UHPLC-MS Metabolomic Fingerprinting, Antioxidant, and Enzyme Inhibition Activities of Himantormia lugubris from Antarctica

Abstract

Himantormia lugubris is a Chilean native small lichen shrub growing in the Antarctica region. In this study, the metabolite fingerprinting and the antioxidant and enzyme inhibitory potential from this species and its four major isolated compounds were investigated for the first time. Using ultra-high performance liquid chromatography coupled to quadrupole-Orbitrap mass spectrometry analysis (UHPLC-Q-Orbitrap-MS), several metabolites were identified including specific compounds as chemotaxonomical markers, while major metabolites were quantified in this species. A good inhibition activity against cholinesterase (acetylcholinesterase (AChE) IC50: 12.38 ± 0.09 µg/mL, butyrylcholinesterase (BChE) IC50: 31.54 ± 0.20 µg/mL) and tyrosinase (22.32 ± 0.21 µg/mL) enzymes of the alcoholic extract and the main compounds (IC50: 28.82 ± 0.10 µg/mL, 36.43 ± 0.08 µg/mL, and 7.25 ± 0.18 µg/mL, respectively, for the most active phenolic atranol) was found. The extract showed a total phenolic content of 47.4 + 0.0 mg of gallic acid equivalents/g. In addition, antioxidant activity was assessed using bleaching of DPPH and ORAC (IC50: 75.3 ± 0.02 µg/mL and 32.7 ± 0.7 μmol Trolox/g lichen, respectively) and FRAP (27.8 ± 0.0 μmol Trolox equivalent/g) experiments. The findings suggest that H. lugubris is a rich source of bioactive compounds with potentiality in the prevention of neurodegenerative or noncommunicable chronic diseases.

Phenolic Secondary Metabolites and Antiradical and Antibacterial Activities of Different Extracts of Usnea barbata (L.) Weber ex F.H.Wigg from Călimani Mountains, Romania

“…Therefore, they are considered important representatives with biopharmaceutical potential [ 9 ]. Due to remarkable antioxidant [ 10 ] and antibacterial [ 11 ] properties, lichens represent a promising source of protective [ 12 , 13 , 14 ] and antibiotic drugs [ 15 , 16 , 17 ].…”

Phenolic Fingerprinting and Bioactivity Profiling of Extracts and Isolated Compounds from Gypothamnium pinifolium Phil.

“…Regel (Bromeliaceae) showed potent inhibition of AChE for the pulp and seeds, the IC 50 for AChE was 4.49 ± 0.08 µg/mL and 4.38 µg/mL, respectively [ 35 ]. Recently, for the ethanolic extract of Himantormia lugubris from Antarctica, a good inhibition for AChE with an IC 50 of 12.38 µg/mL [ 36 ] was found. However, the AChE inhibitions produced by the G. pinifolium extracts used in this research are more potent.…”

“…Also, for Artemisia copa Phil. (Asteraceae), ethanolic extract showed a potent anticholinesterase activity, with IC 50 of 3.92 ± 0.08 µg/mL for AChE and 44.13 ± 0.10 µg/mL for BChE [ 16 ], for this last assay and in comparison with G. pinifolium extract the IC 50 values showed a less potent activity, the same occurs if we compare the results for G. sphacelata for which the IC 50 for pulp was 73.86 ± 0.09 µg/mL and for seeds 78.57 ± 0.06 µg/mL [ 35 ], and for the ethanolic extract of H. lugubris the enzyme inhibition against BChE was 31.54 ± 0.02 µg/mL, a value close to G. pinifolium ethyl acetate extract and less potent that n -hexane extract [ 36 ]. Likewise, for Weinmannia trichosperma Cav., the in vitro inhibitory effects against 5-hLOX, AChE, and BChE were investigated for the aqueous extract, and interesting activity as a 5-hLOX inhibitor was found.…”

“…Furthermore, for tyrosinase inhibition, H. lugubris showed moderate activity with an IC 50 of 22.32 ± 0.21 µg/mL, and in comparison with the potent inhibition produced by G. pinifolium n -hexane and ethyl acetate extracts with IC 50 values of 9.25 ± 0.15 µg/mL and 12.32 ± 0.21 µg/mL, respectively, showed a better capacity for inhibiting this enzyme [ 36 ]. Recently, for Ovidia pillopillo (Gay) Meissner (Thymelaeaceae) ethanolic extract, the IC 50 value for tyrosinase inhibition was 9.92 ± 0.05 µg/mL, a potent and close result to that produced by G. pinifolium n -hexane extract.…”

Unravelling Novel Phytochemicals and Anticholinesterase Activity in Irish Cladonia portentosa

“…We found in the literature [ 34 ] that the following four lichenic acids biosynthesised by Ascomycetes , the fungal partner in the lichen Cladonia portentosa , may give an [M-H] − at m / z 375.1 Da: placodiolic acid (C 19 H 20 O 8 , MW 376.4 g/mol) ( 3 ), pseudoplacodiolic acid (C 19 H 20 O 8 , MW 376.4 g/mol) ( 4 ), conprotocetraric acid (C 18 H 16 O 9 , MW 376.3 g/mol) and decarboxythamnolic acid (C 18 H 16 O 9 , MW 376.3 g/mol). Placodiolic and pseudoplacodiolic acids are functional isomeric derivatives of usnic acid ( Table 2 ) and may follow the fragmentation pattern that satisfies tandem MS spectra of peaks eluting at 36.9 min and 37.6 min ( Figure 5 and Figure 6 ) [ 38 , 39 ]. These molecules are tetrahydrodibenzofurans and have been reported in the lichens of genera Lecanora , Rhizoplaca , Leprocaulon , Phoma and Hematoma [ 40 , 41 , 42 ].…”