Coumarins.

To: herblist <HERB.EGE.EDU.TR
Date: Wed, 17 Aug 1994 06:20:33 EDT
From: Mahmut Miski <miski.KODAK.COM>
Subject: Re: Re[4]: giant fennel

>> some other varieties don't have high level of coumarins and are not toxic.
>What are coumarins? I've never heard of this.

Coumarins are unsaturated aromatic lactones and many of them have medicinal properties. Since they act as vitamin K antagonist, they tend to prevent blood clotting (which prolongs bleeding time). Certain type of coumarins, especially 4-hydroxycoumarins (like warfarin), are used as medicines in strictly controlled dosage forms. If it is taken relatively larger quantities they cause internal bleeding. There are some cattle poisoning cases reported in Italy from Ferula species due to the internal bleeding caused by 4-hydroxycoumarins, this poisoning also known as ferulosis.

>> some claims about the presence of furanocoumarins in Ferula species (so far I wasn't able to substantiate that claim) and these compounds are known as photosensitizers. If you handle them with bare hand you may have unpleasant experiences afterwards.
>What are furanocoumarins? Do these "problems" exist in certain plant families? Or is it just species problem?

Furanocoumarins are coumarins that has an additional furan ring system attached to the phenyl ring system of coumarins in linear fashion. These compounds can increase skin sensitivity. After ingesting these compounds and exposing skin to the sunlight, one can get skin ulcerations in fairly short time. Ironically, the same compounds are used (in controlled fashion) to cure variety of illnesses such as a type of deadly skin cancer and vitiligo.

Coumarins are practically found in almost every plant family, plants use them as growth inhibitors (anti-auxins) as well as defense compounds. However, in the plants of certain families such as Leguminoseae (bean family), Rutaceae (citrus family) and Umbelliferae (a.k.a. Apiaceae) (parsley-fennel family) coumarins exist in larger quantities.