaweed / Q000737:chemistry*; D014280:Triglycerides / Q000378:metabolism*; D024341:Xanthophylls / Q000378:metabolism / Q000494:pharmacology*; D019207:beta Carotene / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology
D014280:Triglycerides; D024341:Xanthophylls; D019207:beta Carotene; C025164:fucoxanthin; D002338:Carotenoids; C483031:fucoxanthinol; D008049:Lipase