Highly oxygenated guaiane-type sesquiterpene lactones from Artemisia sacrorum and their antihepatoma activity.

The ethanol and EtOAc extracts of Artemisia sacrorum exhibited inhibitory effect against HepG2, Huh7, and SK-Hep-1 cell lines with inhibitory ratios of 65.5%, 28.1%, 84.6%, and 93.5%, 82.0%, 89.0% at 200 µg/mL. Twenty-three undescribed guaiane-type sesquiterpene lactones, artemisacrolides A‒W, were isolated from A. sacrorum under the guidance of antihepatoma activity. Their structures were elucidated by spectral data (HRESIMS, IR, UV, 1D and 2D NMR), ECD calculations, and a single-crystal X-ray diffraction. Artemisacrolides A‒U were guaiane-type sesquiterpene lactones possessing α-methylene-γ-lactone and containing acetoxyl groups at C-8, and artemisacrolides V and W represented the first report from the genus Artemisia with a 1,10-rearranged guaiane-type sesquiterpene lactone. Antihepatoma assay suggested that artemisacrolides A‒U demonstrated better inhibitory activity in Huh7 and SK-Hep-1 cells than those of HepG2 cells. Among them, nine compounds exhibited significant inhibitory activity against Huh7 cells with IC50 values of 8.2-14.3 µM, superior or equal to that of sorafenib; seven compounds demonstrated obvious activity against SK-Hep-1 cells with IC50 values of 13.5-19.2 µM, which were equivalent to that of sorafenib. Artemisacrolides B and E were the most active ones in three human hepatoma cell lines with IC50 values of 21.9, 8.2, 16.9 and 22.6, 9.0, 17.3 µM.

Artemongolins A-K, undescribed germacrane-guaiane sesquiterpenoid dimers from Artemisia mongolica and their antihepatoma activities.

Artemongolins A-K (1-11), which are undescribed sesquiterpenoid dimers, were obtained from Artemisia mongolica and characterized through comprehensive spectral data, including HRESIMS, IR, 1D and 2D NMR, and ECD calculations. The absolute configurations of compounds 1, 4, and 7 were undoubtedly determined by a single-crystal X-ray crystallography. Artemongolins A-K (1-11) featured a rare 5/7/5/5/5/10 hexacyclic system composed of a germacrene and a guaianolide by a fused 2-oxaspiro[4,4]nonane-1-one ring system. Antihepatoma evaluation against three human hepatoma cell lines demonstrated that the most active compounds 5 and 6 displayed inhibitory activity with IC50 values of 88.6 and 57.0 (HepG2), 59.1 and 26.4 (Huh7), and 67.5 and 32.5 (SK-Hep-1) µM, respectively.

Artemeriosides A-F, the first examples of natural sesquiterpenoids substituted by a 6'-O-crontonyl ß-glucopyranoside from Artemisia annua.

Artemeriosides A-F (1-6), six novel sesquiterpenoids containing a 6'-O-crontonyl ß-glucopyranoside, were isolated from Artemisia annua L. Their structures were determined by spectral data including HRESIMS, IR, UV, 1D and 2D NMR, and ECD calculations. Compounds 1-6 represented the first examples of natural sesquiterpenoid substituted by 6'-O-crontonyl ß-glucopyranoside. By antihepatoma assay, compounds 1 and 2 demonstrated inhibitory effect against both HepG2 and SK-Hep-1 cells with inhibitory ratios of 77.0%, 88.8%, and 86.8%, 83.9% at 200.0 µM, and compound 1 showed inhibitory activity against Huh7 cells with inhibitory ratio of 56.8%.

Artemannuols A-C, novel sesquiterpenoid-flavonol hybrids with antihepatoma activity from Artemisia annua.

Artemisia annua, also known as "Qinghao" in Chinese, is a famous traditional Chinese medicine and has been used for the treatment of malaria and various tumors. In this study, three novel sesquiterpenoid-flavonol hybrids, artemannuols A-C (1-3), were isolated and elucidated by extensive spectral data and ECD calculations. Structurally, artemannuols A-C (1-3) are the first examples of sesquiterpenoid-flavonol hybrids fused by an ether bond, among which artemannuols A and B (1 and 2) are composed of bisabolane-type sesquiterpenoid and flavonol moieties, and artemannuol C (3) is composed of humulane-type sesquiterpenoid and flavonol moieties. The antihepatoma assay suggested that compounds 1-3 showed inhibitory effects against HepG2, Huh7, and SK-Hep-1 cell lines with IC50 values in the range of 32.7 to 70.4 µM.

Rubiginosin B selectively inhibits Treg cell differentiation and enhances anti-tumor immune responses by targeting calcineurin-NFAT signaling pathway.

BACKGROUND: The accumulation of CD4+Foxp3+ regulatory T cells (Tregs) in the tumor microenvironment (TME) dampens anti-tumor immune responses and promotes tumor progression. Therefore, the elimination of Tregs has become a strategy to enhance the efficacy of tumor immunotherapy, although it is still a daunting challenge. Rhododendron brachypodum (R. brachypodum) is a perennial shrub mainly distributed in Southwestern China, whereas the chemical constituents in this plant remain elusive. PURPOSE: To identify small-molecule inhibitors of Tregs from R. brachypodum. METHODS: Meroterpenoids in R. brachypodum were isolated by column chromatography under the guidance of LCMS analyses. The structures of isolates were identified by spectroscopic data and quantum calculations. The activities of compounds were first evaluated on CD4+ T cell differentiation by flow cytometry in Th1, Th2, Th17, and Treg polarizing conditions, and then on CT26 and MC38 murine colorectal carcinoma cells-allografted mice models. The mechanism of action was first investigated by determining Foxp3 degradation in Jurkat T cells transfected with pLVX-TetOne-Puro-Foxp3-tGFP, and then through analyses of Foxp3 expression on several pre-transcriptional signaling molecules. RESULTS: Two new prenylated phenolic acids (1 and 2) and a chromane meroterpenoid, rubiginosin B (RGB, 3) were obtained from R. brachypodum. The structure of S-anthopogochromene C (1) was rectified according to the electronic circular dichroism (ECD) experiment, and rhodobrachypodic acid (2) was proposed as the precursor of RGB by photochemical transformation. In this investigation, we first found that RGB (3) selectively suppressed the de novo differentiation of TGFß-induced CD4+Foxp3+ regulatory T cells (iTregs), overcome the immunosuppressive TME, and consequently inhibited the growth of tumor in mouse models. The mechanistic study revealed that RGB could target calcineurin, inhibited the nuclear factor of activated T cells (NFAT) dephosphorylation, and down-regulated Foxp3 expression. The hypothetical binding modes of RGB with calcineurin were predicted by molecular docking, and the interactions were mainly hydrophobic effects and hydrogen bonds. CONCLUSION: These results suggest that RGB enhances anti-tumor immune responses by inhibiting Treg cell differentiation through calcineurin-NFAT signaling pathway, and therefore RGB or its analogs may be used as adjuvant agents meriting further investigation.

Artemiprinolides A-M, thirteen undescribed sesquiterpenoid dimers from Artemisia princeps and their antihepatoma activity.

Bioassay-guided investigation of the active fraction of Artemisia princeps led to 13 undescribed sesquiterpenoid dimers, artemiprinolides A-M (1-13), together with 11 known ones (14-24). Their structures were elucidated by comprehensive spectroscopic data and absolute configurations were assigned based on single crystal X-ray diffraction data and ECD calculations. Structurally, all compounds were postulated to be derived from the Diels-Alder cycloaddition. The isolated dimers except 11 and 15 were assayed for their cytotoxicity against HepG2, Huh7, and SK-Hep-1 cell lines, of which four compounds (3, 13, 17, 18) exhibited obvious cytotoxicity with IC50 values ranging from 8.8 to 20.1 µM. Interestingly, the most active compounds 1 and 16 manifested significant cytotoxicity on the three tested hepatoma cell lines with IC50 values of 5.4, 4.1 (HepG2), 7.7, 5.6 (Huh7), and 11.8, 15.7 µM (SK-Hep-1), respectively, which were better than sorafenib. Compound 1 dose-dependently inhibited cell migration and invasion, and significantly induced the HepG2 cell arrest in G2/M phase by downregulating cdc2 and pcdc2 and upregulating cyclinB1; and induced apoptosis by downregulating Bcl-2 expression and upregulating Bax level. The molecular docking study implied that the carbonyl at the C-12' of 1 had a strong binding affinity with PRKACA.

New eudesmanolides from Artemisia verlotorum and their potential targets of hepatocellular carcinoma by network pharmacology.

Fractionation of the ethanol extract of Artemisia verlotorum led to the identification of eight undescribed eudesmane-type sesquiterpenoids, artemverlolides A-H (1-8). Their structures were determined by spectral analyses (HRESIMS, 1D and 2D NMR, IR, and ECD). Network pharmacology predicted that compounds 1-8 might be target on AURKA, CCNA2, CYP2C19, and EPHX2 with possibly antihepatoma effect from Swiss TargetPrediction and Gene Expression Omnibus database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses showed that the targets significantly enriched in FoxO signaling pathway. The molecular docking suggested that compound 8 had high binding affinity with AURKA. Furthermore, the interaction between compound 8 and AURKA was determined by Surface Plasmon Resonance (SPR) assay. The result suggested that compound 8 bound to AURKA with KD value of 68.0µM and was consistent with the predicted data, demonstrating that AURKA might be one of acting targets of 8.

Artemongolides A-F, undescribed sesquiterpenoid dimers from Artemisia mongolica and their antihepatic fibrosis activities.

Artemongolides A-E (1-5), an unusual class of diseco-guaianolides featuring a rare fused 7-methylbicyclo[2.2.1]-2-ene-7-heptanol ring system, and artemongolide F (6), the first example of [4 + 2] Diels-Alder type adducts presumably incorporating a chain farnesane sesquiterpene and a guaianolide diene, were isolated from the whole plant of Artemisia mongolica. Their structures were elucidated based on the spectroscopic analyses of UV, IR, MS, and 1D and 2D NMR spectra. The absolute configurations of artemongolides A (1) and F (6) were determined by single-crystal X-ray crystallography, and those of artemongolides B-E (2-5) were established by ECD calculations. Cytotoxicity evaluation suggested that compound 1 exhibited activity against HSC-LX2 cells with an IC50 value of 165.0 µM, equivalent to that of the positive control silybin (IC50, 146.4 µM). Preliminary mechanism studies revealed that compound 1 could inhibit the deposition of human collagen type I (Col I), human hyaluronic acid (HA), and human laminin (HL) with IC50 values of 123.8, 160.4, and 139.20 µM.

Artemleucolides A-L, eudesmane-type sesquiterpenoids from Artemisia leucophylla and their antihepatoma cytotoxicity.

Twelve undescribed and 13 known eudesmane-type sesquiterpenoids were obtained from Artemisia leucophylla, and structurally elucidated based on comprehensive analyses of spectral data, including HRESIMS, IR, 1D and 2D NMR, and ECD calculation. The absolute configuration of compound 1 was determined by a single X-ray single crystal diffraction. Chemically, compounds 1-5 featured unprecedented 1,2-seco-1-nor-eudesmane-type skeleton with a cis-fused 6/5 bicyclic system. Antihepatoma evaluation against three human hepatoma cell lines (HepG2, Huh7, and SK-Hep-1) for all compounds demonstrated that compound 7 displayed the most active cytotoxicity with IC50 values of 35.1, 35.0, and 32.7 µΜ.

Distepharinamide, a novel dimeric proaporphine alkaloid from Diploclisia glaucescens, inhibits the differentiation and proliferative expansion of CD4+Foxp3+ regulatory T cells.

BACKGROUND: CD4+Foxp3+ regulatory T cells (Tregs) represent the primary cellular mechanism of tumor immune evasion. Elimination of Treg activity by the pharmacological agent may enhance anti-tumor immune responses. However, Treg-eliminating agents, especially those with small molecules, are rarely reported. PURPOSE: To identify small molecule inhibitors of Treg cells from natural products. METHODS: Compounds from Diploclisia glaucescens were isolated by column chromatography, and structures were identified by spectroscopic evidence and quantum calculations. The tet-On system for Foxp3-GFP expression in Jurkat T cells was generated to screen Treg inhibitors based on Foxp3 expression. The effect of the compound on TNF-induced proliferative expansion of naturally occurring Tregs (nTregs) and TGF-ß-induced generation of Tregs (iTregs) from naive CD4+ Tcells was further examined. RESULTS: A novel dimeric proaporphine alkaloid, designated as distepharinamide (DSA) with a symmetric structure isolated from the stems of D. glaucescens, restrained the doxycycline (Doxy)-induced Foxp3-tGFP expression, decreased the half-life of Foxp3 mRNA as well as reduced the mRNA levels of chemokine receptors (CCR4, CCR8 and CCR10) in Jurkat T cells with inducible Foxp3-tGFP expression. In lymphocytes or purified Tregs from wild-type C57BL/6 mice or from C57BL/6-Tg(Foxp3-DTR/EGFP)23.2Spar/Mmjax mice, DSA markedly inhibited TNF-induced proliferative expansion of Tregs present in the unfractionated CD4+ T cells, accompanied by the down-regulation of TNFR2, CD25 and CTLA4 expression on Tregs. Furthermore, DSA potently inhibited TGF-ß-induced differentiation of Foxp3-expressing iTregs. Importantly, the expression of Foxp3 mRNA by both nTregs and iTregs was decreased by DSA treatment. Nevertheless, DSA at the same concentrations did not inhibit the proliferation of conventional CD4+ and CD8+ T cells stimulated by anti-CD3/CD28 antibodies. CONCLUSION: DSA, a novel dimeric proaporphine alkaloid, potently inhibited the expansion of nTregs and generation of iTregs. Therefore, DSA or its analogs may merit further investigation as novel immunotherapeutic agents.

Artemzhongdianolides A1-A21, antihepatic fibrosis guaiane-type sesquiterpenoid dimers from Artemisia zhongdianensis.

In the search for new antihepatic fibrosis candidates, it was observed that the EtOH extract of Artemisia zhongdianensis and EtOAc fraction had cytotoxicity against hepatic stellate cell line LX2 (HSC-LX2) with the inhibitory ratios of 85.7 % and 83.9 % at 400 µg/mL. 21 new guaianolide dimers, artemzhongdianolides A1 - A21 (1-21) were isolated from the active fractions under the guidance of bioassay, and elucidated by spectral analyses (HRESIMS, 1D and 2D NMR, IR, ECD). The absolute stereochemistry of compounds 1, 13, and 14 was determined by single-crystal X-ray diffraction analyses. Cytotoxicity evaluation suggested that nine compounds exhibited activity against HSC-LX2 with IC50 values ranging from 14.0 to 95.2 µM. Of them, compounds 2, 6, and 13 displayed significant cytotoxicity against HSC-LX2 with IC50 values of 22.1, 24.3 and 14.0 µM, which were 6 to 10 times more active than the positive drug silybin (IC50, 148.6 µM). Preliminary mechanism study revealed that compounds 2, 6, and 13 could markedly inhibited the deposition of human collagen type Ⅰ (Col Ⅰ), human hyaluronic acid (HA), and human laminin (HL) with IC50 values of 37.9, 54.8, and 28.0 µM (Col Ⅰ), 29.5, 25.3, and 42.9 µM (HL), 31.2, 94.6, and 12.4 µM (HA), which were 1.5 to 13-fold more potent than silybin.

Artemidubolides A-T, cytotoxic unreported guaiane-type sesquiterpenoid dimers against three hepatoma cell lines from Artemisia dubia.

A random bioassay revealed that the EtOH extract and EtOAc fraction of Artemisia dubia Wall. (Asteraceae) exhibited cytotoxic activity against HepG2 cells with inhibitory ratios of 57.1% and 84.2% at a concentration of 100.0 µg/mL. Bio-guided isolation combined by LC-MS-IT-TOF analyses of the active fractions led to the isolation of 20 previously undescribed guaiane-type sesquiterpenoid dimers named artemidubolides A-T (1-20). Their structures and the absolute configurations were determined by comprehensive spectral analyses, comparison of the experimental and calculated ECD spectra, and seven compounds (artemidubolides A, B, D, F, K, O and R) were confirmed unequivocally by single crystal X-ray diffraction analysis. Structurally, artemidubolides A-Q were [4 + 2] Diels-Alder adducts of two monomeric guaianolides, and artemidubolides R-T were linked though an ester bond. All the isolated compounds were evaluated for their hepatomatic cytotoxicity against HepG2, Huh7, and SK-Hep-1 cell lines to demonstrate that 18 compounds exhibited obvious cytotoxicity against three tested hepatoma cell lines with IC50 values in the range of 5.4-87.6 µM. Importantly, artemidubolides B, D, and M exhibited hepatoma cytotoxicity with IC50 values of 5.4, 5.7, and 9.7 (HepG2), 8.2, 4.3, and 12.2 (Huh7), and 13.4, 8.4, and 12.9 µM (SK-Hep-1), respectively. Mechanism investigation in HepG2 cells suggested the most active artemidubolide D dose-dependently inhibited cell migration and invasion, induced G1/M cell cycle arrest by down-regulating proteins CDK4, CDK6 and CyclinD1 and up-regulating the level of protein P21; and induced apoptosis by down-regulated of PARP-1 and BCL-2 expression and up-regulating Bax and cleaved PARP-1 levels.

Norlignans as potent GLP-1 secretagogues from the fruits of Amomum villosum.

The dried fruit of Amomum villosum (Amomi Fructus) is an important spices and traditional Chinese medicine. In this study, the EtOH extract of Amomi Fructus was revealed with hypoglycemic effects on db/db mice by increasing plasma insulin levels. After extracted with EtOAc, the EtOAc fraction showed increased activity in stimulating glucagon-like peptide-1 (GLP-1) secretion compared with the EtOH extract. In order to clarify the antidiabetic constituents, four undescribed norlignans, amovillosumins A‒D, were isolated from the EtOAc fraction, and the subsequent chiral resolution yielded three pairs of enantiomers. Their structures were determined by extensive spectroscopic data (1D and 2D NMR, HRESIMS, IR, UV and [α]D) and ECD calculations. Amovillosumins A and B significantly stimulated GLP-1 secretion by 375.1% and 222.7% at 25.0 µM, and 166.9% and 62.7% at 12.5 µM, representing a new type of GLP-1 secretagogues.

New diarylheptanoid dimers as GLP-1 secretagogues and multiple-enzyme inhibitors from Alpinia katsumadai.

Ten new diarylheptanoid dimers, katsumadainols C1 - C10 (1-10), were isolated from the seeds of Alpinia katsumada and elucidated by extensive spectroscopic methods, ECD calculations, and single-crystal X-ray diffraction. Their antidiabetic effects were evaluated by the stimulation of GLP-1 secretion in STC-1 cells and inhibition against four diabetes-related enzymes, GPa, α-glucosidase, PTP1B, and DPP4. Compounds 1-5 and 7-10 significantly stimulated GLP-1 secretion by 267.5-433.1% (25.0 µM) and 117.8-348.2% (12.5 µM). Compounds 1-4 exhibited significant inhibition on GPa with IC50 values of 18.0-31.3 µM; compounds 1-5 showed obvious inhibition on α-glucosidase with IC50 values of 6.9-18.2 µM; compounds 1-5 and 10 possessed PTP1B inhibitory activity with IC50 values ranging from 35.5 to 80.1 µM. This investigation first disclosed compounds 1-4 as intriguing GLP-1 secretagogues and GPa, α-glucosidase, and PTP1B inhibitors, which provided valuable clues for searching multiple-target antidiabetic candidates from Zingiberaceae plants.

Artemicapillasins A-N, cytotoxic coumaric acid analogues against hepatic stellate cell LX2 from Artemisia capillaris (Yin-Chen).

Under the guidance of bioassay against HSC-LX2, the EtOH extract and the EtOAc fraction of Artemisia capillaris (Yin-Chen) exhibited cytotoxic activity against HSC-LX2 with inhibitory ratios of 39.7% and 68.7% at the concentration of 400.0 µg/mL. Bioassay-guided investigation of Fr. D (the active fraction) yielded 14 new coumaric acid analogues, artemicapillasins A-N (1-14). The structures of the isolates were elucidated by spectroscopic analyses involving UV, IR, MS, 1D and 2D NMR spectra and ECD calculations. Cytotoxic activity against HSC-LX2 cells of these isolates was performed to reveal that 12 compounds demonstrated cytotoxicity with inhibitory ratios more than 50% at 400 µM. The most active artemicapillasin B (2) gave an IC50 value of 24.5 µM, which was about 7 times more toxic than the positive drug silybin (IC50, 162.3 µM). Importantly, artemicapillasin B (2) showed significant inhibition on the deposition of human collagen type I (Col I), human laminin (HL) and human hyaluronic acid (HA) with IC50 values of 11.0, 14.4 and 13.8 µM, which was about 7, 11 and 5 times more active than silybin. Artemicapillasin B (2) as an interesting antihepatic fibrosis candidate is worth in-depth study.

Artematrovirenins A-P, guaiane-type sesquiterpenoids with cytotoxicities against two hepatoma cell lines from Artemisia atrovirens.

Random screening revealed that the EtOH extract of Artemisia atrovirens showed significant cytotoxicity against two human hepatoma cell lines (HepG2 and Huh7) with the inhibitory ratio of 98.9% and 99.7% at the concentration of 100 µg/mL. Further bioactivity-guided isolation of active fraction led to 16 new guaiane-type sesquiterpenoids, artematrovirenins A-P (1-16). Their structures were elucidated by extensive spectroscopic data. The absolute stereochemistry of compounds 1 and 14 was determined by single-crystal X-ray diffraction analyses. Pharmacological evaluation suggested that five compounds (3, 5, 8, 10, and 15) exhibited cytotoxicity, compounds 3 and 5 displayed cytotoxicity against HepG2 cell line with an IC50 values of 8.0 and 16.0 µM, as well as against Huh7 cell line with values of 18.2 and 32.2 µM.

Artatrovirenols A and B: Two Cagelike Sesquiterpenoids from Artemisia atrovirens.

Artatrovirenols A and B (1 and 2), two novel cagelike sesquiterpenoids, possess a unique 5/5/6/5/5-pentacyclic and a 5/5/6/5-tetracyclic system with an unprecedented tetracyclo[5.3.1.1.4,1101,5]dodecane scaffold from Artemisia atrovirens. The structures of compounds 1 and 2 including their absolute stereochemistry were elucidated through extensive spectroscopic analyses, X-ray crystallography, and quantum chemical calculations. Plausible biosynthetic pathways for the new isolates were proposed from the naturally occurring arglabin (3) via the key intramolecular Diels-Alder cycloaddition. Compound 1 showed cytotoxicity against three human hepatoma cell lines (HepG2, SMMC-7721, and Huh7) with half maximal inhibitory concentration values of 123.8, 44.0, and 142.6 µΜ, respectively.

Nineteen New Flavanol-Fatty Alcohol Hybrids with α-Glucosidase and PTP1B Dual Inhibition: One Unusual Type of Antidiabetic Constituent from Amomum tsao-ko.

The dried fruits of Amomum tsao-ko were first revealed to have hypoglycemic effects on db/db mice at a concentration of 200 mg/kg. In order to clarify the antidiabetic constituents, 19 new flavanol-fatty alcohol hybrids, tsaokoflavanols A-S (1-19), were isolated and determined by extensive spectroscopic data and ECD calculations. Most of the compounds showed α-glucosidase and PTP1B dual inhibition, among which 1, 2, 6, 11, and 18 exhibited obvious activity against α-glucosidase with IC50 values of 5.2-9.0 µM, 20-35 times stronger than that of acarbose (IC50, 180.0 µM); meanwhile, 6, 10-12, and 19 were PTP1B/TCPTP-selective inhibitors with IC50 values of 56.4-80.4 µM, 2-4 times stronger than that of suramin sodium (IC50, 200.5 µM). Enzyme kinetics study indicated that compounds 1, 2, 6, and 11 were α-glucosidase and PTP1B mixed-type inhibitors with Ki values of 13.0, 11.7, 2.9, and 5.3 µM and 142.3, 88.9, 39.2, and 40.8 µM, respectively. Docking simulations proved the importance of hemiacetal hydroxy, the orientation of 3,4-dihydroxyphenyl, and the length of alkyl in binding with α-glucosidase and PTP1B.

Artemyrianolides A-S, Cytotoxic Sesquiterpenoids from Artemisia myriantha.

Random screening suggested that the EtOH extract of Artemisia myriantha (Asteraceae) and its EtOAc fraction had cytotoxicity against HepG2 cells with inhibitory ratios of 30.6% and 53.5% at 50.0 µg/mL. Bioassay-guided isolation of the most active fractions (Fr. C and Fr. D) afforded 19 new sesquiterpenolides, artemyrianolides A-S (1-19), involving 13 germacranolides (1-13), four guaianolides (14-17), and two eudesmanolides (18 and 19), together with 16 known sesquiterpenoids (20-35). The new compounds were characterized by physical data analyses (HRESIMS, IR, 1D and 2D NMR, ECD), and the absolute configurations of compounds 1, 2, and 11 were determined by X-ray crystallography. Structurally, compounds 2 and 11-13 maintain an uncommon cis-fused 10/5 bicyclic system and compound 12 possesses an unusual (7S) configuration. Twenty of the compounds exhibited cytotoxicity against HepG2, Huh7, and SMMC-7721 cell lines. Compound 9 showed cytotoxic activity on both HepG2 and Huh7 cells with IC50 values of 8.6 and 8.8 µM, and compounds 8 and 33 showed cytotoxicity to the three human hepatoma cell lines with IC50 values of 4.9 and 7.4 µM (HepG2), 4.3 and 7.8 µM (Huh7), and 3.1 and 9.8 µM (SMMC-7721), respectively.

Cytotoxic sesquiterpenoids against hepatic stellate cell line LX2 from Artemisia lavandulaefolia.

The preliminary assay suggested that the EtOH extract of Artemisia lavandulaefolia had cytotoxicity against hepatic stellate cell line LX2 (HSC-LX2) with an inhibitory ratio of 94.1% at 400 µg/mL. Bioassay-guided investigation led to eleven new sesquiterpenoids, artemilavanolides C-F (1-4) and artemlavandulolides A-G (5-11), as well as thirteen known compounds (12-24). Their structures were elucidated by extensive spectroscopic data and X-ray crystallographic analysis. Cytotoxicity evaluation suggested that fourteen compounds exhibited activity against HSC-LX2; compounds 22, 23 and 24 were comparable to the positive control, silybin (IC50, 162.3 µM); compounds 6, 9 and 16 showed moderate activity with IC50 values of 109.3, 114.0 and 124.2 µM. Importantly, compounds 14, 15 and 18 displayed significant cytotoxicity against HSC-LX2 with IC50 values of 52.1, 16.5 and 21.3 µM, and inhibitory activity on the deposition of human collagen type I (Col I) and human laminin (HL) with IC50 values ranging from 7.3 to 71.6 µM and from 18.6 to 72.9 µM.