Potent inhibition of fatty acid synthase by parasitic loranthus [Taxillus chinensis (dc.) danser] and its constituent avicularin.
The medicinal herb parasitic loranthus in a screen was found to inhibit fatty acid synthase (EC 2.3.1.85, FAS) and reduce body weight of rats in our previous study. Now we have determined the inhibitory characteristics and kinetic parameters of extracts of parasitic loranthus [Taxillus chinensis (DC.) Danser]. The parasitic loranthus extracts (PLE) inhibits FAS reversibly and irreversibly and with an IC50 value of 0.48 microg/ml, appears to be the most potent inhibitor reported to date. PLE contains various potent inhibitors and may react with different sites on FAS. The irreversible inhibition exhibits a time-dependent biphasic process including a speedy fast-phase during the initial several minutes. The fast-phase inhibition seems to be caused by some potent but low-concentration component(s) in the extracts. In addition, we have found that avicularin existing in this herb can potently inhibit FAS. This glycosylated flavonoid and quercetin play an effective role in inhibiting FAS by parasitic loranthus.
Department of Biology, Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
Yan
Y
Wang
Shu-Yan
SY
Zhang
Xiao-Feng
XF
Ma
Wei-Xi
WX
Tian
D000818:Animals; D004365:Drugs, Chinese Herbal / Q000494:pharmacology*; D004372:Ducks; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D064429:Fatty Acid Synthases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D005419:Flavonoids / Q000494:pharmacology*; D006031:Glycosylation; D020128:Inhibitory Concentration 50; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D028183:Loranthaceae / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D011794:Quercetin / Q000494:pharmacology
D004365:Drugs, Chinese Herbal; D004791:Enzyme Inhibitors; D005419:Flavonoids; D010936:Plant Extracts; C041388:avicularin; D011794:Quercetin; D064429:Fatty Acid Synthases