Three new sesquiterpenes from roots of Curcuma longa

Objective: To study the chemical constituents from the roots of Curcuma longa.Methods: The structures of the new compounds were elucidated based on extensive spectral analysis, including 1D and 2D NMR, MS, UV, and CD analysis.Results: Two new sesquiterpene compounds (1S,2R,5R,7S,8R)-2,8-epoxy-5-hydroxybisabola-3,10-dioen-9-one (1), (1R,2R,5R,7S,8R)-2,8-epoxy-5-hydroxybisabola-3,10-dioen-9-one (2), and a new natural product 6-(4-Hydroxymethylphenyl)-2-methyl-hept-2-ene-4-one (3) together with three known compounds ar-turmerone (4), 2-methyl-6-(4-hydroxyphenyl-3-methyl)-2-hepten-4-one (5) and 2-methyl-6-(4-hydroxyphenyl)-2-hepten-4-one (6) were isolated from C. longa root extract with 95% ethanol.Conclusion: In the study, three new compounds were isolated from C. longa, and their absolute configurations were determined.     

Three new sesquiterpenes from the red alga Laurencia perforata

From the lipophilic extract of the red alga Laurencia perforata three new sesquiterpenes, (1S,2S,4S,5S, 6S,8R)-4-hydroxy-2,5,6-trimethyl-11-methylenetricyclo[6.2.1.0(1,6)]undecan-3-one (1, 4-hydroxy-1,8-epi-isotenerone), (3R,4R,4aR,9R)-3,9-dihydroxy-1,4,4a,7-tetramethyl-3,4,4a,5,8,9-hexahydro-2H-benzo[a]cyclohepten-2-one (9-hydroxy-3-epi-perforenone A, 2), and 3-epi-perforenone A (3), were isolated. The structures of all isolates were determined from their spectroscopic data (NMR, MS, IR, UV). Unusual for a species of this algal genus was the apparent absence of halogenated compounds.     

Three new diterpenoids based on the novel sarcopetalane skeleton from Croton sarcopetalus

The roots of Croton sarcopetalus afforded three new diterpenoids (2-4) with a novel carbon skeleton that seems to be derived biosynthetically from a pimarane precursor. The essential oil of the roots gave trans-methylisoeugenol as the main constituent, along with 22 further compounds.     

Oxachamigrenes,new halogenated sesquiterpenes from Laurencia obtusa

Two new sesquiterpenes belonging to a novel oxacyclic structural type of chamigrene skeleton, oxachamigrene (1) and 5-acetoxyoxachamigrene (2), have been isolated from the red alga Laurencia obtusa. The structures of the compounds were determined on the basis of spectroscopic evidence. A biogenetic route for these metabolites has been proposed.     

Vasorelaxant effect of new neo-clerodane diterpenoids isolated from Croton schiedeanus

The vasorelaxant effect of two new neo-clerodane diterpenoids, (12R)-12-hydroxycascarillone and 5beta-hydroxy-cis-dehydrocrotonin, in addition to the known cis-dehydrocrotonin and trans-dehydrocrotonin, all them previously isolated by us from Croton schiedeanus Schlecht, was studied in isolated aorta rings contracted by high K+ (80 mM) or phenylephrine (1 microM). According to their IC50 values to KCl induced contraction, the potency order was (12R)-12-hydroxycascarillone > cis-dehydrocrotonin > 5beta-hydroxy-cis-dehydrocrotonin > trans-dehydrocrotonin (0.3, 1.5, 96 and >100 mM, respectively). The possible cooperativity between diterpenoid compounds and the predominant flavonoid (ayanin) was studied. The vasorelaxant activity of cis-dehydrocrotonin and ayanin was increased when both compounds were incorporated simultaneously to the aortic rings precontracted with phenylephrine. These results suggest that Croton schiedeanus induces its effects via the synergistic actions of several vasodilator substances, among which neo-clerodane diterpenoids play an important role.     

Two new subergane-based sesquiterpenes from a Taiwanese Gorgonian coral Subergorgia suberosa

Chemical investigation of the ethyl acetate extract of the Taiwanese Gorgonian coral Subergorgia suberosa has resulted in the isolation of two new subergane-based sesquiterpenes, subergorgiol (1) and 2beta-acetoxysubergorgic acid (2), along with four known compounds, subergorgic acid methyl ester (3), 2beta-acetoxy methyl ester of subergorgic acid (4), 2beta-hydroxysubergorgic acid (5), and subergorgic acid (6). The structures of the new metabolites 1 and 2 were determined on the basis of extensive spectral analyses. Subergorgiol (1) may be the biosynthetic precursor of 2-6. Compound 3 was found to exhibit moderate cytotoxicity against the growth of HeLa cancer cells.     

New diterpenes from Croton insularis

Two new diterpenes (1 and 2) have been isolated from the aerial parts of Croton insularis. Their structures have been established by NMR and mass spectral data, and the absolute configuration of 1 and related trachylobane diterpenes was determined through a series of chemical correlations.     

Neoclerodane diterpenoids from Croton eluteria

Five new neoclerodane diterpenoids, rel-(3R,4S,5R,7R,8S,9R,10S,12R,20S)-7-acetoxy-15,16,12,20-diepoxy-3,4-dihydroxy-20-methoxyneocleroda-13(16),14-diene (1), rel-(3R,4S,5R,7R,8S,9R,10S,12R,20S)-7-acetoxy-15,16,12,20-diepoxy-3,4,20-trihydroxyneocleroda-13(16),14-diene (2), rel-(3R,4S,5S,6R,7S,8S, 9R,10S,12R,20S)-6,7-diacetoxy-3,4,15,16,12,20-triepoxy-20-hydroxyneocleroda-13(16),14-diene (3), rel-(3R,4S,5R,7R,8S,9R,10S,12R,20S)-7-acetoxy-3,4,15,16,12,20-triepoxy-20-hydroxyneocleroda-13(16),14-diene (4), and rel-(3R,4S,5R,7R,8S,9R,10S,12R,20R)-7,20-diacetoxy-3,4,15,16,12,20-triepoxyneocleroda-13(16),14-diene (5), have been isolated from the bark of Croton eluteria. The structures of the compounds 1-5 (cascarillins E-I) were determined by spectroscopic data interpretation.     

Neocrotocembranal from Croton oblongifolius.

A new cembranoid diterpene, neocrotocembranal (3), was isolated from the stem bark of Croton oblongifolius. Its structure was established on the basis of spectroscopic analysis. This compound inhibited platelet aggregation induced by thrombin, with an IC50 value of 47.21 microg/mL, and exhibited cytotoxicity against P-388 cells in vitro, with an IC(50) value of 6.48 microg/mL.     

Dendocarbins A--N, new drimane sesquiterpenes from the nudibranch Dendrodoris carbunculosa.

Fourteen new sesquiterpenes of the drimane series dendocarbins A--N (1--14) were obtained from ethanol extracts of the Japanese nudibranch Dendrodoris carbunculosa, together with two known compounds, isodrimeninol (15) and 11-epivaldiviolide (16). All structures were elucidated mainly from spectral data, and most of these sesquiterpenes were found to exhibit cytotoxicity. In addition, isodrimeninol (15), the major sesquiterpene of this animal, was found to have a sharp peppery taste.     

Minor sesquiterpenes with new carbon skeletons from the brown alga Dictyopteris divaricata

Five minor sesquiterpenes (1-5) with two novel carbon skeletons, together with a minor new oplopane sesquiterpene (6), have been isolated from the brown alga Dictyopteris divaricata. By means of spectroscopic data including IR, HRMS, 1D and 2D NMR, and CD, their structures including absolute configurations were assigned as (+)-(1R,5S,6S,9R)-3-acetyl-1-hydroxy-6-isopropyl-9-methylbicyclo[4.3.0]non-3-ene (1), (+)-(1R,3S,4S,5R,6S,9R)-3-acetyl-1,4-dihydroxy-6-isopropyl-9-methylbicyclo[4.3.0]nonane (2), (+)-(1R,3R,4R,5R,6S,9R)-3-acetyl-1,4-dihydroxy-6-isopropyl-9-methylbicyclo[4.3.0]nonane (3), (+)-(1S,2R,6S,9R)-1-hydroxy-2-(1-hydroxyethyl)-6-isopropyl-9-methylbicyclo[4.3.0]non-4-en-3-one (4), (-)-(5S,6R,9S)-2-acetyl-5-hydroxy-6-isopropyl-9-methylbicyclo[4.3.0]non-1-en-3-one (5), and (-)-(1S,6S,9R)-4-acetyl-1-hydroxy-6-isopropyl-9-methylbicyclo[4.3.0]non-4-en-3-one (6). Biogenetically, the carbon skeletons of 1-6 may be derived from the co-occurring cadinane skeleton by different ring contraction rearrangements. Compounds 1-6 were inactive (IC(50) > 10 mug/mL) against several human cancer cell lines.     

Eremophilane sesquiterpenes from Ligularia macrophylla

New eremophilane sesquiterpenes, 6beta-sarracinoyloxy-1beta,10beta-epoxy-furanoeremophilane (1), 6alpha-angeloyloxy-10betaH-furanoeremophil-1-one (2), 1alpha-hydroxy-9-deoxycacalol (3), and 1beta-hydroxy-11(R,S)-8-oxoeremophil-6,9-dien-12-al (4a+4b), together with five known sesquiterpenes (5-9) were isolated from the roots and rhizomes of Ligularia macrophylla. The structures were elucidated by spectroscopic methods including 2D NMR techniques, and the structure of 1 was confirmed by a single-crystal X-ray diffraction experiment. The compounds were also evaluated for cytotoxic activity against human lung carcinoma (A-549) and human breast adenocarcinoma (MCF-7) and were found to show only very weak cytotoxicity.     

Cytotoxic sesquiterpenes from Aplysia dactylomela

Three new chamigrenes, compound 1, acetyldeschloroelatol 2 (2-bromo-1,1,9-trimethyl-5-methylenespiro[5.5]undec-8-en-3-yl acetate), and acetylelatol 4 (2-bromo-8-chloro-1,1,9-trimethyl-5-methylenespiro[5.5]undec-8-en-3-yl acetate), and the known metabolites deschloroelatol 3, elatol 5, 8-acetylcaespitol 6, and caespitol 7 have been isolated from the sea hare Aplysia dactylomela. The structures of 1, 2, and 4 were determined on the basis of spectroscopic evidences. The in vitro cytotoxicity of six of these compounds against two cancer cell lines (HeLa and Hep-2) and nontumoral Vero cells was evaluated. The results support the hypothesis that the acetate derivatives decrease the toxicity of the corresponding alcohols in a strategy to store toxic metabolites acquired through the diet.     

New sesquiterpenes from Ferula sinaica

The CH2Cl2 extract of Ferula sinaica afforded twelve sesquiterpenes including three new daucanes, 14-hydroxyvaginatin, 4 beta, 8 beta, 9 alpha-trihydroxy-6 alpha-p-hydroxy-benzoyloxydaucane, and isolancerotriol.     

New sesquiterpenes from Capsicum annuum

The ethyl acetate soluble fraction of a MeOH extract of the dried stems and roots of Capsicum annum gave 10 new sesquiterpenoids (1-10) and nine known compounds. The structures of the new compounds were elucidated on the basis of spectroscopic evidence. The isolated new compounds were evaluated for their cytotoxic activities.     

Daucane sesquiterpenes from Ferula hermonis

The roots of Ferula hermonis Boiss yielded two new daucane esters, 14-(4'-hydroxybenzoyloxy)dauc-4,8-diene (1) and 14-(4'-hydroxy-3'-methoxybenzoyloxy)dauc-4,8-diene (2), together with the four known sesquiterpenes jaeschkeanadiol p-hydroxybenzoate (3), jaeschkeanadiol benzoate (4), jaeschkeanadiol (5), and epoxyjaeschkeanadiol (6). The identities of the isolated compounds were ascertained primarily using NMR and MS data. Compounds 1 and 3 exhibited antimicrobial activity against Staphylococcus aureus with IC(50) 1.5 and 3.5 microg/mL, respectively, and against Methicillin-resistant S. aureus with IC(50) 2.0 and 4.0 microg/mL, respectively.     

Muurolane sesquiterpenes from illicium tsangii

A dichloromethane extract of Illicium tsangii has yielded five novel muurolane sesquiterpenes (1, 2, 6, 7, 9) and three new menthane monoterpenes (10-12) in addition to several known compounds. Biogenetic relationships among the sesquiterpenes are discussed.     

New sesquiterpenes from Pluchea arabica

Two new sesquiterpenes, godotol A (1) and godotol B (2), were isolated from Pluchea arabica. Their structures were determined by analysis of NMR data. The absolute configurations of 1 and 2 were established by Mosher ester methodology. The godotols displayed weak activity against bacteria and the brine shrimp larvae. They were also inactive in the DPPH antioxidant assay.     

Daucane sesquiterpenes from Ferula hermonis

The dried roots of Ferula hermonis yielded three new daucanes, (1R,4R)-4-hydroxydauca-7-ene-6-one (1), (1R,4R)-4-hydroxydauca-7-ene-6,9-dione (2), and (1R,3S,8S)-3-ethoxy-8-angeloyloxydauca-4-en-9-one (3), together with the three known sesquiterpenes, ferutinin, teferidin, and (+)-alpha-bisabolol. The structures of compounds 1-3 were elucidated on the basis of spectroscopic evidence. The effect of these compounds on the proliferation of estrogen-dependent MCF-7 cells was evaluated, and it was found that compounds 1 and 3 exhibited proliferative activity, whereas 2 showed an antiproliferative effect.     

Minor sesquiterpenes from Maytenus chubutensis

Four new minor dihydro-beta-agarofuran-skeleton sesquiterpenes, 9 beta-benzoyloxy-1 alpha,2 alpha,6 beta-triacetoxy-15-hydroxydihydro-beta- agarofuran [1], 9 beta-benzoyloxy-1 alpha,2 alpha,6 beta,15-tetracetoxydihydro-beta-agarofuran [6], 9 alpha-benzoyloxy-1 alpha,2 alpha,6 beta-triacetoxy- 8 alpha,15-dihydroxydihydro-beta-agarofuran [7], and 9 alpha-benzoyloxy-1 alpha,2 alpha,6 beta,8 alpha-tetracetoxy-15- hydroxydihydro-beta-agarofuran [8] were isolated from the aerial parts of Maytenus chubutensis and identified by spectroscopy and chemical reactions.