Two New Fumarprotocetraric Acid Lactones Identified and Characterized by UHPLC-PDA/ESI/ORBITRAP/MS/MS from the Antarctic Lichen <i>Cladonia metacorallifera</i>

Abstract

Lichens are symbiotic organisms between algae and fungi, which are makers of secondary compounds named as lichen substances. Hyphenated techniques have significantly helped natural product chemistry, especially UHPLC/ESI/MS/MS in the identification, separation, and tentative characterization of secondary metabolites from natural sources. Twenty-five compounds were detected from the Antarctic lichen Cladonia metacorallifera for the first time using UHPLC-PDA/ESI/Orbitrap/MS/MS. Compounds 5 and 7 are reported as new compounds, based on their MS/MS fragmentation routes, and considered as fumarprotocetraric acid derivatives. Besides, ten known phenolic identified as orsellinic acid, ethyl 4-carboxyorsellinate, psoromic acid isomer, succinprotocetraric acid, siphulellic acid, connorstictic acid, cryptostictic acid, lecanoric acid, lobaric acid and gyrophoric acid are noticed for the first time in the Cladonia genus.

Keywords

• Antarctica
• <i>Cladonia</i>
• depsides
• depsidones
• Fumarprotocetraric acid
• lichens