Two new cytotoxic ent-clerodane diterpenoids from Scutellaria barbata

Two new ent-clerodane diterpenoids have been isolated from Scutellaria barbata, and their structures were established by detailed spectroscopic analyses as (13R)-6α,7β-dihydroxy-8β,13-epoxy-11β-nicotinyloxy-ent-clerodan-3-en-15,16-olide (scutelinquanine D, 1) and (11E)-6α-acetoxy-7β,8β-dihydroxy-ent-clerodan-3,11,13-trien-15,16-olide (6-acetoxybarbatin C, 2). In vitro, the isolated two new compounds showed significant cytotoxic activities against three human cancer cell lines (HONE-1 nasopharyngeal, KB oral epidermoid carcinoma, and HT29 colorectal carcinoma cells), and gave IC(50) values in the range of 2.5-6.6?μM.     

Microbial transformation of deoxyandrographolide by Fusarium graminearum AS 3.4598

Biotransformation of deoxyandrographolide (1) by Fusarium graminearum AS 3.4598 was investigated in this paper. And five transformed products of 1 by F. graminearum AS 3.4598 were obtained. Their chemical structures were characterized as 3-oxo-8α,17β-epoxy-14-deoxyandrographolide (2), 3-oxo-14-deoxyandrographolide (3), 3-oxo-17,19-dihydroxyl-8,13-ent-labdadien-15,16-olide (4), 1β-hydroxyl-14-deoxyandrographolide (5), and 7β-hydroxyl-14-deoxyandrographolide (6) by spectral methods including 2D NMR. Among them, products 2, 4, and 5 are new.     

A new isopimarane-type diterpene and a new natural atisane-type diterpene from Excoecaria agallocha

From the woods of Excoecaria agallocha, a new isopimarane-type diterpene, 3α,11β-dihydroxy-ent-isopimara-8(14),15-dien-2-one (1) and a new natural atisane-type diterpene, 16β-hydroxy-ent-atisan-3-one (2) were isolated together with three known compounds, ribenone (3), ent-labda-8(17),13E-diene-3β,15-diol (4), and ent-3β-hydroxybeyer-15-ene-2,12-dione (5). Their structures were determined by spectral data and x-ray crystallography evidence.     

Two new sesquiterpene lactone glycosides from Artemisia frigida Willd.

The investigation of EtOAc-soluble fraction from the aerial parts of Artemisia frigida has led to the isolation of two new sesquiterpene lactone glycosides, named as artemofriginoside A and artemofriginoside B. Their structures were characterized as 3β-(β-d-glucopyranosyloxy)-8β-(p-hydroxyphenylacetyloxy)-4(15),10(14),11(13)-guaiatrien-1α,5β,6β,7αH-12,6-olide (1) and β-(β-d-glucopyranosyloxy)-8β-(2-hydroxy-3-methylbutanoyloxy)-4(15),10(14),11(13)-guaiatrien-1α,5β,6β,7αH-12,6-olide (2), on the basis of 1D and 2D NMR spectral analysis.     

Chemical constituents of Isodon nervosus and their cytotoxicity

Two new ent-kaurane diterpenoids, 6,20,15α-trihydroxy-6,7-seco-1α,7-olide-ent-kaur-16-ene (1) and 7β,12α-dihydroxy-6β,15β-diacetoxy-7α,20-epoxy-ent-kaur-2,16-dien-1-one (2), together with the six known compounds, were isolated from the aerial part of Isodon nervosus. The structures of the new compounds were determined by spectral methods (1D, 2D NMR, and MS). Six compounds were assayed for their cytotoxicity against HL60, SMMC-7721, and HeLa human cell lines. Compounds 5, 7, and 8 showed significant cytotoxicity.     

Two new eremophilenolides from Ligularia lapathifolia

From the roots of Ligularia lapathifolia two new eremophilane-type sesquiterpenes have been isolated. Their structures were established as 3β-angeloyloxy-8β-hydroxy-6α,15β-epoxy-eremophil-7(11)-en-12,8α-olide (1) and 8βH-eremophil-3,7(11)-dien-12,8α (15,6α)-diolide (2) by spectroscopic methods including 2D NMR experiments.     

New cytotoxic sesquiterpene lactones from Anthemis scrobicularis

Four new sesquiterpene lactones, 4α-hydroxy-guaia-10(14),11(13)-diene-12,6α-olide (1), 4α-hydroxy-9α-acetoxy-guaia-1(10),2-diene-12,6α-olide (4), 4α-hydroxy-9β-acetoxy-guaia-1(10),2-diene-12,6α-olide (5), and 1α,4α-dihydroxy-9α-acetoxy-guaia-10(14),2-diene-12,6α-olide (6), were isolated from the aerial parts of Anthemis scrobicularis. Their structures were elucidated on the basis of their IR, NMR, and MS spectroscopic data. In addition, two known sesquiterpene lactones micheliolide (2) and achillin (3) were also isolated. The cytotoxicity of some of the isolated compounds was tested against HCT 116, HepG-2, and MCF-7 cell lines. Micheliolide and 4α-hydroxy-guaia-10(14),11(13)-diene-12,6α-olide showed pronounced inhibitory activity while 4α-hydroxy-9α-acetoxy-guaia-1(10),2-diene-12,6α-olide showed weak activity.     

The sesquiterpenes from the roots of Cacalia roborowskii

A new sesquiterpene cacaroborin (1) was isolated from the roots of Cacalia roborowskii, together with three known ones, cinalbicol (2), isopetasin (3), and 3α-angeloyloxylactone (4). The structure of compound 1 was elucidated as 1β,10α-dihydroxy-8α-methoxyeremophil-7(11)-en-8β,12-olide on the basis of spectral evidence (1D, 2D NMR, IR, EI-MS, and HR-ESI-MS) and X-ray diffraction analysis.     

Two new eudesmanolides from Inula racemosa

Two new eudesmane-type sesquiterpene lactones were isolated from the roots of Inula racemosa and their structures were elucidated as 3β-hydroxy-11α,13-dihydroalantolactone (1) and 11α-hydroxy-eudesm-5-en-8β,12-olide (2). Their cytotoxic activities against five human cancer cell lines had been tested and compound 2 exhibited weak cytotoxic activity against BEL-7402 and HCT-8 cell lines. The anti-inflammatory activities were also tested, but neither of them showed any activities.     

Sesquiterpenoids and further diterpenoids from the rare Chloranthaceae plant Chloranthus sessilifolius

Abstract

Two new dimeric lindenane-type sesquiterpenoids (1 and 2, named chlorasessilifols A and B, resp.), one new ent-podocarpane-type C₁₇ norditerpenoid (3), and one new ent-torarane-type diterpenoid (4), along with seven known terpenoids, were isolated from the whole plant of Chloranthus sessilifolius. The new structures were established by means of spectroscopic methods and/or observed cotton effects in the circular dichroism spectra. Among the isolates, 3α,7β-dihydroxy-ent-abieta-8,11,13-triene (11) exhibited significant anti-neuroinflammatory activity by inhibiting the nitric oxide production in lipopolysaccharide-stimulated murine BV-2 microglial cells, with an IC₅₀ value of 4.3 μM.     

A New Sesquiterpene Lactone from Tsoongiodendron Odorum Chun

Abstract

A new sesquiterpene lactone (1) was obtained from the cytotoxic fraction of 95% ethanol extract of root barks of Tsoongiodendron odorum Chun together with two known sesquiterpene lactones, costunolide (2) and parthenolide (3). The structure of 1 was elucidated as 5α, 6α, 7β, 10β-11α, 13-dihydro-4(15)-eudesmene-12, 6-olide on the basis of chemical and spectral evidence including X-ray diffraction analysis. Costunolide showed cytotoxic activity against human leukemia (HL-60) cell line. Parthenolide showed promising cytotoxic activities in vitro against HCT-8, Bel-7402, SKOV3, KB, HELA and EJ cell lines. Also, the cytotoxic ethyl acetate fraction of ethanol extract of the root barks from which three chemical components were isolated showed promising cytotoxic activities in vitro against KB, BGC-823, Bel-7402, HCT-8, HL-60 cell lines.     

Three new cassane diterpenes from the seeds of Caesalpinia minax Hance

Three new cassane-diterpene-lactones, methyl 1α,7β-diacetoxy-5α,12α-dihydroxy-cass-13(15)-en-16,12-olide-17β-carboxylate (1), methyl 7β-acetoxy-1α,5α,12α-trihydroxy-cass-13(15)-en-16,12-olide-17β-carboxylate (2), and 12α-ethoxyl-1α,6α,7β-triacetoxy-5α,14β-dihydroxy-cass-13(15)-en-16,12-olide (3), were isolated from the seeds of Caesalpinia minax Hance. Their structures were established on the basis of HR-ESI-MS, 1D and 2D NMR spectral analysis.     

Two new triterpenoids from the resin of Styrax tonkinensis

Two new triterpenoids, 3β,6β-dihydroxy-12-oxo-13Hα-olean-28,19β-olide (1) and 3-oxo-olean-11,13(18)-dien-28,19β-olide (2) were isolated from the resin of Styrax tonkinensis (Pier.) Craib. The structures of both triterpenoids were determined by physicochemical and spectroscopic methods. Compound 1 is the second triterpene found with cis-fused C/D ring from the resin, which is rarely observed in oleanane-type triterpenes.     

Microbial transformation of alantolactone by Mucor polymorphosporus

Two new transformed sesquiterpenes of alantolactone by Mucor polymorphosporus were obtained. They were characterized as 3β-hydroxy-11βH-eudesm-5-en-8β,12-olide (2) and 3β,11α-dihydroxy-eudesm-5-en-8β,12-olide (3), on the basis of spectral methods including 2D NMR. And product 3 was an unusual hydroxylation derivative of alantolactone at C-11.     

Anti-tumour clerodane-type diterpenes from Mitrephora thorelii

Bioassay-guided fractionation of the crude extract of Mitrephora thorelii (Annonaceae) led to the isolation of two clerodane-type diterpenes. Their structures were characterised on the basis of spectroscopic methods as 6α,16,18-trihydroxycleroda-3(4),13(14)-dien-15,16-olide (1) and 16-hydroxycleroda-3(4),13(14)-dien-15,16-olide (2). Compound 1 is a new compound. Compounds 1 and 2 exhibited inhibitory activity against the proliferation of human hepatoma BEL-7402 cells in vitro. Compound 2 also showed an in vivo anti-tumour effect against the growth of hepatoma H22 in mice.     

Terpenoids from the tuber of Cremastra appendiculata

Two new terpenoids including a cadinane sesquiterpene (1), and an ent-kaurane diterpene diglycoside (2), together with a known triterpene containing 32 carbons (3), have been isolated from the ethanolic extract of Cremastra appendiculata. Their structures were established by the spectroscopic methods including the IR, MS, 1D-, and 2D-NMR experiments as ( ? )-cadin-4,10(15)-dien-11-oic acid (1), ( ? )-ent-12β-hydroxykaur-16-en-19-oic acid, 19-O-β-d-xylopyranosyl-(1 → 6)-O-β-d-glucopyranoside (2), and (+)-24,24-dimethyl-25,32-cyclo-5α-lanosta-9(11)-en-3β-ol (3). Compounds 1–3 were evaluated against several human cancer cell lines. Compound 3 showed in vitro-selective cytotoxicity against human breast cancer cell lines (MCF-7) with an IC₅₀ of 3.18 μM, but 1 and 2 were inactive (IC₅₀>10 μg/ml).     

Diterpenoids from the freshwater green algae Rhizoclonium hieroglyphicum with antibacterial activity

Three new isopimarane diterpenes 7β-hydroxy-19α-methylmalonyloxy-isopimara-8(14),15-diene (1), 7β-hydroxy-14-oxo-isopimara-8(9),15-dien-19oic acid (2), and 7β-hydroxy-14-oxo-19α-methylmalonyloxy-isopimara-9(11),15-diene (3) in addition to the known compounds isopimaric acid (4), 7oxo-13-epi-pimara-14,15-dien-18oic acid (5), 7oxo-13-epi-pimara-8,15-dien-18oic acid (6), and 6β-hydroxyisopimaric acid (7) were isolated from the hexane extract of Rhizoclonium hieroglyphicum. The structures of compounds 1–7 were established by 1D and 2D NMR techniques. The isolated diterpenoids were screened for antimicrobial activity against gram-positive and gram-negative bacteria and yeast strains.     

Cholinesterase and BACE1 inhibitory diterpenoids from <Emphasis Type="Italic">Aralia cordata</Emphasis>

Fourteen diterpenes were isolated from the n-hexane fraction of the roots of Aralia cordata (syn. = A. continentalis). Through spectroscopy, the chemical structures were determined as: ent-pimara-8(14),15-diene-19-oic acid (1); ent-kaur-16-en-19-oic-acid (2); 18-nor-ent-pimara-8(14),15-diene-4β-ol (3); 18-nor-ent-kaur-16-ene-4β-ol (4); ent-pimara-8(14),15-diene-19-ol (5); 7α-hydroxy-ent-pimara-8(14),15-diene-19-oic acid (6); 7β-hydroxy-ent-pimara-8(14),15-diene-19-oic acid (7); ent-pimar-15-en-8α,19-diol (8); 7-oxo-ent-pimara-8(14),15-diene-19-oic acid (9); 16α-hydroxy-17-isovaleroyloxy-ent-kauran-19-oic acid (10); 17-hydroxy-ent-kaur-15-en-19-oic acid (11); 15α,16α-epoxy-17-hydroxy-ent-kauran-19-oic acid (12); 16α,17-dihydroxy-ent-kauran-19-oic acid (13); and 16α-methoxy-17-hydroxy-ent-kauran-19-oic acid (14). Compounds 4, 5, 8, 12, and 14 were first isolated from this plant. The anti-Alzheimer and antioxidant effects of ent-pimarane-type diterpenes 1, 3, 5, 8, and 9, as well as ent-kaurane-type diterpenes 2, 4, and 10∼13, were evaluated via β-site amyloid precursor protein cleaving enzyme 1 (BACE1), acetylcholinesterase (AChE), butyrylcholinesterase (BChE), peroxynitrite (ONOO⁻), and nitric oxide (NO·) assays. Of the compounds tested, 8 exerted the most effective BChE inhibition with an IC₅₀ value of 7.58 μM, followed by 3, 13, 11, 2, and 10. Compounds 9∼11 exhibited good BACE1 inhibitory activities with IC₅₀ values of 18.58∼24.10 μM. However, 11 showed marginal AChE inhibitory effect, and all compounds tested showed no scavenging activities on ONOO⁻ and NO· at a concentration of 100 μM.     

Antioxidant compounds from the stem bark of Garcinia atroviridis

A new xanthone, namely garcinexanthone G (1), along with eight known compounds, stigmasta-5,22-dien-3β-ol (2), stigmasta-5,22-dien-3-O-β-glucopyranoside (3), 3β-acetoxy-11α,12α-epoxyoleanan-28,13β-olide (4), 2,6-dimethoxy-p-benzoquinone (5), 1,3,5-trihydroxy-2-methoxyxanthone (6), 1,3,7-trihydroxyxanthone (7), kaempferol (8) and quercetin (9), were isolated from the stem bark of Garcinia atroviridis. Their structures were elucidated based on spectroscopic methods including nuclear magnetic resonance (NMR-1D and 2D), UV, IR, and mass spectrometry. All the isolated compounds were evaluated for their antioxidant properties based on the DPPH radical scavenging activities. Results showed that 1,3,7-trihydroxyxanthone and quercetin showed significant antioxidant activities with EC₅₀ values of 16.20 and 12.68 μg/ml, respectively, as compared to the control, ascorbic acid (7.4 μg/ml).     

Studies on the chemical constituents of Valeriana fauriei Briq

Nine compounds were isolated from the roots of Valeriana fauriei Briq, of which one is a new germacrane-type sesquiterpenoid named as valerianin E and its structure was elucidated as bicyclo[8, 1, 0] 5β-hydroxyl-7β-acetoxyl-5α,11, 11′-trimethyl-E-1(10)–ene-4α, 15-olide (1). In addition, two were first reported from this genus and the others were isolated for the first time from the title plant.