Inhibition of acetylcholinesterase by a pseudozoanthoxanthin-like compound isolated from the zoanthid Parazoanthus axinellae (O. Schmidt).
An ethanolic extract from a zoanthid crust coral Parazoanthus axinellae was lethal to mice and crabs and exhibited anticholinesterase activity. The isolation of several AChE inhibitors with the aid of RP-HPLC is described. The most abundant of the inhibitors present in the P. axinellae extract was identified as pseudozoanthoxanthin or an almost identical compound which belongs to the chemically well-characterized series of tetrazacyclopentazulene natural pigments from the genera Parazoanthus, Epizoanthus, Zoanthus and Palythoa. The inhibitor has a mol. wt of 242 and acts as a competitive inhibitor with a Ki of 4 microM. The inhibitor exhibited a strong blue fluorescence. In vivo action of crude extract and the isolated inhibitor showed a typical picture of systemic acetylcholinesterase inhibition. Atropinization of experimental animals prior to injection of the inhibitor almost entirely neutralized its activity.
Turk
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Department of Biology, Biotechnical Faculty, University of Ljubljana, Slovenia.
Macek
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Suput
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D000818:Animals; D001919:Bradycardia / Q000139:chemically induced; D002800:Cholinesterase Inhibitors / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity*; D002851:Chromatography, High Pressure Liquid; D003064:Cnidarian Venoms / Q000302:isolation & purification / Q000633:toxicity; D005260:Female; D007093:Imidazoles / Q000737:chemistry* / Q000302:isolation & purification / Q000633:toxicity*; D008297:Male; D013058:Mass Spectrometry; D051379:Mice; D010243:Paralysis / Q000139:chemically induced; D011817:Rabbits; D013050:Spectrometry, Fluorescence
D002800:Cholinesterase Inhibitors; D003064:Cnidarian Venoms; D007093:Imidazoles; C094407:pseudozoanthoxanthin; C009702:zoanthoxantin