New Sesquiterpenoids from Ligularia duciformis

From the whole plants of Ligularia duciformis, four new sesquiterpenoids, 3β‐acetoxy‐6β‐methoxyeremophila‐7(11),9(10)‐dien‐12,8β‐olide ( 1 ), 3β‐acetoxy‐8α‐hydroxy‐6β‐methoxyeremophila‐7(11),9(10)‐dien‐12,8β‐olide ( 2 ), 3β‐acetoxy‐10β‐hydroxy‐6β,8β‐dimethoxyeremophil‐7(11)‐en‐12,8α‐olide ( 3 ), and 3β‐acetoxy‐6β,8β,10β‐trihydroxyeremophil‐7(11)‐en‐12,8α‐olide ( 4 ) were isolated. Their structures were established by high‐field NMR techniques (¹H,¹H‐COSY, ¹³C‐APT, HMQC, HMBC, and NOESY) and HR‐ESI‐MS analysis, together with comparison of the spectroscopic data with those of structurally related compounds. In addition, the cytotoxicity of the new compounds against human hepatic cancer cells Bel‐7402, human pneumonic cancer cells A‐549, and human colonic cancer cells HCT‐8 were evaluated, the new compounds showed no cytotoxicity against the three tumor cells (all IC₅₀ values >200 μM ).     

Eudesmanolides and Guaianolides from Carpesium triste

A new eudesmanolide, 1‐oxo‐11αH‐eudesma‐2,4(14)‐dien‐12,8β‐olide ( 1 ), and four new guaianolides, 9β,10β‐epoxy‐4α‐hydroxy‐1βH,11αH‐guaian‐12,8α‐olide ( 2 ), 9β,10β‐epoxy‐4α‐hydroxy‐1βH,11βH‐guaian‐12,8α‐olide ( 3 ), 4α,9α‐dihydroxy‐1βH,11αH‐guai‐10(14)‐en‐12,8α‐olide ( 4 ), and 4α,9α‐dihydroxy‐1βH,11βH‐guai‐10(14)‐en‐12,8α‐olide ( 5 ), together with one known eudesmanolide and two known germacranolides, were isolated from the whole plants of Carpesium triste. Their structures and relative configurations were elucidated on the basis of spectroscopic methods, including 2D‐NMR techniques.     

Sesquiterpene Lactones from Anthemis melanolepis

From the aerial parts of A. melanolepis, two new sesquiterpene lactones, melanolepin B ( = 1α,4β,8α‐trihydroxyeudesm‐11(13)‐en‐12,6α‐olide; 1 ) and melanolepin C (= 1α,10β‐epoxy‐8β‐hydroxygermacra‐4(15),11(13)‐dien‐12,6α‐olide; 2 ), were isolated, together with four known compounds, desacetyllaurenobiolide, dentatin A, taraxasterol, and (3S,5R)‐loliolide. Compound 1 was found to have the rare cis‐fused eudesmane skeleton. The structures of the isolated compounds were established by means of NMR (¹H, ¹H‐COSY, ¹H,¹³C‐HSQC, HMBC, NOESY) and MS analyses.     

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.     

Four Novel Eremophilanolides from Ligularia sagitta

Four new eremophilanolides, isolated from Ligularia sagitta, were identified as (1β,3β,6β,8β,10β)‐6‐acetoxy‐3‐(angeloyloxy)‐1,10‐epoxy‐8‐hydroxyeremophil‐7(11)‐en‐8,12α‐olide ( 1 ), (1β,3β,6β,8β,10β)‐3‐(angeloyloxy)‐1,10‐epoxy‐6,8‐dihydroxyeremophil‐7(11)‐en‐8,12α‐olide ( 2 ), (1β,3β,6β,8β,10β)‐3‐(angeloyloxy)‐1,10‐epoxy‐8‐ethoxy‐6‐hydroxyeremophil‐7(11)‐en‐8,12α‐olide ( 3 ), and (1β,3β,8β,10β)‐3‐(angeloyloxy)‐1,10‐epoxy‐8‐hydroxyeremophil‐7(11)‐en‐8,12α‐olide ( 4 ). Their structures were elucidated by spectroscopic methods, including 2D‐NMR techniques and chemical transformations.     

Diversity of Sesquiterpenoids from Carpesium cernuum

Two new sesquiterpene lactones, 6β‐hydroxy‐8α‐ethoxyeremophil‐7(11)‐en‐12,8β‐olide ( 1 ) and 4β,10β‐dihydroxy‐1αH,5αH,11αH‐guaian‐12,8β‐olide ( 2 ), together with 22 known sesquiterpenoids with various structural types, were isolated from Carpesium cernuum (Compositae). Their structures and configurations were elucidated by extensive 1D‐ and 2D‐NMR spectroscopic analysis in combination with MS experiments, and comparison with literature data of related compounds.     

Sesquiterpenoids from Chloranthus spicatus （Thunb.） Makino

Two new sesquiterpenoids, namely 1β,4β-dihydroxy-5 α,8β（H）-eudesm-7（11）Z-en-8,12-olide （1） and 1β,4α-dihydroxy-5α,8β（H）-eudesm-7（11）Z-en-8,12-olide （2）, along with six known ones, homalomenol A （3）, oplodiol （4）, 5α,7α（H）-6,8-cycloeudesma-1β,4β-diol （5）, oplopanone （6）, 4β,10α-dihydroxyaromadendrane （7） and spathulenol （8）, were isolated from the aerial part of Chloranthus spicatus （Thunb.） Makino, and their structures were established by spectroscopic methods.     

华泽兰的七个新的倍半萜

Seven new sesquiterpenoids, namely eupatochinilides Ⅰ-Ⅶ （1-7）, together with eight known compounds, euponin （8）, mollisorin A （9）, niveusin B （10）, 8β-（4＇-acetoxy-tiglyloxy）-3β-hydroxy-6Hβ,7Hα-germacra-1（10）E,4E,11（13）-trien-6,12-olide （11）, eupalinifide B （12）, 8β-（4＇-hydroxytigloyloxy）-5-desoxy-8-desacyleuparotin （13）, 3-deacetyeupalinin A （14）, and 15-hydroxyleptocarpin （15）, were isolated from the ethanolic extract of the whole plant of Eupatorium chinense L. Their structures and stereochemistry were established by spectroscopic methods and GIAO based ^13C NMR chemical shift calculations.     

New Eremophilenolides from Senecio dianthus

From the aerial parts of Senecio dianthus, four new eremophilenolides ( 1 – 4 , resp.) and one new eremophilenolide alkaloid ( 5 ), of the relatively uncommon eremophilenoid‐type sesquiterpenoid lactones, were isolated together with three known sesquiterpenoid lactones, 10β‐hydroxyeremophil‐7(11)‐en‐12,8α‐olide ( 6 ), 8β,10β‐dihydroxyeremophil‐7(11)‐en‐12,8α‐olide ( 7 ), and 10α‐hydroxy‐1‐oxoeremophila‐7(11),8(9)‐dien‐12,8‐olide ( 8 ). On the basis of IR, MS, and NMR data, particularly 2D‐NMR analyses, the structures of the new compounds were established as: 2β‐(angeloyloxy)‐10β‐hydroxyeremophil‐7(11)‐en‐12,8α‐olide ( 1 ), 6β‐(angeloyloxy)‐10β‐hydroxyeremophil‐7(11)‐en‐12,8α‐olide ( 2 ), 2β‐(angeloyloxy)‐8β,10β‐dihydroxyeremophil‐7(11)‐en‐12,8α‐olide ( 3 ), 2β‐(angeloyloxy)‐8α‐hydroxyeremophila‐7(11),9(10)‐dien‐12,8β‐olide ( 4 ), and 8β‐amino‐10β‐hydroxyeremophil‐7(11)‐en‐12,8α‐olide ( 5 ). In addition, the relative configuration of 1 was corroborated by X‐ray diffraction analysis.     

Terpenoids from the Roots of Ligularia muliensis

Three new eremophilane‐type sesquiterpenes, (6β,8α)‐6‐(acetyloxy)‐8‐hydroxyeremophil‐7(11)‐en‐12,8‐olide ( 1 ), (6α,8α)‐6‐hydroxyeremophil‐7(11)‐en‐12,8‐olide ( 2 ), and (6α,8α)‐6‐(acetyloxy)eremophil‐7(11)‐en‐12,8‐olide ( 3 ) ((8α)‐eremophil‐7(11)‐en‐12,8‐olide = (4aR,5S,8aR,9aS)‐4a,5,6,7,8,8a,9,9a‐octahydro‐3,4a,5‐trimethylnaphtho[2,3‐b]furan‐2(4H)‐one), besides the recently elucidated eremoligularin ( 4 ) and bieremoligularolide ( 5 ), as well as a new highly oxygenated monoterpene, rel‐(1R,2R,3R,4S,5S)‐p‐menthane‐1,2,3,5‐tetrol ( 12 ), together with six known constituents, i.e., the sesquiterpenes 6 and 7 , the norsesquiterpenes 8 – 10 , and the monoterpene 13 , were isolated from the roots of Ligularia muliensis. In addition, an attempt to dimerize 1 to a bieremophilenolide (Scheme) resulted in the generation of the new derivative (6β,8β)‐6‐(acetyloxy)‐8‐chloroeremophil‐7(11)‐en‐12,8‐olide ( 11 ). The new structures were established by means of detailed spectroscopic analysis (IR, FAB‐, EI‐, or HR‐ESI‐MS as well as 1D‐ and 2D‐NMR experiments). Compounds 4 and 5 were evaluated for their antitumor effects in vitro (Table 3).     

Three New Sesquiterpenoids from Echinops ritro L.

From the whole plants of E. ritro L., the three new sesquiterpenoids (3α,4α,6α)‐3,13‐dihydroxyguaia‐7(11),10(14)‐dieno‐12,6‐lactone ( 1 ), (3α,4α,6α,11β)‐3‐hydroxyguai‐1(10)‐eno‐12,6‐lactone ( 2 ), and (11α)‐11,13‐dihydroarglanilic acid methyl ester (=(4β,6α,11α)‐4,6‐dihydroxy‐1‐oxoeudesm‐2‐en‐12‐oic acid methyl ester; 3 ), together with eight known sesquiterpenoids, were isolated. Their structures were elucidated through analysis of spectroscopic data including extensive 2D‐NMR.     

Three New 24‐Nortriterpenoids from the Roots of Ilex asprella

Asprellols A–C ( 1 – 3 , resp.), three new 24‐nortriterpenoids, were isolated from the CHCl₃‐soluble fraction of 95% EtOH extract of the roots of Ilex asprella, together with a known nortriterpenoid. The structures of the new compounds were elucidated as 2,6β,20β‐trihydroxy‐3‐oxo‐11α,12α‐epoxy‐24‐norursa‐1,4‐dien‐28,13β‐olide ( 1 ), 2,6β‐dihydroxy‐3‐oxo‐11α,12α‐epoxy‐24‐norursa‐1,4,20(30)‐trien‐28,13β‐olide ( 2 ), and 2,6β‐dihydroxy‐3‐oxo‐11α,12α‐epoxy‐24‐noroleana‐1,4‐dien‐28,13β‐olide ( 3 ) on the basis of spectroscopic analyses.     

Novel Sesquiterpenoids from Siegesbeckia orientalis

Five new sesquiterpenoids, namely, 8β‐(angeloyloxy)‐4β,6α,15‐trihydroxy‐14‐oxoguaia‐9,11(13)‐dien‐12‐oic acid 12,6‐lactone ( 1 ), 4β,6α,15‐trihydroxy‐8β‐(isobutyryloxy)‐14‐oxoguaia‐9,11(13)‐dien‐12‐oic acid 12,6‐lactone ( 2 ), 11,12,13‐trinorguai‐6‐ene‐4β,10β‐diol ( 3 ), (1(10)E,4E,8Z)‐8‐(angeloyloxy)‐6α,15‐dihydroxy‐14‐oxogermacra‐(1(10),4,8,11(13)‐tetraen‐12‐oic acid 12,6‐lactone ( 9 ), and (1(10)E,4β)‐8β‐(angeloyloxy)‐6α,14,15‐trihydroxygermacra‐1(10),11(13)‐dien‐12‐oic acid 12,6‐lactone ( 11 ), and three new artifacts, (1(10)E,4Z)‐8β‐(angeloyloxy)‐9α‐ethoxy‐6α,15‐dihydroxy‐14‐oxogermacra‐1(10),4,11(13)‐trien‐12‐oic acid 12,6‐lactone ( 6 ), (1(10)E,4Z)‐8β‐(angeloyloxy)‐9α,13‐diethoxy‐6α,15‐dihydroxy‐14‐oxogermacra‐1(10),4‐dien‐12‐oic acid 12,6‐lactone ( 7 ), and (1(10)E,4Z)‐8β‐(angeloyloxy)‐9α‐ethoxy‐6α,15‐dihydroxy‐13‐methoxy‐14‐oxogermacra‐1(10),4‐dien‐12‐oic acid 12,6‐lactone ( 8 ), together with the three known sesquiterpenoids 4, 5 , and 10 , were isolated from the aerial parts of Siegesbeckia orientalis L. Their structures were established by spectral methods, especially 1D‐ and 2D‐NMR spectral methods.     

Eremophilane‐Type Sesquiterpenes from the Roots of Ligularia virgaurea

From the roots of Ligularia virgaurea, five new eremophilane‐type sesquiterpenes were isolated, including three new eremophilenolides, 6β‐(angeloyloxy)‐1α,8β,10β‐trihydroxyeremophil‐7(11)‐en‐12,8α‐olide ( 1 ), 6β‐(angeloyloxy)‐1β,10β‐epoxy‐8β‐ethoxyeremophil‐7(11)‐en‐12,8α‐olide ( 2 ), and 1β,10β‐epoxy‐8β‐ethoxy‐6β‐[(2‐methylacryloyl)oxy]eremophil‐7(11)‐en‐12,8α‐olide ( 3 ), two new noreremophilanes, 3β‐[(2‐methylacryloyl)oxy]‐8‐oxo‐12‐noreremophil‐6‐en‐11‐one ( 9 ), and 9β‐hydroxy‐8‐oxo‐12‐noreremophil‐6‐en‐11‐one ( 10 ), and six known eremophilanes, namely 4 – 8 , and 11 . Their structures were elucidated by means of spectral methods, such as IR, HR‐ESI‐MS, and 1D‐ and 2D‐NMR, and by comparison of the spectral data with those reported for structurally related compounds.     

Three New Abietane‐type Diterpenes from the Bark of Cryptomeria japonica

Three new abietane‐type diterpenoids, 7β‐acetoxy‐12‐methoxyabieta‐8,11,13‐triene‐6α,11‐diol ( 1 ), 7α‐acetoxy‐12‐methoxyabieta‐8,11,13‐triene‐6α,11‐diol ( 2 ), and 6α‐acetoxy‐12‐methoxyabieta‐8,11,13‐triene‐7α,11‐diol ( 3 ), as well as two known abietane‐type diterpenoids, 12‐methoxyabieta‐8,11,13‐triene‐6α,7β,11‐triol ( 4 ) and 6α‐acetoxy‐12‐methoxyabieta‐8,11,13‐triene‐7β,11‐diol ( 5 ), were isolated from the MeOH extract of the bark of Cryptomeria japonica. Their structures were determined by analysis of spectroscopic data and comparison of NMR data with those of related metabolites.     

Sesquiterpenoids from the Resinous Exudates of Commiphora opobalsamum (Burseraceae)

Phytochemical investigation of the exudates of Commiphora opobalsamum led to the isolation of three new sesquiterpenoids, 2α‐methoxy‐6‐oxogermacra‐1(10),7(11)‐dien‐8,12‐olide ( 1 ), 5β‐10α‐hydroxy‐2α‐methoxy‐6‐oxoguaia‐7(11),8‐dien‐8,12‐olide ( 2 ), and furanocadina‐1(10),6,8‐triene‐4‐ol ( 3 ), together with six known compounds. Their structures were elucidated on the basis of spectroscopic methods.     

Two New Diterpenoids and other Constituents from Isodon Nervosus

Two new ent‐kaurane diterpenoids, 15β‐hydroxy‐6,7‐seco‐6,11β:6,20‐diepoxy‐1α,7‐olide‐ent‐kaur‐16‐ene ( 1 ), 11α,15α‐dihydroxy‐6β‐methoxy‐6,7‐seco‐6,20‐epoxy‐1α,7‐olide‐ent‐kaur‐16‐ene ( 2 ), together with four known diterpenoids, nodosin ( 3 ), isodocarpin ( 4 ), odonicin ( 5 ) and maoyecrystal F ( 6 ) were isolated from the aerial parts of Isodon nervosus. The structures of the new compounds were elucidated on the basis of their spectral evidence, especially on 2D NMR.     

A New Cembranoid Diterpene and Other Related Metabolites from the South‐China‐Sea Soft Coral Lobophytum crassum

A new hydroperoxy‐substituted cembranoid diterpene, 2‐hydroperoxysarcophine (= (1aR*,4E,11E,14aR*)‐2,3,6,7,10a,13,14,14a‐octahydro‐10a‐hydroperoxy‐1a,5,8,12‐tetramethyloxireno[9,10]cyclotetradeca[1,2‐b]furan‐9(1aH)‐one; 1 ), was isolated from the marine soft coral Lobophytum crassum. Also isolated were two other cembranoid diterpenes, obtained for the first time from a natural source, i.e., 7β,8β‐epoxy‐4α‐hydroxycembra‐1(15),2,11‐trien‐16,2‐olide ( 2 ) and 7β,8β‐epoxy‐4β‐hydroxycembra‐1(15),2,11‐trien‐16,2‐olide ( 3 ), along with three further cembranoid derivatives, five sterols, and two open‐chain metabolites. Their structures and relative configurations were elucidated on the basis of extensive spectroscopic analyses including 1D‐ and 2D‐NMR, and HR‐ESI‐MS experiments.     

Semisynthesis and absolute configuration of a novel rearranged 19,20‐δ‐lactone (9βH)‐pimarane diterpene

Annonalide (3β,20‐epoxy‐3α,16‐dihydroxy‐15‐oxo‐7‐pimaren‐19,6β‐olide, C₂₀H₂₆O₆, 1 ) is the major (9βH)‐pimarane diterpene isolated from tubers of Cassimirella ampla, and it exhibits cytotoxic properties upon interaction with ctDNA. We have prepared new derivatives of 1 by modification of the (9βH)‐pimarane backbone and report here the semisynthesis and absolute configuration of a novel rearranged 19,20‐δ‐lactone (9βH)‐pimarane. Our approach was the reduction of the carbonyl groups of 1 with sodium borohydride, at positions C15 (no stereoselectivity) and C3 (stereoselective reduction), followed by rearrangement of the 6,19‐γ‐lactone ring into the six‐membered 19,20‐δ‐lactone ring in 4a (3β,6β,16‐trihydroxy‐7‐pimaren‐19,20β‐olide monohydrate, C₂₀H₃₀O₆·H₂O). The absolute structure of the new compound, 4a , was determined unambiguously with a Flack parameter x of −0.01 (11), supporting the stereochemistry assignment of 1 redetermined here. Besides the changes in the pattern of covalent bonds caused by reduction and lactone rearrangement, the conformation of one of the three fused cyclohexane rings is profoundly different in 4a , adopting a chair conformation instead of the boat shape found in 1 . Furthermore, the intramolecular hydrogen bond present in 1 is lost in new compound 4a , due to hydrogen bonding between the 3‐OH group and the solvent water molecule.     

A new clerodane diterpene with antifeedant activity from Teucrium tomentosum

A new diterpene, viz. 3β‐acetoxy‐4α,18:15,16‐di­epoxy‐6β,12‐di­hydroxy­neocleroda‐13(16),14‐dien‐19,20‐olide, C₂₂H₂₈O₈, exhibiting antifeedant activity against Spodoptera litura was isolated from the aerial parts of Teucrium tomentosum and its structure is reported. One of the two fused rings has a distorted‐chair conformation and the other has a chair conformation. The mol­ecules in the crystal are stabilized via O—H...O and C—H...O hydrogen bonds.