Comparative analysis of Laurencia tristicha and Laurencia okamurai based on qualitative and quantitative HPLC determination

A simple and reliable HPLC-DAD method for qualitative and quantitative determination of sesquiterpenes in Laurencia tristicha and L. okamurai was developed, and then applied to compare the sesquiterpenes in the two alga species. Except for the difference in content, L. tristicha and L. okamurai are very similar in chemical compositions. The content of laurinterol, the most abundant component in both species, is much higher in L. okamurai than in L. tristicha, while debromolaurinterol and aplysinol are the second abundant components of L. tristicha and L. okamurai, respectively. The current results confirmed the great chemotaxonomic importance of laurane-type sesquiterpenes, especially the main constituents of laurinterol, debromolaurinterol, and aplysinol, for L. tristicha and L. okamurai.     

Within-plant distribution and emission of sesquiterpenes from Copaifera officinalis

Copaifera officinalis, the diesel tree, is known for massive production of oleoresin, mainly composed of sesquiterpene hydrocarbons. In this study, composition of these sesquiterpenes and their concentrations in leaves, stems and roots of C. officinalis at two developmental stages, including the three-week old (TW) seedlings and two-year old (TY) trees, were determined. The leaves of TW seedlings and TY trees contained similar number of sesquiterpenes, which also had comparable concentrations. The stems of TW seedlings had higher concentrations of sesquiterpenes than those of TY trees. In contrast, the number of sesquiterpene species and their concentrations in the roots of TW seedlings were much lower than those in the roots of TY trees. Cluster analysis of sesquiterpenes estimated that there are at least four terpene synthase genes involved in the production of sesquiterpenes in C. officinalis. Because sesquiterpenes are highly volatile, emissions of sesquiterpenes from healthy and wounded TW seedlings were examined using headspace analysis. Whereas very low emission of sesquiterpenes was detected from undamaged plants, the physically injured seedlings emitted a large number of sesquiterpenes, the quality and the relative quantity of which were similar to those in leaves determined using organic extraction. The implications of our findings to the biosynthetic pathways leading to the production of sesquiterpenes as well as their biological roles in C. officinalis are discussed.     

Sesquiterpenes from Xylaria sp., an endophytic fungus associated with Piper aduncum (Piperaceae)

Two new presilphiperfolane sesquiterpenes, 1 and 2, were isolated from the ethyl acetate extract of Xylaria sp., obtained from the leaves of Piper aduncum, along with two known eremophilane sesquiterpenes, phaseolinone (3) and phomenone (4). Chemical structures of 1 and 2 were established by analysis of spectroscopic data. The four compounds were tested in vitro for antifungal and cytotoxicity activities using CHO (Chinese hamster ovary). Compounds 1 and 2 did not show any antifungal and cytotoxic activity. Compounds 3 and 4 displayed moderate cytotoxic activities, as well as 4 antifungal activity.     

Flavonoids and terpenoids of Chenopodium graveolens

Three flavonoids, four terpenoids and three steroids were isolated from Chenopodium graveolens. These included pinostrobin, stigmasterol, stigmast-22-en-3-ol, 3α-sitosteryl-glucoside, geranyl acetate, pinocembrin, chrysin, cryptomeridiol, and two new sesquiterpenes which were characterized by spectral means as (+)-8α-hydroxyelemol and (+)-8α-acetoxycryptomeridiol.     

Sesquiterpenes from Perezia carpholepis

The previously unknown curcuquinol monoisovalerate and the known sesquiterpenes cyperene, cyperone, parvifoline, perezone, and α- and β-pipitzol were found in the roots of Perezia carpholepis. The structure of the new sesquiterpene was deduced from spectral data and by transformation into curcuquinone. Parvifoline and its derived acetate, previously thought to be oily materials, were characterized as crystalline compounds.     

<Emphasis Type="Italic">Anemia tomentosa</Emphasis> var. <Emphasis Type="Italic">anthriscifolia</Emphasis> in vitro culture: sporophyte development and volatile compound profile of an aromatic fern

Anemia tomentosa var. anthriscifolia is an aromatic fern with a pleasant woody aroma and antimycobacterial activity. In this paper, we describe for the first time its spore-derived gametophyte development and the effect of indole-3-acetic acid and jasmonic acid on in vitro gametophyte/sporophyte development, as well as volatile compound production. Volatiles were obtained by simultaneous distillation and extraction (SDE) and analyzed by high resolution gas chromatography coupled with mass spectrometry. Spore-derived gametophytes were able to develop into sporophytes independently of the media culture composition, even when no plant growth regulator was added. Fifty different substances were detected in all in vitro A. tomentosa SDE extracts, while 20 were detected in the wild SDE plant extract. Monoterpenes were more prevalent (69.8–89.8%) than sesquiterpenes (9.4–28.7%) in in vitro plants, while sesquiterpenes represent 97.5% of the volatiles produced by the wild-grown plants. The major monoterpene components in in vitro plants were α-pinene (9.3–24.3%), trans-pinocarveol (20.6–27.9%), pinocarvone (15.4–25.1%) and myrtenyl acetate (6.4–12.3%). The triquinane sesquiterpenes silphiperfol-6-ene (0.6–2.9%), α-guaiene (0.5–2.5%), β-barbatene (1.1–3.9%) and 9-epi-presilphiperfolan-1-ol (2.5–5.6%) represent the most abundant sesquiterpenes. The changes in the monoterpene/sesquiterpene rates between micropropagated and wild plants are not related to the presence of JA or IAA in the media culture. Further studies are still needed to obtain a complete understanding of the factors leading to these results, which could be related to differences in the irradiance levels of in vitro plants versus those from a wild environment, as well as the developmental stage of the plants. This is the first report of the use of plant growth regulators on Anemia tomentosa in vitro culture development and their effects on volatile profiles.     

Sesquiterpenes from Japanese liverworts

Five Japanese liverworts (Bazzania sp.) were examined for sesquiterpenes. B. japonica and B. pompeana contained two new drimane-type sesquiterpene esters, albicanyl 3,4-dihydroxycinnamate and albicanyl 2,4dihydroxycinnamate. Tridensenone, a new aromadendrane-type sesquiterpene ketone was isolated from B. tridens. The stereostructures of these new sesquiterpenes were elucidated mainly by spectrometry. Barbatane-, bazzanane- and cuparane-type sesquiterpenes were found in all of the five species investigated. These sesquiterpenes, along with the new drimane- and aromadendrane-type sesquiterpenes are useful chemosystematic markers.     

A re-examination of corn (Zea mays L.) ear volatiles

Helicoverpa zea (Boddie) is a major insect pest of corn and other agricultural crops. An improved understanding of semiochemcials that control adult behavior is needed to develop alternative control measures. In this study, overnight SPME collection of volatiles from corn ears enclosed in Teflon bags in the field at two stages of development were made. C₈–C₁₀ aldehydes, a C₈-alcohol, C₆–C₉ alcohol acetates, and numerous monoterpenes, sesquiterpenes, sequiterpene alcohols, and geosmin were identified after thermal desorption and GC/MS. Structural assignments of the alcohol acetates, Z-3-hexenyl acetate, 2-heptyl acetate, 2-nonyl acetate, and 4-nonyl acetate, the monoterpenes, α- and β-ocimene, and geosmin were made by analysis of standards that were purchased or prepared in the laboratory. All other assignments were based on published Kovat’s retention time indices (KI) and mass spectra. Pair-wise comparison of the relative amounts of each component between two groups of corn ears defined by silk weight did not identify significant differences, thus it is unknown whether or not silk weight impacted volatile emission composition and rate. To our knowledge three compounds detected in SPME collections, 2-heptyl acetate, 2-nonyl acetate, and 4-nonyl acetate have not been previously reported in corn ear or silk volatiles. Their impact on the flight response of gravid earworm females was evaluated in a flight chamber. No significant response to the individual compounds or a blend of all three was observed. Thus, their impact on moth behavior remains uncertain.     

Phytochemical investigation on the fruiting body of Russula aruea Pers

Phytochemical investigation of ethyl acetate fraction from Russula aruea Pers fruiting body led to the isolation and identification of one new isolactarane sesquiterpene (1) and 11 known compounds, including four sesquiterpenes (2-5), four sterols (6–9), one allitol (10), and two fatty acids (11–12). The structure of compound 1 was elucidated by means of spectroscopic analysis, including 1D and 2D NMR, HR-ESI-MS, and X-Ray experiments. Compounds 1–3 and 5–12 are herein reported for the first time from Russula genus, while compound 4 is firstly described in R. aruea. The sesquiterpenes in R. aruea could serve as chemotaxonomic markers.     

Sesquiterpenes from Porella species

The Porella liverworts contain abundant sesquiterpenes. ent-Biocyclogermacrene, three ent-aromadendrenes, a unique hydrocarbon, α-pinguisene and two drimane type sesquiterpenes were obtained together with the intensly pungent component, tadeonal, from P. vernicosa and P. gracillima. P. macroloba contained the same sesquiterpenes except for the absence of ent-bicyclogermacrene and the ent-aromadendrenes. The fragrant odor of P. perrottetiana was composed of α-pinene and camphor.     

Smelling the tree and the forest: elm background odours affect egg parasitoid orientation to herbivore induced terpenoids

Parasitic insects use herbivore induced plant volatiles as signals for host location. However, their responses to these volatiles in the background of natural habitat odours need further evaluation for developing successful biological control strategies. Field elms (Ulmus minor Miller (Ulmaceae)) release a blend of volatiles in response to oviposition of the elm leaf beetle, Xanthogaleruca luteola Müller (Coleoptera: Chrysomelidae), a major urban and forest pest in the USA and Australia. This induced blend attracts the beneficial egg parasitoid Oomyzus gallerucae Fonscolombe (Hymenoptera: Eulophidae). Our olfactory assays showed that an odorous background of non-attractive host plant volatiles from feeding damaged elms or (Z)-3-hexenyl acetate masks the attractive effect of the host-induced (E)-β-caryophyllene to O. gallerucae. Quantitative GC–MS analyses revealed decreased concentrations of (Z)-3-hexenyl acetate accompanied by highly increased concentrations of sesquiterpenes in oviposition and feeding treated elms compared to undamaged elms. This finding hints to how the parasitoid might distinguish between different odorous backgrounds. It is corroborated by the outcome of our field study in natural elm stands, where the egg parasitoid parasitized more host egg masses due to an artificially induced blend of elm terpenoids.     

Sesquiterpenes and alkaloids from Cleistopholis patens

The root bark of Cleistopholis patens collected in Ghana yielded two sesquiterpenes and five alkaloids. The sesquiterpenes have been characterised as the acyclic methyl-(?)-(trans)-(trans)-10,11-dihydroxyfarnesoate and its monocyclic derivative methyl-(+)-10-hydroxy-6,11-cyclofarnes-7(14)-enoate. The alkaloids were of the unusual aza-polycyclic and naphthyridine groups and included one new member of both classes. Examination of stem bark samples from the same source and from Sierre Leone showed the presence of the sesquiterpenes and the oxoaporphine alkaloid liriodenine but neither of the rarer alkaloid types.     

The essential oil of greater galanga (Alpinia galanga) from Malaysia

The essential oil of A. galanga, a common spice in Malaysia, was prepared from fresh and dried rhizomes and analysed by means of capillary GC and GC/MS. Forty components were identified (only three of which were previously reported), accounting for 83–93% of the oil, depending on its method of preparation. Apart from monoterpenes, monoterpene alcohols and esters, and sesquiterpenes, also methyleugenol, eugenol acetate, chavicol (4-allylphenol) and chavicol acetate were present. This is the first time the latter substance has been reported in nature. Standardization of GC is proposed and tentatively applied towards a more systematic use of the Kováts indices as an aid in the identification of the constituents of essential oils.     

Sesquiterpenes and nor sesquiterpenes from Schefflera leucantha R.Vig. (Araliaceae)

One new nor sesquiterpenes, Schesesquiterpene (1), together with nine reported sesquiterpenes and nor sesquiterpenes (2–10) were obtained from Schefflera leucantha R.Vig. (Araliaceae). The structures were determined according to spectroscopic data analysis and chemical evidence. Noteworthily, Compound 7 was isolated as a new natural product, and other compounds (2–6 and 8–10) were obtained from the family Araliaceae for the first time.     

Chemical and phylogenetic relationships among Aristolochia L. (Aristolochiaceae) from southeastern Brazil

In this report, a molecular phylogeny based on the plastid gene matK and on the region between the genes trnL and trnF, and a chemical relationship based on the pattern of sesquiterpenes, is proposed for Aristolochia species from southeastern Brazil. We found that Aristolochia is a monophyletic genus and species considered to be derived contain labdanoic acids (LAs) in their leaves. The phenetic relationship recovered with sesquiterpenes did not agree with the phylogenetic relationships for Aristolochia, and three main clusters were recognized, namely, germacrene-D, germacrene-C and Z-caryophyllene groups. The presence of different sesquiterpene structures in species that are phylogenetically closely related may reflect adaptations to avoid predation of herbivores specialized in feeding on Aristolochiaceae plants.     

Foliage sesquiterpenes of Dacrydium cupressinum: identification,variation and biosynthesis

The major sesquiterpenes in the foliage of Dacrydium cupressinum are α-longipinene, longifolene, longibornyl acetate, caryophyllene, caryophyllene oxide, humulene, α- and β-selinene, β- and δ-elemene, aromadendrene and the rare 9βH-caryophyllene. Sesquiterpene levels vary greatly from tree to tree. As this variation is largely independent of environmental factors, genetic control is proposed. Longifolene and α-longipinene levels are closely correlated, as are those of caryophyllene and humulene. The biosynthetic implications of these correlations are discussed.     

Sesquiterpenes from Lactarius blennius

Six sesquiterpene lactones were isolated from Lactarius blennius. The structures of two new sesquiterpenes, blennin A and blennin B were determinated by spectroscopic methods and the structure of the seco-compound, blennin C, is revised. The two known furan sesquiterpenes and lactarorufin A were also identified.     

Sesquiterpenoids of Riccardia and Pallavicinia species

Riccardia species (Metzgeriales) contain various types of sesquiterpenes. R. jackii produces ent-selinane-, ent-aromadendrane-and ent-bicyclogermacrane-type sesquiterpenes together with (R)-cuparene and α-barbatene. Aneura pinguis (= Riccardia pinguis) is chemically quite different from R. multifida and R. jackii. The former produces a large amount of pinguisone. R. multifida contains 6-(3-methyl-2-butenyl)-indole and (+)-β-elemene as the major components. Pallavicinia longispina (Dilaenaceae; Metzgeriales) produces mainly spathulenol. The chiral properties of the sesquiterpenes isolated from R. jackii are quite similar to those of red algae, Laurencia species.     

Agarofuran sesquiterpenes from Schaefferia argentinensis

Sixteen dihydro-β-agarofuran sesquiterpenes were isolated from the aerial parts of Schaefferia argentinensis Speg. Their structures were determined by a combination of 1D and 2D NMR and MS techniques. The in vitro antiproliferative activity of the major sesquiterpenes was examined in T47D, MCF7, and MDA-MB231 human cancer cell lines, but was found to be marginal.