Teanol,a new brominated sesquiterpene from the Thailand Laurencia mariannensis

We examined the constitution of Laurencia mariannensis collected from the east coast of Tean Island, Thailand. The structure of a new brominated rearranged cyclolaurane-type sesquiterpene, named teanol (1), is reported. This is the first report on biology and chemistry of the Thailand red algal genus Laurencia (Rhodomelaceae, Ceramiales).     

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.     

Chemical relationship between red algae genus Laurencia and sea hare (Aplysia dactylomela Rang) in the North Borneo Island

Red algae genus Laurencia is an interesting alga with the ability to produce halogenated secondary metabolites that exhibits ecological and pharmaceutical potential. In nature, Laurencia is selectively grazed by sea hares (Aplysia dactylomela). In this study, Laurencia populations in three islands (Mantanani, Sulug, and Dinawan Islands) in the coastal waters of North Borneo were investigated and their chemical relationship with sea hare determined. Four species of Laurencia were found to grow abundantly in these waters, Laurencia snackeyi, Laurencia majuscula, Laurencia nangii, and Laurencia similis. Sea hares, Aplysia dactylomela, found grazing on Laurencia were collected and their chemical composition determined. A total of 20 halogenated metabolites were isolated and identified via spectroscopic data. Isolated compounds could be grouped into syndrean (5), chamigrane (6), non-chamigrane sesquiterpene (3), cuparane (1), bromoindole (2), and C15 acetogenin (acetylene type) (3). Sea hares from Mantanani, Sulug, and Dinawan Islands contained a total of 9, 10, and 10 compounds, respectively. In addition, 12-acetoxypalisadin B (1), which was isolated from sea hares of Sulug Island is a first record of its existence in nature.     

Snyderol derivatives from Laurencia obtusa collected in Corsica

8-keto-10-dehydrobromo-γ-snyderol (1), a new sesquiterpene exhibiting the unusual γ-snyderane skeleton, was isolated from the ethyl acetate extract of Laurencia obtusa collected in Ajaccio (Corsica, France). (1) was isolated and fully characterized by detailed spectroscopic analysis. Six known compounds were identified after column chromatography steps using a ¹³C NMR based computerized method developed in our laboratory: α-snyderol (2), two rearranged derivatives of α-snyderol (3,4), 8-keto-10-dehydrobromo-β-snyderol (5), β-snyderol (6) and 8-hydroxy-β-snyderol (7).     

New antibacterial sesquiterpene aminoquinones from a Vietnamese marine sponge of Spongia sp.

Two new sesquiterpene aminoquinones, langcoquinones A (1) and B (2), together with seven known meroterpenoids (3⿿9), were isolated from the marine sponge Spongia sp. collected in Vietnam. Their structures were determined on the basis of spectroscopic analyses and comparisons with published data. The antibacterial activities of the isolated compounds (1⿿9) were investigated against four bacterial strains. Among these, the new sesquiterpene aminoquinones (1 and 2) and the known related compounds (3, 5, 6, 8, and 9) exhibited significant antibacterial activities against Staphylococcus aureus and Bacillus subtilis, with MICs ranging from 6.25 to 12.5 μM.     

Taxonomy of the genus Laena from Yunnan in China,with description of eight new species (Coleoptera: Tenebrionidae: Lagriinae)

Eight new species of the genus Laena Dejean, 1821 (subfamily Lagriinae, tribe Laenini) from Yunnan Province of China were described and illustrated: L. acutidentata Wei & Ren, sp. nov., L. brevicarina Wei & Ren, sp. nov., L. dongchuana Zhao & Ren, sp. nov., L. glabridentipa Wei & Ren, sp. nov., L. nuda Zhao & Ren, sp. nov., L. raropuncta Wei & Ren, sp. nov., L. rugulosa Wei & Ren, sp. nov. and L. spinicla Wei & Ren, sp. nov.. Illustrations and a key to the known Laena species from Yunnan Province are provided.www.zoobank.org/urn:urn:lsid:zoobank.org:pub:FDEDA1E8-2F2E-4732-8DB4-FE2D7BDC75D8.     

Metabolites from Penicillium sp., an endophytic fungus from the liverwort Riccardia multifida (L.) S. Gray

Two new metabolites, (3aR,9bR)-6,9b-dihydroxy-8-methoxy-1-methylcyclopentene[c]isochromen-3,5-dione (1) and 6-hydroxyl-deoxyfunicone (2), together with five known compounds (3–7), were obtained from Penicillium sp., an endophytic fungus from the Chinese liverwort Riccardia multifida (L.) S. Gray. Their structures were determined by extensive analysis of their spectroscopic data. Allelopathic test showed that compounds 2 and 4 significantly retarded germination of Arabidopsis thaliana seeds.     

Gout prophylactic constituents from the flower buds of Lonicera japonica

Two new sesquiterpene glycosides (R)-dehydroxyabscisic alcohol β-d-apiofuranosyl-(1″ → 6′)-β-d-glucopyranoside (1) and (−)-(1S,2R,6R,7R)-1,2,6-trimethyl-8-hydroxy methyltricyclic[5.3.1.0^2,6]-undec-8-en-10-one β-d-apiofuranosyl-(1″ → 6′)-β-d-glucopyranoside (2), were isolated from the flower buds of Lonicera japonica. Their structures were determined by spectroscopic and chemical methods. Compound 2 could significantly decrease monosodium urate-mediated cytokine production from activated macrophage through lowering IL-1β and TNFα.     

A new bicyclic sesquiterpene from the marine sponge associated fungus Emericellopsis minima

A new sesquiterpene (5E)-2-methyl-5-[(1′R*, 5′R*)-2-methylidene-7-oxobicyclo[3.2.1]oct-6-ylidene]-4-oxopentanoic acid (1) was isolated, in addition to the dihydroisocoumarin cis-(3R, 4R)-4-hydroxymellein, ergosterol peroxide and helvolic acid, from the culture of the fungus Emericellopsis minima associated with the marine sponge Hyrtios erecta. The structures of all the compounds were elucidated using spectroscopic data from 1D, 2D NMR and HRESITOFMS. Compounds 1 and cis-(3R, 4R)-4-hydroxymellein were found to show neither antimicrobial nor the in vitro growth inhibitory activities on three human tumor cell lines.     

Phylogenetic Re-Evaluation of the Laurencia Complex (Rhodophyta) with a Description of L. Succulenta Sp. Nov. from Korea

Laurencia succulenta sp. nov. (Rhodophyta) is described from Korea. This species exhibits vegetative and reproductive structures typical of the genus, but is distinct from similar species in its epiphytic habitat and the fleshy, robust, thick and subcompressed thalli with basically distichous branching. In addition, it is readily distinguished from the most similar species, such as L. nipponica Yamada and L. okamurae Yamada, by the cystocarps with a somewhat protuberant ostiole. In a phylogenetic analysis of 47 species of the Laurencia Lamouroux complex from various localities around the world based on 49 morphological characters, four major clades (Laurencia, Chondrophycus palisadus (Yamada) Nam group, C. cartilagineus (Yamada) Garbary et Harper group and Osmundea Stackhouse assemblage), each of which forms a monophyletic group, were recognized. Among these, the Laurencia clade is basal to the overall assemblage, and is defined by the vegetative axis with four rather than two pericentral cells. The Osmundea clade is supported by autapomorphic characters for the genus, features associated with spermatangial formation of the filament type and tetrasporangial production from epidermal cells. By contrast, Chondrophycus, a genus characterized by a combination of features (vegetative axis with two pericentral cells, trichoblast-type spermatangial development and tetrasporangial production from pericentral cells), is paraphyletic, and the species were separated into two well-supported clades, the C. palisadus group and C. cartilagineus group. These clades are distinguished from each other by the position of the first pericentral cell relative to the trichoblast, the presence or absence of fertility at the second pericentral cells and number of sterile pericentral cells in the tetrasporangial axis, the pattern of formation of spermatangial branches on trichoblasts, post-fertilization feature associated with the formation time of the auxiliary cell, and, probably, the number of pericentral cells in the procarp-bearing segment. Of these features, the side position of the first pericentral cell in the latter group (a synapomorphy for the C. cartilagineus group plus Osmundea) suggests that the C. cartilagineus group is more closely related to Osmundea than to the C. palisadus group. This cladistic analysis indicates that Chondrophycus is not monophyletic, suggesting that the C. palisadus group should be separated from Chondrophycus at the genus level. Based on this result, Palisada (Yamada) stat. nov. is proposed for the group, together with an emendation of the generic delineation of Chondrophycus, and relevant nomenclatural changes for several Chondrophycus species are also included. In addition, Corynecladia J. Agardh is reinstated for the type species L. clavata Sonder.     

Two new sesquiterpenes from Ligularia dictyoneura

The detailed investigation of the whole plant of Ligularia dictyoneura was performed during a search for unique chemical skeletons. One novel noreremophilane-type sesquiterpene, (4S, 5R, 8R, 10S)-1-nor-10-hydroxy-8-methoxyeremophil-7(11)-en-12,8-olide (1) and one new highly oxygenated eremophilane, 1β-angeloyloxy-6α, 10β-dihydroxyeremophil-7(11), 8-dien-12, 8-olide (2), were obtained. Their structures, including the absolute configuration, were elucidated by spectroscopic data and CD analysis.     

Sesquiterpene lactones from the aerial parts of Xanthium sibiricum and their cytotoxic effects on human cancer cell lines

The EtOH extract of the aerial parts of Xanthium sibiricum afforded six sesquiterpene lactones (STLs), including two new eremophilanolides. The structures of the new compounds were established on the basis of spectroscopic methods and the modified Mosher's method to be the C-11 epimers of 2S,4S,5R,7R,8R-2-hydroxy-eremophil-1(10)-en-12,8-olide [11R: 1 (sibiriolide C); 11S: 2 (sibiriolide D)]. The isolated compounds were evaluated for their in vitro cytotoxicities against five human cancer cell lines (Huh-7 hepatocarcinoma, KB nasopharynx carcinoma, Jurkat T cell lymphoblast, BGC-823 and KE-97 gastric carcinoma) using the CellTiter-Glo? luminescent cell viability assay method. Compounds 4–6, each possessing an α-methylene-γ-lactone moiety, were found to have noteworthy cytotoxic effects with IC₅₀ values ranging from 1.1 to 18.0 μM.     

Eremophilane-type sesquiterpene lactones from Ligularia hodgsonii Hook

A dimeric eremophilane sesquiterpene lactone with a cyclobutane ring, biliguhodgsonolide (1) and an uncommon seco-sesquiterpene derivative, (4S,5S,6R,10R)-8,9-seco-12-hydroxyeremophil-7(11)-en-14,6;12,8-diolid-9-al (2), were isolated from the roots and rhizomes of Ligularia hodgsonii Hook. Their structures, including the absolute stereochemistry, were elucidated by spectroscopic data and CD analysis. The cyclobutane ring was confirmed by single-crystal X-ray diffraction.     

Distribution of the Argentine ant, Linepithema humile, along the Seto Inland Sea, western Japan: Result of surveys in 2003–2005

The distribution of the Argentine ant, Linepithema humile, was investigated in 65 cities or towns along the Seto Inland Sea, western Japan in 2003–2005. Our results include all available information of their distribution in Japan until 2005. Argentine ants have invaded Aichi Prefecture (Tahara‐shi), Hyogo Prefecture (Kobe‐shi), Hiroshima Prefecture (Hiroshima‐shi, Fuchu‐cho, Hatsukaichi‐shi, Ono‐cho and Otake‐shi), and Yamaguchi Prefecture (Iwakuni‐shi and Yanai‐shi). The most widespread distribution was found around Hatsukaichi‐shi including the westernmost part of Hiroshima‐shi and the easternmost of Ono‐cho.     

An experimental approach to study the biosynthesis of brominated metabolites by the red algal genus Laurencia

The production of labeled brominated metabolites with radioactive ⁸²Br in Laurencia species was investigated as part of a study of the biosynthesis of halogenated metabolites from species belonging to the red algal genus Laurencia (Rhodomelaceae, Ceramiales). Radiobromide [⁸²Br], thin-layer chromatography (TLC), and TLC–autoradioluminography (ARLG) were used. When cultured in artificial seawater medium (ASP₁₂NTA including Na⁸²Br) under 16:8 h light:dark (LD) illumination cycles for 24 h, each of the strains of Laurencia, Laurencia japonensis Abe et Masuda, Laurencia nipponica Yamada (laurencin-producing race and laureatin-producing race), and Laurencia okamurae Yamada, produced species- (or race-) specific ⁸²Br-containing metabolites. In the case of the laurencin-producing race of L. nipponica, laurencin and deacetyllaurencin were found to be produced in approximately 1:1 ratio, though laurencin is the major metabolite in the wild sample. Furthermore, when cultured in the dark, the production rates of brominated metabolites in Laurencia spp. were found to be diminished. The present study strongly indicates that the use of radiobromine [⁸²Br] in combination with the TLC–ARLG method is an effective approach for investigating the biosynthesis of brominated metabolites in Laurencia.     

Contrasting chemistry of fruits and leaves of two Pseudowintera species: Sesquiterpene dialdehyde cinnamates and prenylated flavonoids

Two new sesquiterpene dialdehydes, cinnamate 7 and coumarate 8, were isolated from the fruits of Pseudowintera colorata. The known sesquiterpene dialdehydes polygodial 1 and 9-deoxymuzigadial 2 were also found in these fruits, at 5% w/w compared to 0.5% in the leaves. Fruits of Pseudowintera axillaris contained no sesquiterpene dialdehyde cinnamates, even though these are present in the leaves, but did contain prenylated flavanones 11–13. Compounds 7 and 8 are further examples of the rare sesquiterpene dialdehyde cinnamate combination, found exclusively in the family Winteraceae. This is the first report of the uncommon prenylated flavanones in Winteraceae.     

A pair of new sesquiterpene isomers containing spiro heterocyclic skeleton from plant-derived fungus Botryosphaeria dothidea

A pair of new sesquiterpene isomers containing a spiro heterocyclic skeleton, dothimes A (1) and B (2), together with six known compounds, quindoline (3), (S)-3-(3-indolyl)lactic acid methyl ester (4), dankasterone B (5), dibutyl phthalate (6), (1S,3R,4R,7S)-3,4-dihydroxy-α-bisabolol (7), and p-hydroxybenzaldehyde (8), were isolated from the plant-derived fungus Botryosphaeria dothidea. The structures of all isolated compounds were determined based on extensive spectroscopic analyses, including 1D/2D nuclear magnetic resonance (NMR), and high resolution electrospray ionization mass spectrometry (HRESIMS) data, as well as by comparison with literature reports. Compounds 1 and 2 exhibited inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production with IC₅₀ values of 63.66 and 58.29 μM, respectively.     

Chemical variation in a new bromochamigrene derivative from the red seaweed Laurencia pacifica

The secondary metabolite chemistry of the red seaweed Laurencia pacifica Kylin varies geographically. The La Jolla, Calif. population (type locality) contains the sesquiterpene prepacifenol, while L. pacifica collected south of Ensenada, Mexico contains a new bromochamigrene derivative, the structure of which is described herein. Since chamigrene synthesis in Laurencia species has been demonstrated to be reasonably species-specific, L. pacifica may be a mixture of morphologically similar forms.