Synthesis,biological evaluation and molecular docking studies of trans-indole-3-acrylamide derivatives,a new class of tubulin polymerization inhibitors

In this study, we synthesized a series of trans-indole-3-acrylamide derivatives (3a–k) and investigated their activity for inhibition of cell proliferation against five human cancer cell lines (HeLa, MCF7, MDA-MB-231, Raji and HL-60) by MTT assay. Compound 3e showed significant antiproliferative activity against both the Raji and HL-60 cell lines with IC₅₀ values of 9.5 and 5.1 μM, respectively. Compound 3e also exhibited moderate inhibitory activity on tubulin polymerization (IC₅₀ = 17 μM). Flow cytometric analysis of cultured cells treated with 3e also demonstrated that the compound caused cell cycle arrest at the G2/M phase in HL-60 and HeLa cells. Moreover, 3e, the most active compound, caused an apoptotic cell death through the activation of caspase-3. Docking simulations suggested that 3e binds to the colchicine site of tubulin.     

Synthesis and activity of novel tetrazole compounds and their pyrazole-4-carbonitrile precursors against Leishmania spp

A new series of 5-(1-aryl-3-methyl-1H-pyrazol-4-yl)-1H-tetrazole derivatives (4a–m) and their precursor 1-aryl-3-methyl-1H-pyrazole-4-carbonitriles (3a–m) were synthesized and evaluated as antileishmanials against Leishmania braziliensis and Leishmania amazonensis promastigotes in vitro. In parallel, the cytotoxicity of these compounds was evaluated on the RAW 264.7 cell line. The results showed that among the assayed compounds the substituted 3-chlorophenyl (4a) (IC₅₀/24 h = 15 ± 0.14 μM) and 3,4-dichlorophenyl tetrazoles (4d) (IC₅₀/24 h = 26 ± 0.09 μM) were the most potent against L. braziliensis promastigotes, as compared the reference drug pentamidine, which presented IC₅₀ = 13 ± 0.04 μM. In addition, 4a and 4d derivatives were less cytotoxic than pentamidine. However, these tetrazole derivatives (4) and pyrazole-4-carbonitriles precursors (3) differ against each of the tested species and were more effective against L.braziliensis than on L. amazonensis.     

Cytotoxic activity of butane type of 1,7-seco-2,7′-cyclolignanes and apoptosis induction by Caspase 9 and 3

All stereoisomers of methoxybutane and fluorobutane type of 1,7-seco-2,7′-cyclolignane were synthesized and cytotoxic activities of these compounds were compared with those of all stereoisomers of butane and butanol type compounds. Both enantiomers of butane type secocyclolignane showed higher cytotoxic activity (IC₅₀ = 16–20 μM) than methoxy type compounds, whereas none was observed for all the stereoisomers of butanol type secocyclolignane, however, (−)-Kadangustin J showed stereospecific cytotoxic activity (IC₅₀ = 47–67 μM). Since (R)-9′-fluoro derivative 23 was most potent (IC₅₀ = 19 μM) among the corresponding fluoro stereoisomers, (R)-9′-alkyl derivatives were synthesized, hydrophobic 9′-heptyl derivative 27 showing highest activity (IC₅₀ = 3.7 μM against HL-60, IC₅₀ = 3.1 μM against HeLa) in this experiment. Apoptosis induction caused by Caspase 3 and 9 for (R)-9′-heptyl derivative 27 was observed in the research on the mechanism. A degradation of DNA into small fragments was also shown by DNA ladder assay.     

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).     

Isolation,structure, and bioactivities of abiesadines A–Y, 25 new diterpenes from Abies georgei Orr

Twenty-five new (abiesadines A–Y, 1–25) and 29 known (26–54) diterpenes were isolated from the aerial parts of Abies georgei. Abiesadine A (1) is a novel 8,14-seco-abietane, while abiesadine B (2) is a novel 9,10-seco-abietane. The structures of the new compounds were established on the basis of spectroscopic data analysis. Manool (52) showed the strongest effect against LPS-induced NO production in RAW264.7 macrophages with the IC₅₀ value of 11.0 μg/mL. In another anti-inflammatory assay against TNFα-triggered NF-κB activity, (12R,13R)-8,12-epoxy-14-labden-13-ol (54) exhibited the strongest effect (IC₅₀ = 8.7 μg/mL). For antitumor assays, pomiferin A (26) and 8,11,13-abietatriene-7α,18-diol (29) both showed the most significant activity against LOVO cells (IC₅₀ = 9.2 μg/mL). While 7-oxocallitrisic acid (46) exhibited significant cytotoxicity against QGY-7703 tumor cells (IC₅₀ = 10.2 μg/mL).     

Rubiyunnanins C-H, cytotoxic cyclic hexapeptides from Rubia yunnanensis inhibiting nitric oxide production and NF-κB activation

Six new (rubiyunnanins C–H, 1–6) and five known (7–11) cyclic hexapeptides were isolated from the roots of Rubia yunnanensis (Franch.) Diels. The structures and stereochemistry of 1–6 were established by extensive spectroscopic analyses and chemical methods. All compounds (1–11) not only exhibited cytotoxic activities against a panel of eleven cancer cell lines with IC₅₀ values ranging from 0.001 to 56.24 μM, but also exerted inhibitory activities against nitric oxide (NO) production in LPS and IFN-γ-induced RAW 264.7 murine macrophages with IC₅₀ values ranging from 0.05 to 12.68 μM. Furthermore, this is the first time it is being reported that compounds 2 and 7–10 significantly inhibited TNF-α-induced NF-κB activation in HEK-293-NF-κB luciferase stable cells with IC₅₀ values of 35.07, 0.03, 1.69, 12.64 and 1.18 μM, respectively.     

Anti-tubercular activities of 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-amine analogues endowed with high activity toward non-replicative Mycobacterium tuberculosis

Thirty three derivatives of 2-substituted 5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-amine analogues were synthesized by molecular modification of a reported antimycobacterial molecule (GSK163574A). Compounds were evaluated in vitro against actively replicative and nutrient starved non-replicative Mycobacterium tuberculosis (MTB), enzymatic screening and cytotoxicity against RAW 264.7 cell line. Among the compounds, 2-ethyl-N-phenethyl-5,6,7,8-tetrahydrobenzo[4,5]thieno[2,3-d]pyrimidin-4-amine (5c) was found to be the most active compound against non-replicative MTB with 2.7 log reduction of bacteria at 10 μg/mL and was more potent than isoniazid (1.2 log reduction) and rifampicin (2.0 log reduction) at same dose level. Compound 5c also showed activity against MTB alanine dehydrogenase enzyme with IC₅₀ of 1.82 ± 0.42 μM and showed 25% cytotoxicity against RAW 264.7 cell line at 50 μg/mL.     

Synthesis of new heterocyclic lupeol derivatives as nitric oxide and pro-inflammatory cytokine inhibitors

A series of heterocyclic derivatives including indoles, pyrazines along with oximes and esters were synthesized from lupeol and evaluated for anti-inflammatory activity through inhibition of lipopolysaccharide (LPS) induced nitric oxide (NO) production in RAW 264.7 and J774A.1 cells. All the synthesized molecules of lupeol were found to be more active in inhibiting NO production with an IC₅₀ of 18.4–48.7 μM in both the cell lines when compared to the specific nitric oxide synthase (NOS) inhibitor, L-NAME (IC₅₀ = 69.21 and 73.18 μM on RAW 264.7 and J774A.1 cells, respectively). The halogen substitution at phenyl ring of indole moiety leads to potent inhibition of NO production with half maximal concentration ranging from 18.4 to 41.7 μM. Furthermore, alkyl (11, 12) and p-bromo/iodo (15, 16) substituted compounds at a concentration of 20 μg/mL exhibited mild inhibition (29–42%) of LPS-induced tumor necrosis factor alpha (TNF-α) and weak inhibition (10–22%) towards interleukin 1-beta (IL-1β) production in both the cell lines. All the derivatives were found to be non-cytotoxic when tested at their IC₅₀ (μM). These findings suggest that the derivatives of lupeol could be a lead to potent inhibitors of NO.     

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.     

Synthesis,anti-cancer and anti-inflammatory activity of novel 2-substituted isoflavenes

Fifteen novel 2-substituted isoflavenes were synthesised via nucleophilic addition to isoflavylium salts. Twelve of the newly synthesised isoflavenes, along with the unsubstituted parent isoflavene, were tested in cell viability assays against the SHEP neuroblastoma and MDA-MB-231 breast adenocarcinoma cell lines. While the 2-substituted isoflavenes displayed a range of anti-proliferative activities, in most cases they were less active that the unsubstituted isoflavene (IC₅₀ = 9.9 μM vs SHEP; IC₅₀ = 33 μM vs MDA-MB-231). However, compound 7f, derived from the reaction between isoflavylium salt 5 and para-methoxyacetophenone, showed improved anti-proliferative activity against breast cancer cells (IC₅₀ = 7.6 μM). Furthermore, compound 7f, as well as analogues 7a, 7c, 11d and 14, inhibited the production of interleukin-6 in LPS-activated RAW 264.7 cells.     

Nitric oxide inhibitory principles from Derris trifoliata stems

Nine rotenoids were isolated from the hexane and dichloromethane extracts of Derris trifoliata stems and were tested for nitric oxide (NO) inhibitory activity using RAW264.7 cells. The result indicated that 12a-hydroxyrotenone (7) possessed very potent NO inhibitory activity with an IC₅₀ value of 0.002 μM, followed by 1 (deguelin, IC₅₀=0.008 μM), 9 (12a-hydroxyelliptone, IC₅₀=0.010 μM) and 2 (α-toxicarol, IC₅₀=0.013 μM), respectively. In addition, the DPPH scavenging activity of rotenoids was also investigated. It was found that 6a,12a-dehydrodeguelin (5) possessed the highest activity against DPPH with an IC₅₀ value of 7.4 μM, followed by deguelin (1, IC₅₀=27.4 μM). All compounds did not show any cytotoxicity at their IC₅₀ values for NO inhibitory activity.Structure–activity relationships (SARs) of these rotenoids against NO release are as follows: (1) hydroxylation at C12a dramatically increased activity, (2) prenylation at furan ring increased activity markedly and (3) hydrogenation of a double bond at C6a–C12a conferred higher activity. For the DPPH radical scavenging effect, it was found that (1) introduction of a double bond at C6a–C12a increased activity and (2) hydroxylation of C11 at the D-ring decreased activity. As regards active compounds of Derris trifoliata stems, the isolated compounds are responsible for the NO inhibitory effect, especially 7, 1, 9 and 2, whereas 5 and 1 are those for the DPPH scavenging activity.     

Identification and development of 2-methylimidazo[1,2-a]pyridine-3-carboxamides as Mycobacterium tuberculosis pantothenate synthetase inhibitors

In the present study, we used crystal structure of mycobacterial pantothenate synthetase (PS) bound with 2-(2-(benzofuran-2-ylsulfonylcarbamoyl)-5-methoxy-1H-indol-1-yl) acetic acid inhibitor for virtual screening of antitubercular compound database to identify new scaffolds. One of the identified lead was modified synthetically to obtain thirty novel analogues. These synthesized compounds were evaluated for Mycobacterium tuberculosis (MTB) PS inhibition study, in vitro antimycobacterial activities and cytotoxicity against RAW 264.7 cell line. Among the compounds tested, N′-(1-naphthoyl)-2-methylimidazo[1,2-a]pyridine-3-carbohydrazide (5b) was found to be the most active compound with IC₅₀ of 1.90 ± 0.12 μM against MTB PS, MIC of 4.53 μM against MTB with no cytotoxicity at 50 μM. The binding affinity of the most potent inhibitor 5b was further confirmed biophysically through differential scanning fluorimetry.     

Pinostrobin and Cajanus lactone isolated from Cajanus cajan (L.) leaves inhibits TNF-α and IL-1β production: In vitro and in vivo experimentation

The tumor necrosis factor alpha (TNF-α) and interleukin 1 beta (IL-1β) inhibitory activities of Cajanus cajan (leaves) crude methanolic extract, its fractions and its phytochemical constituents were evaluated in lipopolysaccharide (LPS) stimulated RAW 264.7 and J774A.1 cells. Phytochemical investigation of the active ethyl acetate (CCE) and n-butanol (CCB) fractions of C. cajan L. leaves yielded 14 compounds. It was observed that both pinostrobin (9) and cajanus lactone (4) were found to be most active in inhibiting TNF-α (IC₅₀ < 22 μM) and IL-1β (IC₅₀ < 40 μM) whereas compounds 2, 3, 5–8, 10 and 14 showed moderate and mild effects (IC₅₀ = 35.50–81.22 μM for TNF-α and 38.23–89.10 μM for IL-1β) in both the cell lines. Furthermore, at dose of 20 mg/kg, both pinostrobin (9) and cajanus lactone (4) were found to reduce LPS-induced TNF-α levels by 48.6% and 55.0% respectively and IL-1β levels by 53.1% and 41.8% respectively in Sprague Dawley (SD) rats. These findings suggest that C. cajan L. leaves can be developed as an effective herbal remedy for the treatment and prevention of inflammation or associated ailments.     

Tanzawaic acid derivatives from a marine isolate of Penicillium sp. (SF-6013) with anti-inflammatory and PTP1B inhibitory activities

Chemical investigation of a marine-derived fungus Penicillium sp. SF-6013 resulted in the discovery of a new tanzawaic acid derivative, 2E,4Z-tanzawaic acid D (1), together with four known analogues, tanzawaic acids A (2) and D (3), a salt form of tanzawaic acid E (4), and tanzawaic acid B (5). Their structures were mainly determined by analysis of NMR and MS data, along with chemical methods. Preliminary screening for anti-inflammatory effects in lipopolysaccharide (LPS)-activated microglial BV-2 cells showed that compounds 1, 2, and 5 inhibited the production of nitric oxide (NO) with IC₅₀ values of 37.8, 7.1, and 42.5 μM, respectively. Compound 2 also inhibited NO production in LPS-stimulated RAW264.7 murine macrophages with an IC₅₀ value of 27.0 μM. Moreover, these inhibitory effects correlated with the suppressive effect of compound 2 on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in LPS-stimulated RAW264.7 and BV2 cells. In addition, compounds 2 and 5 significantly inhibited the activity of protein tyrosine phosphatase 1B (PTP1B) with the same IC₅₀ value (8.2 μM).     

A novel sesquiterpene quinone from Hainan sponge Dysidea villosa

A new sesquiterpene quinone, 21-dehydroxybolinaquinone (5), together with two known related analogues, bolinaquinone (6) and dysidine (7), had been isolated from the Hainan sponge Dysidea villosa. The structure of the new compound 5 was elucidated on the basis of detailed analysis of spectroscopic data and by comparison with related model compounds. Compounds 5–7 were evaluated for the inhibitory activity against hPTP1B, a potential drug target for treatment of type-II diabetes and obesity, and cytotoxic activity against Hela cell line. The results showed that dysidine (7) had the strongest hPTP1B inhibitory activity with an IC₅₀ value of 6.70 μM and 6 had significant cytotoxic activity against Hela cell line with an IC₅₀ value of 5.45 μM. New compound 5 showed moderate PTP1B inhibitory activity and cytotoxicity with IC₅₀ values of 39.50 and 19.45 μM, respectively.     

Triterpenes from the roots of Lantana montevidensis with antiprotozoal activity

Bioassay guided fractionation of the roots of Lantana montevidensis (Verbenaceae) has resulted in the isolation and identification of three new triterpenoids; 13β-hydroxy-3-oxo-olean-11-en-28-oic acid (1), 12β,13β-dihydroxyolean-3-oxo-28-oic acid (2) and 12β,13β,22β-trihydroxyolean-3-oxo-28-oic acid (3) in addition to nine known compounds: oleanonic acid (4), oleanolic acid (5), 3β,25β-dihydroxy-olean-12-en-28-oic acid (6), lantadene A (7), 19α-hydroxy-3-oxo-olean-12-en-28-oic acid (8) pomolic acid (9), camaric acid (10) together with β-sitosterol (11) and β-sitosterol-3-O-β-d-glucoside (12). The structures of the isolated metabolites were elucidated based on comprehensive 1D and 2D NMR spectroscopic data as well as HR-ESI–MS. The extracts and the isolated metabolites were evaluated for their antiprotozoal and antimicrobial activities. Compound 2 showed antibacterial activity against Staphylococcus aureus and methicillin resistant S. aureus with IC₅₀ values against both organisms of 2.1 μM and compound 10 showed activity against same organisms with IC₅₀ values 8.74 and 8.09 μM, respectively, compared to the positive control ciprofloxacin (IC₅₀ = 0.3 μM against S. aureus and MRSA). Compounds 1, 4, 5, 6, and 10 showed moderate antileishmanial activity with IC₅₀ values ranging between (2.54–14.95 μM) and IC₉₀ values ranging between (11.90–19.47 μM), using pentamidine as a control (IC₅₀ values 2.09 ≥ 16.8 μM) and IC₉₀ values ranging between (4.72 ≥ 16.8 μM). These compounds also showed highly potent antitrypanosomal activity with IC₅₀ values ranging between (0.39–7.12 μM) and IC₉₀ values ranging between (1.91–10.51 μM), which are more efficient than the DFMO, the antitrypanosomal drug employed as positive control (IC₅₀ and IC₉₀values 11.82 and 30.82 μM).     

Terpenoids with cytotoxic activity from the branches and leaves of Pyrus pashia

Twenty terpenoids, including a new triterpenoid (1) and a new monoterpenoid (20), were isolated from the branches and leaves of Pyrus pashia. The structures of two new compounds were determined to be 2α, 3β, 27-trihydroxyolean-12-en-28-oic acid (1) and (4α)-3-(5,5-dimethyltetrahydrofuranyl)-1-buten-3-ol 3-O-β-d-glucopyranoside (20) on the basis of spectroscopic analysis (IR, HRESIMS, 1D and 2D NMR) and chemical method. Some of the isolated compounds were evaluated for their cytotoxic activity against a panel of human cancer cell lines by MTT assay, using cisplatin as a positive control. Compound 14 exhibited cytotoxic activities against A549 (IC₅₀ = 19.18 ± 4.26 μM), Hela (IC₅₀ = 12.56 ± 3.89 μM), SGC7901 (IC₅₀ = 10.48 ± 1.95 μM) and NHI-1975 (IC₅₀ = 7.38 ± 2.31 μM) cell lines as well as compound 12 displayed cytotoxic activities against A549 (IC₅₀ = 14.71 ± 1.47 μM) and Hela (IC₅₀ = 12.22 ± 1.88 μM) cell lines.     

Development of novel tetrahydrothieno[2,3-c]pyridine-3-carboxamide based Mycobacterium tuberculosis pantothenate synthetase inhibitors: Molecular hybridization from known antimycobacterial leads

Twenty six 2,6-disubstituted 4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxamide derivatives were designed by molecular hybridization approach using and synthesized from piperidin-4-one by five step synthesis. Compounds were evaluated for Mycobacterium tuberculosis (MTB) pantothenate synthetase (PS) inhibition study, in vitro activities against MTB, cytotoxicity against RAW 264.7 cell line. Among the compounds, 6-(4-nitrophenylsulfonyl)-2-(5-nitrothiophene-2-carboxamido)-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxamide (11) was found to be the most active compound with IC₅₀ of 5.87 ± 0.12 μM against MTB PS, inhibited MTB with MIC of 9.28 μM and it was non-cytotoxic at 50 μM. The binding affinity of the most potent inhibitor 11 was further confirmed biophysically through differential scanning fluorimetry.     

Development of benzo[d]oxazol-2(3H)-ones derivatives as novel inhibitors of Mycobacterium tuberculosis InhA

A series of twenty seven substituted 2-(2-oxobenzo[d]oxazol-3(2H)-yl)acetamide derivatives were designed based on our earlier reported Mycobacterium tuberculosis (MTB) enoyl-acyl carrier protein reductase (InhA) lead. Compounds were evaluated for MTB InhA inhibition study, in vitro activity against drug-sensitive and -resistant MTB strains, and cytotoxicity against RAW 264.7 cell line. Among the compounds tested, 2-(6-nitro-2-oxobenzo[d]oxazol-3(2H)-yl)-N-(5-nitrothiazol-2-yl)acetamide (30) was found to be the most promising compound with IC₅₀ of 5.12 ± 0.44 μM against MTB InhA, inhibited drug sensitive MTB with MIC 17.11 μM and was non-cytotoxic at 100 μM. The interaction with protein and enhancement of protein stability in complex with compound 30 was further confirmed biophysically by differential scanning fluorimetry.