Chemical Analysis of the Essential Oil from Siparuna echinata (Kunth) A. DC. (Siparunaceae) of Ecuador and Isolation of the Rare Terpenoid Sipaucin A

The phytochemical research on the species Siparuna echinata, collected in the Province of Loja (Ecuador), led to the isolation of a rare sesquiterpenoid, called Sipaucin A. The structure was confirmed by nuclear magnetic resonance (NMR) and mass spectrometry (MS). Furthermore, the essential oil of the fruits was obtained by hydrodistillation and analyzed by gas chromatography, coupled to mass spectrometry (GC-MS) and flame ionization detector (GC-FID). Twenty-seven compounds were identified in a polydimethylsiloxane column (DB-5ms) and nineteen in a polyethylene glycol column (HP-INNOWax). Major compounds were α-pinene (24.3%, 20.3%), β-pinene (21.7%, 22.7%), β-myrcene (11.3%, 14.8%), limonene (10.0%, 11.3%), cis-ocimene (8.5%, 8.1%), and trans-ocimene (8.9%, 8.4%). In addition to the chemical analysis, the essential oil was submitted to enantioselective analysis of two major chiral monotherpenes, determining an enantiomeric excess of 100.0% for (+)-α-pinene and 6.7% for (+)-β-pinene.