Fumihiro Nagashima

Phytochemical and biological studies of bryophytes.

The bryophytes contain the Marchantiophyta (liverworts), Bryophyta (mosses) and Anthocerotophyta (hornworts). Of these, the Marchantiophyta have a cellular oil body which produce a number of mono-, sesqui- and di-terpenoids, aromatic compounds like bibenzyl, bis-bibenzyls and acetogenins. Most sesqui- and di-terpenoids obtained from liverworts are enantiomers of those found in higher plants. Many of these compounds display a characteristic odor, and can have interesting biological activities. These include: allergenic contact dermatitis, antimicrobial, antifungal and antiviral, cytotoxic, insecticidal, insect antifeedant, superoxide anion radical release, 5-lipoxygenase, calmodulin, hyaluronidase, cyclooxygenase, DNA polymerase β, and α-glucosidase and NO production inhibitory, antioxidant, piscicidal, neurotrophic and muscle relaxing activities among others. Each liverwort biosynthesizes unique components, which are valuable for their chemotaxonomic classification. Typical chemical structures and biological activity of the selected liverwort constituents as well as the hemi- and total synthesis of some biologically active compounds are summarized.

Terpenoids from some Japanese liverworts

Six Japanese liverworts, Jungermannia comata, J. truncata, J. vulcanicola, Jamesoniella autumnalis, Jackiella javanica and Spruceanthus polymorphus were chemically investigated. J. comata contained a bis(bibenzyl), perrottetin E, as a major component. Jungermannia truncata and Jamesoniella autumnalis elaborated ent-11α-hydroxykauren-15-one, (16R)-ent-l1α-hydroxykauran-15-one and ent-kauren-15-one. (+)-α-Bisabolol, α-terpineol and three new kaurene-type diterpenoids, ent-kaurene-3β, 15α-diol, ent-15α-hydroxykaurene-3β-yl acetate and ent-3β-hydroxykaurene-15-one, were isolated from J. vulcanicola. α-Monocyclonerolidol was the the major compound of S. polymorphus. Jackiella javanica produced a neolignan, (-)-licarin A, and two new germacrane-type sesquiterpenoids, ent-germacra-4(15),5,10(14)-trien-1β-ol and ent-germacra-4(15),5,10(14)-trien-1α-ol, together with ent-verticillane-type diterpenoids. The structures of the new compounds were characterized by 1H and 13C NMR spectral data and chemical evidence. The chemosystematics of the six liverworts is discussed.

Sesquiterpenoids from the liverworts Bazzania trilobata and Porella canariensis

A new myltaylane-type sesquiterpene alcohol and nine known sesquiterpenoids were isolated from Bazzania trilobata. The absolute stereostructure of (1S,4S)-cis-5-hydroxycalamenene was revised to be (1R,4R)-cis-5-hydroxycalamenene by the X-ray crystallographic analysis of its p-bromobenzoate derivative. Four previously known sesquiterpenoids were isolated from Porella canariensis, together with an artefact of a pinguisane-type sesquiterpene lactone. Their structures were determined by the use of extensive NMR techniques.

Fatty acids and cyclic bis(bibenzyls) from the New Zealand liverwort Monoclea forsteri

Abstract Two novel fatty acids named monocleic and monocleolic acids and two new cyclic bis(bibenzyls) riccardins D and C were isolated from the New Zealand large thalloid liverwort Monoclea forsteri together with the previously known bis(bibenzyls) riccardin C and perrottetin E. The structures of the new fatty acids were established to be 10-keto-octadec-6-yn-8(E)-enoic acid and 10-hydroxy-octadec-6-yn-8(E)-enoic acid by the chemical and 1H and 13CNMR spectral data. The structures of the new bis(bibenzyls) were also determined by the extensive 2D COSY NMR and different NOE spectroscopy. The present species is chemically different from members of the Metzgeriales and the Marchantiales.

Terpenoids and aromatic compounds from six liverworts

The structure of perrottetianal B, a sacculatane-type diterpene dialdehyde, which has previously been isolated from the liverwort Porella perrottetiana was revised to 15-hydroxyperrottetianal by the analysis of NMR spectra. The distribution of the known sesqui- and diterpenoids, as well as bis-bibenzyl derivatives, in Swiss liverworts Barbilophozia lycopodioides, B. floerkei and French B. barbata and Japanese Jungermannia comata is discussed. Perrottetin E, a cyclic bis-bibenzyl isolated from Jungermannia comata showed inhibitory activity for thrombin (IC50 18 μM).

Terpenoids and aromatic compounds from selected Ecuadorian liverworts

Abstract Seven Ecuadorian liverworts have been investigated chemically. Frullania brasiliensis elaborates arbusculin B and (−)-α-bisabolol and is classified as chemotype I of the Frullaniaceae. Herbertus acanthelius and H. subdentatus produce isocuparene-type sesquiterpenoids as the major components. 1,4-Dimethylazulene was isolated from Plagiochila micropterys and Macrolejeunea pallescens and the former species is classified as chemotype I of the Plagiochilaceae. The major component of Marchantia plicata is marchantin A, a chemical marker for the Marchantiales. Plagiochila alternans is a very isolated species in the Plagiochilaceae, because it produces a pinguisane-type sesquiterpenoid as the major component.

Rare prenylated flavonoids from Tephrosia purpurea.

Chemical investigations of aerial parts of Tephrosia purpurea yielded the rare prenylated flavonoids, tephropurpulin A (1) and isoglabratephrin (2), in addition to a previously identified flavonoid, glabratephrin (3). Structures were established by 1D and 2D NMR spectroscopy, as well as by HR-MS analysis; for compounds 2 and 3, structures were confirmed by X-ray analysis.

Terpenoids from the Japanese liverworts Jackiella javanica and Jungermannia infusca

Abstract Five ent -verticillane-type diterpenoids have been isolated from the Japanese liverwort Jackiella javanica , along with previously known sesqui- and di-terpenoids. The chemical shifts of the 1 H and 13 C NMR spectra of ent -verticillane-type diterpenoids are given. A new monocyclic diterpenoid, infuscatrienol, three known sesqui- and di-terpenoids, and a bis -bibenzyl derivative have been isolated from the Japanese Jungermannia infusca .

MARCHANTIOPHYTA (LIVERWORTS) : RICH SOURCES OF MACROCYCLIC BIS(BIBENZYLS)

The Marchantiophyta (liverworts) produce which show interesting biological activity such as antimicrobial, antifungal, antiobesity and muscle relaxing activity etc. and are of very valuable for the chemosystematic and evolutional study of the Marchantiophyta and pteridophytes. The isolation, identification, structural elucidation and total synthesis of these characteristic natural products and their biological activity are reviewed.

Sesqui- and diterpenoids from the Japanese liverwort Jungermannia hattoriana

A labdane-type diterpenoid, an acorane-type and three cuparane-type sesquiterpenoids have been isolated from the Japanese liverwort Jungermannia hattoriana (Amak.) Amak. as new natural products, together with a known monoterpenoid, three cuparane-type sesquiterpenoids and three labdane- and a pimarane-type diterpenoids. Their structures were determined by spectral analysis, chemical degradation and X-ray crystallographic analysis.