Comparative analysis of the aroma chemicals of Melissa officinalis using hydrodistillation and HS-SPME techniques

Abstract

Headspace solid-phase micro extraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC–MS) has been used for the chemical analysis of Melissa officinalis (leaves) cultivated in Institute Germplasm. The HS-SPME analysis led to the identification of 22 components constituting 99.1% of the total volatile constituents present in the leaves whereas its hydrodistillate led to the identification of 24 volatile constituents constituting 98.1% of the volatile material. The chemical composition of the SPME and hydrodistilled extract of M. officinalis leaves comprised mainly of oxygenated monoterpenes (78.5% and 57.8% respectively) and sesquiterpene hydrocarbons (14.9% and 29.7% respectively). The major components identified in the HS-SPME extract were citronellal (31.1%), citronellol (18.3%), β-caryophyllene (12.0%), (E)-citral (11.9%), (Z)-citral (9.6%), geraniol (3.6%), (Z)-β-ocimene (3.1%) and 1-octen-3-ol (2.0%) whereas hydrodistilled essential oil was rich in (Z)-citral (19.6%), β-caryophyllene (13.2%), (E)-citral (11.2%), citronellal (10.2%), germacrene-d (8.3%), δ-3-carene (5.0%), 6-methyl-5-hepten-2-one (3.7%) and citronellyl acetate (3.7%). The comparative analysis of volatile constituents of M. officinalis leaf extract using HS-SPME and hydrodistillation techniques shows both qualitative as well as quantitative differences. The current study is the first report involving rapid analysis of volatile components of M. officinalis by HS-SPME.