Comprehensive Liverwort Metabolome Profiling

A total of 211 compound classes were identified in the positive and negative ion modes. To visualize the compound class diversity, a sunburst plot was conducted (Fig. 4). The most prominently detected classes overall were carboxylic acids and derivatives (mainly due to amino acids, peptides, and analogues), followed by benzene and substituted derivatives, fatty acyls (largely fatty amides), organooxygen compounds (mostly carbohydrates and carbohydrate conjugates), prenol lipids (mostly diterpenoids, retinoids, and sesquiterpenoids), and flavonoids (mostly flavonoid glycosides and hydroxyflavonoids). A large number of features were also classified as stilbenes, the chemical class represented in the ClassyFire chemical ontology that encompasses the characteristic bibenzyls found in Radula spp. Known compounds from liverworts were tentatively annotated and are listed in Table 1.
Fig. 4

Sunburst plot showing an overview on the richness of classified metabolite compounds. Broad compound classes are represented in the center while specific classifications are represented on the exterior. Colours correspond to the assigned classes. Due to readability the names of some classes were removed from the plot. An interactive zoomable plot is available in the supplementary vignettes and on Zenodo

Table 1

Tentatively annotated liverwort specialized metabolites. Full details are found in the Supplementary Information

Compound	Formula	Molar Mass	Ionization	Tentative Feature
Bisabola-1,3,5,7(14),10- pentaene	C15H20	200.32	Positive	FT0671, FT0672
Ar-tenuifolene	C15H20	200.32	Positive	FT0671, FT0672
Eudesma-1,4(15)-11- triene	C15H22	202.23	Positive	FT0692
Myli-4(15)-ene	C15H22	202.33	Positive	FT0692
Cis-calamenene	C15H22	202.33	Positive	FT0692
Cuparene	C15H22	202.33	Positive	FT0692
Xanthorrizol	C15H22O	218.33	Positive	FT0828 - FT0832
2-cuparenol	C15H22O	218.33	Positive	FT0828 - FT0832
Cyclocolorenone	C15H22O	218.33	Positive	FT0828 - FT0832
β-herbertenol	C15H22O	218.33	Positive	FT0828 - FT0832
Trans-Nerolidol	C15H26O	222.37	Positive	FT0861
(E)-farnesol	C15H26O	222.37	Positive	FT0861
3-[2-(3-Methoxyphenyl)ethyl]phenol	C15H16O2	228.29	Positive	FT0923, FT0925
3,4′-Dimethoxybibenzyl	C16H18O2	242.31	Positive	FT1057, FT1059
1,2-Bis(3-methoxyphenyl)ethane	C16H18O2	242.32	Positive	FT1057, FT1059
Lunularic acid	C15H14O4	258.1	Negative	FT0814-FT0820
Radulanin A	C19H20O2	280.37	Positive	FT1451, FT1454, FT1458
2,2-Dimethyl-5-hydroxy- 7-(2-phenylethyl)- chromene*	C19H20O2	280.4	Positive	FT1454, FT1458
4-(3-Methyl-2-butenyl)-5-phenethylbenzene-1,3-diol	C19H22O2	282.38	Positive	FT1480, FT1483, FT1484, FT1487
			Negative	FT1001, FT1008, FT1009, FT1011
4-Prenyldihydropinosylvin	C19H22O2	282.38	Positive	FT1480, FT1483, FT1484, FT1487
			Negative	FT1001, FT1008, FT1009, FT1011
Radulanin A methyl ether	C20H22O2	294.39	Positive	FT1623, FT1624, FT1625, FT1626, FT1627
			Negative	FT1111, FT1112
8-[2-(4-Hydroxyphenyl)ethyl]-3-methyl-2,5-dihydro-1-benzoxepin-6-ol	C19H20O3	296.37	Negative	FT1132, FT1133, FT1135, FT1136, FT1139, FT1140, FT1141, FT1142, FT1143, FT1144, FT1147
5-Methoxy-2-(3-methylbut-2-en-1-yl)-3-(2-phenylethyl)phenol	C20H24O2	296.41	Positive	FT1658, FT1660
			Negative	FT1146, FT1148
4-(3-Methyl-2-Butenyl)-5-(2-Phenylethyl)-3-Methoxyphenol	C20H24O2	296.41	Positive	FT1658, FT1660
			Negative	FT1146, FT1148
2-[(3,3-Dimethyloxiran-2-yl)methyl]-5-(2-phenylethyl)benzene-1,3-diol	C20H24O2	296.41	Positive	FT1658, FT1660
			Negative	FT1146, FT1148
3-Methoxy-5-(2-phenylethyl)-2-prenylphenol	C20H24O2	296.41	Positive	FT1658, FT1660
			Negative	FT1146, FT1148
2-[(3,3-Dimethyloxiran-2-yl)methyl]-5-(2-phenylethyl)benzene-1,3-diol	C19H22O3	298.38	Negative	FT1167, FT1168
Kaempferol 3-methyl-ether	C16H12O6	300.26	Negative	FT1200, FT1201
2,2-Dimethyl-5-hydroxy-7-(2-phenylethyl)-2 H-1-benzopyran-6-carboxylic acid	C20H20O4	324.38	Negative	FT1483, FT1484, FT1485, FT1486, FT1489, FT1491, FT1494, FT1496
Radulanin E	C20H20O4	324.38	Negative	FT1483, FT1484, FT1485, FT1486, FT1489, FT1491, FT1494, FT1496
Radulanin H	C20H20O4	324.4	Positive	FT2017 - FT2020
			Negative	FT1484-1486, FT1489-1494, FT1496