Dimeric and esterified sesquiterpenes from the liverwort Chiastocaulon caledonicum

This is the first chemical investigation of Chiastocaulon caledonicum, an endemic liverwort from New Caledonia. We herein present the isolation of thirteen compounds including seven undescribed sesquiterpenoids, namely four barbatane- and three myltaylane-type sesquiterpenes. The structures of these compounds were elucidated based on the interpretation of their chemical and spectroscopic/spectrometric data. Chiastocaulins A and B are the first examples of dimers based on two myltaylane units. The chemotaxonomic importance and the biosynthesis of the chiastocaulin structure are discussed. Terpenoid dimers formed via a Diels-Alder cyclization are thought to be specific to the Plagiochilaceae family.

Chemotaxonomy and cytotoxicity of the liverwort Porella Viridissima

The first chemotaxonomic study based on volatile components of Porella viridissima (Mitt.) Grolle is reported. The GC-MS analysis of ether extract was performed; ten santalane and five pinguisane-type sesquiterpenes were identified together with perrottetianal A as major diterpene. Most of detected santalane-type sesquiterpenes are reported for the first time in liverwort. P. viridissima was found to belong to the chemotype III (pinguisane/sacculatane) and shared chemical similarities with P. navicularis. Perrotettianal A was isolated and has shown strong cytotoxicity against ovarian cancer.

Chemotypes and Biomarkers of Seven Species of New Caledonian Liverworts from the Bazzanioideae Subfamily

Volatile components of seven species of the Bazzanioideae sub-family (Lepidoziaceae) native to New Caledonia, including three endemic species (Bazzania marginata, Acromastigum caledonicum and A. tenax), were analyzed by GC-FID-MS in order to index these plants to known or new chemotypes. Detected volatile constituents in studied species were constituted mainly by sesquiterpene, as well as diterpene compounds. All so-established compositions cannot successfully index some of them to known chemotypes but afforded the discovery of new chemotypes such as cuparane/fusicoccane. The major component of B. francana was isolated and characterized as a new zierane-type sesquiterpene called ziera-12(13),10(14)-dien-5-ol (23). In addition, qualitative intraspecies variations of chemical composition were very important particularly for B. francana which possessed three clearly defined different compositions. We report here also the first phytochemical investigation of Acromastigum species. Moreover, crude diethyl ether extract of B. vitatta afforded a new bis(bibenzyl) called vittatin (51), for which a putative biosynthesis was suggested.

Species delimitation and biogeography of a southern hemisphere liverwort clade, Frullania subgenus Microfrullania (Frullaniaceae, Marchantiophyta)

Frullania subgenus Microfrullania is a clade of ca. 15 liverwort species occurring in Australasia, Malesia, and southern South America. We used combined nuclear and chloroplast sequence data from 265 ingroup accessions to test species circumscriptions and estimate the biogeographic history of the subgenus. With dense infra-specific sampling, we document an important role of long-distance dispersal in establishing phylogeographic patterns of extant species. At deeper time scales, a combination of phylogenetic analyses, divergence time estimation and ancestral range estimation were used to reject vicariance and to document the role of long-distance dispersal in explaining the evolution and biogeography of the clade across the southern Hemisphere. A backbone phylogeny for the subgenus is proposed, providing insight into evolution of morphological patterns and establishing the basis for an improved sectional classification of species within Microfrullania. Several species complexes are identified, the presence of two undescribed but genetically and morphologically distinct species is noted, and previously neglected names are discussed.

Volatile Constituents of New Caledonian Frullania Species

Volatile components of seven Frullania species (Frullaniaceae) from New Caledonia, including five endemic species (F. bella, F. scalaris, F. mamnmillosa, F. cornita and F. falsicornuta), were analyzed by GC-MS in order to index these plants to known chemotypes. Constituents detected in these Frullania species were mainly sesquiterpenes, as well as the bibenzyl dihydrognetin, and the flavonoid naringinin-5,7,4'-trimethyl ether. These compositions allowed an indexation of Frullania species from New Caledonia to cyclocolorenone, sesquiterpene lactone and bibenzyl chemotypes. In addition, qualitative intraspecies variations of chemical composition were very important and made indexation to known chemotypes very tricky. Moreover, two of the endemic liverworts did not possess any biomarker that linked to a known chemotype.

Volatile Constituents of New Caledonian Frullania Species

Volatile components of seven Frullania species (Frullaniaceae) from New Caledonia, including five endemic species ( F. bella, F. scalaris, F. mammillosa, F. cornuta and F. falsicornuta), were analyzed by GC-MS in order to index these plants to known chemotypes. Constituents detected in these Frullania species were mainly sesquiterpenes, as well as the bibenzyl dihydrognetin, and the flavonoid naringinin-5,7,4'-trimethyl ether. These compositions allowed an indexation of Frullania species from New Caledonia to cyclocolorenone, sesquiterpene lactone and bibenzyl chemotypes. In addition, qualitative intraspecies variations of chemical composition were very important and made indexation to known chemotypes very tricky. Moreover, two of the endemic liverworts did not possess any biomarker that linked to a known chemotype.

Chemical Originalities of New Caledonian Liverworts from Lejeuneaceae Family

Lejeuneaceae is the largest family of liverworts in the world. Through the analyses of the chemical composition of some species, it has been demonstrated that they may represent an important source of original and bioactive molecules. None of the 146 species that occur in New Caledonia has been studied yet. Here we describe the terpenoid content of twelve New Caledonian species, including two endemics. We describe here, for the first time, the presence of frullanolide in the Lejeuneaceae, occurring as a major compound in the extract from Colura leratii, and a rarely observed santalene derivative from Acrolejeunea securifolia subsp. caledonica. These analyses also highlight species that probably contain original structures, such as Schiffneriolejeunea tumida var. hasskarliana, Cheilolejeunea spp and Thysananthus retusus. The results obtained here also confirm several previous hypotheses about the chemosystematics of the Lejeuneaceae. For example, lepidozene can be considered as a chemosystematic marker of the Ptychantoideae subfamily, considering its abundance in many Ptychantoideae. On the other hand, some results are different from those described previously. For example, we detected no fusicoccane derivatives in any of the Lejeuneaceae species analyzed here, whereas they were previously described as a marker of the Ptychantoideae. This suggests that the available data toward the chemistry of the Lejeuneaceae are not sufficient to be confident with some of the previous chemosystematic conclusions.

Chemical Originalities of New Caledonian Liverworts from Lejeuneaceae Family

Lejeuneaceae is the largest family of liverworts in the world. Through the analyses of the chemical composition of some species, it has been demonstrated that they may represent an important source of original and bioactive molecules. None of the 146 species that occur in New Caledonia has been studied yet. Here we describe the terpenoid content of twelve New Caledonian species, including two endemics. We describe here, for the first time, the presence of frullanolide in the Lejeuneaceae, occurring as a major compound in the extract from Colura leratii, and a rarely observed santalene derivative from Acrolejeunea securifolia subsp. caledonica. These analyses also highlight species that probably contain original structures, such as Schiffneriolejeunea tumida var. hasskarliana, Cheilolejeunea spp and Thysananthus retusus. The results obtained here also confirm several previous hypotheses about the chemosystematics of the Lejeuneaceae. For example, lepidozene can be considered as a chemosystematic marker of the Ptychantoideae subfamily, considering its abundance in many Ptychantoideae. On the other hand, some results are different from those described previously. For example, we detected no fusicoccane derivatives in any of the Lejeuneaceae species analyzed here, whereas they were previously described as a marker of the Ptychantoideae. This suggests that the available data toward the chemistry of the Lejeuneaceae are not sufficient to be confident with some of the previous chemosystematic conclusions.

Sesquiterpene hydrocarbons from the liverwort Treubia isignensis var. isignensis with chemotaxonomic significance

The New Caledonian endemic Treubia isignensis var. isignensis, which is known as a morphologically primitive liverwort, was extracted with diethyl ether and the crude extract analyzed by TLC and GC/MS. The species is chemically very primitive because it produces only maaliane-, eudesmane-, aristolane and gorgonane sesquiterpene hydrocarbons, which are significant chemical marker of the species; neither oxygenated terpenoids nor aromatic compounds were detected.

Sesquiterpene Hydrocarbons from the Liverwort Treubia isignensis var. isignensis with Chemotaxonomic Significance

The New Caledonian endemic Treubia isignensis var. isignensis, which is known as a morphologically primitive liverwort, was extracted with diethyl ether and the crude extract analyzed by TLC and GC/MS. The species is chemically very primitive because it produces only maaliane-, eudesmane-, aristolane and gorgonane sesquiterpene hydrocarbons, which are significant chemical marker of the species; neither oxygenated terpenoids nor aromatic compounds were detected.