Discovery and development of direct Xa inhibitors Xa was identified as a promising target for the development of new anticoagulants in the early 1980s. In 1987 the first factor Xa inhibitor, the naturally occurring compound antistasin, was isolated from the salivary glands of the Mexican leech "Haementeria officinalis". Antistasin is a polypeptide and a potent Xa inhibitor. In 1990 another naturally occurring Xa inhibitor was isolated, tick anticoagulant peptide (TAP) from extracts of the tick "Ornithodoros moubata". TAP and antistasin were used to estimate factor Xa as a drug target. Blood coagulation is a complex process by which the blood forms clots. It is an essential part
Anatoxin-a(S) Anatoxin-a(S) Anatoxin-a(S) "Salivary" is a naturally occurring cyanotoxin commonly isolated from cyanobacteria (specifically of the genus "Anabaena") and causes excess salivation in mammals via inhibition of acetylcholinesterase. Anatoxin-a(S) is structurally a cyclic "N"-hydroxyguanine organophosphate with a phosphate ester moiety. The main mechanism of action for anatoxin-a(S) is by irreversibly inhibiting the active site of acetylcholinesterase leading to excess acetylcholine in the parasympathetic and peripheral nervous systems; inducing poisoning via nicotinic and muscarinic cholinergic receptor stimulation. Treatment of afflicted case by atropine has attested to suppress the muscarinic mediated toxicity; which prevents the namesake salivation that similarly reacts to prevent the