Terpenoids from the seed of chamaecyparis pisifera: the structures of six diterpenoids

Six new diterpenes, 12-hydroxy-20-nor-abieta-1(10),2,8,11,13-pentaene, pisiferanol (10S,12-dihydroxy-9(10 → 20)-abeo-abieta-8,11,13-triene), pisiferadinol (20S-hydroxypisiferanol), 12-deoxypisiferanol, 1β-hydroxyisopisiferin (1R,12-dihydroxy-9(10 → 2O)abeo-abieta-8,10(20),11,13-tetraene), and the dimethylamine salt of O-methylpisiferic acid were isolated from the seed of Chamaecyparis pisifera. The structures of these diterpenes were established by spectral and chemical methods. In addition, 15 mono-, four sesqui- and nine diterpenes were identified.     

Labdane diterpenes from Brickellia glomerata

The leaves of B. glomerata afforded three new labdane diterpenes. Their structures and stereochemistry were established by spectroscopic methods and chemical transformations.     

Flavones and diterpenes of Pamburus missionis (rutaceae)

A new flavone and two diterpenes have been isolated from the extracts of Pamburus missionis. The flavone was identified as an isopentylated apigenin derivative on the basis of spectroscopic studies on it and its diacetate. One of the diterpenes has been identified as daniellic acid and the second as a closely related butenolide.     

Phytane and neoclerodane diterpenes from the aerial parts of Inula nervosa Wall.

Three new aliphatic diterpenes (1–3), together with three known neoclerodane-type diterpenes (4–6) were isolated from the aerial parts of Inula nervosa Wall. The structures of 1-3 were elucidated on the basis of 1D and 2D spectroscopic analysis. Additionally, phytane-type and neoclerodane-type diterpenes have not been reported in any species of the genus Inula yet. The phytane-type and neoclerodane-type diterpenes obtained from I. nervosa Wall. suggest this plant maybe have remote genetic relations with other Inula species.     

Phytochemistry and chemotaxonomy of Sideritis species from the Mediterranean region

The phytochemical content of the Mediterranean species of the Sideritis genus has been reviewed. The components included in this review are monoterpenes, sesquiterpenes, diterpenes, triterpenes, sterols, flavones, coumarins and phenylpropanoids. From the chemotaxonomic point of view, we have divided the species from this region into four groups. The first of this is formed by taxa containing triterpenes, but not diterpenes. A second group is constituted by species having bicyclic diterpenes of the labdane type and not diterpenes. The third group is characterized by its content in tetracyclic diterpenes of the ent-kaurene type. A fourth group is composed of plants with tetracyclic diterpenes of the ent-beyer-15-ene and/or ent-atis-13-ene class. In addition, the relations of these Mediterranean species with those of the Macaronesian region have been examined.     

Biologically active abietane and ent-kaurane diterpenoids and other constituents from Erythroxylum suberosum

Bioassay-guided fractionation of the ethanol extract from the branches of Erythroxylum suberosum, which was toxic to brine shrimp larvae, afforded five diterpenes bearing abietane and ent-kaurane-type skeletons from an active fraction. From these, four were new, 7-oxo-16-hydroxy-abiet-15(17)-en-19-al, 16-hydroxyabiet-15(17)-en-7-one, 7α,16-dihydroxy-abiet-15(17)-en-19-al and ent-12α-hydroxy-kaur-16-en-19-al, while methyl ent-7α,15β-dihydroxy-kaur-16-en-19-oate is reported for the first time as a natural product. This is also the first reported occurrence of abietane-type diterpenes in the genus Erythroxylum. The flavonoid ombuin-3-rutinoside was isolated from an inactive fraction, while rutin (quercetin-3-rutinoside) was obtained from the non-toxic ethanol extract of the leaves. The structures of the new and known compounds were established by analyses of 1D- and 2D-NMR and mass spectrometry data.     

Morphogenetic Potential of Embryo- and Seedling-Derived Callus of Elaeis guineensis Jacq. var. pisifera Becc.

The oil palm of commerce, Elaeis guineensis (tenera), derivesfrom hybridization of variety dura x pisifera. Germ plasm ofpisifera is limited, however, because of varying degrees offemale sterility. Efforts to increase the range of availablepisifera male germ plasm have thus far been limited to fertilepisiferas but it is anticipated that clonal multiplication ofembryos and explanted organs from less female-fertile, but nonethelessfertile, male, plants could play a significant role in breedingprogrammes. Callus has been produced from mature pisifera embryosand leaf explants from young plantlets using a half-strengthMurashige and Skoog medium supplemented with inositol, caseinhydrolysate, activated charcoal and varying concentrations ofauxins. After sub-culture on media of similar composition, organizedstructures can develop. Those which form in stale nutrient media(e.g. left in the same medium for up to 3 months) give riseto embryonal structures which do not readily develop furtherand can be regarded as neomorphs. If callus once formed is transferredto media with lower auxin concentrations (40–0 mg l^–1)embryonal buds and well-formed shoots are produced; additionof gibberellic acid (GA₃) fosters the production of well-organizedshoots accompanied by roots. Elaeis guineensis var pisifera, oil palm, tissue culture, micropropagation, embryo development, morphogenetic potential, callus     

Foliage diterpenes of Dacrydium Intermedium: identification,variation and biosynthesis

The major diterpenes in the foliage of Dacrydium intermedium have been identified as rimuene, ent-rosadiene, ent-beyerene, phyllocladene, ent-kaurene, sclarene and ent-sclarene. ent-Rosadiene and ent-sclarene have not been reported previously from natural sources. Considerable tree-to-tree variations are encountered and genetic control is proposed. Biosynthetic mechanisms are put forward to explain the presence of diterpenes of both enantiomeric series. A lack of mono- and sesquiterpenes in both D. intermedium and D. fonkii, which ties in with Quinn's proposed revision of the Dacrydium genus, is also noted.     

Abietane diterpenoids from the root of Salvia lavandulaefolia

Two new derivatives of royleanone, 7α-ethoxyroyleanone and 7α-ethoxy-12-O-methyl-royleanone, besides the previously known diterpenes royleanone, 6,7-dehydroroyleanone, 7α-acetoxyroyleanone and inuroyleanol, have been isolated from the root of Salvia lavandulaefolia. The triterpenoid O-acetyloleanolic aldehyde has also been obtained from the same source.     

New diterpenes from Sideritis sicula

Two new diterpenes have been isolated from Sideritis sicula: sideripol, ent-18-acetoxy-7α-hydroxykaur-15-ene and epoxysideritriol, ent-15β,16β-epoxykauran-7α,17,18-triol. The previously known diterpene eubol, ent-7α-acetoxykaur-16-en-15β,18 diol has also been obtained from the same source.     

Structural diversity and geographical distribution of halogenated secondary metabolites in red algae,Laurencia nangii Masuda (Rhodomelaceae,Ceramiales), in the coastal waters of North Borneo Island

The red algae genus Laurencia (Rhodomelaceae, Ceramiales) is known as a prolific producer of halogenated secondary metabolites with a high level of species diversity and geographical distribution. In North Borneo Island, Malaysia, there are four main Laurencia species: Laurencia snackeyi, Laurencia majuscula, Laurencia similis and L. nangii. Although the chemistry of Laurencia is well studied, the diversity of compounds in L. nangii has not been thoroughly investigated. Therefore, we studied the chemical constituents of seven populations of L. nangii from Tunku Abdul Rahman Marine Park (two populations), Dinawan Island (one population), Tun Mustapha Marine Park (two populations) and Tun Sakaran Marine Park (two populations). Halogenated compounds were isolated and the structures determined via spectroscopic methods. A total of 20 metabolites belonging to the classes of sesquiterpenes, acetylenes, bromoallenes, diterpenes and triterpenes were identified. Populations from Tunku Abdul Rahman Marine Park and Dinawan Island contained non-chamigrane-type sesquiterpenes, acetylenes and diterpenes. Populations from Tun Mustapha Marine Park contained chamigrane-type sesquiterpenes, acetylenes and diterpenes. However, the chemical compositions of populations from Tun Sakaran Marine Park were found to differ significantly, containing chamigrane-type and non-chamigrane-type sesquiterpenes, bromoallenes and triterpenes. This investigation has revealed the presence of interesting chemotaxonomical markers in populations of L. nangii and the existence of chemical races in this species.     

NtPDR1, a plasma membrane ABC transporter from Nicotiana tabacum, is involved in diterpene transport

ATP-binding cassette transporters are involved in the active transport of a wide variety of metabolites in prokaryotes and eukaryotes. One subfamily, the Pleiotropic Drug Resistance (PDR) transporters, or full-size ABCG transporters, are found only in fungi and plants. NtPDR1 was originally identified in Nicotiana tabacum suspension cells (BY2), in which its expression was induced by microbial elicitors. To obtain information on its expression in plants, we generated NtPDR1-specific antibodies and, using Western blotting, found that this transporter is localized in roots, leaves, and flowers and this was confirmed in transgenic plants expressing the ß-glucuronidase reporter gene fused to the NtPDR1 promoter region. Expression was seen in the lateral roots and in the long glandular trichomes of the leaves, stem, and flowers. Western blot analysis and in situ immunolocalization showed NtPDR1 to be localized in the plasma membrane. Induction of NtPDR1 expression by various compounds was tested in N. tabacum BY2 cells. Induction of expression was observed with the hormones methyl jasmonate and naphthalene acetic acid and diterpenes. Constitutive ectopic expression of NtPDR1 in N. tabacum BY2 cells resulted in increased resistance to several diterpenes. Transport tests directly demonstrated the ability of NtPDR1 to transport diterpenes. These data suggest that NtPDR1 is involved in plant defense through diterpene transport.     

Diterpene content of the alga Dictyota ciliolata from a Moroccan lagoon

Analysis of the secondary metabolites content of the brown alga Dictyota ciliolata, collected from Oualidia lagoon (Morocco), revealed the presence of xenicane and guaiane homologous diterpenes. Two new xenicanes, 1 and 2, co-occurring with the known dictyodial, dictyol C and dictyol H, have been isolated and characterized by spectral methods, mainly by NMR techniques. Compound 2 displayed mild antifungal activity against Candida albicans.     

Diterpenoid hydrocarbons in the sea grass Amphibolis antartica

The leaves of Amphibolis antartica from Shark Bay, Western Australia contain a previously unreported cleistanthene hydrocarbon. Other collections of the sea grass near Perth also contained sandaracopimaradiene and isopimaradiene. Concentrations of the diterpenes increase with leaf age, while n-hydrocarbon content decreases with leaf age.     

Diterpenes from Dictyota dichotoma

Two new and two known diterpenes were isolated from Dictyota dichotoma. The structures of the new diterpenes were elucidated from spectral and X-ra     

New Diterpenes of Torreya nucifera Sieb. et Zucc.

Three new labdane type diterpenes; 4-epiagathadiol (named kayadiol), 18-hydroxymanool (named torreferol), 18-hydroxy-13-epimanool (named 13-epitorreferol), were isolated from the non-steam-volatile fraction of leaves of Torreya nucifera Sieb. et Zucc. (Taxaceae, Japanese name “Kaya”).

This is the first reported isolation these three diterpenes in a natural source.     

Mannic acid,a new ent-kaurane dimer diterpenoid and other chemical constituents from different parts of Diospyros mannii

A new dimeric ent-kaurane diterpene, mannic acid (1), and 19 known compounds were isolated from the methanol extract of the stems, roots and leaves of Diospyros mannii Hiern (Ebenaceae). Their structures were established by NMR and MS data. This is the first report of asperglaucide from the family Ebenaceae, while mannic acid (1) and xylopic acid (2) are the first ent-kaurane diterpenes isolated from this family. Their chemotaxonomic value is discussed.     

Ent-labdane derivatives from gutierrezia grandis

Two new diterpenes, 3α-angeloyloxy-18-hydroxy-13-furyl-ent-labda-8(17)-ene and 3α-hydroxy-18-angeloyloxy- 13-furyl-ent-labda-8(17)-ene and an only recently reported third diterpene, 3α, 18-dihydroxy-13-furyl-ent-labda-8(17)-ene, were isolated from the leaves of Gutierrezia grandis. Their structures were determined by mass spectral, IR, ¹H NMR and ¹³C NMR data was well as chemical evidence.     

Phytotoxic Allelochemicals From Roots and Root Exudates of Leafy Spurge (Euphorbia esula L.)

Invasive plants are a widespread problem but the mechanisms used by these plants to become invasive are often unknown. The production of phytotoxic natural products by invasive weeds is one mechanism by which these species may become successful competitors. Here we conducted a bioactivity-driven fractionation of root extracts and exudates from the invasive plant leafy spurge (Euphorbia esula L.), and structurally characterized jatrophane diterpenes and ellagic acid derivatives. Ellagic acid derivatives and one of the jatrophane diterpenes, esulone A, have been previously reported from leafy spurge, but another of the jatrophane diterpenes, kasuinine B, has not. We show that these compounds are phytotoxic but affect plants in different ways, either inducing overall plant necrosis or reducing root branching and elongation.Key Words: phytotoxicity, allelochemicals, roots, root exudates, jatrophane diterpenes, kansuinine B, ellagic acid derivatives, leafy spurge, Euphorbia esula, Arabidopsis thaliana     

Chemistry and biological activities of Calceolaria spp. (Calceolariaceae: scrophulariaceae)

Calceolaria spp. is regarded both as a notorious weed and a popular ornamental garden plant and have medicinal application. Some taxa of the America distributed Calceolaria genus are toxic to insects and its effect has been associated with the presence of diterpenes, triterpenes and naphthoquinones. However, Calceolaria spp. also produces a number of flavonoids and phenylpropanoids that have been shown to possess interesting biological activities. All these aspects are considered in this review to allow an evaluation of the potential for utilization of the large biodiversity of Calceolaria available. The phytochemistry of many members of the Calceolaria genus is included.