Long Chain Alkyl Esters of Hydroxycinnamic Acids as Promising Anticancer Agents: Selective Induction of Apoptosis in Cancer Cells.

Cancer is the major cause of morbidity and mortality worldwide. Hydroxycinnamic acids (HCAs) are naturally occurring compounds and their alkyl esters may possess enhanced biological activities. We evaluated C4, C14, C16, and C18 alkyl esters of p-coumaric, ferulic, sinapic, and caffeic acids (19 compounds) for their cytotoxic activity against four human cancer cells and also examined their effect on cell cycle alteration and apoptosis induction. The tetradecyl (1c) and hexadecyl (1d) esters of p-coumaric acid and tetradecyl ester of caffeic acid (4c), but not the parental HCAs, were selectively effective against MOLT-4 (human lymphoblastic leukemia) cells with IC50 values of 0.123 ± 0.012, 0.301 ± 0.069 and 1.0 ± 0.1 µM, respectively. Compounds 1c, 1d, and 4c significantly increased apoptotic cells in sub-G1 phase and activated the caspase-3 enzyme in MOLT-4 cells. Compound 1c was 15.4 and 23.6 times more potent than doxorubicin and cisplatin, respectively, against the drug resistant MES-SA-DX5 uterine sarcoma cells. These p-coumarate esters were several times less effective against NIH/3T3 fibroblast cells. Docking studies showed that 1c may cause cytotoxicity by interaction with carbonic anhydrase IX. In conclusion, long chain alkyl esters of p-coumaric acid are promising scaffolds for selective apoptosis induction in cancer cells.

Effects of silymarin on biochemical and oxidative stress markers in end-stage renal disease patients undergoing peritoneal dialysis.

Introduction End-stage renal disease (ESRD) patients especially those undergoing dialysis are vulnerable to several complications, in particular those related to oxidative stress. Silymarin is an herbal medicine commonly used as an antioxidant in different pathologies. Methods To evaluate the effect of silymarin on biochemical and oxidative stress markers, 50 ESRD patients undergoing peritoneal dialysis were randomly divided into two groups of silymarin (n = 28) and control (n = 22) and received silymarin (140 mg every 8 hours) or placebo for 2 months, respectively. Ferric reducing antioxidant power and total 8-iso-prostaglandin F2α were measured in plasma, while catalase enzyme activity was measured in erythrocytes of both groups before and after treatment. Findings Ferric reducing antioxidant power values after treatment were significantly decreased in silymarin group compared to before treatment values (17.2 ± 2.9 and 15.9 ± 3.1 µM equivalent of quercetin/dL, respectively, P < 0.05). Conversely, catalase levels were increased 17.3% after silymarin consumption, while it was decreased 9.1% in control group. Further, hemoglobin (from 10.94 ± 2.17 to 11.54 ± 2.03 g/dL, P < 0.05) and albumin levels (from 3.48 ± 0.67 to 3.61 ± 0.53 g/dL, P < 0.05) were significantly increased after silymarin administration. Discussion It is concluded that silymarin could be regarded as a supplementary therapy for ESRD patients undergoing peritoneal dialysis in order to reduce complications.

Structure-activity relationship studies of 4-methylcoumarin derivatives as anticancer agents.

CONTEXT: Cancer is a leading cause of death worldwide and novel chemotherapeutic agents with better efficacy and safety profiles are much needed. Coumarins are natural polyphenolic compounds with important pharmacological activities, which are present in many dietary plants and herbal remedies. OBJECTIVES: The objective of this study is to investigate natural and synthetic coumarin derivatives with considerable anticancer capacity against three human cancer cell lines. MATERIALS AND METHODS: We synthesized 27 coumarin derivatives (mostly having 4-methyl moiety) and examined their cytotoxic effect on three human cancer cell lines, K562 (chronic myelogenous leukemia), LS180 (colon adenocarcinoma), and MCF-7 (breast adenocarcinoma) by MTT reduction assay. Screened compounds included 7-hydroxy-4-methylcoumarins (7-HMCs), 7-acetoxy-4-methylcoumarins (7-AMCs), and different dihydroxy-4-methylcoumarin (DHMC) and diacetoxy-4-methylcoumarin (DAMC) derivatives. Some compounds with methoxy, amine, and bromine substitutions were also examined. RESULTS: 7,8-DHMCs bearing alkyl groups at C3 position were the most effective subgroup, and of which, the most potent is compound 11, with an n-decyl chain at C3, which had IC50 values of 42.4, 25.2, and 25.1 µM against K562, LS180, and MCF-7 cells, respectively. The second most active subgroup was 7,8-DAMCs containing ethoxycarbonylmethyl and ethoxycarbonylethyl moieties at C3 position. Compound 27 (6-bromo-4-bromomethyl-7-hydroxycoumarin), the only derivative containing bromine also showed reasonable cytotoxic activities (IC50 range: 32.7-45.8 µM). DISCUSSION AND CONCLUSION: This structure-activity relationship (SAR) study of 4-methylcoumarins shows that further investigation of these derivatives may lead to the discovery of novel anticancer agents.

Cytotoxic activity assessment, QSAR and docking study of novel bis-carboxamide derivatives of 4-pyrones synthesized by Ugi four-component reaction.

Fourteen novel bis-carboxamide derivatives of 4-pyrones were designed and synthesized via Ugi four-component reactions of 4-pyrone carbaldehydes, aromatic amines, isocyanides and carboxylic acids. The cytotoxic activity of synthesized derivatives was evaluated against LS180, MCF-7 and HL-60 cell lines using MTT reduction assay. Synthesized compounds demonstrated strong cytotoxic potential in HL-60 cell line. Compound 12n was the most potent derivative with IC50 values of 16.1, 9.1 and 13.8 µM in LS180, MCF-7 and HL-60 cells, respectively. The results of MLR-QSAR study indicated that topological property of these derivatives directly influenced the cytotoxic potential in HL-60 cell line. Docking study of compounds, conducted for ATP binding site of Src tyrosine kinase, demonstrated the key H-bond interaction with Met 347 of the hinge region.

Electrochemical and catalytic investigations of dopamine and uric acid by modified carbon nanotube paste electrode.

The redox response of a modified carbon nanotube paste electrode of 2,2'-[1, 2-ethanediylbis(nitriloethylidyne)]-bis-hydroquinone was investigated. Mixture of dopamine (DA) and uric acid (UA), can be separated from one another with a potential difference of 180 mV between them at a scan rate of 25 mVs(-1) by cyclic voltammetry. These conditions are sufficient to allow determination of DA and UA both individually and simultaneously. The electrocatalytic currents increases linearly with the DA and UA concentrations in the ranges of 0.1-900 microM and 20-650 microM, and the detection limits for DA and UA, were 0.087 and 15 muM, respectively. The diffusion coefficient (D/cm(2) s(-1)=7.3x10(-6)) and the kinetic parameters such as the electron transfer coefficient, (alpha=0.32) and the heterogeneous rate constant, (k'/cm s(-1)=2.21x10(-3)) for DA were determined using electrochemical approaches.

Electrochemical behavior of ascorbic acid at a 2,2'-[3,6-Dioxa-1,8-octanediylbis(nitriloethylidyne)]-bis-hydroquinone carbon paste electrode.

Electrocatalytic oxidation of ascorbic acid (AA) at a carbon paste electrode, chemically modified 2,2'-[3,6-dioxa-1,8-octanediylbis(nitriloethylidyne)]-bis-hydroquinone, was thoroughly investigated. The results of cyclic voltammetry, double potential-step chronoamperometry, linear sweep voltammetry and differential pulse voltammetry (DPV) studies were used for the prediction of the mechanism of electrochemical oxidation of AA mediated with 2,2'-[3,6-dioxa-1,8-octanediylbis(nitriloethylidyne)]-bis-hydroquinone at the surface of the modified electrode. The diffusion coefficient (D = 2.45 x 10(-5) cm(2) s(-1)) and the kinetic parameters such as the electron transfer coefficient (alpha = 0.34) were also determined. The results of DPV using the 2,2'-[3,6-dioxa-1,8-octanediylbis(nitriloethylidyne)]-bis-hydroquinone-modified electrode were applied in a highly sensitive determination of AA in drug samples. A linear range of 3.0 x 10(-6) - 1.2 x 10(-4) M and the detection limit (3sigma) 3.8 x 10(-7) M were obtained for DPV determination of AA in buffered pH 7.00 solutions (0.1 M phosphate buffer).