Volatile Components Emitted from the Liverwort Marchantia paleacea subsp. diptera

Area of Science:

• Plant biochemistry
• Natural product chemistry
• Phytochemistry

Background:

• Liverworts are bryophytes known for producing diverse secondary metabolites.
• The volatile organic compounds (VOCs) of Marchantia species are not extensively characterized.
• Understanding liverwort VOCs can reveal novel biosynthetic pathways and potential applications.

Purpose of the Study:

• To investigate the volatile chemical constituents of the thalloid liverwort Marchantia paleacea subsp. diptera.
• To identify the major volatile compounds and determine their stereochemistry.
• To report the presence of perillaldehyde in liverworts for the first time.

Main Methods:

• Headspace solid-phase microextraction (HS-SPME) coupled with Gas Chromatography-Mass Spectrometry (GC-MS) for volatile profiling.
• Multi-dimensional Gas Chromatography-Mass Spectrometry (MD GC-MS) with a chiral column for enantiomeric separation and determination.
• Chiral analysis to ascertain the stereochemistry of key compounds.

Main Results:

• Perillaldehyde was identified as the major volatile component, constituting approximately 50% of the total volatiles.
• Minor volatile components included β-pinene, limonene, β-caryophyllene, α-selinene, and β-selinene.
• Both perillaldehyde and limonene were found to be predominantly the (S)-(-)-enantiomers (over 99.0%), with trace amounts of (R)-enantiomers (less than 0.5%).

Conclusions:

• This study reports perillaldehyde as a major volatile constituent of Marchantia paleacea subsp. diptera, marking its first discovery in liverworts.
• The stereochemical analysis revealed a strong enantiomeric preference for the (S)-(-)-form of perillaldehyde and its precursor, limonene.
• The findings contribute to the understanding of monoterpene biosynthesis and distribution in the plant kingdom.