W. John Cole

Phytochemical, morphological, and molecular evidence for the occurrence of the neotropical liverwort Plagiochila stricta in the Canary Islands, new to Macaronesia

Abstract Plant material from the Canary Islands similar to Plagiochila spinulosa (Dicks.) Dumort. has been identified as the Neotropical liverwort P. stricta Lindenb. The secondary metabolite profiles of CDCl3 extracts of both Neotropical and Macaronesian specimens of P. stricta are distinct from those of P. spinulosa in containing alloocimene and neoalloocimene as the principal monoterpenes rather than β-phellandrene; the two species also show differences in the 9,10-dihydrophenanthrenes and other aromatic compounds present. Phylogenetic analyses of ITS nrDNA sequence variation place P. spinulosa sister to P. stricta. Morphologically, P. stricta from Tenerife is distinguished most easily from P. spinulosa by the scarcely decurrent antical leaf margin.

A phytochemical and morphological study of the liverwort Plagiochila retrorsa Gottsche, new to Europe

Abstract The Neotropical liverwort Plagiochila retrorsa Gottsche is conspecific with P. sharpii H.L.Blomq., known previously as a Southern Appalachian endemic, as well as P. tricarinata Carl and P. permista Spruce var. subintegerrima Herzog from Costa Rica. It has been discovered recently in the Azores and Madeira, new to Europe. Illustrations, SEM micrographs of spores and elaters, nuclear magnetic resonance (NMR) fingerprints and gas chromatography–mass spectrometry (GC-MS) data are presented, based on American and European material. Costa Rican material used for an earlier phytochemical study has now also been identified as P. retrorsa. Although NMR fingerprinting initiated the present discoveries, the NMR fingerprint of P. retrorsa is not unique and NMR fingerprinting alone is not sufficient to identify the species. P. retrorsa belongs to the 9,10-dihydrophenanthrene chemotype group and the two principal secondary metabolites are 3,5-dimethoxy-9,10-dihydrophenanthren-2-ol and methyl 4-hydroxy-4′-O-methyllunularate.

Plagiochila rutilans (Hepaticae): A Poorly Known Species from Tropical America

Abstract The neotropical liverwort, Plagiochila rutilans Lindenb., is conspecific with P. remotifolia Hampe & Gottsche, P. farlowii Steph., P. harrisana Steph, and P. organensis Herzog. Plagiochila standleyi Carl is reduced to a variety of P. rutilans. Plagiochila gymnocalycina (Lehm. & Lindenb.) Mont. and P. portoricensis Hampe & Gottsche (= P. simplex (Sw.) Lindenb.) are excluded from the synonymy of P. rutilans. Plagiochila rutilans var. liebmanniana Gottsche is a synonym of P. crispabilis Lindenb.; P. rutilans var. laxa Lindenb. and var. angustifolia Herzog are conspecific with P. gymnocalycina. Sporophytes of P. rutilans are described for the first time. Fresh material of P. rutilans exhibits a distinct odor of peppermint caused by the presence of several menthane monoterpenoids, principally pulegone. NMR (nuclear magnetic resonance) fingerprints and GC-MS data indicate that the lipophilic secondary metabolite profiles are distinct for the two varieties accepted in this study.

[FeS/FeS2], a redox system for the origin of life (some experiments on the pyrite-hypothesis).

The FeS/FeS2 redox system, whose importance is stressed in recent theories on the origin of life, has been tested experimentally. In this paper it is demonstrated by thermodynamical calculations as well as by experiments, that cyclohexanone, which served as model compound, can be reduced by the aforementioned redox system. Reactions were carried out in methanol and DMF at 25 °C and at 100 °C. Besides products that were synthesised in both solvents, like cyclohexanethiol and dicyclohexyldisulphide, special compounds were obtained in methanol and in DMF, because of the involvement of the respective solvent in the reaction. Yields of reduced compounds were lower in methanol owing to a compound that hindered the reduction (cyclohexylketal). With increasing temperature and duration the amount of reduced compoinds increased. Further experiments have shown that 1,1-cyclohexanedithiol is likely to be a necessary intermediate for the reduced products. The experiments give evidence to the ‘pyrite hypothesis’, which postulates that the FeS/FeS2 redox system was of importance for the origin of life.

Killarniensolide, methyl orsellinates and 9,10-dihydrophenanthrenes from the liverwort Plagiochila killarniensis from Scotland and the Azores

Abstract Methyl everninate has been identified as the major constituent of the deuterochloroform extract of ten specimens of the liverwort Plagiochila killarniensis . Using NMR fingerprinting and GC–MS, the new methyl 6-hydroxy-2-methyl-3,4-methylenedioxybenzoate and three other methyl orsellinate derivatives were identified as minor components. 9,10-Dihydro-3,5-dimethoxyphenanthren-2-ol and 9,10-dihydro-3-methoxyphenanthrene-4,5-diol, previously reported from a Neotropical Plagiochila , were also present. Killarniensolide, a new phthalide, was isolated; its structure was elucidated as 3- (2-hydroxy-4,5-dimethoxybenzyl)-7-methoxyphthalide by NMR spectroscopy, GC–MS and isolation of an acetate derivative. Chemical differences between specimens from Scotland and the Azores were relatively minor but characteristic; small differences between some of the Scottish materials were also observed.

Cyclic ferroceneboronates as derivatives for the gas chromatographic separation and characterisation of diols and related compounds

Abstract Cyclic ferroceneboronate derivatives have been obtained readily from a range of 1,2- and 1,3-diols, and from one α- and two β-hydroxyacids, three β-hydroxyamines and one γ-hydroxyamine. The pinacol ester was stable to thin-layer chromatography. The ferroceneboronates of diols afforded particularly good gas chromatographic peaks, and are well suited to the analyses of diols of low molecular weight. The mass spectra (electron impact ionisation) are dominated by molecular ions, which are usually the base peaks and carry a high proportion of the total ion current. Characteristic isotope patterns reflect the presence of 10 B, 54 Fe and 57 Fe as minor natural isotopes of appreciable abundances.

Highly oxygenated naphthalenes and acetophenones from the liverwort Adelanthus decipiens from the British Isles and South America

Abstract Ten highly oxygenated naphthalene and acetophenone derivatives, including five new natural products, have been identified in CDCl 3 extracts of Adelanthus decipiens from Scotland, Wales, Ireland, Colombia and Ecuador. Although not all ten compounds were detected in the extracts of all the eight liverwort gatherings examined (two fresh and six herbariumn specimens), the general picture is one of different distributions of compounds rather than the presence or absence of particular compounds in the different samples of liverwort. 1,2-Dimethoxy-3,4-methylenedioxynaphthalene (wettstein A) is the major component in material from the British Isles whereas 1,2,4-trimethoxynaphthalene is the major component in one Colombian specimen and 1,2,3-trimethoxynaphthalene is the major naphthalene derivative in another (the subject of a GC-MS study in 1980). Pentamethoxyacetophenone is the major component in the specimen from Ecuador. The feasibility of using small amounts of herbarium material to undertake this type of study has been demonstrated.

Morphological and phytochemical studies of Plagiochila papillifolia Steph., a Neotropical liverwort new to Europe

Abstract The Neotropical liverwort Plagiochila papillifolia Steph. is conspecific with P. caespiticia Spruce ex Herzog (nom. inval.), P . deciduifolia Steph., P . solmsii Steph. and P . verruculosa R.M.Schust.; it is reported from the Azores, new to Europe. Morphologically it shows affinity with sect. Bidentes Carl; phytochemically, several of its lipophilic secondary metabolites are the same as those of P . retrorsa Gottsche, another Neotropical species reported only recently from Macaronesia.

Aromatic compounds from the liverwort Plagiochila spinulosa

Abstract Two known and five novel 9,10-dihydrophenanthrene derivatives, two orsellinic acid derivatives and a lunularic acid derivative have been isolated from the liverwort Plagiochilaspinulosa and identified following NMR studies. A further known 9,10-dihydrophenanthrene derivative has been identified using 1 H NMR fingerprinting of the extracts.

Atlanticol, an epoxybicyclogermacrenol from the liverwort Plagiochila atlanticaF. Rose

The proton NMR fingerprints of the CDCl(3) extracts of small quantities of seven specimens of the liverwort Plagiochila atlantica from Scotland and England are very similar and are dominated by the spectrum of the 2,3-secoaromadendrane plagiochiline C. Atlanticol, a new epoxybicyclogermacrenol, was present in all the extracts to the extent of ca. 10% of plagiochiline C and was isolated using TLC. Characterisation and structural elucidation by means of NMR, GC/GC-MS and HREI (and CI) MS showed that atlanticol is (1R*,2R*,3S*,4E,6S*,7S*,10S*)-3,14-diacetoxy-1,10-epoxybicyclogermacr-4-en-2-ol. The secondary metabolites of P. atlantica are characteristically different from those of P. spinulosa, the liverwort with which P. atlantica has most often been confused.