3 December 2018

Menisdaurin – deck the halls with boughs of holly

Natural toxin

“Deck the halls with boughs of holly, 'Tis the season to be jolly…” Despite its toxicity, holly has been connected to Christmas time for centuries, is used for decoration and makes a prominent appearance in many popular Christmas songs.

The evergreen tree or shrub Ilex aquifolium (I. aquifolium or common holly) is a species of the family Aquifoliaceae and native in many European countries. As a pioneer species, holly can often be found in margins of forests where it can grow up to several meters high but it is also cultivated as an ornamental plant.

Structure of Menisdaurin 

Several compounds found in berries and leaves of holly are proposed to be toxic, but up to now, the main toxin has not been identified. Menisdaurin ((Z)-1-Cyanomethylen-4R-hydroxy-6S-(beta-D-glucopyranosyloxy)-2-cyclohexen, CAS 67765-58-6) is a non-cyanogenic phytotoxin of the subclass nitriles. On average, holly berries contain up to 0.7%, leaves 0.2% of Menisdaurin with regards to their dry weight. In addition to the nitrile, several triterpenester, triterpensaponines and ilex-lactone can be found in both fruits and leaves. The ingestion of only 2 berries can induce vomiting in kids. Higher doses (20-30 berries) may lead to arrhythmia, drowsiness or inflammations of the gastrointestinal tract that in severe cases could cause death.

SMILES: C1[C@@H](C=C/C(=C/C#N)/[C@@H]1O[C@H]2[C@@H]([C@H]([C@@H]([C@H](O2)CO)O)O)O)O