New Epoxy‐Substituted Nitrogenous Bisabolene‐Type Sesquiterpenes from a Hainan Sponge Axinyssa sp.

Two new uncommon epoxy‐substituted nitrogenous bisabolene‐type sesquiterpenes, 3‐formamido‐7,8‐epoxy‐α‐bisabolane ( 4 ), 3‐isocyano‐7,8‐epoxy‐α‐bisabolane ( 5 ), together with three known related sesquiterpenes, 1 – 3 , were isolated from the Hainan sponge Axinyssa sp. Their structures were determined on the basis of extensive spectroscopic analyses and by comparison of their NMR data with those of structurally related compounds.     

New Nitrogenous Bisabolene‐Type Sesquiterpenes from a Hainan Sponge Axinyssa aff. variabilis

Two new uncommon nitrogenous sesquiterpenes, 11‐ethoxy‐3‐formamidotheonellin ( 1 ) and 7‐ethoxy‐3‐formamidobisabolane‐8,10‐diene ( 2 ), together with two known related sesquiterpenes, 3‐formamidotheonellin (=theonellin formamide; 3 ) and theonellin isothiocyanate ( 4 ), were isolated from the Hainan sponge Axinyssa aff. variabilis. Their structures were determined on the basis of extensive spectroscopic analysis and by comparison of their NMR data with those of known compounds.     

New Sesquiterpene Formamides from the Marine Sponge Axinyssa sp.

Chemical investigation of an extract of the marine sponge Axinyssa sp., collected from the South China Sea, led to the isolation and identification of two new sesquiterpene formamides, (4R*,5R*,10R*)‐4‐formamidoeudesm‐7‐ene ( 1 ) and (4R*,5R*,7S*,10R*)‐4‐formamidoeudesman‐11‐ol ( 2 ), together with the known 4α‐formamidogorgon‐11‐ene ( 3 ). Their structures were elucidated by spectroscopic methods, including 1D‐ and 2D‐NMR spectroscopy, high‐resolution ESI‐TOF mass spectrometry, as well as X‐ray single‐crystal diffraction experiments. Possible biosynthetic pathways for 1 – 3 were also proposed. The human nasopharyngeal cancer cell line CNE‐2, human cervical cancer cell line HeLa, and human normal liver cell line L02 were used to examine the cytotoxic activities of 1 – 3 in vitro. As the results, 1 showed significant cytotoxic activity against CNE‐2, HeLa, and L02 cell lines with the IC₅₀ values of 13.8, 7.5, and 38.0 μg/ml, resp.     

New Highly Oxidized Formamidobisabolene‐Derived Sesquiterpenes from a Hainan Sponge Axinyssa variabilis

Two new highly oxidized formamidobisabolene sesquiterpenes ( 1 and 2 ), together with seven known related analogues ( 3 – 9 ), were isolated from a Hainan sponge Axinyssa variabilis. Their structures were determined by extensive 1D‐ and 2D‐NMR and MS spectra analyses, and by comparison of their spectroscopic data with those of the related model compounds. The plausible biosynthetic relationship between compounds 1 – 9 has also been described.     

Lingshuine,an Unexpected Passerini Product from the Hainan Sponge Axinyssa variabilis

Lingshuine ( 1 ), a novel sesquiterpene amide, along with three known N‐containing compounds, 2 – 4 , have been isolated from the Hainan sponge Axinyssa variabilis. The structure of 1 was elucidated by detailed analysis of the spectroscopic data and by chemical methods. Lingshuine represents the first example of a Passerini product formed during the isolation process.     

Two New Sesquiterpenes from the Fungus Stereum sp.

Two new sesquiterpenes, stereumin F ( 1 ) and stereumin G ( 2 ), together with two known compounds (3β,5α,22E,24R)‐5,8‐epidioxyergosta‐6,22‐dien‐3‐ol ( 3 ) and 4‐(2‐hydroxyethyl)phenol ( 4 ), were isolated from the AcOEt extract of the culture broth and the MeOH extract of the mycelium of the fungal strain Stereum sp. CCTCC AF 207024. Their structures were established on the basis of spectral analyses.     

New Sesquiterpenes from a Taiwanese Marine Sponge of the Genus Parahigginsia

An undescribed Taiwanese marine sponge of the genus Parahigginsia yielded two new sesquiterpene hydrocarbons-parahigginine ( 1 ) and parahigginone ( 2 ). The structures of the new compounds were established on the basis of NMR spectroscopic and mass spectrometric data. Compounds 1 and 2 exhibited moderate cytotoxicity against murine P-388 and human KB-16, A-549, and HT-29 tumor cells.     

New Oplopane‐Type Sesquiterpenes from Ligularia narynensis

Four new, highly oxygenated oplopane‐type sesquiterpenes ( 3 – 6 ) were isolated from the roots of Ligularia narynensis, together with four known compounds, and their structures were elucidated by spectroscopic methods and comparison with literature data. Selected congeners were evaluated for their in vitro cytotoxic activities against cultured SMMC‐7721 (human hepatoma), L02 (human hepatocyte), and HL‐60 (human promyelocytic leukemia) cells, but were found to be inactive.     

Sesquiterpenes from the marine algicolous fungus Drechslera sp.

A marine fungal isolate, identified as Drechslera sp., was mass cultivated and found to produce a new naturally occurring seco-sativene type sesquiterpene helminthosporic acid (1) and three known sesquiterpenes, helminthosporol (2), drechslerine A (3) and (+) secolongifolene-diol (4). The structures of all compounds were determined by interpretation of their spectroscopic data 1D (¹H and ¹³C), 2D (COSY, DQF, NOE, HSQC and HMBC) NMR, MS, UV and IR analyses. All compounds have been tested toward antioxidants, antimicrobial and antifouling effects.     

Two New Sesquiterpenes from Myrrh

Two new sesquiterpenes, named 9‐methoxymyrrhone ( 1 ) and rel‐(1S,2S,3R,4S)‐1,2‐epoxy‐3‐methoxyfuranogermacr‐10(15)‐en‐6‐one ( 2 ), together with nine known compounds ( 3 – 11 ), were isolated from the resin of Commiphora opobalsamum. The structures were established by HR‐ESI‐MS, 1D‐, and 2D‐NMR spectroscopic analyses.     

New Cadinane‐Type Sesquiterpenes from the Roots of Taiwania cryptomerioides Hayata

Six new cadinane‐type sesquiterpenes, (1β,4β,5α,10α)‐1,4‐epoxymuurolan‐5‐ol ( 1 ), (4α,10β)‐4,10‐dihydroxycadin‐1(6)‐en‐5‐one ( 2 ), (2β,3α,4β,6β)‐2,3‐dihydroxycadin‐1(10)‐en‐5‐one ( 3 ), (2β,3α)‐α‐corocalene‐2,3‐diol ( 4 ), (7S)‐α‐calacoren‐14‐ol ( 5 ), and (8β,9β,10β)‐8,9‐epoxycalamenene‐3,10‐diol ( 6 ) together with one known compound, (8β,9β,10β)‐8,9‐epoxycalamenen‐10‐ol ( 7 ), were isolated from the roots of Taiwania cryptomerioides. The structures of the new constituents were essentially elucidated by spectral evidence.     

Sesquiterpenes from the Marine Red Alga Laurencia saitoi

Together with five known sesquiterpenes, EtOH extraction of Laurencia saitoi yielded four new compounds, including three sesquiterpenes and one norsesquiterpene derivative. Their structures and relative configurations were elucidated by spectroscopic methods, including 1D‐ and 2D‐NMR (¹H,¹H‐COSY, HMQC, HMBC, and NOESY), as well as low‐ and high‐resolution mass‐spectrometric analyses.     

New Sesquiterpenes from Chloranthus japonicus

Chemical investigation of the roots of Chloranthus japonicus Sieb . has resulted in the isolation and characterization of four new eudesmane‐type sesquiterpenes including two new sesquiterpene cinnamates, along with one new and two known sesquiterpene dimers. Their structures were established by spectroscopic means and by comparison with the respective literature values.     

Three New Sesquiterpenes from Laggera pterodonta

A new eremophilane sesquiterpene, (2β)‐2‐deoxo‐2‐methoxytessaric acid ( 1 ), and two new eudesmane sesquiterpenes, (3β,10α)‐3‐methoxyleudesma‐4,11(13)‐dien‐12‐oic acid ( 2 ) and (3α,4β,8α)‐4‐(acetyloxy)‐3‐(2,3‐dihydroxy)‐2‐methyl‐1‐oxobutoxy‐8‐hydroxyeudesm‐7(11)‐eno‐12,8‐lactone ( 3 ), along with the ten known compounds 4 – 13 were isolated from the aerial parts of Laggera pterodonta. The structures of the new compounds were elucidated by spectroscopic analyses, including 2D‐NMR data.     

Two New Sesquiterpenes from Ligularia lankongensis

In continuation of a systematic investigation into the chemotaxonomic and bioactive components of pyrrolizidine alkaloids and sesquiterpenoids of Ligularia plants, two new, highly oxygenated, rare bisabolene sesquiterpenes, compounds 1 and 2 , were isolated from the roots of Ligularia lankongensis. Their structures and relative configurations were elucidated by means of 1D‐ and 2D‐NMR as well as MS analyses.     

Five New Eremophilane Sesquiterpenes from Ligularia przewalskii

Five new eremophilane‐type sesquiterpenes, 3β‐(acetyloxy)‐7‐hydroxynoreremophila‐6,9‐dien‐8‐one ( 1 ), 8β‐hydroxy‐2‐dehydroxyliguhodgsonal ( 2 ), 3β‐(acetyloxy)‐11‐methoxy‐8‐oxoeremophila‐6,9‐dien‐12‐oic acid ( 3 ), 3β‐(acetyloxy)‐11‐(2′‐methylbutanoyloxy)‐8‐oxoeremophila‐6,9‐dien‐12‐oic acid ( 4 ), and 3β‐(acetyloxy)‐6α‐hydroxyligularenolide ( 5 ), along with the three known compounds 6 – 8 , were isolated from the roots of Ligularia przewalskii. The structures of the new compounds were elucidated through spectral studies including HR‐EI‐MS, IR, and NMR data.     

New Sterol Derivatives from the Marine Sponge Xestospongia sp.

Chemical examination of a marine sponge Xestospongia sp. resulted in the isolation of 20 sterol derivatives ( 1 – 20 ), including eight new sterols namely aragusterols J – L ( 1 – 3 ), (5α,7α,12β,22E)‐7,12,18‐trihydroxystigmast‐22‐en‐3‐one ( 4 ), (5α,7α,12β,24R)‐ and (5α,7α,12β,24S)‐7,12,20‐trihydroxystigmastan‐3‐one ( 5 / 6 ), and (5α,7α,12β,22E,24R)‐ and (5α,7α,12β,22E,24S)‐7,12,20‐trihydroxyergost‐22‐en‐3‐one ( 7 / 8 ). The structures of new compounds were determined through extensive spectroscopic analyses and chemical conversion. The sterol diversity was mainly characterized by the presence of a cyclopropane unit at side chain, while compound 4 with 18‐hydroxymethyl group was found in stigmasterol family for the first time. Cytotoxic test revealed the inhibitory effects of compounds 1 , 4 , and 17 against human leukemia cell line K562 with IC₅₀ values of 18.3, 24.1, and 34.3 μm , respectively.     

New Sesquiterpenes from Ligulariopsis Shichuana

A thorough investigation of Ligulariopsis shichuana afforded five new sesquiterpenes, including 1β,10β‐epoxy‐3α‐angeloyloxy‐9β‐acetoxy‐8α,11β‐dihydroxybakkenolide ( 1 ), 1β,7‐dihydroxy‐3β‐acetoxy‐noreremophil‐6(7),9(10)‐dien‐8‐one ( 2 ), 8α‐hydroxy‐3‐oxoeremophil‐1(2),7(11),9(10)‐trien‐8β(12)‐olide ( 3 ), 1β,10β‐dihydroxy‐3β‐acetoxyeremophil‐7(11),8(9)‐dien‐8(12)‐olide ( 4 ) and 1β,10β‐epoxy‐8,12‐dihydroxy‐3β‐acetoxy‐9β‐angeloyloxyeremophil‐7(11)‐en‐8,12‐disemiketal ( 5 ). Their structures were established by spectroscopic methods and 2D NMR techniques. In addition, bakkenolide ( 1 ) and eremophilenolides ( 5 ) showed antibacterial and cytotoxic activities.