New sesquiterpenoids of Bombax malabaricum

Hemigossypol-6-methyl ether, reported to be present in the root bark of Bombax malabaricum, has been shown to be isohemigossypol-1-methyl ether. Isohemigossypol-1,2-dimethyl ether, 8-formyl-7-hydroxy-5-isopropyl-2-methoxy-3-methyl-1,4-naphthaquinone, 7-hydroxycadalene and an unidentified phenolic compound have also been isolated. Long range couplings in the ¹H NMR spectrum of isohemigossypol-1-methyl ether have been established by decoupling experiments.     

Essential oil variation in Calyptranthes spruceana

Two chemical races in Calyptranthes spruceana were examined. One of them contains limonene, geranial and perillaldehyde as the main constituents of its essential oil. The other is shown to contain α-pinene, β-pinene, neral and geranial as its major oil components.     

Cuauthemone sesquiterpenoids from Blumea alata

The investigation of five Blumea species afforded, in addition to known compounds, several cuauthemone derivatives, most of them being 7,11-epoxides, some thymol derivatives, an eremophilane epoxide and a himachalane diol. From Pterocaulon virgatum a further himachalane derivative was isolated. The structures were elucidated by spectroscopic methods and in part by partial synthesis.     

土壤逐渐干旱对菖蒲生长及光合荧光特性的影响

在土壤逐渐干旱过程中,连续测定典型湿地植物菖蒲生长发育状况及叶片叶绿素荧光参数,结果表明:短期内(实验第O-3天)土壤水分含量下降(土壤含水率自53.86％下降至42.6％)有利于菖蒲生长,干旱组菖蒲叶片Fv/ Fm、Yield、qP显著高于对照组(实验期间土壤平均含水率为53.49±0.6％)(P＜0.05),qN则低于对照组;随着土壤进一步干旱(土壤含水率自42.6％下降至18.02％,实验第3-9天),菖蒲叶片qN值则由0迅速上升至0.403,显著高于对照组(P＜0.05),Fv/Fm值与对照相比无显著差异(P＞0.05),叶片保持较高的热耗散以维持光合结构PSⅡ保持正常,并能以降低叶片含水率、叶面积(叶片卷曲避光)减少水分蒸腾及降低根系含水率促进水分吸收的方式进行自我保护;随着土壤干旱程度加剧(土壤含水率自18.02％下降至4.5％、实验第9-12天),菖蒲叶片Fv/ Fm、yield、qP值显著低于对照组(P＜0.05),qN值降为0,光合结构PSⅡ受到损坏,第11天、12天,叶片含水率分别降至75.79％和68.78％,此时菖蒲也逐步以自小叶片至大叶片的顺序枯萎衰亡,表明在土壤水分快速下降过程中过高的生物量将不利于菖蒲保持水分,而80％左右的叶片含水率是维持菖蒲存活的临界值.     

Changes in the sweet proteins (thaumatins) in thaumatococcus danielli fruits during development

The thaumatin content (forms TO, TI and TII) of fruits from Thaumatococcus danielli at various stages of maturation were examined. The amounts of all three forms of sweet protein increased during maturation to reach a total of about 50 mg/g in mature aril tissue in fruits from both the Ashanti and Kadjebe regions of Ghana. TO was a minor form in fruits at all stages of development from both regions. The major regional difference was that TII was absent from the Kadjebe fruits; however, the total level of sweet proteins was maintained by increased levels of TO and TI. Structural and immunological comparisons of the three thaumatin forms showed that TO is closely related to the other two forms which are known to differ at only five positions in their primary structure.     

Sesquiterpenes of six Porella species (hepaticae)

The distribution in six Porella species of drimane-, aromadendrane- and pinguisane-type sesquiterpenes and norsesquiterpenes is described. The sharp pungent substance of P. gracillissima, P. fauriei and P. macroloba is (+)-tadeonal.     

Sesquiterpenes from Artemisia princeps

Copaene, cyperene, caryophyllene, β-farnesene, α-himachalene, γ-humulene and farnesyl acetate were isolated from the root of Artemisia princeps. As a result of isomerization studies on γ-humulene, the main constituent, a preferred conformation was proposed.     

New sesquiterpenes from Pleocarphus revolutus

Six new sesquiterpenes of the guaiane and isopatchoulenone types have been isolated from the Chilean plant Pleocarphus revolutus. Of these, the compound hydroxy-isopatchoulenone and related esters showed cytotoxicity towards TLX5 mouse mammary lymphoma cells.     

Enantiomeric type sesquiterpenoids of the liverwort Marchantia polymorpha

A series of ent-sesquiterpenoids corresponding to the optical antipodes of those in higher plants have been isolated from the liverwort Marchantia polymorpha. These sesquiterpenoids provide yet another example of the peculiar stereospecificity of the biogenesis of the liverwort sesquiterpenoids and suggest a special taxonomic position of the liverworts in the plant kingdom.     

Volatile constituents of spanish origanum (Coridothymus capitatus) essential oil

Analysis of the neutral fraction of Coridothymus capitatus essential oil (Spanish origanum oil) revealed 61 components. Of the new components reported there were 25 monoterpenes, 9 sesquiterpenes, 5 aliphatic, 1 phenol and 1 phenyl ether.     

光照和生长阶段对菖蒲根系泌氧的影响

以自然湖泊沉积物为研究基质,利用微型电机控制溶氧微电极实现纵向精确微位移,在照光与遮光条件下,对典型湿地植物菖蒲幼苗、成株根系根基部起总根长1/4处(根1/4)、根系中部(根1/2)、从根基部起总根长3/4处(根3/4)及根尖(根1)处根系微界面径向溶氧浓度变化进行原位精确测定。结果表明:无论有无光照,菖蒲幼苗、成株根系不同部位均存在从根表面至沉积物氧饱和度由高到低的氧扩散层,其厚度0.18—0.68 mm;根1/2、3/4、1处氧扩散能力菖蒲成株较幼苗显著增强(P<0.01),根1/4处二者则无显著差异(P>0.05);光照对菖蒲幼苗、成株根系不同部位氧扩散能力的影响存在差异,光照对菖蒲幼苗根1/2及菖蒲成株根1/2、根3/4处影响显著(照光组显著高于遮光组,P<0.01),而对菖蒲幼苗根1/4、根3/4、根1及菖蒲成株根1/4、根1处无显著影响(P>0.05);从根系泌氧空间差异上看,照光条件下菖蒲幼苗、成株分别表现为根1/2>根3/4≈根1≈根1/4(P<0.01,P>0.05)和根1/2>根3/4>根1>根1/4(P<0.01),遮光条件下菖蒲幼苗、成株分别表现为根1/2≈根3/4≈根1≈根1/4(P>0.05)和根1/2>根3/4≈根1>根1/4(P<0.01,P>0.05)。     

UV-B is required for normal development of oil glands in Ocimum basilicum L. (sweet basil)

Plants of Ocimum basilicum L. grown under glass were exposed to short treatments with supplementary UV-B. The effect of UV-B on volatile essential oil content was analysed and compared with morphological effects on the peltate and capitate glandular trichomes. In the absence of UV-B, both peltate and capitate glands were incompletely developed in both mature and developing leaves, the oil sacs being wrinkled and only partially filled. UV-B was found to have two main effects on the glandular trichomes. During the first 4 d of treatment, both peltate and capitate glands filled and their morphology reflected their 'normal' mature development as reported in the literature. During the following days there was a large increase in the number of broken oil sacs among the peltate glands as the mature glands broke open, releasing volatiles. Neither the number of glands nor the qualitative or quantitative composition of the volatiles was affected by UV-B. There seems to be a requirement for UV-B for the filling of the glandular trichomes of basil.     

A glucomannan from the tubers of Arum orientale

Two glucomannans (A and B), and an attendant polysaccharide (C) have been isolated from the tubers of Arum orientale (L.) by gel chromatography. Glucomannan B was found to be composed of d-glucose and d-mannose in a molar ratio of 2:3·1, and traces of uronic acid. IR spectra, enzymatic hydrolysis with α- and β-amylase, and periodate oxidation followed by reduction, showed the presence of a β-(1→4) glucoside linkage in this glucomannan, and of hexose residues in a β-pyranose form.     

Volatile constituents of Cupressus dupreziana and the sesquiterpenes of Cupressus sempervirens

Analysis of wood essential oil of Cupressus dupreziana revealed 26 components: 13 monoterpenes and 13 sesquiterpenes. The main components were carv     

Volatile constituents of the leaves of Cupressus dupreziana and Cupressus sempervirens

The essential oils of the leaves of Cupressus dupreziana and Cupressus sempervirens were compared. The composition of the hydrocarbon fraction showed a great similarity between the two species.     

Volatile phenolic constituents of spanish origanum (Coridothymus capitatus) essential oil

Analysis of the phenolic fraction of Coridothymus capitatus essential oil (Spanish origanum oil) indicated 7 major components. One of them is the well known carvacrol and among the others there are one diisopropylphenol and 5 methyldiisopropylphenols, which are found for the first time from a natural source.     

New sweet diterpene glucosides from Stevia rebaudiana

From the leaves of Stevia rebaudiana, two new sweet glucosides, rebaudiosides A and B, were isolated besides the known glucosides, stevioside and steviolbioside. On the basis of IR, MS, ¹H and ¹³C NMR as well as chemical evidences, the structure of rebaudioside B was assigned as 13-O-[β-glucosyl(1-2)-β-glucosyl(1-3)]-β-glucosyl-steviol and rebaudioside A was formulated as its β-glucosyl ester.     

Varietal differences in the constituents of citronella oil

Gas chromatography of citronella oil showed that the Ceylon variety (Lenabatu) contained large amounts of monoterpene hydrocarbons, while the Java variety (Mahapengiri) contained only small amounts, mainly limonene. Both types contained comparable amounts of geraniol, and the Java type more of citronellol and citronellal. In addition the Ceylon type contained tricyclene, methyl eugenol, methyl isoeugenol, eugenol and l-borneol. The GLC profiles enable the identification of the type of oil and the detection of kerosene as a possible adulterant. The variety that grows wild in Ceylon (Mana) was quite different to both cultivated types.     

6-Oxodendrolasin, 6-hydroxydendrolasin, 9-oxofarnesol and 9-hydroxyfarnesol,stress metabolites of the sweet potato

Four sesquiterpene stress metabolites, 6-oxodendrolasin, 6-hydroxydendrolasin, 9-oxofarnesol, and 9-hydroxyfarnesol have been isolated from mercuric chloride-treated sweet potatoes. The metabolites have been synthesized and feeding studies have been carried out to determine the extent of incorporation of ¹⁴C-labelled 6-oxodendrolasin and 9-hydroxyfarnesol into ipomeamarone.     

New coumarins from Coleonema album

Six coumarins have been isolated from the aerial parts of Coleonema album and identified as ulopterol, 7-(3′, 3′-dimethylallyloxy)-coumarin, (R)-(+)-2′,3′-epoxy-suberosin, and the novel coumarins (R)-(+)-7-(2′, 3′-epoxy-3′-methylbutoxy)-coumarin, (R)-(+)-7-(2′,3′-dihydroxy-3′-dihydroxy-3′-methylbutoxy)-coumarin and (R)-(+)-7-methoxy-8-(2′,3′-epoxy-3′-methylbutoxy)-coumarin.