From akriman@darwin.helios.nd.edu Thu Mar 9 21:10:50 2000 Received: from mxu4.u.washington.edu (mxu4.u.washington.edu [140.142.33.8]) by lists.u.washington.edu (8.9.3+UW99.09/8.9.3+UW99.09) with ESMTP id VAA34142 for ; Thu, 9 Mar 2000 21:10:49 -0800 Received: from darwin.helios.nd.edu (akriman@darwin.helios.nd.edu [129.74.250.114]) by mxu4.u.washington.edu (8.9.3+UW00.02/8.9.3+UW99.09) with ESMTP id VAA27705 for ; Thu, 9 Mar 2000 21:10:48 -0800 Received: (from akriman@localhost) by darwin.helios.nd.edu (8.9.2/8.9.2) id AAA28964 for classics@u.washington.edu; Fri, 10 Mar 2000 00:10:46 -0500 (EST) Date: Fri, 10 Mar 2000 00:10:46 -0500 (EST) From: Alfred M Kriman Message-Id: <200003100510.AAA28964@darwin.helios.nd.edu> To: classics@u.washington.edu Subject: coumarins I wrote: > rat poison is a tasteless seasoning (I think the standard is "arsenic" -- > really arsenic trioxide) added to some bait the rat willingly scarfs down. Peter Green added > Actually a favorite rat poison is coumarin, which innumerable sufferers > from mild strokes or extra-high blood-pressure also scarf down (in diluted > form, be it said) as a reliable blood-thinner. >From what I have been able to learn, this is not completely correct, and there are some likely ways in which some apparent misunderstandings could have arisen. The term _coumarin_ is used loosely for a number of chemicals that were originally extracted from the coumarou tree. At least one of those chemicals is at least slightly toxic, is used in insecticides and might well be used to mask the odor of poison in rat poison. Another, related but quite distinct chemical, also sometimes called coumarin, is an anticoagulant drug. When a plant is injured, it releases a variety of chemicals as a kind of immune response against the insects that may have caused or may take advantage of the plant's injury. One of these chemicals has a pleasant, slightly vanilla-like odor (it's apparently a component in the smell of fresh-cut hay), and for this reason has found commercial applications (US annual production above a million pounds). That is the chemical properly called _coumarin_ (*). Extracted from sweet clover, from tonka bean (the fruit of Dipterix odorata -- modern name of the coumarou tree), from other plants, or synthesized, coumarin is used as a flavor enhancer in food and tobacco, an ingredient in perfumes and soaps, and as an odor-masking agent in paint, insecticides, and even plastics. It is a skin irritant and there are indications that it is carcinogenic; it is suspected to be a cardiovascular and gastrointenstinal or liver toxicant, but the evidence is still inconclusive. It was discovered early in the 19c., so I guess it was grandfathered in at the time of the Food, Drug and Cosmetics Act. It's not currently regulated nationally or, apparently, by any state. What concern there is about it is not that it's very dangerous, but that it's slightly dangerous and very widely used. It's apparently not effective enough against insects to be the principal component of any insecticide. If it is ever used in rat poison, it's probably just to mask the odor of the real poison. The main way coumarin is involved in the decease of rats and mice is that studies to determine carcinogenicity usually involve "sacrificing" the experimental animal to inspect for damage. The name coumarin is also used, reasonably enough, for plant extract that contains coumarin -- i.e., for impure coumarin obtained naturally. By extension, "coumarin" also refers to another chemical (dicoumerol) that was originally extracted from the same mix. It is _dicumerol_ that reduces the action of vitamin-K-related clotting factors. As with almost any drug, overdoses are toxic. (*) Coumarin proper is a double-ring compound with formula C9H6O2. Dicumerol has formula C19H12O6. Structural details can be found under these names in the CRC handbook. .