Synthesis and antitumor properties of novel alizarin analogs

Series of novel hybrids of alizarin and diamide scaffold (3a–3h, 7a–7h) were designed and synthesized. In vitro antitumor activities of all compounds against HepG-2, CNE, Spca-2, Hct-116, and MGC-803 cell lines were evaluated, and employing standard MTT assay compared with commercial anticancer drug 5-fluorouracil (5-FU). Compounds 7b, 7c, 7d, and 7e showed relatively high cytotoxicity. Especially, compound 7c exhibited the best cytotoxicity against CNE cells with IC₅₀ 9.08 µM, which was even stronger than that of 5-FU. All the synthesized compounds exhibited low cytotoxicity against HUVEC cells. The action mechanism of representative compound 7c was preliminarily investigated by flow cytometry, which indicated that the compound can induce cell apoptosis in CNE cells. Cell cycle analysis showed that compound 7c mainly arrested CNE cells in G1 stage. In addition, the binding properties of a model analog 7c to DNA were investigated by different methods (fluorescence, CD spectroscopy), and the results indicated that 7c showed a moderate preference for binding ct-DNA.     

The induction of apoptosis by a newly synthesized diosgenyl saponin through the suppression of estrogen receptor-α in MCF-7 human breast cancer cells

Estrogen receptor (ER)-α is an important therapeutic target in the clinical treatment of breast cancer. A potential down-regulator of ER-α, diosgenyl α-l-rhamnopyranosyl-(1→2)-[β-d-xylopyranosyl-(1→4)]-α-l-arabinopyranoside is a newly synthesized diosgenyl saponin named compound 22. This study evaluated the in vitro mechanism of compound 22 as an anticancer agent for breast cancer. Our results indicated that compound 22 selectively inhibited proliferation and induced apoptosis in ER-positive MCF-7 cells, compared with ER-negative MDA-MB-231 and MCF-10A cells. Western blot analysis showed that compound 22 decreased the expression of procaspase-3, procaspase-8, and survivin; and increased the expression of Fas ligand and cleaved PARP1 in MCF-7 cells, indicating that compound 22-induced apoptosis was mediated by the extrinsic pathway. This apoptosis was associated with the suppression of ER-α protein and mRNA expression and the inhibition of ER-DNA binding to the estrogen responsive element. Moreover, ER-α mediated gene expression such as c-Myc and cyclin D₁ was reduced, and the activation of p38 and ERK 1/2 was significantly decreased after treatment with compound 22 in MCF-7 cells. Taken together, these results demonstrate that compound 22 down-regulates ER-α expression and induces apoptosis through the extrinsic pathway, suggesting that compound 22 may be effective in the treatment of ER-positive breast cancer.     

Dual and/or selective DNA-PK,PI3K inhibition and isoform selectivity of some new and known 2-amino-substituted-1,3-benzoxazines and substituted-1,3-naphthoxazines

The 2-morpholino-substituted-benzoxazines 7a and 7b were used in the synthesis of 2-morpholino-di-O-benzyl, O-pyridin-2yl, 3-yl and 4yl-methoxy)-1,3-benzoxazines 8a–8d, and N-(2-morpholino-4-oxo-4H-benz[e][1,3]oxazin-7-yl)-N-(pyridin-2-and-3-ylmethyl)acetamides 8e and 8f. The DNA-dependent protein kinase (DNA-PK) and phosphatidylinositol 3-kinase (PI3K) α, β, γ, and δ isoforms were studied for the new compounds 8a–8f and PI3K for the 18 previously synthesized compounds 9–26. The most active DNA-PK inhibitors were the 2-morpholino-O-substituted linear or angular naphthoxazine compounds 18–20 and 21–22 which showed potent and selective DNA-PK activity (IC₅₀ from 0.01 to 2.43 µM) over PI3K. 8-(2-(4-Methylpiperazin-1-yl)ethoxy)-2-morpholino compound 13, and 8-methyl-2-(pyridin-3-yl(pyridin-3-ylmethyl)amino)-7-(pyridin-3-ylmethoxy) compound 25 showed selective DNA-PK inhibition. 2-morpholino-8-substituted-benzoxazine 9 (8-ph) and 10–12 (8-(pyridine-2-, 3-, or 4-ylmethoxy) showed high-to-moderate inhibition of PI3K and DNA-PK. A similar pattern for DNA-PK nonselectivity over PI3K was observed for compounds with 7,8-O-bis-substituted 8a, 8c, and 8d. No DNA-PK selectivity over PI3K was observed regardless whether the substitution was phenyl, pyridin-2-ylmethoxy, pyridin-3-ylmethoxy, and pyridin-4-ylmethoxy.     

Synthesis and biological activity of novel Schiff bases derived from metronidazole

A number of novel Schiff bases (5a–i) and (7a–d) derived from metronidazole were synthesized. Reaction of 2-(2-methyl-5-nitro-imidazol-1-yl)-ethyl ester toluene-4-sulfonate with 4-hydroxybenzaldehyde and with 3-hydroxybenzaldehyde in the presence of a base afforded 4-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethoxy)benzaldehyde (5) and 3-(2-(2-methyl-5-nitro-1H-imidazol-1-yl)ethoxy)benzaldehyde (7), respectively. The reaction of aldehydes 5 and 7 with a number of primary aromatic amines produced Schiff bases 5a–i and 7a–d, respectively. Structures of these compounds were confirmed through different spectroscopic methods such as ¹H-NMR, ¹³C-NMR, mass spectrometry, and also by elemental analyses. The prepared compounds were evaluated in vitro for their antigiardial, anti-trichomonal, antibacterial, and antifungal activities. Compounds 5e, 5g, 5i, 7a, 7b, 7c, and 7d exhibited remarkable antigiardial activity and were found to be more active than metronidazole with IC₅₀ of 7.2, 3.3, 1.5, 5.8, 4.5, 2.9, and 3.8 µg/mL, respectively. Compounds 5a and 5c also exhibited antigiradial activity with similar IC₅₀ values compared to the reference drug metronidazole with IC₅₀ of 7.2 µg/mL. The other compounds 5b, 5d, 5f, and 5 h also showed antigiardial activity but with higher IC₅₀ compared to the reference drug. Compounds were also tested for their anti-trichomonal activity, they, however, exhibited higher IC₅₀ compared to the reference drug metronidazole (7.4 µg/mL), except for compound 5a which exhibited anti-trichomonal activity with an IC₅₀ of 6.3 µg/mL. On the bases of preliminary screening, the newly synthesized compounds exhibited moderate to potent antimicrobial activities. Compound 5e inhibited the growth of Methicillin resistant Staphylococcus aureus (MRSA) and Bacillus cereus and compound 5c inhibited Candida Pathogenic fungus at 50 μg/mL compared with the positive control (Nystatin) which inhibits Candida at 25 μg/mL.     

Synthesis of 3-amino-1,4-dihydropyridine derivativevia an intramolecular rearrangement of 1,4-dihydropyridine-3-hydroxamate

2,6-Dimethyl-4-(3′-nitrophenyl)-3-methoxylaminocarbonyl-1,4-dihydropyridine-5-carboxylic acid methylester,3b reacted with 2-cyanoethanol or benzylalcohol to give the corresponding cyanoethylurethane compound6c in 40.6% yield and benzylurethane compound6d in 32% yield. The cyanoethylurethane6c was hydrolized in ethanolic NaOH to give 2,6-dimethyl-4-(3′-nitrophenyl)-1,4-dihydropyridine-3-amino-5-carboxylic acid 5-methyl ester. HCl8 in 64.8% yield. Another acid hydrolysis of benzylurethane6d gave 2,6-dimethyl-4-(3′-nitrophenyl)-1,4-dihydropyridine-3-amino-5-carboxylic acid 5-methylester. HBr11 in 54.7% yield.     

Investigation of piperidine derivatives in ex vivo models of pain and platelet aggregation

Piperidine derivatives are known to exhibit analgesic activities and are likely to possess the ability to block the effects of prostaglandins through inhibition of downstream signaling pathways. The present study investigated the activity of five derivatives (PD2-6) of 4-(4??-bromophenyl)-4-piperidinol (PD1), against pain and platelet aggregation mediated by the release of prostaglandins and thromboxane A2, respectively. The results showed that compound PD1 and its two phenacyl derivatives PD3 and PD5 exhibited a highly significant analgesic effect (p < 0.01), whereas PD4 and PD6 also showed significant activity. PD3, the most active analgesic compound when docked to the opioid receptor, had interactions between the oxygen of its nitro group and the amino group of ARG 573, indicating a distance of 1.2563 ?. The antiplatelet data showed that compound PD5 (4-(4??-bromo-phenyl)-4-hydroxy-1-[2-(2??,4??-dimethoxyphenyl)-2-oxo-ethyl]-piperidinium bromide) had an IC₅₀ = 0.06 mM, which was the most active compound, whereas PD3 was the second most active compound against platelet aggregating factor-induced aggregation with an IC₅₀ = 80 mM. Acetyl salicylic acid (IC₅₀ = 150 ??M) was used as a positive control.     

Synthesis and anti-HIV-1 screening of novel N′-(1-(aryl)ethylidene)-2-(5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]thiazin-4(1H)-yl)acetohydrazides

A novel series of N′-(1-(aryl)ethylidene)-2-(5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]thiazin-4(1H)-yl)acetohydrazides was synthesized. The synthesis was carried out by thermal method as well as ultrasonic bath to reduce reaction time and to enhance product yields. The synthesized compounds were characterized by spectroscopic techniques like NMR, infrared and EIMS. The structure of compound 5w was elucidated by X-ray crystallography. The titled compounds were evaluated for anti-human immunodeficiency virus type 1 (anti-HIV-1) and cytotoxic activities. Biological studies indicated that amongst these compounds, 5a, b, j, h and i showed the activity with median effective concentration (EC₅₀) values less than 20 μM. Compound 5i exhibited the most potent anti-HIV-1 activity (EC₅₀ = 3.2 μM) while 5h showed anti-HIV-1 activity (EC₅₀ = 3.8 μM) with no toxicity at all in primary human lymphocytes, CEM and VERO cells.     

Phytochemical constituents of Mongolian traditional medicinal plants, Chamaerhodos erecta and C. altaica, and its constituents prevents the extracellular matrix degradation factors

Activity-guided isolation of the n-butanol fraction of Chamaerhodos erecta and water soluble fraction of C. altaica resulted in the isolation of 39 compounds, including new compounds identified as 4,5-dihydroxybenzaldehyde-3-O-β-d-glucopyranoside (1) from C. erecta and quercetin-3-O-β-d-glucuronopyranosyl-4′-O-β-d-glucopyranoside (2) from C. altaica. A total of 37 other compounds were identified based on physico-chemical properties and spectroscopic data. Antioxidative activity was evaluated using a DPPH radical-scavenging method, hyaluronidase inhibitory activity, and advanced glycation end products production inhibitory activity of isolated compounds. Some flavonols (4, 6, 9–11, 14, 15), catechins (18, 19), an amino acid (20), a lignan glucoside (23), and tannins (29–39) exhibited potential a free radical scavenging activity while the new compound (1) showed weak activity. A catechin (18) and some of the tannins (32, 33, 35, 36, 38) had moderate hyaluronidase inhibitory activity. Some of flavonoids and tannins prevented advanced glycation end products production, and the IC₅₀ of compounds 3, 9, 14–16, 33, 34, 36, 38, and 39 were determined.     

Synthesis and evaluation of anticonvulsant and antidepressant activities of 7-alkyl-7H-tetrazolo[1,5-g]purine derivatives

Seventeen 7-alkyl-7H-tetrazolo[1,5-g]purine derivatives were synthesized, and their anticonvulsant and antidepressant activities were evaluated in a mouse model. The anticonvulsant effect and neurotoxicity of the compounds were evaluated with a maximal electroshock test and a rotated test in mice, respectively. Most of the compounds had anticonvulsant activity; among the compounds studied, 7-(3-chlorobenzyl)-7H-tetrazolo[1,5-g]purine (3h) was found to be the most potent compound with a median effective dose (ED₅₀) value of 28.9 mg/kg and a protective index value of 15.8, possessing better anticonvulsant activity and higher safety than the marketed drug carbamazepine. To explain the possible mechanism of anticonvulsant activity, compound 3h was tested in pentylenetetrazole-induced seizures tests, and the results suggest that compound 3h exerts anticonvulsant activity through a GABA-mediated mechanism. Forced swimming test showed that at a dose of 40 mg/kg, five compounds have significant antidepressant activity, the most active compound was 7-(2-chlorobenzyl)-7H-tetrazolo[1,5-g]purine (3g), which decreased immobility time by 56 %.     

Zeaoxazolinone,a new antifungal agent from Zea mays roots

A new 7-methoxy-2-benzoxazolinone dimer named zeaoxazolinone (2), together with four known compounds; 9-Z-hexadecenoic acid (1), 6-methoxy-benzoxazolinone (3), gallic acid (4), and β-sitosterol-3-O-β-d-glucopyranoside (5) were isolated from Zea mays L. roots. The structural elucidation of isolated metabolites was established on the basis of UV, IR, 1D, 2D NMR, and MS spectral analyses. Compound 2 exhibited a potent antifungal activity against Aspergillus flavus, Fusarium oxysporum, and Candida albicans.     

Synthesis, anti-inflammatory, and structure antioxidant activity relationship of novel 4-quinazoline

The practice of medicinal chemistry is devoted to the discovery and development of new agents for treating disease. A new derivative of methyl 2-((E)-3-(3,4-dihydroxyphenyl)acrylamido)benzoate 2 was synthesized by reacting the amino group of methyl anthranilate 1 with caffeic acid in the presence of PCl₃. Cyclcondensation of 2 with hydrazine hydrate afforded the corresponding 2,3-dihydro-2-(3,4-dihydroxyphenyl) pyrazolo[5,1-b]quinazolin-9(1H)-one 3. The median lethal doses (LD_50s) of compounds 2 and 3 in mice were 1,135 and 495 mg/kg b.w., respectively. The anti-inflammatory, reducing power, chelating activity on Fe²⁺, free radical-scavenging, and total antioxidant activities were more pronounced in compound 2 compared to compound 3. On the other hand, antipyretic activity was more pronounced in compound 3 compared to compound 2. Antioxidant activity of compounds 2 and 3 increased with increased concentrations. Total antioxidant activity of compounds 2, 3 and both standards decreased in the order of α-tocopherol > compound 2 > trolox > BHA > BHT > compound 3. Administration of compounds 2 and 3 orally to the rats at dose of 50, 100, and 150 mg/kg b.w., for 10 days showed non-significant changes in serum level of GOT, GPT, ALP, γ-GT, and LDH as compared with the control group. In addition, oral administration of the compound 2 at a concentration of 100 and 150 mg/kg b.w. and compound 3 at a concentration of 150 mg/kg b.w. daily to normal rats for 10 days showed a significant increase in liver GSH, GPx, GR, and GST activities and significant decrease in TBARS level. But, administration of diclofenac sodium (30 mg/kg b.w.) orally to the rats daily for 10 days to rats showed significant increase in serum SGOT, SGPT, ALP, γ-GT, and LDH and significant decrease in liver GSH, GPx, GR, and GST activities. These findings suggest that compounds 2 and 3 exhibited good antioxidant and anti-inflammatory activity and also showed effects on liver enzymes.     

In vitro antimicrobial activity of o-phenylenediamine-tert-butyl-N-1,2,3-triazole carbamate analogs

In an attempt to design and synthesize effective antimicrobial agents using click chemistry, mono- and di-alkyne-substituted monoboc protected o-phenylenediamines were reacted with different substituted aryl azides which yielded 18 new compounds (4a–4k and 5a–5f, 5l). Structures of all newly synthesized compounds were established by ¹H and ¹³C NMR analysis. The intermediate compound 1 was also confirmed by X-ray crystallography. The title compounds were screened for their antibacterial activity against Gram +ve bacteria (Staphylococcus aureus and Enterococcus faecalis), Gram ?ve bacteria (Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa), and their antifungal profile were tested on (Candida tropicalis, Candida albicans, Candida krusei, and Cryptococcus neoformans) as well as on molds such as (Aspergillus niger, Aspergillus fumigatus). The compounds 4k and 5f both showed maximum potency against S. aureus (ATCC 25323) strain with MIC value of 6.25 µg/ml, which is comparable with standard drug ciprofloxacin (MIC 6.25 µg/ml) while remaining compounds showed moderate to weak activity. Further, all compounds showed average antifungal activity in the range of 100–200 µg/ml.     

Synthesis, antimicrobial, and antioxidant activities of some new indole analogues containing pyrimidine and fused pyrimidine systems

To examine new leads with potential antimicrobial and antioxidant activities, a new series of tetrahydropyrimidines (2a–c, 3a–c and 4a–c), pyrazolo[3,4-d]pyrimidines (5a–c), and ditetrazolo[1,5-a;1′,5′-c]pyrimidines (6a–c) were synthesized in this study using appropriate synthetic routes. The newly synthesized compounds have been tested for their antimicrobial and antioxidant activities against DPPH stable free radical. In the case of antibacterial activity, compounds 2a, 6a, and 6c exhibited the maximum zone of inhibition against Staphylococcus aureus; compound 6c exhibited maximum zone of inhibition against Pseudomonas aeruginosa; and compound 2a showed maximum inhibitory growth against Klebsiella pneumonia. While in the case of antifungal activities, compound 5a showed good zone of inhibition against Aspergillus oryzae, compounds 2b and 6a exhibited maximum zone of inhibition against Aspergillus niger. In case of antioxidant activities, compound 2a showed the highest DPPH radical scavenging activity.     

Synthesis,biological evaluation of certain pyrazolo[3,4-d]pyrimidines as novel anti-inflammatory and analgesic agents

In the present study, a series of pyrazolo[3,4-d]pyrimidin-4(5H)-ones linked at 5-position to thiazoline or thiazolidinone ring systems through imino linkage (5–8) was designed and synthesized. The compounds were assessed for their anti-inflammatory activity and analgesic in vivo. Also, their ability to inhibit ovine COX-1/COX-2 isozymes was evaluated using in vitro cyclooxygenase (COX) inhibition assay. The newly synthesized compounds 7, 8d, and 8e showed potent anti-inflammatory and analgesic activity. Moreover, compound 7 displayed preferential COX-2 inhibitory potency (IC₅₀ = 0.53 µM and COX-2 selectivity index = 10.07) which is more potent than the standard drug meloxicam. Interestingly, the tested compounds showed excellent gastrointestinal safety profile and were well tolerated by experimental animals with high safety margins than the reference drug meloxicam.     

Cytotoxic dibenzocyclooctadiene lignans from Kadsura coccinea

Three new dibenzocyclooctadiene lignans, kadusurain A–C (1–3), together with two known compounds kadsuphilin A (4) and B (5), were isolated from an EtOAc fraction of the 80 % acetone extract of Kadsura coccinea (Lem.) A. C. Smith. Their structures were established by 1D and 2D NMR techniques, and mass spectroscopy. Anti-proliferative effect of isolated compounds was evaluated against four human tumor cell lines (A549, HCT116, HL-60, and HepG2), and it was found that compound 1 exhibited significant antiproliferative effects with IC₅₀ values ranging from 1.05 to 12.56 μg/ml.     

Bioactive anthraquinones from endophytic fungus Aspergillus versicolor isolated from red sea algae

The marine fungus Aspergillus versicolor was isolated from the inner tissue of the Red Sea green alga Halimeda opuntia. The fungus was identified by its morphology and 18s rDNA. Cultivation of this fungal strain led to a new metabolite named isorhodoptilometrin-1-methyl ether (1) along with the known compounds emodin (2), 1-methyl emodin (3), evariquinone (4), 7-hydroxyemodin 6,8-methyl ether (5), siderin (6), arugosin C (7), and variculanol (8). The structures were elucidated on the basis of NMR spectroscopic analysis and mass spectrometry. The biological properties of ethyl acetate extract and compounds 1–3 and 6–8 were explored for antimicrobial activity, anti-cancer activity and inhibition of Hepatitis C virus (HCV) protease.     

Potential anti-tubercular and in vitro anti-inflammatory agents: 9-substituted 1,8-dioxo-octahydroxanthenes through cascade/domino reaction by citric fruit juices

A series of 9-substituted 1,8-dioxo-octahydroxanthenes, 3a–k were synthesized and evaluated for their anti-tubercular and in vitro anti-inflammatory potential. Compounds 3b, 3d, 3e, 3f, 3g, and 3k demonstrated their potential anti-tubercular activity at 0.4 μg/ml comparable to streptomycin and pyrazinamide (standard drugs) screened by Microplate Alamar Blue assay against Mycobacterium tuberculosis H37 Ra. Compounds 3j, 3e, 3f, and 3c showed good in vitro anti-inflammatory activity by the inhibition of enzyme MMP-2 75, 65, 70, and 60 % and inhibition of enzyme MMP-9 by 90, 70, 60, and 60 %, respectively by gelatin zymography on gel electrophoresis. Standard drug tetracycline (300 μg/ml) is used as positive control which showed 90 % inhibition. The percentage inhibition was determined by a gel documentation system. DMSO was used as solvent control which did not show any inhibition.     

Synthesis of new oxadiazole derivatives as anti-inflammatory, analgesic, and antimicrobial agents

In search of pharmalogically active molecules in the class of oxadiazoles, the present article deals with the synthesis of 5-(5′-fluoro-2′-methoxybiphenyl-3-yl)-1,3,4-oxadiazol-2(3H)-one 2 from its hydrazide analog 1. The compound 2 was regioselectively N-alkylated with alkyl halides and produced the compounds 3a–f. Compound 3f was further functionalized with substituted benzenesulfonyl chlorides to give compounds 3g–j. The synthesized compounds were characterized by elemental and spectral analysis. Newly synthesized compounds were tested for their in vivo anti-inflammatory, analgesic, and in vitro antimicrobial activities. The compounds 3a–c were found to have promising anti-inflammatory and analgesic activities. Compounds 3b, 3f, and 3g showed significant antibacterial and antifungal activities.     

Synthesis,molecular properties and DFT studies of new phosphoramidates as potential urease inhibitors

In this work, new phosphoramidates were prepared and screened for their putative urease inhibitory activity. The importance of this class of compounds is related to the wide range of biological activities which they exhibit. Consequently, higher activity shown by phosphoramidates 3a, 4b, 5a, 5b, 5c, and 9a suggests that they could serve as lead substances for the development of novel synthetic compounds with enhanced inhibitory ureolitic activity. Their predicted ADMET properties are also in accordance with the general requirements for drug-like compounds. Structure–activity relationship analyses suggest that the presence of cyclohexylamine group is an important structural feature associated with enhanced activities. DFT calculations were performed to obtain the energy values of HOMO and LUMO, and dipole moment.     

A polybromodiphenyl ether from an Indonesian marine sponge Lamellodysidea herbacea and its chemical derivatives inhibit protein tyrosine phosphatase 1B, an important target for diabetes treatment

The ethanol extract of an Indonesian marine sponge Lamellodysidea herbacea inhibited the activity of protein tyrosine phosphatase 1B (PTP1B), an important target enzyme for the treatment of type II diabetes. Bioassay-guided isolation yielded a known polybromodiphenyl ether (1) as a sole bioactive component. The structure of 1 was confirmed by spectroscopic data for 1 and its methyl ether derivative (2). Compound 1 markedly inhibited the PTP1B activity (IC₅₀ = 0.85 μM) and showed a moderate cytotoxicity against two human cancer cell lines, HCT-15 (colon) and Jurkat (T-cell lymphoma) cells. On the other hand, compound 2 maintained potent inhibitory activity against PTP1B (IC₅₀ = 1.7 μM) but did not show apparent cytotoxicity at 18 μM against these cancer cells. Four ester derivatives [acetyl (3), butyryl (4), hexanoyl (5), and benzoyl (6)] were prepared from 1 and their activities evaluated against PTP1B and two cancer cell lines to investigate the structure–activity relationships. Although compounds 3–6 exhibited potent inhibitory effects against PTP1B activity, cytotoxicity against HCT-15 and Jurkat cells was observed as a similar efficacy to that of 1. From these results, compound 2 was found to be the best inhibitor of PTP1B with no apparent cytotoxicity. Therefore, 2 may be a lead compound for making a new type of PTP1B inhibitor. Moreover, compound 2 did not inhibit the cell growth of Huh-7 cells (hepatoma). Hepatocytes are one of the locations of PTP1B, and Huh-7 cells are used to study the mechanism of action of compound 2.