Isopilosine-Synonyms Carpiline; Carpidine; Pilosine-Pilocarpus microphyllus

2.3.3 Isopilosine

Synonyms Carpiline; Carpidine; Pilosine (this compound was originally called pilosine i.e., the cis-isomer of isopilosine.

Biological Source It is obtained from the dried leaflets of Pilocarpus microphyllus (Rutaceae), which has the total alkaloidal content (0.5-1.%) that consists principally pilocarpine along with small portion of isopilosine, pilosine and related structures.

Chemical Structure

[3S-[3α (S*), 4β]]-Dihydro-3-(hydroxyphenylmethyl)-4-[(1-methyl-1H-imidazol-5-yl) methyl]-2 (3H)-furanone. (C₁₆H₁₈N₂O₃).

Isolation It is isolated from the leaves of P. microphyllus Stapf. (Rutaceae) by adopting standard procedures.*

Characteristic Features

1. It is obtained as needles from ethanol mp 182-182.5°C.

2. Its specific rotation [α ]_D²⁰  + 839^o ethanol; uv_max (ethanol) : 210 nm (log € 4.10).

Biosynthesis of Imidazole Alkaloids L-Histidine, an amino acid contains an imidazole ring; and is, therefore, the most probable precursor of alkaloids containing this ring system. The imidazole alkaloids usually found in Jaborandi leaves (P. microphyllus and P. jaborandi; Rutaceae) are most likely derived from histidine; however, sufficient experimental data are lacking. Interestingly, the additional carbon atoms may originate from acetate or supposedly from threonine in the case of pilocarpine, whereas pilosine incorporates a phenylpropane C₆H₃ unit as shown below.
Source:Pharmacognosy And Pharmacobiotechnology By Ashutosh Kar