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| Names | |
|---|---|
| IUPAC name (3S,9Z)-Heptadeca-1,9-diene-4,6-diyn-3-ol | |
| Other names Carotatoxin, panaxynol | |
| Identifiers | |
3D model (JSmol) | |
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| UNII | |
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| Properties | |
| C17H24O | |
| Molar mass | 244.378 g·mol−1 |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Falcarinol (also known ascarotatoxin orpanaxynol) is a natural pesticide andfatty alcohol found incarrots (Daucus carota),Panaxginseng andivy. In carrots, it occurs in a concentration of approximately 2 mg/kg.[1][2] As atoxin, it protectsroots from fungal diseases, such as liquorice rot that causes black spots on the roots during storage. The compound is sensitive to light and heat.
Falcarinol is apolyyne with two carbon-carbon triple bonds and two double bonds.[3] The double bond at the carbon 9 position hascis stereochemistry was introduced by the desaturation, which requires oxygen and NADPH (or NADH) cofactors and creates a bend in the molecule.It is structurally related tooenanthotoxin andcicutoxin.
Falcarinol is an intense irritant that can causeallergic reactions andcontact dermatitis.[4] It was shown that falcarinol acts as a covalentcannabinoid receptor type 1inverse agonist and blocks the effect ofanandamide inkeratinocytes, leading to pro-allergic effects in human skin.[5] Normal consumption of carrots has no toxic effect in humans.[6]
Starting witholeic acid (1), which possesses a cis double bond at the carbon 9 position from desaturation and a bound of phospholipids (-PL), a bifunctional desaturase/acetylnase system occurred with oxygen (a) to introduce the second cis double bond at the carbon 12 position to formlinoleic acid (2). This step was then repeated to turn the cis double bond at the carbon 12 position into a triple bond (also called acetylenic bond) to formcrepenynic acid (3). Crepenynic acid was reacted with oxygen (b) to form a second cis double bond at the carbon 14 position (conjugated position) leading to the formation ofdehydrocrepenynic acid (4). Allylic isomerization (c) was responsible for the changes from the cis double bond at the carbon 14 position into the triple bond (5) and formation of the more favoredtrans (E) double bond at the carbon 17 position (6). Finally, after forming the intermediate (7) bydecarboxylation (d), falcarinol (8) was produced byhydroxylation (e) at the carbon 16 position that introduced the (R)-configuration to the system.[7]
