Metabolomic Profiling, Antioxidant and Enzyme Inhibition Properties and Molecular Docking Analysis of Antarctic Lichens

Abstract

The lichen species Lecania brialmontii, Pseudephebe pubescens, and Sphaerophorus globosus are part of the prominent lichenoflora of the Antarctic territory. In this work, we report the metabolomic identification of ethanolic extracts of these species, their antioxidant and cholinesterase enzyme inhibitory activity, and conduct a molecular docking analysis with typical compounds. Eighteen compounds were identified by UHPLC-ESI-QTOF-MS in L. brialmontii, 18 compounds in P. pubescens, and 14 compounds in S. globosus. The content of phenolic compounds was variable among the species, ranging from 0.279 to 2.821 mg AG/g, and all three species showed high inhibition potential on the cholinesterase enzymes. Molecular docking showed important interactions between AChE and BChE with the selected compounds. This study evidences the chemical fingerprint of three species of the order Lecanorales that support the continuation of the study of other biological activities and their potential for medical research.

Keywords: Antarctica; Lecania; Pseudephebe; Sphaerophorus; antioxidant; bioactive compounds; enzyme inhibition; neuroprotective potential.

Figure 1

Lichens thallus in the polar tundra of King George Island, Maritime Antarctic (a) Lecania brialmontii; (b) Pseudephebe pubescens; (c) Sphaerophorus globosus.

Figure 2

UHPLC-MS Chromatograms (a) Lecania brialmontii; (b) Pseudephebe pubescens; (c) Sphaerophorus globosus.

Figure 3

Binding mode and predicted intermolecular interactions of selected compounds from Lecania brialmontii, Pseudephebe pubescens and Sphaerophorus globosus extracts and residues of the Torpedo californica acetylcholinesterase (TcAChE) catalytic site; (A) Barbatic acid at the catalytic site; (B) Lecanoric acid at the catalytic site; (C) Brialmontin 2 at the catalytic site; (D) Tetra-hydroxytricosanoic acid at the catalytic site; (E) Sphaerophorin at the catalytic site; (F) Sekikaic acid at the catalytic site.

Figure 4

Two-dimensional diagram of compounds from Lecania brialmontii, Pseudephebe pubescens and Sphaerophorus globosus extracts and residues of the Torpedo californica acetylcholinesterase (TcAChE) catalytic site; (A) Barbatic acid at the catalytic site; (B) Lecanoric acid at the catalytic site; (C) Brialmontin 2 at the catalytic site; (D) Tetrahydroxytricosanoic acid at the catalytic site; (E) Sphaerophorin at the catalytic site; (F) Sekikaic acid at the catalytic site. Yellow dotted lines indicate hydrogen bond interactions; cyan dotted lines represent π-π interactions; magenta dotted lines represent T-shape; and red dotted lines indicate salt bridge interactions.

Figure 5

Binding mode and predicted intermolecular interactions of selected compounds from Lecania brialmontii, Pseudephebe pubescens and Sphaerophorus globosus extracts and residues of the human butyrylcholinesterase (hBChE) catalytic site; (A) Barbatic acid at the catalytic site; (B) Lecanoric acid at the catalytic site; (C) Brialmontin 2 at the catalytic site; (D) Tetrahydroxy-tricosanoic acid at the catalytic site; (E) Sphaerophorin at the catalytic site; (F) Sekikaic acid at the catalytic site.

Figure 6

Two-dimensional diagram of compounds from Lecania brialmontii, Pseudephebe pubescens and Sphaerophorus globosus extracts and residues of the human butyrylcholinesterase (hBChE) catalytic site; (A) Barbatic acid at the catalytic site; (B) Lecanoric acid at the catalytic site; (C) Brialmontin 2 at the catalytic site; (D) Tetrahydroxytricosanoic acid at the catalytic site; (E) Sphaerophorin at the catalytic site; (F) Sekikaic acid at the catalytic site. Yellow dotted lines indicate hydrogen bond interactions; cyan dotted lines represent π-π interactions; magenta dotted lines represent T-shape; and red dotted lines indicate salt bridge interactions.