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.     

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.     

Bioactive terpenoids from sunflower leaves cv. Peredovick

The CH(2)Cl(2) extract of dried leaves of Helianthus annuus L. cv. Peredovick(R) has yielded, in addition to the known sesquiterpene lactones annuolide E and leptocarpin, and the sesquiterpenes heliannuols A, C, D, F, G, H, I, the new bisnorsesquiterpene, annuionone E, and the new sesquiterpenes heliannuol L, helibisabonol A and helibisabonol B. Structural elucidation was based on extensive spectral (one and two-dimensional NMR experiments) and theoretical studies. The sesquiterpenes heliannuol A and helibisabonol A and the sesquiterpene lactone leptocarpin inhibited the growth of etiolated wheat coleoptiles.     

Novel Zierane‐ and Guaiane‐Type Sesquiterpenes from the Root of Melicope denhamii

Two novel zierane‐type sesquiterpenes, named melicodenones A and B ( 1 and 2 , resp.), and three new guaiane‐type sesquiterpenes, named melicodenones C–E ( 3 – 5 ), were isolated from the root of Melicope denhamii (Seem. ) T. G. Hartley together with zierone ( 6 ). Their structures were established by extensive NMR‐spectroscopic analyses. Compounds 1 – 6 were tested for cytotoxicity using human colon cancer DLD‐1 cells, and melicodenone A ( 1 ) was found to exhibit moderate activity.     

Eremophilane Sesquiterpenes and Benzene Derivatives from the Endophyte Microdiplodia sp. WGHS5

Three new eremophilane sesquiterpenes phomadecalins G−I ( 1 – 3 ) and two new benzene derivatives microdiplzenes A and B ( 12 and 13 ), together with nine known eremophilane sesquiterpenes ( 4 – 11 and 14 ) were isolated from an endophytic fungus, Microdiplodia sp. WGHS5. Their structures were elucidated by the interpretation of HR-ESI-MS and NMR data; meanwhile, the absolute configurations of new compounds were determined on the base of ECD calculations. All compounds were evaluated for the antimicrobial activities and antiproliferative effect on human gastric cancer cell lines (BGC-823).     

Incorporation of 1-[1-(13)C]Deoxy-D-xylulose in chamomile sesquiterpenes.

Incorporation of synthetically prepared 1-[1-(13)C]deoxy-d-xylulose into chamomile sesquiterpenes has been achieved by injecting an aqueous solution into the anthodia of the plant. The analysis of labeling patterns and absolute (13)C abundances of the isolated sesquiterpenes bisabololoxide A (1), bisabololoxide B (2), and chamazulene (3) using quantitative (13)C NMR spectroscopy showed that 1-[1-(13)C]deoxy-d-xylulose was efficiently incorporated in all three isoprene building blocks of the sesquiterpenes. A significantly lower (13)C abundance of the labeled carbon atom in the biogenetically terminal isoprene unit confirms the mixed biosynthesis of this unit, involving both the mevalonic acid pathway and the methylerythritol phosphate pathway.     

Sesquiterpene coumarins from the roots of Ferula assa-foetida.

From the chloroform extract of the roots of Ferula assa-foetida, two sesquiterpene coumarins designated assafoetidnol A and assafoetidnol B were isolated, in addition to six known compounds, gummosin, polyanthin, badrakemin, neveskone, samarcandin and galbanic acid. The structures of the sesquiterpenes new compounds were established by spectroscopic methods.     

Effects of sesquiterpenes and triterpenes from the rhizome of Alisma orientale on nitric oxide production in lipopolysaccharide-activated macrophages: absolute stereostructures of alismaketones-B 23-acetate and -C 23-acetate

The methanolic extract from a Chinese herbal medicine, the rhizome of Alisma orientale, was found to exhibit inhibitory activity of nitric oxide (NO) production in lipopolysaccharide (LPS)activated macrophages. Novel triterpenes, alismaketones-B 23-acetate and -C 23-acetate, were isolated from the active extract together with eight sesquiterpenes and eighteen protostane-type triterpenes. The absolute stereostructures of new triterpenes were characterized on the basis of chemical and physicochemical evidence, which included the chemical correlations with known triterpenes. The guaiane-type sesquiterpenes (alismol, orientalols A and C) and protostane- and seco-protostane-types triterpenes (alisols C monoacetate, E-23-acetate, F, H, I, L-23-acetate, and M-23-acetate, alismaketones-B 23-acetate and -C 23-acetate, alismalactone 23-acetate, and 3-methylalismalactone 23-acetate) inhibited LPS-induced NO production (IC50 = 8.4-68 microM). Other triterpenes (alisols A, A monoacetate, B, B monoacetate, E, G, K-23-acetate, and N-23-acetate and 11-deoxyalisol B) also showed the potent inhibitory activity, but they showed cytotoxic effects more than 30 microM (MTT assay). In addition, alismol and alisol F were found to suppress iNOS induction.     

Hepatoprotective constituents from zedoariae rhizoma: absolute stereostructures of three new carabrane-type sesquiterpenes, curcumenolactones A, B, and C

New carabrane-type sesquiterpene lactones, curcumenolactones A, B, and C, were isolated from the 80% aqueous acetone extract of Zedoariae Rhizoma (Zingiberaceae), together with 41 sesquiterpenes and two diarylheptanoids. The absolute stereostructures of curcumenolactones A, B, and C were determined on the basis of physicochemical evidence, which included nuclear Overhauser effect (NOE) and circular dichroic (CD) spectroscopic analyses. Curcumenone, a principal carabrane-type sesquiterpene from Zedoariae Rhizoma, was found to show potent protective effect on D-galactosamine/lipopolysaccharide-induced acute liver injury in mice. In addition, curcumenolactones A and B and the other constituents showed protective effect on D-galactosamine-induced cytotoxicity in primary cultured rat hepatocytes.     

Two novel aromatic valerenane-type sesquiterpenes from the Chinese green alga Caulerpa taxifolia

Caulerpal A (2) and B (3), two novel sesquiterpenes possessing an uncommon aromatic valerenane-type carbon skeleton, along with one known metabolite, caulerpin (4), have been isolated from the Chinese green alga Caulerpa taxifolia (Vahl) C. Agardh. Their structures and relative stereochemistry were elucidated on the basis of extensive spectroscopic analysis. Compounds 2-4 were evaluated for their inhibitory activity against hPTP1B and the result showed that only compound 4 had a strong PTP1B inhibitory activity with an IC50 value of 3.77 microM.     

Antibacterial activity of halogenated sesquiterpenes from Malaysian Laurencia spp

During our studies on Malaysian Laurencia species, brominated metabolites, tiomanene, acetylmajapolene B, and acetylmajapolene A were isolated from an unrecorded species collected at Pulau Tioman, Pahang along with known majapolene B and majapolene A. Acetylmajapolene A was a mixture of diastereomers as in the case of majapolene A. Tiomanene may be a plausible precursor for acetylmajapolenes B and A. In addition, three known halogenated sesquiterpenes and two known halogenated C₁₅ acetogenins were found from other two unrecorded species collected at Pulau Karah, Terengganu and Pulau Nyireh, Terengganu, respectively. Some of these halogenated metabolites showed moderate antibacterial activity against some marine bacteria.     

New plant growth promoters,repraesentins A,B and C,from Lactarius repraesentaneus

Three new plant growth regulatory sesquiterpenoids were isolated from the Lactarius repraesentaneus fungus. Their structures were elucidated to be a protoilludene sesquiterpene, namely repraesentin A (1), and two related sesquiterpenes, namely repraesentins B (2) and C (3). Compounds 1-3 showed promotion activities toward the radicle elongation of lettuce seedlings by 136%, 118% and 184% at 67 ppm, respectively.     

New Sesquiterpenes from Aspergillus terreus Thom

Four neutral sesquiterpenes were isolated from the culture filtrate of of Aspergillus terreus THOM NO. 14 which produces two sesquiterpene antibiotics, terrecyclic acid A and terrecyclol. On the basis of spectroscopic data the structures of four neutral sesquiterpenes were elucidated. One of these is quadrone, a known antitumor substance, but isoquadrone, 8-hydroxyquadrone and 6-hydroxyisoquadrone are new sesquiterpenes. Although terrecyclic acid A exhibits antimicrobial and antitumor activities, these four scarcely show these activities.     

Neurotrophic secoaromadendrane-type sesquiterpenes from the liverwort Plagiochila fruticosa

A new sesquiterpene dialdehyde, plagiochilal B, isolated from the liverwort Plagiochila fruticosa exhibits not only acceleration of neurite sprouting but also enhancement of choline acetyltransferase activity on a neuronal cell culture of fetal rat cerebral hemisphere at 10⁻⁵ M. Additionally, two new secoaromadendranes, plagiochilines J and K were isolated. The structures of the new secoaromadendrane-type sesquiterpenes were established by extensive 2D NMR data and chemical correlation with plagiochiline A.     

1,2-Dehydrolactarolide A, a new plant growth regulatory lactarane sesquiterpene from Lactarius vellereus

A new lactarane sesquiterpene, 1,2-dehydrolactarolide A (1), together with lactarorufin A (2), 3-O-ethyllactarolide A (3) and 3-O-ethyllactarolide B (4), was isolated from a mushroom of the Russulaceae family, Lactarius vellereus. Additionally, two lactarane sesquiterpenes, lactarorufin A (2) and lactarolide A (5) were isolated from L. subpiperatus. 1,2-Dehydrolactarolide A (1) showed promotional activity (152% at 3.6 x 10(1) microM) toward radicle elongation in lettuce seedlings.     

Anti-hyperlipidemic sesquiterpenes and new sesquiterpene glycosides from the leaves of artichoke (Cynara scolymus L.): structure requirement and mode of action

The methanolic extract from the leaves of artichoke (Cynara scolymus L.) was found to suppress serum triglyceride elevation in olive oil-loaded mice. Through bioassay-guided separation, sesquiterpenes (cynaropicrin, aguerin B, and grosheimin) were isolated as the active components together with new sesquiterpene glycosides (cynarascolosides A, B, and C). The oxygen functional groups at the 3- and 8-positions and exo-methylene moiety in alpha-methylene-gamma-butyrolactone ring were found to be essential for the anti-hyperlipidemic activity of guaiane-type sesquiterpene. In addition, inhibition of gastric emptying was shown to be partly involved in anti-hyperlipidemic activity.     

Sesquiterpenes from the fruits of Illicium jiadifengpi B.N. Chang

The phytochemical investigation of the fruits of Illicium jiadifengpi B. N. Chang led to the isolation of 14 sesquiterpenes (1–14). Among these, compounds 11–14 were identified for the first time from this species. The results indicate that majucin-type sesquiterpenes may be chemotaxonomic markers of I. jiadifengpi.     

Chemical constituents from the fungus Stereum sp. YMF1.04183

The chemical constituents of the basidiomycete Stereum sp. YMF1.04183 were studied. Three new sesquiterpenes, stereumenes A–C (1–3), were isolated and identified from the EtOAc extract of Stereum sp. YMF1.04183 culture broth. Stereumene B showed weak nematicidal activity against Caenorhabditis elegans.     

Phytochemical studies of the southern Australian marine alga, Laurencia elata

Chemical profiling of the southern Australian marine alga Laurencia elata (Rhodomelaceae) employing on-flow and stop-flow HPLC–NMR methodology followed by off-line chemical investigations resulted in the isolation of two C₁₆ chamigrenes, cycloelatanene A and B together with three previously reported sesquiterpenes, (3Z)-chlorofucin, pacifenol and elatenyne. The chemical structures were elucidated via detailed spectroscopic analyses.     

Sesquiterpenes from the conifer root rot pathogen Heterobasidion occidentale

Investigation of the production of secondary metabolites of Heterobasidion occidentale led to the isolation and identification of six sesquiterpenes (illudolone A and B, illudolactone A and B, deoxyfomannosin A and B) along with the well-known sesquiterpene fomannosin and the previously described benzohydrofuran fomannoxin. The structures and relative configurations of the compounds were determined by 1D and 2D NMR spectroscopic analysis as well as by HRMS. Their absolute configuration and biosynthesis were suggested and discussed in relation to fomannosin. Four compounds showed growth inhibiting activity against several basidiomycetes, Phlebiopsis gigantea, Phanerochaete chrysosporium and H. occidentale, and toxicity towards the moss Physcomitrella patens. In addition, one compound displayed activity against the bacterium Variovorax paradoxus as well as against the ascomycete Fusarium oxysporum.