Masao Toyota

Chemical structures of macrocyclic bis(bibenzyls) isolated from liverworts (Hepaticae)

Liverworts (Hepaticae) produce a number of macrocyclic bis(bibenzyls) which show interesting biological activity and are of very valuable for the chemosystematic study of liverworts. The structural elucidation of these characteristic natural products are reviewed.

Intraspecific Variation of Floral Scent Chemistry in Magnolia kobus DC. (Magnoliaceae)

Magnolia kobus was examined at 32 sites in Japan (109 female-stage flowers from 52 plants) by GC-MS. Major chemical compounds (a total of 36 chemicals) emitted from the flowers were: linalool (and its oxides), limonene, cis- and trans-β-Ocimene, benzaldehyde, benzyl alcohol, benzyl cyanide, and 2-aminobenzaldehyde. Linalool and its oxides were the most abundant components of floral scents in 21 individuals. The rate at which chemical volatiles were emitted ranged from 0.002 to 0.929 μg/flower/hour (average 0.211). High quantitative and qualitative variation in floral scent chemistry among individuals was found throughout the range of M. kobus, especially in central Honshu. The high variability in floral scent chemistry may be due to the importance of visual cues in the reproductive biology of M. kobus which flowers in early spring, resulting in decreased selection for specific floral scent profiles. Alternatively, different scent compounds or chemical profiles may be equally effective in attracting pollinators.

Naphthalene—a constituent of Magnolia flowers

Ether extracts of petals, gynoecia and leaves of nine Magnolia taxa were analysed using GC-mass spectrometry. The extracts of flowers and gynoecia of five taxa (M. denudata, M. liliiflora, M. tomentosa, M. p. var. praecocissima and var. borealis) contained naphthalene as their main component. The extracts of M. salicifolia characteristically contained several phenylpropanoids including eugenol methyl ether. Two well known sesquiterpene lactones, dehydrocostuslactone and porthenolide, were found in extracts of flowers and leaves of two taxa.

Terpenoid biotransformation in mammals. V. Metabolism of (+)-citronellal, (+-)-7-hydroxycitronellal, citral, (-)-perillaldehyde, (-)-myrtenal, cuminaldehyde, thujone, and (+-)-carvone in rabbits.

1. The metabolism of (+)-citronellal, (+-)-7-hydroxycitronellal, citral, (-)-perillaldehyde, (-)-myrtenal, cuminaldehyde, thujone, and (+-)-carvone was studied in rabbits. 2. In (+-)-7-hydroxycitronellal, (-)-perillaldehyde, (-)-myrtenal and cuminaldehydes, both primary alcohols and carboxylic acids were formed. 3. In (-)-citronellal and citral, regioselective oxidation was found and a trans-positioned methyl group was carboxylated in each case. 4. In o-cuminaldehyde, reduction but not oxidation, was found.

De novo sequencing and transcriptome analysis of the central nervous system of mollusc Lymnaea stagnalis by deep RNA sequencing.

The pond snail Lymnaea stagnalis is among several mollusc species that have been well investigated due to the simplicity of their nervous systems and large identifiable neurons. Nonetheless, despite the continued attention given to the physiological characteristics of its nervous system, the genetic information of the Lymnaea central nervous system (CNS) has not yet been fully explored. The absence of genetic information is a large disadvantage for transcriptome sequencing because it makes transcriptome assembly difficult. We here performed transcriptome sequencing for Lymnaea CNS using an Illumina Genome Analyzer IIx platform and obtained 81.9 M of 100 base pair (bp) single end reads. For de novo assembly, five programs were used: ABySS, Velvet, OASES, Trinity and Rnnotator. Based on a comparison of the assemblies, we chose the Rnnotator dataset for the following blast searches and gene ontology analyses. The present dataset, 116,355 contigs of Lymnaea transcriptome shotgun assembly (TSA), contained longer sequences and was much larger compared to the previously reported Lymnaea expression sequence tag (EST) established by classical Sanger sequencing. The TSA sequences were subjected to blast analyses against several protein databases and Aplysia EST data. The results demonstrated that about 20,000 sequences had significant similarity to the reported sequences using a cutoff value of 1e-6, and showed the lack of molluscan sequences in the public databases. The richness of the present TSA data allowed us to identify a large number of new transcripts in Lymnaea and molluscan species.

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.

Terpenoid biotransformation in mammals. IV Biotransformation of (+)-longifolene, (-)-caryophyllene, (-)-caryophyllene oxide, (-)-cyclocolorenone, (+)-nootkatone, (-)-elemol, (-)-abietic acid and (+)-dehydroabietic acid in rabbits.

The metabolism of (+)-longifolene, (-)-caryophyllene, (-)-caryophyllene oxide, (-)-cyclocolorenone, (+)-nootkatone, (-)-elemol, (-)-abietic acid and (+)-dehydroabietic acid was studied in rabbits. Each of these sesquiterpenoids was converted to primary, secondary or tertiary alcohols, among which the primary alcohol was predominant. A vinylic methyl group and an exomethylene group were easily hydroxylated and converted to a glycol via an epoxide in many cases. Eight new metabolites were determined by chemical and spectroscopic methods.

Sesquiterpenes from Porella species

Abstract The Porella liverworts contain abundant sesquiterpenes. ent-Biocyclogermacrene, three ent-aromadendrenes, a unique hydrocarbon, α-pinguisene and two drimane type sesquiterpenes were obtained together with the intensly pungent component, tadeonal, from P. vernicosa and P. gracillima. P. macroloba contained the same sesquiterpenes except for the absence of ent-bicyclogermacrene and the ent-aromadendrenes. The fragrant odor of P. perrottetiana was composed of α-pinene and camphor.

Sesquiterpenes from Japanese liverworts

Abstract Five Japanese liverworts (Bazzania sp.) were examined for sesquiterpenes. B. japonica and B. pompeana contained two new drimane-type sesquiterpene esters, albicanyl 3,4-dihydroxycinnamate and albicanyl 2,4dihydroxycinnamate. Tridensenone, a new aromadendrane-type sesquiterpene ketone was isolated from B. tridens. The stereostructures of these new sesquiterpenes were elucidated mainly by spectrometry. Barbatane-, bazzanane- and cuparane-type sesquiterpenes were found in all of the five species investigated. These sesquiterpenes, along with the new drimane- and aromadendrane-type sesquiterpenes are useful chemosystematic markers.

Total assignment of 1H and 13C NMR spectra of marchantins isolated from liverworts and its application to structure determination of two new macrocyclic bis(bibenzyls) from Plagiochasma intermedium and Riccardia multifida

Abstract 1 H and 13 C NMR spectra of five marchantins isolated from Marchantia species (Liverwort) have been completely assigned using NOE difference, 13 C- 1 H correlation and long-range proton selective decoupling (LSPD) spectra. The structures of two macrocyclic bis(bibenzyls) have been determined by use of this assignment.