Hironao Tanaka

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.

Sesqui- and diterpenoids from Plagiochila species

Abstract Two new 2,3-secoaromadendrane-type sesquiterpenoids, plagiochiline N and acetoxyisoplagiochilide, and a new aromadendrane-type sesquiterpenoid, ent-4β,10α-dihydroxyaromadendrane, were isolated from the Japanese liverwort Plagiochila ovalifolia along with some previously known sesqui- and diterpenoids. A new pinguisane-type sesquiterpenoid, named dehydropinguisone was isolated from the New Zealand liverwort Plagiochila retrospectans . Their stereostructures have been determined by NMR techniques and X-ray crystallographic analysis. The chemosystematics of some Plagiochila species are discussed.

Eudesmane-type sesquiterpene lactones from the Japanese liverwort Frullania densiloba

Three new eudesmane-type sesquiterpene lactones, ent-α-cyclodihydrocostunolide, and densilobolide-A and -B, were isolated from the Japanese liverwort Frullania densiloba. Their structures were determined by extensive NMR techniques, chemical degradation and X-ray crystallographic analysis.

Clerodane- and halimane-type diterpenoids from the liverwort Jungermannia hyalina

Abstract Three new clerodane- and one new halimane-type diterpenoids: ent-3β,4β-epoxyclerod-13E-en-15-ol; 3R ∗ , 4R ∗ - dihydroxyclerod -13E- en-15-al ; 3R ∗ , 4R ∗ - dihydroxyclerod -13Z- en-15-al ; and 3ξ-hydroxy-5(10), 13E-halimadien-15-al, were isolated from the German liverwort Jungermannia hyalina, together with the previously known clerodane-type diterpenoids ent-3β,4β-epoxyclerod-13E-en-15-al; ent-3β,4β-epoxyclerod-13Z-en-15-al and kolavenol. The structures were determined by extensive NMR techniques and chemical degradation.

Sesqui- and di-terpenoids from the liverwort Jungermannia vulcanicola

Abstract A new chiloscyphane-type sesquiterpenoid, dihydrochiloscypholone, was isolated from the liverwort Jungermannia vulcanicola , together with the previously known chiloscypholone. Another collection of J. vulcanicola gave a new labdane-type diterpenoid along with the previously known ent -13-epi-manool. Their structures were determined by extensive NMR techniques and chemical transformation. There are at least three chemo-types of J. vulcanicola .

Ent-kaurane-type diterpenoids from the liverwort Jungermannia rotundata

Three new ent-kaurane-type diterpenoids, named rotundeic acids A-C, have been isolated from the Japanese liverwort Jungermannia rotundata. Their structures were determined to be ent-15α-hydroxykaur-16-en-20-oic acid, ent-15α-acetoxykaur-16-en-20-oic acid and ent-9α-hydroxykaur-16-en-20-oic acid by extensive NMR techniques.

Sesquiterpenoids from a Cell Suspension Culture of the Liverwort Porella vernicosa Lindb

The liverwort Porella vernicosa Lindb. was cultured in vitro in Murashige and Skoogs medium. The pungent sesquiterpene dialdehyde, polygodial, was found as the major metabolite (20.3%). The second major metabolite was norpinguisone methyl ester (18.7%). In addition β-bisabolene (12.7%), drimenol (8.4%), cyclocolorenone (7.5%) and other drimane and pinguisane sesquiterpenoids were identified by GC-MS analysis. In the field-grown liverwort, the major metabolite was norpinguisone (24.5%) accompanied by polygodial (21.7%) and cyclocolorenone (13.4%). Thus the content of polygodial in the mixture of metabolites produced by P. vernicosa cultured in vitro was similar to that in the field-grown plant