Hisayoshi Kofujita

A diterpene quinone from the bark of Cryptomeria japonica

A diterpene, cryptoquinone, was isolated from the bark of Cryptomeria japonica, the structure, 7,11,14-trioxoabieta-8,12-diene, was established by spectral analyses and X-ray crystallography. This diterpene quinone showed moderate antifungal activities against Pyricularia orizae and Alternaria alternata, and cytotoxic activity against mouse lymphoid neoplasm (P388) cells with an IC(50) of 0.26 microg/ml.

Antifungal diterpenes from the bark of Cryptomeria japonica D. Don

Abstract Bioassay-guided isolation of compounds from n-hexane extracts of the bark of Cryptomeria japonica resulted in six abietane- and two pimarane-type diterpenoids, including a new compound, 12-methoxy-6α,11-dihydroxyabieta-8,11,13-triene. The structure of the new substance was established by spectral analyses and comparison with related compounds. The antifungal activities of these diterpenes were evaluated against the phytopathogenic fungi Alternaria alternata, Pyricularia oryzae, Rhizoctonia solani and Fusarium oxysporum. The diterpenes showed moderate antifungal activity against the fungi examined.

Antioxidant activity and mechanism of the abietane-type diterpene ferruginol

The antioxidant activity of the abietane-type diterpene ferruginol was evaluated by comparison with that of carnosic acid, ( ± )-α-tocopherol and dibutylhydroxytoluene using 2,2-diphenyl-1-picrylhydrazyl, β-carotene bleaching and linoleic acid assays. Ferruginol had the lowest antioxidant activity of this group using the 2,2-diphenyl-1-picrylhydrazyl and β-carotene methods in polar solvent buffer. However, ferruginol exhibited stronger activity than carnosic acid and α-tocopherol for linoleic acid oxidation under non-solvent conditions. Five peaks corresponding to ferruginol derivatives were detected through GC-MS analysis of the reaction between ferruginol and methyl linoleate. The three reaction products were identified as dehydroferruginol, 7β-hydroxyferruginol and sugiol, and the other two peaks were assumed to be 7α-hydroxyferruginol and the quinone methide derivative of ferruginol. The time course of the reaction suggests that the quinone methide was produced early in the reaction and reacted further to produce dehydroferruginol, 7-hydroxyferruginol and sugiol. Thus, we inferred that quinone methide formation was a key step in the antioxidant reaction of ferruginol.

Prominent Differences in Leaf Fatty Acid Composition in the F1 Hybrid Compared with Parent Trees Larix gmelinii var. japonica and L. kaempferi

Fatty acid (FA) compositions in leaves were investigated for two families of F1 hybrids of Larix gmelinii var. japonica × L. kaempferi (F1) and their parent clones. Twenty-one FAs, from C12 to C32, were found in the leaves of both adult trees and seedlings. The levels of 18:1/(18:2 + 18:3) increased in the order L. kaempferi, F1, and L. gmelinii var. japonica, with significant differences between L. gmelinii var. japonica and F1 in adult trees, but these differences were not found in the seedlings. Moreover, in the adult trees, the 18:1/(18:2 + 18:3) levels in the neutral phospholipid fraction and the ΣC18/ΣC16, especially in the glycolipid fraction, showed significant differences among the three species. These characteristics are discussed from the viewpoint of lipid synthesis in the endoplasmic reticulum and chloroplasts, and of the activities and substrate specificities in sequential FA desaturation. Linear discriminant analysis suggested that the FA compositions are useable as an index in the identification of hybrid seedlings.

Synthesis of dihydroxyphenacyl glycosides for biological and medicinal study: β-oxoacteoside from Paulownia tomentosa

The protected structure of β-oxoacteoside (tomentoside A), 2-oxo-2-(3,4-dihydroxyphenyl)ethyl 3-O-(2,3,4-tri-O-acetyl-α-l-rhamnopyranosyl)-4-O-caffeoyl-β-d-glucopyranoside 14 was synthesized in 14% overall yield in 11 steps, starting from d-glucose for biological and medicinal studies of phenylpropanoid glycosides. The first step was the preparation of a 3-O-rhamnopyranosyl disaccharide sugar core 2 from a suitably protected rhamnosyl trichloroacetimidate 10 and glucose derivative (diacetone-d-glucose 1) in 71% yield. To the glucose moiety of this sugar core, several protection/deprotection procedures were performed sequentially to obtain a fully acetylated sugar core 7 with a 4-OH group on the glucose moiety, in 57% yield in five steps. Thereafter, to the 4-OH group of the glucose moiety, selective 4-O-caffeoylation was achieved by proton-transfer esterification with 3,4-di-O-allylcaffeic acid 16 to give the caffeoyl disaccharide 11 in 97% yield. Then, it was converted to trichloroacetimidate 13 for a glycosylation donor in 90% in two steps. Finally, anomeric glycosylation was conducted with 2-oxo-2-(3,4-di-allyloxyphenyl)ethyl alcohol 19 with catalytic amounts of BF3·Et2O to give 2-oxo-2-(3,4-di-allyloxyphenyl)ethyl 2,6-di-O-acetyl-3-O-(2,3,4-tri-O-acetyl-α-l-rhamnopyranosyl)-4-O-(3,4-di-allyloxycaffeoyl)-β-d-glucopyranoside 14 in 60% yield. Deprotected intermediates of compounds 2, 11, 14, and 19 which were obtained in high yield would be useful for biological and medicinal studies of phenylpropanoid glycosides.

A Comparative Study of Binding Sites for Diisopropyl Phosphorofluoridate in Membrane and Cytosol Preparations from Spinal Cord and Brain of Hens

Biochemical events in the initiation of organophosphorus induced delayed neurotoxicity (OPIDN) are not well understood. To find new putative target(s) for OPIDN, we investigated the biochemical and pharmacological characteristics of [3H] diisopropyl phosphorofluoridate (DFP) binding to membrane and cytosol preparations from the brain and spinal cord of hens in vitro. [3H]DFP binding to both preparations was determined by the specific binding obtained by subtracting non-specific binding from total binding. The specific binding sites of [3H]DFP were found not only on membrane but also in cytosol. Kd values were higher and Bmax values were lower in cytosol than in membrane. Moreover, the Kd values in both membrane and cytosol preparations from spinal cord were lower than those of brain. The Bmax values in membrane and cytosol were similar between brain and spinal cord. The specific binding to both preparations was markedly displaced by unlabeled DFP. The specific binding of DFP to the membrane was highly or partly displaced by organophosphorus compounds (OPs) or a carbamate, respectively. However, both the OPs and the carbamate had considerably weaker blocking effects on the specific binding of DFP to cytosol. None of the compounds known to interact with neuropathy target esterase (NTE) had a strong blocking effect on the specific binding of DFP to either membrane or cytosol. These results show that the specific binding of DFP to the membrane may be binding with cholinesterase (ChE). However, cytosol, especially in spinal cord, may have DFP binding sites other than ChE and NTE.

Ca2+-Signal Transduction Inhibitors, Kujiol A and Kujigamberol B, Isolated from Kuji Amber Using a Mutant Yeast

A podocarpatriene and a labdatriene derivative, named kujiol A [13-methyl-8,11,13-podocarpatrien-19-ol (1)] and kujigamberol B [15,20-dinor-5,7,9-labdatrien-13-ol (2)], respectively, were isolated from Kuji amber through detection with the aid of their growth-restoring activity against a mutant yeast strain ( zds1Δ erg3Δ pdr1Δ pdr3Δ), which is known to be hypersensitive with respect to Ca2+-signal transduction. The structures were elucidated by spectroscopic data analysis. Compounds 1 and 2 are rare organic compounds from Late Cretaceous amber, and the mutant yeast used seems useful for elucidating a variety of new compounds from Kuji amber specimens, produced before the K-Pg boundary.

Antitermitic activity of extracts from Chamaecyparis obtusa branch heartwood

The antitermitic activity of extracts from the branch heartwood of Chamaecyparis obtusa (hinoki) against Japanese termites (Reticulitermes speratus) was compared with that of the trunk. Samples of branch and trunk heartwood were extracted with n-hexane, ethyl acetate, and methanol successively. n-Hexane extracts of branch and trunk heartwood were strongly antitermitic, and branch heartwood contained greater quantities of active n-hexane extracts than trunk heartwood. Germacra-1-(10), 5-dien-4β-ol, t-cadinol, α-cadinol, hinokiresinol, and hinokinin were separated from the branch extracts and the termiticidal and antifeedant activity of these compounds was tested by no-choice and dual-choice test methods. The sesquiterpenoids, germacra-1-(10), 5-dien-4β-ol, t-cadinol and α-cadinol were strongly termiticidal. The norlignan hinokiresinol and lignan hinokinin had weak termiticidal, and strong antifeedant and repellent activity. High concentrations of germacra-1-(10), 5-dien-4β-ol and hinokiresinol were present in branch heartwood. These compounds protect hinoki branches from termites and other harmful organisms. Hinoki branch heartwood, which is usually unused, is a potential source of active antitermitic compounds.

Growth-inhibitory components in Sugi (Cryptomeria japonica) extracts active against Microcystis aeruginosa

Abstract The growth-inhibitory activity of extracts obtained from Sugi (Cryptomeria japonica) effective against Microcystis aeruginosa, an alga that causes harmful algal blooms in freshwater environments, was examined. Each sample of the inner bark, outer bark, heartwood, and leaves of Sugi was extracted with hexane, ethyl acetate, and methanol successively. Inhibitory activities were observed in the inner bark ethyl acetate and methanol extracts, the heartwood hexane extract, the outer bark hexane extract, and the leaf ethyl acetate extract. The inner bark ethyl acetate and methanol extracts showed stronger activities than the other extracts. Catechin, epicatechin, and procyanidin B3 were identified as the active components in the inner bark ethyl acetate and methanol extracts. The terpenoids 1-epicubenol, 4-epicubebol, cubenol, δ-cadinol, sandaracopimarinal, and sandaracopimarinol were the active components of the heartwood hexane extract. Thus, it was indicated that not only the polyphenolic components but also non-phenolic terpenoids had growth inhibition activity against M. aeruginosa.

Screening for condensed tannin-degrading fungi with a synthetic 14C-labeled compound

To find fungi that are potent for degradation of condensed tannin, a two-step screening was used. This involved measurement of fungal growth rate on Japanese cedar (Cryptomeria japonica) bark, followed by determination of [14C]-labeled CO2 generated from fungal degradation of synthetic [14C]-labeled condensed tannin model. In the first screening, 75 strains of wood rot fungi were tested, and 19 strains effectively decreased bark weight and/or the weight of the methanol-soluble fraction. For the second screening, [14C]-labeled condensed tannin model compound was synthesized in 11.8% yield based on radioactivity measurements. Over the incubation period, Coriolus hirsutus K-2671, Lentinus edodes Is, and Lampteromyces japonicus Nn showed higher cumulative [14C]-labeled CO2 emissions than the other strains and mineralized the [14C]-labeled condensed tannin model compound by 3.7%, 3.0%, and 3.0%, respectively. Fractionation of the methanol extracts from the medium by gel permeation chromatography after fungal treatment suggested that fungi that can induce the emission of significant levels of [14C]-labeled CO2 can extensively depolymerize condensed tannins.