Complex sesquiterpenoids with tyrosinase inhibitory activity from the leaves of Chloranthus tianmushanensis

Investigation of the leaves of Chloranthus tianmushanensis resulted in the isolation and characterization of two new sesquiterpene dimers with a rare 18-membered triester ring, tianmushanol (1) and 8-O-methyltianmushanol (2), and four known sesquiterpenes. Their structures were established by spectroscopic means. The inhibitory activities against tyrosinase of all isolates were also evaluated.     

Sesquiterpene lactones from Inula britannica and their cytotoxic and apoptotic effects on human cancer cell lines

Three new sesquiterpenes (1-3), together with four known sesquiterpene lactones, were isolated from the flowers of Inula britannica var. chinensis. Structures were established on the basis of high-field 1D and 2D NMR methods supported by HRMS. All sesquiterpene lactones were tested for cytotoxicity as well as apoptotic ratio in human COLO 205, HT 29, HL-60, and AGS cancer cells. Compounds 3 and 4, two alpha-methylene gamma-lactone-bearing sesquiterpenes, were modestly active in these assays.     

Phytochemistry and antifungal properties of the newly discovered tree Pleodendron costaricense

Gas chromatography analysis of the essential oils of leaves and bark collected from the newly discovered tree Pleodendron costaricense identified alpha-pinene, beta-pinene, beta-myrcene, beta-thujene, and beta-caryophyllene as their major constituents. Phytochemical analysis of P. costaricense parts led to the isolation and identification of delta-tocotrienol, beta-sitosterol, four known drimane-type sesquiterpenes, cinnamodial (1), cinnamosmolide (2), polygodial (3), and mukaadial (4), and two new compounds, a drimane-type sesquiterpene, parritadial (5), and an eremophilane-type sesquiterpene, pleodendione (6). Antifungal assays with the two major compounds, 1 and 2, were carried out, and results showed a high activity of 1 against Alternaria alternata (MIC = 3.9 microg/mL), Candida albicans azole-resistant strain D10, and Wangiella dermatitides (MICs = 15.6 microg/mL). Compound 2 showed less potent antifungal activities than 1 but was more effective against Candida albicans azole-resistant strain CN1A (MIC = 23.4 microg/mL) and Pseudallescheria boydii (MIC = 78.1 microg/mL). A combination of the dialdehyde sesquiterpenes with dillapiol showed a synergistic antifungal effect with 1 and an additive effect with 4 and 5.     

Lindenane sesquiterpene dimers from Chloranthus fortunei

Five new lindenane sesquiterpene dimers ( 1- 5), named shizukaols K-O, and eight known sesquiterpene dimers were isolated from the roots of Chloranthus fortunei. The structures of 1- 5 were elucidated using spectroscopic data, mainly 1D NMR, 2D NMR, and mass spectra.     

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.     

Sesquiterpenes from the Formosan stolonifer Tubipora musica.

Eight new sesquiterpenes, tubipolides A-G (1-7) and tubiporone (8) (novel carbon skeleton), and a known sesquiterpene, spirotubipolide, have been isolated from the Formosan stolonifer Tubipora musica. The structures of compounds 1-8 were determined by 1D and 2D NMR spectral analysis.     

Dactylomelatriol, a biogenetically intriguing omphalane-derived marine sesquiterpene

Dactylomelatriol (1), obtained from the sea hare Aplysia dactylomela, is the first naturally occurring omphalane-derived sesquiterpene from the marine environment. From this species the known chamigrene and modified bisabolene sesquiterpenes 2-6 were also isolated. The structure and relative configuration of 1 were established by spectroscopic evidence. Its chemical structure is related to omphalic acid, the unique terrestrial-derived omphalane sesquiterpene isolated from a liverwort. A biogenetic route for this compound is proposed. The antimicrobial activities of compounds 1-6 were evaluated against a panel of microorganisms.     

New cytotoxic sesquiterpenes from the gorgonian Isis hippuris

Five new suberosane sesquiterpenes, suberosenol A (1), suberosenol B (2), suberosanone (3), suberosenol A acetate (4), and suberosenol B acetate (5), along with the known sesquiterpene subergorgic acid (6), have been isolated from the gorgonian Isis hippuris. The structures of these metabolites were established by spectroscopic and chemical methods. Metabolites 1 and 3-5 were found to exhibit potent cytotoxicity toward P-388, A549, and HT-29 cancer cell lines.     

A cytotoxic sesquiterpene alkaloid from the South China Sea gorgonian Subergorgia suberosa

A new sesquiterpene alkaloid, 6-(9'-purine-6',8'-diolyl)-2beta-suberosanone (1), together with three known sesquiterpenes, suberosenol A (2), subergorgic acid (3), and subergorgiol (4), was isolated from the EtOH/CH2Cl2 extracts of the South China Sea gorgonian Subergorgia suberosa. The structure of 1 was determined through spectroscopic methods. Compound 1 showed moderate cytotoxicity against the human breast carcinoma MDA-MB-231 cell line with an IC50 of 8.87 microg/mL.     

Cytotoxic constituents of the fruits of Cananga odorata

A new guaipyridine sesquiterpene alkaloid, cananodine (1), and two new eudesmane sesquiterpenes, cryptomeridiol 11-alpha-L-rhamnoside (2) and gamma-eudesmol 11-alpha-L-rhamnoside (3), along with gamma-eudesmol (4), were isolated from the fruits of Cananga odorata. The structures of compounds 1-3 were established on the basis of NMR and MS methods. In addition, compounds 1-4 and four previously reported alkaloids, cleistopholine (5), N-trans-feruloyltyramine (6), (+)-ushinsunine-beta-N-oxide (7), and lyscamine (8), were evaluated for cytotoxicity against two human hepatocarcinoma cell lines.     

cis-Eudesmane sesquiterpene glycosides from Liriope muscari and Ophiopogon japonicus

Two new cis-eudesmane sesquiterpene glycosides, liriopeoside A (1) and ophiopogonoside A (2), were extracted and purified from tubers of Liriope muscari and Ophiopogon japonicus, respectively, along with three known compounds. Their structures were elucidated as 1beta,6beta-dihydroxy-cis-eudesm-3-ene-6-O-beta-D-glucopyranoside (1) and 1beta,4beta,6beta-trihydroxy-cis-eudesmane-6-O-beta-D-glucopyranoside (2) by spectral data analysis. The structure and the relative configuration of compound 1 were confirmed by X-ray crystallographic analysis. This is the first time that cis-eudesmane-type sesquiterpenes have been reported from the genera Ophiopogon and Liriope.     

Sesquiterpenes and aliphatic diketones from cultures of the basidiomycete Conocybe siliginea

Five new tremulane-type sesquiterpenes, 11,12-dihydroxy-1-tremulen-5-one (1), 11,12-epoxy-12beta-hydroxy-1-tremulen-5-one (2), 5alpha,12-dihydroxy-1-tremulen-11-yl 2(S)-pyroglutamate (3), 2alpha,11-dihydroxy-1(10)-tremulen-5,12-olide (4), and 10beta,11-dihydroxy-5,6- seco-1,6(13)-tremuladien-5,12-olide (5), as well as three new aliphatic diketones, 2,3-dihydroxydodecane-4,7-dione (9 and 10) and 1-hydroxydecane-2,5-dione (11), together with three known sesquiterpene analogues, tremulenediol A (6), conocenol B (7), and conocenolide A (8), were isolated from cultures of the basidiomycete Conocybe siliginea.     

Sesquiterpenes from Blumea balsamifera

Five new guaiane sesquiterpenes, blumeaenes E1 (1), E2 (2), K (3), L (4), and M (5), and one new eudesmane sesquiterpene, samboginone (6), along with three known compounds, cryptomeridiol, 3,3',5,7-tetrahydroxy-4'-methoxyflavanone, and austroinulin, were isolated from the leaves of the Philippine medicinal herb sambong, Blumea balsamifera. The absolute configuration of the new guaiane core was determined as 1S,7S,9S,10R by employing the modified Mosher's method. In the structure of 1, the absolute configuration of the epoxyangelic acid moiety was identified as 2S,3S using (R)-PGME as a chiral anisotropic auxiliary.     

Capnellenes from the Formosan soft coral Capnella imbricata

Three anti-inflammatory sesquiterpenes, Delta (9(12))-capnellene-8beta,10alpha-diol ( 1), 8alpha-acetoxy-Delta (9(12))-capnellene-10alpha-ol ( 2), and Delta (9(12))-capnellene-10alpha-ol-8-one ( 3), five new sesquiterpenes, Delta (9(12))-capnellene-8beta,15-diol ( 4), Delta (9(12))-capnellene-8beta,10alpha,13-triol ( 5), Delta (9(10))-capnellene-12-ol-8-one ( 6), 8beta,10alpha-diacetoxy-Delta (9(12))-capnellene ( 7), and 8beta-acetoxy-Delta (9(12))-capnellene ( 8), and a known sesquiterpene, Delta (9(12))-capnellene-8beta-ol ( 9), were isolated from the acetone/methylene chloride extracts of the Formosan soft coral Capnella imbricata. The structures of these compounds were elucidated by extensive spectroscopic analysis.     

New seco-prezizaane-type sesquiterpenes, jiadifenin with neurotrophic activity and 1,2-dehydroneomajucin from Illicium jiadifengpi

Two new seco-prezizaane-type sesquiterpenes, 1,2-dehydroneomajucin (1) and jiadifenin (2), were isolated from the methanol extract of the pericarps of Illicium jiadifengpi, indigenous to the southern part of China. Their structures were elucidated on the basis of NMR data. Compound 2, which is an equilibrated mixture of the epimers 2a and 2b on the C-10 acetal carbon, is the first example of a majucin-type seco-prezizaane with an oxo-function at the C-10 position. The proposed structure for 2 was unambiguously confirmed by chemical conversion of the known sesquiterpene (2S)-hydroxy-3,4-dehydroneomajucin (5) to 2. Compounds 2 and 5 were found to significantly promote neurite outgrowth in primary cultures of fetal rat cortical neurons at concentrations from 0.1 to 10 microM.     

Sesquiterpene lactones from the roots of Ferula varia and their cytotoxic activity

The ethyl acetate-soluble fraction from a MeOH extract of the roots of Ferula varia gave six new sesquiterpene lactones (1-6) and five known sesquiterpenes (7-11). Their structures were established on the basis of spectroscopic evidence. The cytotoxic activities of 1-11 were evaluated against selected human cancer cell lines. Compound 4 showed significant selective cytotoxicity against multidrug-resistant cancer cells (KB-C2). The cytotoxicities of compounds 1, 3, 5, 8, and 11 against KB-C2 cells were enhanced in the presence of nontoxic concentrations of colchicine.     

Kopetdaghins A-E, sesquiterpene derivatives from the aerial parts and the roots of Dorema kopetdaghense

Three new sesquiterpene derivatives, kopetdaghins A-C (1-3), one known prenylated coumarin (7), and two known steroid glucosides, sitosterol 3-O-glucoside and stigmasterol 3-O-glucoside, were isolated from the aerial parts of Dorema kopetdaghense. In addition, two new sesquiterpene derivatives, kopetdaghin D (4) and kopetdaghin E (5), together with kopetdaghins A-C and one known sesquiterpene coumarin (6), were isolated from the roots of the plant. The structures of these compounds were elucidated by various 1D and 2D NMR techniques as well as high-resolution positive-ion ESIMS.     

New allo-cedrane type sesquiterpene hemiketals and further sesquiterpene lactones from fruits of Illicium floridanum

Three new tetracyclic sesquiterpene hemiketals possessing the very rare allo-cedrane carbon skeleton, debenzoyl-7-deoxo-1 alpha,7 alpha-dihydroxytashironin, debenzoyl-7-deoxo-7 alpha-hydroxytashironin, and debenzoyl-7-deoxo-7 alpha-hydroxy-3-oxotashironin (1--3), were isolated from the fruits of Illicium floridanum ELLIS (American Star Anise, Star bush). Their structures were elucidated by mass and NMR spectroscopic analyses. The molecular structure of 1, including absolute stereochemistry, was determined by single-crystal X-ray diffraction of its monohydrate. Only one compound of this type, tashironin, has previously been isolated from Illicium tashiroi. Furthermore, a new sesquiterpene lactone of the seco-prezizaane type, 3,4-anhydro-13,14-dihydroxyfloridanolide (4), and the known anislactone B (5) were isolated. The occurrence of further allo-cedrane sesquiterpenes in another Illicium species confirms the hypothesis of previous authors that this type of compound is a biogenetic precursor of the typical seco-prezizaane sesquiterpene lactones found in this genus. Moreover, regarding their co-occurrence with anislactone B as reported here, they may also be considered precursors for the anislactone skeletal type.     

Sesquiterpenes from the Hainan Sponge Dysidea septosa

Five new sesquiterpenes, named lingshuiolides A (1) and B (2), lingshuiperoxide (6), isodysetherin (10), and spirolingshuiolide (12), along with several known related analogues (7- 9, 11, and 13- 15), were isolated from the Hainan marine sponge Dysidea septosa. The structures of new compounds 1, 2, 6, 10, and 12 were determined by detailed analysis of 1D and 2D NMR spectra and by comparison with related model compounds. The absolute configuration of lingshuiolide B (2) was established by using the modified Mosher's method. Spirolingshuiolide (12) represents the first example of a sesquiterpene with a rearranged drimane skeleton. Compounds 7- 9 and 15 exhibited significant inhibitory activity against human protein tyrosine phosphatase 1B (hPTP1B), an enzyme involved in the regulation of insulin signaling. In particular, 15 showed the most potent effect, with an IC 50 value of 1.9 microg/mL.     

Sesquiterpenes and monoterpenes from the bark of Inula macrophylla

Eleven new sesquiterpenes (1--11) and two thymol derivatives (12, 13), along with 12 known sesquiterpenes and monoterpenes, were isolated from the bark of Inula macrophylla. Their structures were determined on the basis of spectral evidence (especially by HREIMS and 2D NMR) as well as chemical transformations. The structure of macrophyllic acid A (1) was confirmed by X-ray analysis, and the absolute configuration of 1 was determined on the basis of the appropriate chemical conversions and the application of a modified Mosher's method.