Synthesis and in vitro antiproliferative evaluation of pyrimido[5,4-c]quinoline-4-(3H)-one derivatives

A series of pyrimido[5,4-c]quinoline-4-(3H)-one derivatives variously substituted at positions 2 and 3 were synthesized and evaluated for their in?vitro antiproliferative activities against a panel of six human cancer cell lines. Biological evaluation revealed that the vast majority of derivatives exhibited moderate tumor growth inhibitory activities. In particular, compound 7e showed effective anti-tumor activity with broad-spectrum toward numerous cell lines and the most active member in this study. This derivative displaying significant activity against KB (IC(50): 4.9?μM), CNE2 (IC(50): 13.8?μM), MGC-803 (IC(50): 4.8?μM), GLC-82 (IC(50): 7.88?μM), MDA-MB-453 (IC(50): 18.2?μM) and MCF-7 (IC(50): 10.1?μM) cell lines could be considered as the most promising and useful template for future development to obtain more potent anti-tumor agent(s).     

Synthesis, molecular modeling and biological evaluation of 2-(benzylthio)-5-aryloxadiazole derivatives as anti-tumor agents

A series of 2-(benzylthio)-5-aryloxadiazole derivatives have been designed and synthesized, and their biological activities are also evaluated for EGFR inhibitory activity. Fourteen compounds among the twenty compounds are reported for the first time. Their chemical structures are characterized by (1)H NMR, MS, and elemental analysis. Anti-proliferative and EGFR inhibition assay results have demonstrated that compound 3e shows the most potent biological activity (IC(50)?=?1.09?μM for MCF-7 and IC(50)?=?1.51?μM for EGFR). Docking simulation has been performed to position compound 3e into the EGFR active site to determine the probable binding model, with an estimated binding free energy value of?-10.7?kcal/mol. Compound 3e with potent inhibitory activity in tumor growth inhibition may be a promising anti-tumor leading compound for the further research.     

Alpha-glucosidase inhibition of natural curcuminoids and curcumin analogs

Natural curcumin (1), demethoxycurcumin (2) and bisdemethoxycurcumin (3) isolated from Curcuma longa (turmeric), and synthetic curcumin analogs (A(1-7), B(1-7), C(1-6) and D(1-7)) were evaluated in vitro for the alpha-glucosidase inhibitory activity via UV and circular dichroism (CD) spectroscopy. The results indicated that natural curcuminoid compound 3 showed a remarkable inhibitory effect with IC(50) of 23.0 microM, and the synthetic compounds A(2), B(2), C(2) and D(2) showed potent inhibitory effects with IC(50) of 2.8, 2.6, 1.6 and 8.2 microM, respectively. Kinetic study exhibited that the mechanism of alpha-glucosidase inhibition of both 3 and C(2) was non-competitive. The structure activity relationship revealed that the ortho dihydroxyl groups could form a more tight interaction with alpha-glucosidase to exert more potential inhibitory activities.     

Identification of cytochrome P450 isoforms involved in 1-hydroxylation of pyrene

Urinary 1-hydroxypyrene (1-OHP) has been used as a biomarker for environmental polyaromatic hydrocarbon (PAH) exposure. However, it is known that there is an interindividual variability in metabolism of pyrene to 1-OHP depending on the activities of the metabolizing enzymes, especially cytochrome P450s (CYPs). In this study, we investigated the 1-hydroxylation of pyrene by 10 forms of cDNA-expressed human P450s in order to identify the principal isoforms of P450s that are involved in the major metabolic pathway of pyrene. The pyrene 1-hydroxylation activity was found to be the highest in CYP1A1 at both 0.5 and 50microM of pyrene, followed by CYP1B1 and 1A2, whereas other enzymes, including CYP2A6, 2C8, 2C9*1, 2C19, 2D6, 2E1, 3A4, and control microsomes, showed very low or undetectable rates of 1-hydroxylation. In conclusion, CYP1A1, 1B1, and 1A2 are major metabolizing enzymes in 1-hydroxylation of pyrene in vitro. This suggests that the individual difference of these enzymes must be included in epidemiological studies to evaluate PAH exposure using urinary 1-OHP.     

Salvia fruticosa Modulates mRNA Expressions and Activity Levels of Xenobiotic Metabolizing CYP1A2, CYP2E1, NQO1, GPx,and GST Enzymes in Human Colorectal Adenocarcinoma HT-29 Cells

Natural products have gained considerable interests because of their use in some industrial areas including nutrition, cosmetic, pharmacy, and medicine. Salvia fruticosa M. (Lamiaceae) is known for its antioxidant, antimicrobial, and antiproliferative activities. Phase I xenobiotic metabolizing enzymes, CYP1A2 and CYP2E1, produce reactive metabolites which are eliminated by the action of phase II enzymes, NQO1, GPx, and glutathione S-transferases (GSTs). In this study, in vitro modulatory effects of S. fruticosa and its major phenolic compound rosmarinic acid (RA) on CYP1A2, CYP2E1, NQO1, GPx, and GSTm1 mRNA expressions and enzyme activities of GPx and GSTs were investigated in HT-29 cells. An mRNA expression analysis revealed that CYP1A2 and CYP2E1 levels were decreased while those of NQO1, GPx, and GSTm1 increased after S. fruticosa and RA treatments. In parallel to gene expressions, enzyme activities of GPx and GSTs by S. fruticosa increased 1.68- and 1.48-fold, respectively. Moreover, RA increased GPx and GSTs activities 1.67- and 1.94-fold, respectively. The results of this preliminary study show that metabolism of xenobiotics may be altered due to changes in the expression and activity of the investigated enzymes by S. fruticosa.     

New N-methylpiperazinyl derivatives of bicyclic antiprotozoal compounds

The 4-methylpiperazinyl group was inserted as substituent at the bridgehead of bicyclic compounds or as terminal group of their aminoacyl and aminoalkyl side chains. The new compounds were tested in?vitro for their activities against the multidrug-resistant K(1) strain of Plasmodium falciparum and Trypanosoma brucei rhodesiense (STIB 900). The results were compared to those of formerly prepared analogues and of drugs in use. A couple of bicyclo-octyl ω-(4-piperazin-1-yl)alkanoates showed high antitrypanosomal (IC(50)≤0.087μM) and antiplasmodial activity (IC(50)≤0.06μM). The most active ω-(4-methylpiperazin-1-yl)alkyl-2-azabicyclo-nonane possessed higher antiplasmodial activity (IC(50)≤0.023μM) and selectivity (S.I.=IC(50) (Cytotox.)/IC(50) (P.?falciparum)=2188) than the antimalarial drug chloroquine (IC(50)=0.15μM, S.I.=1257).     

A novel caryophyllene type sesquiterpene lactone from Asparagus falcatus (Linn.); structure elucidation and anti-angiogenic activity on HUVECs

In this study the novel caryophyllene type sesquiterpene lactone (aspfalcolide) has been isolated from the leaves of Asparagus falcatus (Linn.) and characterized by IR, 1D NMR, 2D NMR, EI-MS, HR-ESI-MS and X-ray single crystal diffraction analysis. The aspfalcolide crystallizes in the orthorhombic space group P2(1)2(1)2(1) with a?=?6.37360(10), b?=?7.6890(2), c?=?27.3281(6)??, α?=?β?=?γ?=?90(°) and Z?=?4. One intermolecular O-H?O hydrogen bond enforces these natural molecules to form infinite chains through the crystal. Aspfalcolide was screened for its anti-angiogenic activity in human umbilical vein endothelial cells (HUVECs) and the result showed the remarkable inhibitory effect of aspfalcolide on the proliferation (IC(50) 1.82?μM), migration and tube formation of HUVECs.     

Turmeric (Curcuma longa L.) volatile oil inhibits key enzymes linked to type 2 diabetes

Anti-diabetic capacity of Curcuma longa volatile oil in terms of its ability to inhibit glucosidase activities was evaluated. Turmeric volatile oils inhibited glucosidase enzymes more effectively than the reference standard drug acarbose. Drying of rhizomes was found to enhance α-glucosidase (IC(50)?=?1.32-0.38?μg/ml) and α-amylase (IC(50)?=?64.7-34.3?μg/ml) inhibitory capacities of volatile oils. Ar-Turmerone, the major volatile component in the rhizome also showed potent α-glucosidase (IC(50)?=?0.28?μg) and α-amylase (IC(50)?=?24.5?μg) inhibition.     

Structure based drug design, synthesis and evaluation of 4-(benzyloxy)-1-phenylbut-2-yn-1-ol derivatives as 5-lipoxygenase inhibitors

A group of 4-(benzyloxy)-1-phenylbut-2-yn-1-ol derivatives were designed using Site point connection method, synthesized and evaluated for their 5-Lipoxygenase (5-LOX) inhibitory activity. Hydrophobic site points in 5-LOX were considered for the study and substitutions were planned such that 4k will have strong hydrophobic group in the corresponding site point. Biological results supported the in silico prediction with compound 4k exhibiting good inhibition with IC(50) value of 8?μM against 5-LOX. The compounds 4j and 4k showed potent cytotoxic effects against various cancer cell lines (COLO-205, MDA-MB-231 and HepG2) but with no effect on normal cell line (HaCaT). The overall trend showed 4k as the most potent compound. Further studies demonstrated the protective effect of 4k in mouse Acute Lung Injury (ALI) model induced by lipopolysaccharide (LPS).     

Modulation of CYP1A1, CYP1A2 and CYP1B1 Expression by Cabbage Juices and Indoles in Human Breast Cell Lines

Epidemiological studies have shown that consumption of cabbage and sauerkraut is connected with significant reduction of breast cancer incidences. Estrogens are considered a major breast cancer risk factor and their metabolism by P450 enzymes substantially contributes to carcinogenic activity. The aim of this study was to investigate the effect of cabbage and sauerkraut juices of different origin on the expression profile of the estrogen metabolism key enzymes (CYP1A1, CYP1A2, CYP1B1) in breast cell lines MCF7, MDA-MB-231, and MCF10A. The effects of cabbage juices were compared with that exerted by indole-3-carbinol (I3C) and 3,3'-diindolylmethane (DIM). The treatment with cabbage juices or indoles for 72?h affected the expression of CYP1 family genes in cell-type dependent manner. Their induction was found in all cell lines, but the ratio of CYP1A1 to CYP1B1 was 1.22- to 10.6-fold in favor to CYP1A1 in MCF7 and MCF10A cells. Increased levels of CYP1A2 in comparison with CYP1B1 were also observed in MCF7 cells. In contrast, in MDA-MB-231 cells CYP1B1 was preferentially induced. Since the cell lines investigated differ in invasion capacity, these results support epidemiological observations and partly explain the mechanism of the chemopreventive activity of white cabbage products.     

Alpha-amylase, α-glucosidase and lipase inhibiting activities of polyphenol-rich extracts from six common bean cultivars of Southern Italy,before and after cooking

Common beans (Phaseolus vulgaris) are a good source of nutrients and phenolic compounds with versatile health benefits. Polyphenol-rich extracts of six ecotypes of P. vulgaris were analysed to determine their phenolic profiles and assayed in vitro for inhibitory effects on digestive enzymes relevant to carbohydrates and lipids metabolism. The extracts inhibited enzyme activities in a dose-dependent manner. IC 50 values ranged from 69?±?1.9 to 126?±?3.2?μg/mL and from 107.01?±?4.5 to 184.20?±?5.7?μg/mL, before and after cooking, for α-amylase, from 39.3?±?4.4 to 74.13?±?6.9?μg/mL and from 51?±?7.7 to 122.1?±?5.2?μg/mL for α-glucosidase and from 63.11?±?7.5 to 103.2?±?5.9?μg/mL and from 92.0?±?6.3 to 128.5?±?7.4?μg/mL for lipase. Results suggest encouraging their consumption, being natural sources of enzyme inhibitors important for type-2 diabetes and obesity prevention/control. Well-monitored in vivo studies would help to establish their beneficial effects, making them worthwhile of further consideration as functional foods.     

Effect of ditaxin and heteranthin and inhibitory effect of Ditaxis heterantha extract on L5178Y tumor development in mice

Ditaxis heterantha seeds are used as spices for flavoring and coloring food. Two new apocarotenoids derived from the seeds, heteranthin and ditaxin, were evaluated for their in vitro cytotoxic effects in murine lymphoma cells lines. Bioabsorption in mice and preventive and antitumor effects of the apocarotenoids were determined. Ditaxin and heteranthin showed cytotoxic effects in vitro against murine malignant cells and normal splenocyte cells. The 50% inhibitory concentration (IC(50)) for ditaxin in splenocytes was 0.1825?mM; in L5178Y, the IC(50) was 0.1923?mM. The heteranthin IC(50) in splenocytes was 0.1325?mM; in L5178Y, the value was 0.3889?mM. The maximum ditaxin plasma concentration was found after 2 hours of administration (mean±standard deviation, 7.5±2.05?μg/mL). Oral administration of the D. heterantha extract (100?mg/kg per day) for 14 days after the L5178Y lymphoma cell implantation showed no significant effect compared with groups that were not pretreated. However, tumor inhibition in groups treated intraperitoneally before inoculation with the L5178Y cells showed a significant difference (P<.001) compared with the groups not pretreated.     

Effects of estrogen metabolite 2-methoxyestradiol on tumor suppressor protein p53 and proliferation of breast cancer cells

An endogenous 17β-estradiol (E(2)) metabolite, 2-methoxyestradiol (2-ME(2)), has been reported to exhibit estrogen receptor (ER)-independent anti-angiogenic and anti-tumor effects. Several mechanisms have been proposed for 2-ME(2) actions, but there is a lack of evidence for a common pathway for all of the cell-types sensitive to this metabolite. We have examined potential alterations in p53 in response to 2-ME(2), E(2) and the microtubule disruptor taxol in T47D breast cancer cells. Cells were cultured for six days in medium depleted of endogenous steroids or effectors. Semi-confluent cells were treated with 2-ME(2) (1?nM - 10?μM), 10?nM E(2) and/or 1?μM taxol and subjected to SDS-PAGE and Western blot analysis, quantitative analysis, or laser-scanning confocal microscopy. Western blot analysis revealed a concentration-dependent biphasic trend in p53 levels. Addition of 10?nM - 1?μM 2-ME(2) induced significant up-regulation in p53, and this response gradually diminished to levels comparable to the control upon treatment with higher concentrations (2.5 - 10 μM). The observed upregulation of p53 induced by 2-ME(2) is inhibited by concurrent treatment with 1?μM taxol. Cell quantitation revealed a significant decrease (50 - 90%) in cell number upon treatment with 1 - 10?μM 2-ME(2) with minimal effect at lower concentrations. No additional effect on cell proliferation was observed when taxol was combined with 10?nM or 1?μM 2-ME(2). In a concentration dependent manner, treatment with 2-ME(2) for 24?h differentially influenced cellular localization of p53. These results may aid in further understanding the relationship between steroid receptors, tumor suppressor proteins, and effects of hormone metabolites on breast cancer cells.     

Synthesis, antiproliferative activities and telomerase inhibition evaluation of novel asymmetrical 1,2-disubstituted amidoanthraquinone derivatives

A series of diversely asymmetrical mono- or disubstituted 1,2-diamidoanthraquinone derivatives were synthesized and evaluated for drug-induced cytotoxicity by SRB assay, telomerase inhibitory activity by TRAP assay, and hTERT expression by SEAP assay. Interestingly, compounds 4, 11, 21, 32 and 36 exhibited selective potent antiproliferative activities by NCI with IC(50) values in the micromolar range. Of these, only compound 8 showed an IC(50) value of 0.95?μM against PC-3 cell lines (human prostate cancer) by SRB assay. All the synthesized compounds exhibited a poor or modest telomerase inhibitory activity by TRAP assay suggesting another mode of action for these compounds. Compound 11 showed broad inhibition against different types of cancer cell lines in the micromolar and submicromolar range.     

Cytochrome P450 and NAT2 polymorphisms and drug metabolism in DOTS

It has been described an increase of the frequency of Directly Observed Therapy Short-course (DOTS) failure in countries with high rates of mycobacterial drug resistance. This increase could be due to the standardized doses of DOTS results in low or insufficient dosage of drugs in plasma. Several members of cytochrome P450 enzymes superfamily could explain the variations on acetylation velocity and in drug disposition. A population with slow acetylation has a higher risk of toxicity, as that potent inhibition of cytochrome P450 (CYP450) isoforms by isoniazid (CYP2C19 y CYP3A) are dependent of INH plasmatic concentration. This inhibitory effect has been described also for CYP12, CYP2C9 and CYP2E1. INH is metabolized by N-acetyltransferase 2 (NAT2). The wide variability interethnic and intraethnic in acetylation velocity is associated with the polymorphisms of NAT2. Patients with rapid acetylation have plasmatic concentration of INH low or insufficient which induces treatment failure. The study of genotypes of P450 and NAT2 allow us to predict therapeutic and individualized dosages.     

Association of Genetic Variants of CYP2C19 and CYP2D6 with Esophageal Squamous Cell Carcinoma Risk in Northern India,Kashmir

Genetic polymorphism in xenobiotic metabolizing enzymes (XMEs) is associated with various malignancies. However, the association of esophageal cancer with XMEs is mixed. The current study was aimed to explore the association of genetic polymorphisms of cytochrome (CYP) 2C19 and CYP2D6 genotypes with esophageal squamous cell carcinoma (ESCC) risk in Kashmir, India. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequencing methods were used for genotyping of 492 ESCC cases and equal number of individually matched controls. Conditional logistic regression models were used to assess odds ratios (ORs) and 95% confidence intervals. Increased ESCC risk was observed in subjects with variant genotypes of CYP2C19 (OR = 3.3) or CYP2D6 (OR = 2.1) and risk was higher (OR = 4.6) in subjects who harbored both the genotypes. Almost same but higher risk turned when subjects were smokers and carried a variant genotype of CYP2C19 (OR = 4.4) or CYP2D6 (OR = 4.7). Risk was appreciably increased in subjects who had family history of any cancer and also harbored a variant genotype of either CYP2C19 (OR = 15.5) or CYP2D6 (OR = 9.7). Subjects harboring a variant genotype of CYP2D6 showed an added risk when they used biomass as fuel (OR = 4.6). In conclusion, variant genotypes of CYP2C19 and CYP2D6 are associated with an increased risk of ESCC.     

杨梅素抑制H460人肺腺癌细胞增殖及细胞外信号调节激酶通路作用

目的研究杨梅素(myricetin)对人肺癌H460细胞的增殖抑制作用、及其作用途径。方法以人肺腺癌系H460细胞为离体研究对象,通过噻唑蓝(MTT)法研究不同浓度的杨梅素对H460细胞生长的抑制作用并测定其半数抑制浓度(IC50);Western blot法检测杨梅素对蛋白激酶B(Akt)、细胞外信号调节激酶(ERK)磷酸化水平及cyclinD1蛋白表达的影响;流式细胞术检测细胞周期。结果杨梅素对H460细胞具有明显的抑制作用,随着杨梅素浓度的增加,细胞的生长抑制率明显升高,杨梅素作用72h的IC50值为60μg/ml。流式检测发现,杨梅素可明显降低G2/M期H460细胞比例,明显增加G0/G1和S期比例,高剂量(60、90μg/ml)杨梅素处理下,H460细胞无法进入G2/M期。蛋白印迹检测证实,杨梅素干预明显抑制ERK磷酸化、下调Cyclin D1表达水平。结论杨梅素剂量依赖性抑制H460细胞增殖与其抑制细胞进入G2/M期有关,ERK-Cyclin D1途径可能在杨梅素细胞周期调控中发挥重要作用。     

In vitro amoebicidal activity of borage (Borago officinalis) extract on Entamoeba histolytica

Borage (Borago officinalis) is a plant with nutritional value that is also used in traditional medicine to treat gastrointestinal disease. This study investigated the amoebicidal activity of a methanol extract of borage. The 50% inhibitory concentration (IC??) of the extract for Entamoeba histolytica was 33 μg/mL. The 50% lethal dose of the extract for brine shrimp was greater than 1,000?μg/mL. The IC?? of the extract for Vero cells was 203.9?μg/mL. These results support the use of borage to prevent diseases associated with E. histolytica infection.     

Inhibition by allyl sulfides and phenethyl isothiocyanate of methyl-n-pentylnitrosamine depentylation by rat esophageal microsomes, human and rat CYP2E1, and Rat CYP2A3

Garlic and Cruciferae are associated with reduced risks of several human cancers, and some of their constituents are anticarcinogenic in animals. Here we studied inhibition of in vitro metabolism of the rat esophageal carcinogen methyl-n-pentylnitrosamine (MPN) by garlic-derived allyl sulfides and by Cruciferae-derived phenethyl isothiocyanate (PEITC) and sulforaphane. The test inhibitors were incubated with [3H]-MPN, NADPH-generating system and rat esophageal microsomes (REM) or a cytochrome P450 (CYP). [3H]-MPN activation by depentylation was assayed by HPLC with radiometric determination of [3H]-pentaldehyde 2,4-dinitrophenylhydrazone. IC50 for depentylation of 40 microM MPN by rat CYP2E1 was 5-12 microM for diallyl sulfide (DAS), diallyl disulfide (DADS), and PEITC and 10-20 microM for diallyl sulfone, allyl mercaptan, and diallyl trisulfide. Maximum inhibition required preincubation of rat CYP2E1 with DAS for 15 min and with DADS for 30 min. Using these preincubation times, Ki for MPN depentylation by REM, rat and human CYP2E1, and rat CYP2A3 was 0.6-1.6 microM for inhibition by DAS and 1.7-70 microM for inhibition by DADS. With PEITC, Ki for MPN depentylation by REM, rat CYP2E1, and rat CYP2A3 was 0.4-4.6 microM. These low Ki and IC50 values may help explain how garlic and Cruciferae inhibit carcinogenesis.