Cytotoxic constituents from the leaves of Jerusalem artichoke (Helianthus tuberosus L.) and their structure–activity relationships

Bioassay-directed phytochemical study of the Jerusalem artichoke (Helianthus tuberosus L.) leaves led to the isolation of a new sesquiterpene lactone of 3-Hydroxy-8β-tigloyloxy-1,10-dehydroariglovin (1), ten known sesquiterpene lactones (2–11) and two known flavones (12–13). Their chemical structures were elucidated on the basis of NMR (1D and 2D) and mass spectroscopic analysis. The cytotoxic activities of those compounds were subsequently tested against the MCF-7, A549 and HeLa cancer cells lines. The results indicated that sesquiterpene lactones 1–11 exhibited consistent cytotoxicity against all three cancer cell lines, while flavones 12 and 13 showed selective inhibitory activity against HeLa cell lines. Among them, compound 3 exhibited significant growth inhibitory activity against all three cell lines. The IC₅₀ values of compound 3 against MCF-7, A549 and HeLa were 1.97 ± 0.04, 7.79 ± 0.44, 9.87 ± 0.20 μg/ml, respectively. In addition, some structure–activity relationships of these sesquiterpene lactones for cytotoxicity were explored and summarized in this study.     

Cytotoxic triterpene saponins from the stem bark of Kalopanax pictus

Three new compounds, 3β,6β,23-trihydroxyolean-12-en-28-oic acid 3-O-α-l-arabinopyranoside (1), kalopanaxsaponin L (2), and kalopanaxsaponin M (13), as well as eleven known compounds (3–12 and 14), were isolated from the stem bark of Kalopanax pictus. Their structures were determined on the basis of extentive spectroscopic analyses and acid hydrolysis. The cytotoxicity of the compounds was evaluated in three human carcinoma cell lines, including HL-60, HCT-116, and MCF-7. Compounds 1, 5–8, 10, and 11 exhibited significantly cytotoxic activity toward HL-60 cells, with IC₅₀ values ranging from 0.1 to 6.9 μM. Compounds 4–7 and 14 showed significant cytotoxicity against HCT-116 cells, with IC₅₀ values ranging from 0.4 to 9.2 μM. Remarkably, the cytotoxic activities of compounds 5–7 against HCT-116 cells were greater than that of the anticancer chemotherapy drug, mitoxantrone (IC₅₀ = 3.7 μM). Compounds 1, 3, 5, and 14 were cytotoxic toward MCF-7 cells with IC₅₀ values in a range of 7.4–14.5 μM.     

Design,synthesis, and quantitative structure–activity relationship of cytotoxic γ-carboline derivatives

Three series of γ-carboline derivatives were designed and synthesized. All the compounds were tested for their cytotoxic activities in vitro against five human tumor cell lines (A549, SGC, HCT116, MCF-7, K562) and one multi-drug resistant subline (K562R). Most compounds showed moderate to potent cytotoxic activities against the tested cell lines. Sulfonate 11f exhibited more potent cytotoxic activities against almost all of the tested cells in comparison with the positive control, taxol, with IC₅₀ values ranging from 0.15 to 4.5 μM. The structure–activity relationships were discussed and a statistically reliable QSAR model (r² = 0.936, q² = 0.581) was established by the CoMFA analysis performed using the cytotoxic data against K562 cell line as a template.     

Two new eudesmanolides from Inula racemosa and their bioactivities

Two new eudesmane-type sesquiterpene lactones, 1-one-4-epi-alantolactone (1) and 4α,13-dihydroxy-5,7(11)-eudesmadien-12,8-olide (2), were isolated from the roots of Inula racemosa, together with six known compounds (3–8). The cytotoxic activities against five human cancer cell lines had been tested and compounds 3, 6, 7 and 8 exhibited moderate cytotoxic activities. Compounds 4 and 8 showed potent in vitro activities against the release of β-glucuronidase in rat polymorphonuclear leukocytes (PMNs) induced by platelet-activating factor (PAF), with the inhibitory ratios 65.4% (P < 0.01) and 80.5% (P < 0.001), at concentration of 10 μM, respectively.     

Chemical constituents of Ligularia alticola Worosch. leaves and their biological activities

Seven eremophilane-type sesquiterpenes (1–7), six cycloartane derivatives (8–13) and α-amyrin acetate (14) were isolated from the leaves of the far-eastern plant Ligularia alticola Worosch. (Family Asteraceae). (4S,5R,8S,10R)-8-Ethoxyeremophil-7(11)-en-12(8)-olide (1), 8α,11-epidioxy-8β-methoxyeremophil-6-ene (2) and 29-norcycloartan-3α-ol (8) have not been previously reported. Fukinone α-epoxide (3) was isolated for the first time from a natural source. The structures of all the compounds were established by the extensive analysis of their 1D and 2D NMR spectra and HR ESI mass spectrometry. The absolute stereochemistry of 1 was determined by comparison of theoretical and experimental ECD spectra with the application of B3LYP-TDDFT and B3LYP-GIAO calculations as well as by NMR spectroscopy. Compound 1 showed cytotoxic action against human cancer HL-60, Raji, and THP-1 cell lines (IC₅₀ 12.6, 6.0 and 6.9 μM, respectively). Compounds 2 and 4 demonstrated significant cytotoxic activities against HL-60 (IC₅₀ 2.8 and 5.8 μM, respectively) and Raji cells (IC₅₀ 2.9 and 4.2 μM, respectively). Compound 6 was cytotoxic against Raji cells (IC₅₀ 4.6 μM). None of tested compounds were cytotoxic against RAW 264.7 cells. Compounds 1 and 4–7 significantly decreased intracellular ROS levels, induced by endotoxic LPS from Escherichia coli in RAW 264.7 murine macrophages.     

Triterpenoid saponins and C-glycosyl flavones from stem bark of Erythrina abyssinica Lam and their cytotoxic effects.

Six new compounds including two oleanane-type triterpenoid saponins (1, 2) and four C-glycosyl flavones (3–6), along with a known saponin (7), three di-C-glycosyl flavones (8–10) and a glycosyl auronol (11), were isolated from the stem bark of Erythrina abyssinica Lam. The structures of the new compounds, identified as 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-galactopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (1), 3-O-[α-l-rhamnopyranosyl-(1 → 2)-β-d-glucopyranosyl-(1 → 2)-β-d-glucuronopyranosyl]-22-O-β-d-glucopyranosyl sophoradiol (2), 6-C-β-glucopyranosyl-8-C-β-quinovopyranosyl apigenin (3), 6-C-β-quinovopyranosyl-8-C-β-glucopyranosyl apigenin (4), 8-C-[6″-O-α-l-rhamnopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (5) and 8-C-[6″-O-β-d-xylopyranosyl-(1‴ → 6″)]-β-glucopyranosyl 7,4′-dihydroxyflavone (6), were determined by comprehensive spectroscopic analysis, including 1D and 2D NMR techniques, mass spectrometry and acid hydrolysis. These new compounds together with the known saponins 7 were evaluated for their cytotoxic activity against MCF-7 (estrogen dependent) and MDA-MB-231 (estrogen independent) cell lines. The new saponin 2 exhibited the highest cytotoxic activity among tested compounds, exerting a selective inhibitory effect against the proliferation of MCF-7 cells, with lower IC₅₀ value (12.90 μM) than that of the positive control, resveratrol (13.91 μM). Structure–activity relationship of these compounds is also discussed.     

Bioactivity-guided isolation of cytotoxic constituents from stem–bark of Premna tomentosa

A bioassay-guided fractionation and chemical investigation of the stem bark of Premna tomentosa resulted in the isolation and characterization of four new icetexane diterpenes (1–4), along with the known compounds coniferaldehyde (5), syringaldehyde (6), lupeol (7), betulin (8), and 2-(4-methoxyphenyl)-2-butanone (9). Their structures were established on the basis of extensive spectroscopic (IR, MS, 2D NMR) data analysis and by comparison with the spectroscopic data reported in the literature. The new compounds exhibited diverse functionalities on a common icetexane diterpene skeleton. In addition, cytotoxic activities of the icetexanes (1–3) were evaluated by determining their inhibitory effects on the human cancer cell lines (MCF-7, HT-29, Hep-G2, A-431, and A-549). Compounds 1 and 3 showed selective inhibitory activity against MCF-7 (15.96 μg/mL and 15.84 μg/mL) and HT-29 cell lines (16.21 μg/mL and 14.57 μg/mL), respectively.     

Synthesis and antiproliferative activities of quebecol and its analogs

Simple and efficient synthesis of quebecol and a number of its analogs was accomplished in five steps. The synthesized compounds were evaluated for antiproliferative activities against human cervix adenocarcinoma (HeLa), human ovarian carcinoma (SK-OV-3), human colon carcinoma (HT-29), and human breast adenocarcinoma (MCF-7) cancer cell lines. Among all the compounds, 7c, 7d, 7f, and 8f exhibited antiproliferative activities against four tested cell lines with inhibition over 80% at 75 μM after 72 h, whereas, compound 7b and 7g were more selective towards MCF-7 cell line. The IC₅₀ values for compounds 7c, 7d, and 7f were 85.1 μM, 78.7 μM, and 80.6 μM against MCF-7 cell line, respectively, showing slightly higher antiproliferative activtiy than the synthesized and isolated quebecol with an IC₅₀ value of 104.2 μM against MCF-7.     

Constituents of the leaves of Pseuderanthemum carruthersii (Seem.) Guill. var. atropurpureum (Bull.) Fosb.

A new iridoid, 5β,6β-dihydroxyantirrhide (1) was isolated from the dried leaves of Pseuderanthemum carruthersii (Seem.) Guill. var. atropurpureum (Bull.) Fosb. (Acanthaceae), together with 13 known compounds, including two iridoids, linarioside and antirrhinoside; five phenylethanoids, echipuroside A, verbascoside, isoverbascoside, isomartynoside and osmanthuside B; and six flavonoids, luteolin 7-O-β-d-glucopyranoside, luteolin 7-O-rutinoside, apigenin 7-O-rutinoside, apigenin 6-C-α-l-arabinopyranosyl–8-C-β-l-arabinopyranoside, apigenin 6,8-di-C-α-l-arabinopyranoside and apigenin 6-C-β-d-xylopyranosyl–8-C-α-l-arabinopyranoside. Their chemical structures were elucidated by 1D and 2D NMR as well as HR-ESI-MS spectroscopic analysis. Some purified compounds were evaluated the acetylcholinesterase inhibition and cytotoxic activities against the HeLa cervical cancer cell line and the MCF-7 breast cancer cell line at the concentration of 100 μg/mL. Luteolin 7-O-β-d-glucopyranoside exhibited cytotoxic activities against both the HeLa cervical cancer cell line and the MCF-7 breast cancer cell line. Verbascoside and isoverbascoside showed strong cytotoxic activity against the MCF-7 breast cancer cell line. The tested compounds showed the AChE inhibitory activity fairly weak.     

3-Substituted-4-hydroxycoumarin as a new scaffold with potent CDK inhibition and promising anticancer effect: Synthesis,molecular modeling and QSAR studies

A new series of 3-substituted-4-hydroxycoumarin derivatives was designed, synthesized, and evaluated for CDK inhibiting and anticancer activities. All the synthesized target compounds showed remarkably high affinity and selectivity towards CDK1B, compared to flavopiridol, with Ki values in the low nanomolar range (Ki = 0.35–0.88 nM). Most of them elicited considerable inhibiting effect against CDK9T1 (Ki = 3.26–23.45 nM). Moreover, all the target compounds were tested in vitro against eighteen types of human tumor cell lines. The hydrazone 3a, N-phenylpyrazoline derivative 6b and 2-aminopyridyl-3-carbonitrile derivative 8c were the most potent anticancer agents against MCF-7 breast cancer cell line (IC₅₀ = 0.21, 0.21 and 0.23 nM, respectively). The target compounds 3a, 6b and 8c were further evaluated in MCF-7 breast cancer mouse xenograft model and showed in vivo efficacy at 10 mg/kg dose. The docking study confirmed a unique binding mode in the active site of CDK1B with better score than flavopiridol. Quantitative structure activity relationship study was done and revealed a highly predictive power R² of 0.81.     

Cytotoxic and anti-angiogenic effects of lanostane triterpenoids from Ganoderma lucidum

Two new lanostane triterpenes, 3α,12β,15α-triacetoxy-5α-lanosta-7,9(11),24-trien-26-oic acid (1) and 5α-lanosta-8,24-diene-26,27-dihydroxy-3,7-dione (2), together with sixteen known compounds (3–18) were isolated from the fruiting bodies of the Vietnamese mushroom Ganoderma lucidum. Their chemical structures were determined by extensive spectroscopic (IR, HR-EI-MS, 1D and 2D NMR) analyses. Potential cytotoxic activities of these compounds were evaluated against human non-small cell lung adenocarcinoma (A549), breast adenocarcinoma (MCF-7), and prostatic small cell carcinoma (PC-3). Among the compounds, 3α,12β,15α-triacetoxy-5α-lanosta-7,9(11),24-trien-26-oic acid (1) showed significant cytotoxic activity against PC-3 cells with an IC₅₀ of 11.5 μM. In studies of anti-angiogenesis activity, ganoderic acid F (17) was found to have the most potent inhibitory effect on the formation of capillary-like structures of human umbilical vein endothelial cells.     

2-Thienyl-4-furyl-6-aryl pyridine derivatives: Synthesis,topoisomerase I and II inhibitory activity,cytotoxicity, and structure–activity relationship study

Designed and synthesized 60 2-thienyl-4-furyl-6-aryl pyridine derivatives were evaluated for their topoisomerase I and II inhibitory activities at 20 μM and 100 μM and cytotoxicity against several human cancer cell lines. Compounds 8, 9, 11–29 showed significant topoisomerase II inhibitory activity and compounds 10 and 11 showed significant topoisomerase I inhibitory activity. Most of the compounds (7–21) possessing 2-(5-chlorothiophen-2-yl)-4-(furan-3-yl) moiety showed higher or similar cytotoxicity against HCT15 cell line as compared to standards. Most of the selected compounds displayed moderate cytotoxicity against MCF-7, HeLa, DU145, and K562 cell lines. Structure–activity relationship study revealed that 2-(5-chlorothiophen-2-yl)-4-(furan-3-yl) moiety has an important role in displaying biological activities.     

Bioactive azaphilones from the fungus Penicillium multicolor CM01

Two new azaphilones, dechloroisochromophilone II (1) and epi-isochromophilone III (2), a new natural product, 5-hydroxy-4-methoxy-5,6-dihydro-2H-pyran-2-one (3), together with eleven known compounds, 4–14 were isolated from the fungus, Penicillium multicolor CM01. Their structures were elucidated by spectroscopic methods. Compounds 2, 8, 10 and 11 exhibited antimalarial activity against Plasmodium falciparum (IC₅₀ 2.1–7.8 μg/mL), while compounds 9 and 10 showed antimycobacterial activity against Mycobacterium tuberculosis (MIC 6.2 and 50.0 μg/mL, respectively). Compounds 2, 4, and 7–11 showed cytotoxicity against three cancer cell lines, KB, MCF-7 and NCI-H187 (IC₅₀ 2.2–35.2 μg/mL). In addition, compounds 1, 5–8 and 11 showed a minimum inhibition requirement to acetylcholinesterase (AChE) assay in the range of 0.03–0.25 nM.     

New phenylpropanoids with cytotoxic activities from Drypetes hainanensis

Phytochemical investigation on Drypetes hainanensis has resulted in the isolation of three new phenylpropanoids, named drypetesins A–C (1–3). Their structures were elucidated by applying various spectroscopic techniques (NMR, UV, IR, MS, and CD). The antiproliferative activities of these compounds were evaluated in vitro against three cultured cancer cell lines. Those new isolates exhibited potent cytotoxic activities against human hepatoma (HepG2), human breast adenocarcinoma (MCF-7), and human lung carcinoma (A-549) cancer cell lines with IC₅₀ value range 5.6–14.8 μM.     

Design,synthesis, in silico and in vitro evaluation of thiophene derivatives: A potent tyrosine phosphatase 1B inhibitor and anticancer activity

A series of novel methyl 4-(4-amidoaryl)-3-methoxythiophene-2-carboxylate derivatives were designed against the active site of protein tyrosine phosphatise 1B (PTP1B) enzyme using MOE.2008.10. These molecules are also subjected for in silico toxicity prediction studies and considering their corresponding drug scores, it implied that, the molecules are promising as anticancer agents. The designed compounds were synthesized by using suitable methods and characterized. They were subjected to inhibitory activity against PTP1B and in vitro anticancer activity by MTT assay. Most of the tested compounds showed potent inhibitory activity against PTP1B, among the compounds tested, compound 5b exhibited the highest activity (IC₅₀ = 5.25 µM) and remarkable cytotoxic activity at 0.09 µM of IC₅₀ against the MCF-7 cell line. In addition to this, compound 5c also showed potential anticancer activity at 2.22 µM of IC₅₀ against MCF-7 and 0.72 µM against HepG2 cell lines as well as PTP1B inhibitory activity at IC₅₀ of 6.37 µM.     

Three new chlorinated phenolic glycosides from Przewalskia tangutica

Three new chlorinated phenolic glycosides, namely przewatangosides A-C (1-3), along with one known compound, globosumoside A (4), were isolated from the whole plants of Przewalskia tangutica. Their structures were unequivocally determined by extensive spectroscopic analysis and chemical method. The cytotoxic activities of the isolated phenolic glycosides (1-4) were evaluated against the five human cancer cell lines A549, MCF-7, SMMC-7721, HepG2 and HL-60. Przewatangoside A (1) exhibited weak cytotoxicity against SMMC-7721 with the IC₅₀ value of 38.1 μM. All the tested compounds were inactive (IC₅₀ > 50 μM) to the normal human hepatocyte cell line (L02).     

Cytotoxic benzophenone and triterpene from Garcinia hombroniana

Garcinia hombroniana (seashore mangosteen) in Malaysia is used to treat itching and as a protective medicine after child birth. This study was aimed to investigate the bioactive chemical constituents of the bark of G. hombroniana. Ethyl acetate and dichloromethane extracts of G. hombroniana yielded two new (1, 9) and thirteen known compounds which were characterized by the spectral techniques of NMR, UV, IR and EI/ESI-MS, and identified as; 2,3′,4,5′-tetrahydroxy-6-methoxybenzophenone (1), 2,3′,4,4′-tetrahydroxy-6-methoxybenzophenone (2), 2,3′,4,6-tetrahydroxybenzophenone (3), 1,3,6,7-tetrahydroxyxanthone (4), 3,3′,4′,5,7-pentahydroxyflavone (5), 3,3′,5,5′,7-pentahydroxyflavanone (6), 3,3′,4′,5,5′,7-hexahydroxyflavone (7), 4′,5,7-trihydroxyflavanone-7-rutinoside (8), 18(13 → 17)-abeo-3β-acetoxy-9α,13β-lanost-24E-en-26-oic acid (9), garcihombronane B (10), garcihombronane D (11), friedelan-3-one (12), lupeol (13), stigmasterol (14) and stigmasterol glucoside (15). In the in vitro cytotoxicity against MCF-7, DBTRG, U2OS and PC-3 cell lines, compounds 1 and 9 displayed good cytotoxic effects against DBTRG cancer cell lines. Compounds 1–8 were also found to possess significant antioxidant activities. Owing to these properties, this study can be further extended to explore more significant bioactive components of this plant.     

Two new rotenoids from the roots of Millettia speciosa

Two new rotenoids, named millettiaosas A–B (1–2), together with four known compounds were isolated from the roots of Millettia speciosa. Their structures were elucidated on the basis of spectroscopic analysis including 1D and 2D NMR techniques and HRESIMS. Evaluation of the two new compounds for cytotoxicity against four human cancer cell lines (MCF-7, HCT-116, A549 and HepG-2) showed moderate activities (10 μM < IC₅₀ < 26 μM).     

Curvularin derivatives from the soil-derived fungus Aspergillus polyporicola PSU-RSPG187

Two new curvularin derivatives, curvulopyran (1) and ent-curvulone A (2), along with ten known compounds including five cytochalasins and five curvularins, were isolated from a culture broth of the soil-derived fungus Aspergillus polyporicola PSU-RSPG187. Their structures were determined by spectroscopic methods. Known aspochalasin D displayed moderate antifungal activity against flucytosine–resistant Cryptococcus neoformans with an MIC value of 32 μg/mL and showed no cytotoxic activity against noncancerous cell lines. In addition, known α,β–dehydrocurvularin exhibited potential cytotoxic activity against both KB and MCF-7 cell lines with the IC₅₀ values of 11.26 and 19.50 μM. Unfortunately, it was strongly active against Vero cell lines.     

Synthesis and antitumor activities of novel hybrid molecules containing 1,3,4-oxadiazole and 1,3,4-thiadiazole bearing Schiff base moiety

A series of novel hybrid molecules containing 1,3,4-oxadiazole and 1,3,4-thiadiazole bearing Schiff base moiety were designed, synthesized and evaluated for their in vitro antitumor activities against SMMC-7721, MCF-7 and A549 human tumor cell lines by CCK-8 assay. The bioassay results demonstrated that most of the tested compounds showed potent antitumor activities, and some compounds exhibited stronger effects than positive control 5-fluorouracil (5-FU) against various cell lines. Among these compounds, compound 8d showed the best inhibitory effect against SMMC-7721 cells, with IC₅₀ value of 2.84 μM. Compounds 8k and 8n displayed highly effective antitumor activities against MCF-7 cells, with IC₅₀ values of 4.56 and 4.25 μM, respectively. Compounds 8a and 8n exhibited significant antiproliferative activity against A549 cells, with IC₅₀ values of 4.11 and 4.13 μM, respectively. The pharmacological results suggest that the substituents of phenyl ring on the 1,3,4-oxadiazole are vital for modulating antiproliferative activities against various tumor cell lines.