Retronecine-obtained from the herbs of Heliotropium europaeum L

A. Retronecine 

The most common base portion of the pyrrolizidine alkaloids is retronecine.

The ‘Necine’ bases are 1-methylpyrrolizidines of different stereochemical configurations and degree of hydroxylation which invariably occur as esters in alkaloids of Senecio, Crotalaria and a plethora of genera of the Boraginaceae as stated earlier.

Biological Source It is obtained from the herbs of Heliotropium europaeum L. (Boraginaceae) (Heliotrope, Turnsole).

Chemical Structure

(1R-trans)-2, 3, 5, 7, a-Tetrahydro-1-hydroxy-1 H-pyrrolizine-7-methanol; (C₈H₁₃NO₂).

Characteristic Features

1. It is obtained as crystals from acetone having mp 119-120°C.

2. It has the specific optical rotation [α]_D²⁰  +4.95⁰ (C = 0.58 in ethanol).

Identification Test It gives the racemic mixture i.e., (±) form as crystals from acetone having mp 130-131°C.

Uses

1. The plant is used for cancer and is popularly known as “Herbe Du Cancer” in Europe.

2. It is also used for snakebite and scorpion stings.