(−)-Carvone: Antispasmodic effect and mode of action

(−)-Carvone is a monoterpene ketone found in spearmint (Mentha spicata var. crispa) essential oil that is widely used as an odor and flavor additive. An intestinal antispasmodic effect was recently reported for (−)-carvone, and it has been shown to be more potent than its (+)-antipode. The mechanism of (−)-carvone action in the intestines has not been investigated. To gain a better understanding of the (−)-carvone antispasmodic effect, we investigated its pharmacological effects in the guinea pig ileum. Terminal portions of the ileum were mounted for isotonic contraction recordings. The effect of (−)-carvone was compared with that of the classical calcium channel blocker (CCB) verapamil. In isolated ileal smooth muscle, (−)-carvone did not produce direct contractile or relaxation responses and did not modify electrically elicited contractions or low K⁺-evoked contractions. The submaximal contractions induced by histamine (p < 0.001), BaCl₂ (p < 0.05), and carbachol (p < 0.01) were significantly reduced by (−)-carvone. The contractile response elicited by high concentrations of carbachol was reduced but not abolished by (−)-carvone. No additive action was detected with co-incubation of (−)-carvone and verapamil on carbachol-induced contraction. (−)-Carvone reduced the contraction induced by high K⁺ and was almost 100 times more potent than verapamil. Thus, (−)-carvone showed a typical and potent CCB-like action. Many effects described for both (−)-carvone and spearmint oil can be explained as a CCB-like mode of action.     

Cloning and Sequence Analysis of a Glucose-6-Phosphate Dehydrogenase Gene PsG6PDH from Freezing-tolerant Populus suaveolens

A 1 207 bp cDNA fragment (PsG6PDH) was amplified by RT-PCR from cold-induced total RNA of the freez- ing-tolerant P. Suaveolens, using primers based on the highly conserved region of published plant glucose-6-phosphate dehydro- genase (G6PDH) genes. The sequence analysis showed that PsG6PDH coding region had 1 101 bp and encoded 367 predicted amino acid residues. Moreover, the nucleotide sequence of PsG6PDH showed 83%, 82%, 79%, 79% and 78% identity, and the derived amino acid sequence shared 44.2%, 44.7%, 42.0%, 40.5% and 43.9% identity with those of the Solanum tuberosum, Nicotiana ta- bacum, Triticum aestivum, Oryza sativa and Arabidopsis thaliana, respectively. The results show that PsG6PDH is a new member of G6PDH gene family and belongs to the cytosolic G6PDH gene. This is the first report on cloning of the G6PDH gene from woody plants.     

6-Carboxydihydroresveratrol 3-O-β-glucopyranoside — A novel natural product from the Cretaceous relict Metasequoia glyptostroboides

Metasequoia glyptostroboides, a tree native to China, is described as a living fossil and has existed for millions of years. The oldest fossils recorded have been dated to the late Cretaceous era. During the time of its existence, the molecular defence system of the tree has apparently resisted millions of generations of pathogens, which encouraged search for novel natural product from this source. Eight compounds have been characterised from needles of M. glyptostroboides, including the novel natural product 6-carboxydihydroresveratrol 3-O-β-glucopyranoside. The structure determinations were based on extensive use of 2D NMR spectroscopic techniques and high-resolution mass spectrometry.     

High Level Expression of Glucose-6-phosphate Dehydrogenase Gene PsG6PDH from Populus suaveolens in E. coli

In order to investigate the functions of the gene PsG6PDH and the mechanisms underlying freezing tolerance of Populus suaveolens, the recombinant expression vector pET-G (pET30a-G6PDH), which contained full encoding region of PsG6PDH gene, was established. The recombinant was identified by lawn-PCR and double enzyme digestion and then transformed into expression host XA90 and induced by isopropyl-a-D-thiogalactoside (IPTG) to express 100 kD polypeptide of G6PDH fusion protein. The results showed that the expressed amount of the fusion protein culminated after 1 mmol·L–1 IPTG treatment for 4 h and that pET-G product was predominately soluble and not extra-cellular secreting.     

Benzyl-β-resorcylates from Cassia obtusifolia

The seed of Cassia obtusifolia Linn have yielded three new compounds, 2-benzyl-4,6-dihydroxy benzoic acid (1), 2-benzyl-4,6-dihydroxy benzoic acid-6-O-β-d-glucopyranoside (2) and 2-benzyl-4,6-dihydroxy benzoic acid-4-O-β-d-glucopyranoside (3). Their structures were determined by spectroscopic methods, including ¹D- and ²D NMR spectroscopy, HR-ESI-MS, as well as by comparison of their spectral data with those of related compounds.     

Mode of action of brown rot decay resistance of acetylated wood: resistance to Fenton’s reagent

Acetylation is known to enhance the resistance of wood to brown rot fungi. As initial decay by some brown rot fungi is assumed to be caused by the Fenton reaction, pine micro-veneers acetylated to various weight percent gains (WPG) were exposed in a solution containing iron ions and hydrogen peroxide, i.e., Fenton’s reagent. Mass loss and tensile strength loss as well as the decomposition of hydrogen peroxide within the incubation time decreased with increasing WPG of the veneers. Incubation of untreated and acetylated veneers in acetate buffer containing ferric ions without H₂O₂ revealed that the modification strongly reduced the uptake of Fe ions by the wood cell wall. FT-IR analysis indicated oxidation of the unmodified control veneers but did not show predominant decay of specific cell wall components. Spectra of acetylated veneers did not reveal any significant changes induced by Fenton’s reagent. It was concluded that one possible reason for the enhanced resistance of acetylated wood to the Fenton reaction could be the reduced or almost completely prevented uptake of Fe ions by the wood cell wall.     

Intratree Variability of Cleavage Resistance of Chinese Fir from Plantation

INTRODUCTION Chinese fir (Cunninghamia lanceolata) is a very important timber species in the southern China (Shi Jisen et al. 1987). It is good, fast-growing, and exempts from serious plant diseases. Its plantation is big in terms of size in the South of China and its storage stock is very rich, which is about 20% of the national commodity wood (Zhou Shuangquan et al. 2000). And the lumber becomes mainly commercial construction materials in China because of straight grain, light and so…     

Construction of cDNA Library from Populus euphratica

1 Introduction Populus euphratica is a salt tolerant tree species, which is mainly distributed in the desert regions in northwest China (Wei 1993). Moreover, it is the only large tree species, which can survive and develop into forest in these arid and saline-alkali areas. P. euphratica forest plays a very important role in restraining the expansion of desert, maintaining ecological environment in west China, protecting the biological diversity and raising the local people抯 living standard…     

Manufacture of Light-weight Composite Panel from Kenaf

Light-weight composite panels were manufactured using kenaf core particles as core material and kenaf bast fiber-woven sheets as top and bottom surfaces. Methylene diphenyldiisocyanate （MDI） resin was used as the adhesive with the resin content of 4% for core particles and 50 g/m^2 for bast fiberwoven sheets. The target board densities were set at 0.35.0.45 and 0.55 g/cm^3. The composite panels were evaluated With Japanese Industrial Standard for Particleboards （JIS A 5908- 2003）.The results show that the composite panel has high modulus of rupture and internal bonding strength. The properties of 0.45 g/cm^3 density composite panel are： MOR 20.4 MPa. MOE 1.94 MPa, IB 0.36 MPa, WA142%, TS 21%. Kenaf is a good raw material for making light-weight composite panels.     

Membrane stabilizing activity — a possible mechanism of action for the anti-inflammatory activity of Cedrus deodara wood oil

The volatile oil of the wood of Cedrus deodara (50 and 100 mg/kg, p.o.) produced a significant inhibition of compound 48/80 and nystatin-induced rat paw edema. It also inhibited heat- as well as hypotonic solution-induced haemolysis of erythrocytes in vitro. The anti-inflammatory activity of the oil could be due to its membrane stabilizing action.     

Chemical characterization of smoke from the production process of wood-plastic composites

The chemical composition of unpleasant smell, emitted from the production process of wood-plastic composites using Manchurian ash sawdust (Fraxinus mandschurica Rupr.) and polypropylene powder as the raw material, was investigated. Wood sawdust and polypropylene powder were subjected to heat treatment to 290°C during 8 min (the conditions were similar to those employed on an industrial scale). The emitted compounds were collected and analyzed by gas chromatography-mass spectrometry (GC-MS). The analytical r...     

Preparation of phenol formaldehyde resin from phenolated wood

The technique for preparing phenol formaldehyde resin from phenolated wood (PWF) and its characters were studied and analyzed. Poplar (Populus spp) wood meal was liquefied by phenol in the presence of sulfuric acid as a catalyst. After the liquefied products were cooled, alkaline catalyst and formaldehyde were added. The mixture was kept at (60±2)°C for 1h and then was heated to (85±2)°C for 1h. The influence of molar ratio of formaldehyde to phenol (F/P) was investigated. The results showed when the molar ratio of formaldehyde to phenol was over 1.8, the PWF adhesives had high bond quality, bond durability and extremely low aldehydes emissions. Foundation item: The research was supported by Sino-Japanese Technical Cooperation Project (2-1-b) and the key technologies R & D Program for the 10th Five-Year Plan (325-11). Biography: LI Gai-yun (1974-), female, Assistant professor in Research Institute of Wood Industry, Chinese Academy of Forestry, Beijing 100091, P. R. China Responsible editor: Zhu Hong     

An enumeration of bryophytes collected from North Korea

InttxiductionDurillg2()-3OAugust1997,tllcsel1iorautl1orCao'fol1gwitllhisfourcolleaguesl1adthcopportu11itytovisittheDem()craticPeoplekRepublicofKorea(Nord1Korea)throughscientificexchangepr`'granlbetWee11CI1inesealldKoreanAcademiesofScie11ces.Tllepresel1treportisbasedmainlyonmorethanl()()collecti()nsnla`Iebyl1in1duringthefieldexcursiono11Mt.KuIl1gallgsal1a11dMt.Myohyangsan.81speciesbeIo11gli1gto52ge11era,26fandliesofmossesandl6speciesbelol1gingto12gellera,1of8miliesofhePaticsarerecor`ed…     

High-frequency Induction of Adventitious Shoots from Leaves of Robinia pseudoacacia by Thidiazuron

INTRODUCTION Black locust (Robinia pseudoacacia L.) is a nitrogen- fixing leguminous tree valuable for its agroforestry qualities (ornamental value, timber production, animal feed, and honey production). Moreover, its fast growing rate and potential for environmental amelioration have drawn attention to the species as one of the leading candidates for woody biomass plantations (Mitchell C P, 1988; Ranney J W, et al, 1988). The amenability of black locust to be regenerated by tissue cul…     

Total contents of Volume 6, 2007

Vol. 6 No. 1 WANG Ge JIANG Zhehui HSE Chung Y SHUPE Todd F Physical and Mechanical Properties of Flakeboard Reinforced with Bamboo Strips (1-8) CHANG Liang WANG Zheng GAO Li GUO Wenjing No-formaldehyde Wood-plastic Composite Plywood in China (9-13) YAN Zh…     

Estimation of Direct Carbon Emissions from Chinese Forest Fires

Therecentresearchesshowthattheemissionsfrombiomassburninghaveshortandlong-termeffectsonatmosphere.Biomassburningistheburningoftheworldsvegetation,includingforests,savannas,andagriculturalland,forlandclearingandland-usechange.Forestfireisthemostimportantpart.Theimmediateeffectofburningistheproductionandreleaseintoatmosphereofgasesandparticulatesresultingfromthecombustionofbiomassmatter(Joel,etal,2000).TheinstantaneouscombustionproductsofvegetationburningincludeCO2,CO,CH4,nonmethanehydrocarbo…     

Extraction of betulin from bark of Betula platyphylla by supercritical carbon dioxide extraction

Betulin, which is a medicinal pentacyclic triterpene, is abundant in the bark of white birch (Betula platyphlly). The bark of birch was collected at Tayuan Forest Farm of Jiagedaqi, Heilongjiang Province in September 2000. Supercritical fluid extraction (SFE) that is a new separation technology has been used for the processing pharmaceutical and natural products. In this paper, the extraction of betulin from the bark of birch by supercritical CO2 extraction was studied. The authors investigated and analyzed a few parameters such as modifier dosage, extraction pressure and extraction temperature. The optimal extraction conditions showed that the modifier dosage used for per gram bark powder was 1.5 mL, the extraction pressure was at 20 Mpa, and the extraction temperature was at 55 ℃. The velocity of flow of liquid CO2 was at 10 kg/h. The pressure and temperature in separation vessel were at 5.5 Mpa and 50 ℃, respectively.     

Rooting of juvenile succulent cuttings from haif‐sib families of Picea abies

Leader shoots from juvenile succulent Norway spruce seedlings were used as cuttings 11 weeks after sowing. The seedlings were grown for 6 additional weeks and then apically dominant and lateral shoots were also used as cuttings. These three cutting categories, leaders, dominants and laterals, rooted 99.4, 99.0 and 97.5 % respectively and performed differently with respect to rooting development, number of roots per cutting and response to IBA and PIBA treatments (synthetic auxins). A large individual variation in number of roots per cutting, which auxin treatments did not reduce, was present within each cutting categoty. Laterals from the three different families included in the study showed a different variation than did leaders and dominants. Generally, the juvenile succulent cuttings were easy to root. Seedlings grown at a rather high light intensity (62 W/m²) had the potential to give good rooting even without hormonal treatments.     

Effect of Isolation of Hainan Island from the Mainland on the Genetic Variation of Podocarpus imbricatus

Random amplified polymorphic DNA (RAPD) markers were used to analyze genetic variation of Podocarpus imbricatus in Hainan Island and Mainland of China. Two populations of Dacrydium pierrei were used as comparison materials. Both Podocarpus imbricatus and Dacrydium pierrei showed a low level of genetic diversity. However, Podocarpus imbricatus showed higher genetic diversity and higher population differentiation than Dacrydium pierrei. The geographic range may affect the geneticdiversity of Podocarpus imbricatus and Dacrydium pierrei signific antly. The UPGMA cluster tree showed that populations of Podocarpus imbricatus in Hainan Island and Guangxi Zhuang Autonomous Region were closer than those in Yunnan Province,indicating possible gene flow between Hainan Island and Guangxi Zhuang Autonomous Region. The young geological history of Hainan Island and the three times of unification and separation between Hainan Island and the Mainland may give the two species more possibilities of gene flow.