Studies on constituents from Chamaecyparis pisifera and antibacterial activity of diterpenes.
In the course of our research for biologically active constituents from coniferous plants, a chromone derivative (1) and an abietane derivative (2) were isolated along with several diterpenes from Chamaecyparis pisifera. Structures of the new compounds were determined to be 5,7-dihydroxy-2-(1-acetyl-2-methoxycarbonylethyl)-chromone and rel-(8R,10R,20S)-8,10,20-trihydroxy-9(10-->20)-abeo-abieta-9,13-dien-12-one by means of spectral methods including two-dimensional NMR experiments. Some of these abietane-type compounds isolated from this plants showed antibacterial activitv against the gram-positive bacteria Staphylococcus aureus and Bacillus subtilis. (+info
Changes in ABA turnover and sensitivity that accompany dormancy termination of yellow-cedar (Chamaecyparis nootkatensis) seeds.
Yellow-cedar (Chamaecyparis nootkatensis [D. Don] Spach) seeds exhibit prolonged coat-imposed dormancy following their dispersal from the parent plant. Analyses were undertaken using S-(+)-[(3)H] abscisic acid (ABA) to monitor the capacity of embryos to metabolize ABA following their isolation from seeds subjected to various dormancy-breaking and control treatments. Radiolabelled phaseic acid (PA) and dihydrophaseic acid (DPA) were detected in embryos and, to a greater extent in the surrounding media, by 48 h regardless of whether the embryos had been excised from seed previously subjected to only a 3 d soak or to a full dormancy-breaking treatment. Of the two enantiomers of ABA, only the natural S-(+)-ABA effectively inhibited germination of isolated embryos. A metabolism-resistant synthetic ABA analogue S-[8',8',8',9',9',9']-hexadeuteroabscisic acid, S-(+)-d6-ABA, consistently slowed the germination rate of excised embryos to a greater extent than that caused by natural S-(+)-ABA. The deuterium-labelled ring methyl groups of the analogue made it more resistant to oxidation by yellow-cedar embryos and thus rendered the analogue more persistent and possessing greater activity. With increasing time of exposure to moist chilling, yellow-cedar embryos became increasingly insensitive to both ABA and to the analogue. Subjecting seed to chemical treatments (GA(3) in combination with 1-propanol) prior to moist chilling strongly enhanced the germinability of whole seeds. This treatment also had a relatively greater impact on ABA metabolism than did moist chilling alone, as indicated by a greater capacity of S-(+)-d6-ABA to inhibit the germination of embryos as compared to S-(+)-ABA. Moist chilling was most critical for reduced ABA sensitivity of embryos. A change in the embryo's ability to metabolize ABA and reduced embryo sensitivity to ABA are two factors associated with dormancy termination of whole seeds of yellow cedar; a change in only one of these factors is insufficient to elicit high germinability. (+info
Linking deer browsing and terpene production among genetic identities in Chamaecyparis nootkatensis and Thuja plicata (Cupressaceae).
To investigate whether differential herbivore browsing reflects genetic variation in plant defense expression, variation in needle terpenes and damage caused by black-tailed deer (Odocoileus hemionus) was analyzed on yellow-cedar (Chamaecyparis nootkatensis) and western redcedar (Thuja plicata). In a 100-genet yellow-cedar population, three genets that were heavily browsed and had extremely low levels of monoterpenes (0-0.36% dry matter), sesquiterpenes, and diterpenes were compared to unbrowsed genets (0.85-3.83% monoterpenes in dry matter). These differences were maintained in individuals protected from browsing, suggesting genetically based variation in constitutive terpene production. In western redcedar, heavily browsed trees had significantly lower total monoterpene concentrations (1.69% dry matter) than lightly browsed trees (3.32% dry matter). One heavily browsed tree expressed no monoterpenes. No differences were found for diterpenes. In both species, the genotypes with extremely low monoterpene concentrations came from the same open-pollinated families. (+info
Novel diterpenes from the heartwood of Chamaecyparis obtusa var. formosana.
Two novel diterpenes, obtusanal B (1) and obtusadione (2), along with obtusanal A (3), obtunone (4), 12-hydroxy-6,7-secoabieta-8,11,13-triene-6,7-dial, 8,12-dihydroxydielmentha-5,9-diene-7,11-dione and myrcene, isolated from the heartwood of Chamaecyparis obtusa var. formosana, were characterized by spectroscopic means, including 2D-NMR techniques. Compounds 1 and 2 are 7(6-->2)abeoabietane and 14(8-->9)abeoabietane type diterpenes, respectively. Their biosyntheses were proposed. (+info
Genetic diversity and the genetic structure of natural populations of Chamaecyparis obtusa: implications for management and conservation.
We investigated 25 natural populations of Chamaecyparis obtusa using 51 cleaved amplified polymorphic sequence (CAPS) markers, which were developed using information on sequence-tagged sites (STS) in Cryptomeria japonica. Most CAPS markers have codominant expression patterns, and are suitable for population studies because of their robustness and convenience. We estimated various genetic diversity parameters, including average heterozygosity (H(e)) and allelic richness and found that the more peripheral populations tended to have lower genetic diversity than central populations, in agreement with a previous theoretical study. The overall genetic differentiation between populations was low, but statistically significant (G(ST)=0.039), and similar to the level reported in a previous allozyme study. We attempted to detect non-neutral loci associated with local adaptation to clarify the relationship between the fixation index (F(ST)) and H(e) values for each locus and found seven candidates non-neutral loci. Phylogenetic tree analysis of the populations and Bayesian clustering analysis revealed a pattern of gradually increasing isolation of populations with increasing geographical distance. Three populations had a high degree of linkage disequilibrium, which we attribute to severe bottlenecks due to human disturbance or competition with other species during their migration from refugia after the most recent glaciation. We concluded that the small populations in western Japan and in Kanto district are more important, from a conservation perspective, than the populations in central Japan, due to their genetic divergence, relatively small sizes and restricted areas. (+info
Neurite outgrowth-promoting active constituents of the Japanese cypress (Chamaecyparis obtusa).
In the screening of biologically active constituents from woody plants, the methanol extract of leaves of Chamaecyparis obtusa showed potent neurite outgrowth-promoting activity in neuronal PC12 cells. The ethyl acetate-soluble fraction of the methanol extract showed potent activity and was separated by means of various chromatographic methods to give the two new compounds 1 and 2, as well as 11 known lignan and sesquiterpene derivatives. The structures of the new compounds were determined to be 9-O-acetyldihydrosesamin (1) and 9-O-(11-hydroxyeudesman-4-yl)dihydrosesamin (2), respectively, in NMR studies including 2D-NMR experiments. Of the 13 compounds, the known compound hinokinin (5) and the new compound 2 showed potent neurite outgrowth-promoting activity in PC 12 cells. (+info
Chitin synthase 2 inhibitory activity of O-methyl pisiferic acid and 8,20-dihydroxy-9(11),13-abietadien-12-one, isolated from Chamaecyparis pisifera.
In the course of search for potent chitin synthase inhibitors from plant extracts, the chitin synthase 2 inhibitors, O-methyl pisiferic acid and 8,20-dihydroxy-9(11),13-abietadien-12-one which have diterpene skeleton, were isolated from the leaves of Chamaecyparis pisifera. These compounds inhibited chitin synthase 2 of Saccharomyces cerevisiae with the IC50 values of 5.8 and 226.4 microM, respectively. Especially, O-methyl pisiferic acid showed 15.3-fold stronger inhibitory activity than polyoxin D (IC50=88.6 microM), a well-known chitin synthase inhibitor. These compounds exhibited weaker inhibitory activities against chitin synthase 1 than chitin synthase 2, whereas it showed no inhibitory activity for chitin synthase 3. The compound exhibited mixed competitive inhibition with respect to UDP-N-acetyl-D-glucosamine as substrate (Ki=5 microM). These results indicated that O-methyl pisiferic acid is a specific inhibitor of chitin synthase 2. The compound also inhibited chitin synthase 1 of Candida albicans, which represents analogues to chitin synthase 2 of S. cerevisiae, with an IC50 of 75.6 microM, which represents 1.8-fold weaker activity than that of polyoxin D. Although O-methyl pisiferic acid has been reported for antibacterial and insecticidal activities, the present study is the first report on its inhibitory activity against chitin synthase 2. (+info
Characterization of pollen dispersion in the neighborhood of Tokyo, Japan in the spring of 2005 and 2006.
The behavior of Japanese cedar (Cryptomeria japonica) and Japanese cypress (Chamaecyparis obtusa) pollens in an urban area was examined through the measurements of the dispersion characteristics at the various sampling locations in both outdoor and indoor environments. Airborne pollens were counted continuously for three months during the Japanese cedar pollen and Japanese cypress seasons in 2005 and 2006 by the use of Durham's pollen trap method in and around Tokyo, Japan. The dispersion of pollens at the rooftop of Kyoritsu Women's University was observed to be at extremely high levels in 2005 compared with previously reported results during the past two decades. As for Japanese cedar pollen, the maximum level was observed as 440 counts cm(-2) day(-1) on 18 March 2005. Japanese cypress pollen dispersed in that area in the latter period was compared with the Japanese cedar pollen dispersions. The maximum dispersion level was observed to be 351 counts cm(-2) day(-1) on 7 April 2005. Total accumulated dispersions of Japanese cedar and Japanese cypress pollens were 5,552 and 1,552 counts cm(-2) for the three months (Feb., Mar. and Apr.) in 2005, respectively. However, the dispersion of both pollens in 2006 was very low. The total accumulated dispersions of Japanese cedar and Japanese cypress pollens were 421 and 98 counts cm(-2) for three months (Feb., Mar. and Apr.) in 2006, respectively. Moreover, the pollen deposition on a walking person in an urban area showed that the pollen counts on feet were observed to be extremely high compared with the ones on the shoulder, back and legs. These findings suggested that pollen fell on the surface of the paved road at first, rebounded to the ambient air and was deposited on the residents again. Furthermore, the regional distribution of the total pollen dispersion in the South Kanto area was characterized on 15-16 March 2005 and on 14-15 March 2006. Although the pollen levels in 2005 were much higher than in 2006, it was commonly observed that higher pollen counts existed in the outlying areas. That is, the pollen counts in an urban area were confirmed to be at a lower level. As for the indoor dispersion of pollens, two cases were evaluated. At the lobby of the main building of Kyoritsu Women's University, the averaged ratio of the indoor to the outdoor pollen count is 4.1%. Another case was at the hospital building of a medical school. The pollen dispersion in the indoor environment was also observed to be low. It was concluded that the indoor pollen would be mainly carried from the outer environment by the movement of air. (+info