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A series of C-10 acetal artemisinin dimers were synthesized using Sonogashira cross-coupling reaction. All these novel semisynthetic artemisinin dimers exhibited excellent growth inhibitory activity against Lung A-549 human cancer cell line.

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Ursolic acid (1), a natural pentacyclic triterpenic acid, afforded a variety of ring-C transformed products (5-11) when treated with N-bromosuccinimide under the influence of a range of protective groups and solvents. The synthesized compounds have been evaluated for cytotoxic activity against prostate PC 3, leukemia THP 1, cervical Hela and lung A-549 cancer cell lines. Among the tested analogs, compounds 5, 8, 9 and 10 showed potent activity against PC 3, THP 1 and Hela cell lines. Especially, compound 10 showed enhanced activity against the Hela cell line than the parent compound. Compounds 5, 8 and 9 showed comparable activities against PC 3 and THP 1 cell lines.

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Therapeutic management of cancer is a great clinical challenge and alternative medicines are being extensively explored to have integrated approach to cure cancer. Aegle marmelos (L.) Correa (Rutaceae) is known for its hypoglycaemic, radioprotective, antidiarrhoeal and many other pharmacological activities. The present study is designed to carryout pharmacognostic standardisation and evaluation of antiproliferative activity of the leaf extracts Aegle marmelos (L.) Correa (Rutaceae) and the chromatographic fractions of the most active extract. Hexane, petroleum ether, chloroform and ethanol extracts of the shade dried leaves were prepared by soxhelation and antiproliferative activity was assessed using human cancer cell lines of lung (A-549), colon (CoLo-05), ovary (IGR-OV-1), prostrate (PC3), leukaemia (THP-1) and breast (MCF-7) cancer. Bioactivity-derived fractionation was carried out for most active extract by column chromatography. The phytochemical studies indicated alkaloids, anthraquinones, terpenoids in the alcohol, chloroform extracts and tannins, terpenoids, reducing sugars in the petroleum ether and hexane extracts. Ethanol extract showed maximum inhibition in colon and breast carcinoma cell lines at a dose of 100 µg/ml. Column chromatography of the ethanol extract yielded five fractions. Out of this, fractions 2, 4 and 5 showed significant inhibition in leukaemia cell line with IC50 of 12.5, 86.2 and >100 µg/ml for fractions 2, 4 and 5, respectively. High-performance thin layer chromatography of the fraction 2 revealed imperatorin as one of the major phytoconstituents. Among the different extracts investigated, ethanol extract exhibited significant antiproliferative activity and its fraction 2 containing furanocoumarin imperatorin showed antiproliferative activity against leukaemia cell line with IC50 of 12.5 µg/ml.

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PURPOSE: The study was designed to screen Sphaeranthus indicus, Ganoderma lucidum, and Urtica dioica for their anticancer activity against human cancer cell lines. Phytochemical screening of active extracts was also planned. METHODS: Petroleum ether, ethanolic, and aqueous extracts of S indicus Linn, G lucidum P Karst, and U dioica Linn were subjected to cytotoxicity studies using 7 different cancer cell lines. Potent cytotoxicity was noted in petroleum ether extract of S indicus (SIP), which inhibited proliferation of various cancer cell lines. Growth inhibition was determined by sulforhodamine B assay. Two biochemical markers, namely ß-sitosterol and 7-hydroxyfrullanolide were isolated and characterized using high-performance thin layer chromatography, melting point, Fourier transform infrared spectroscopy, nuclear magnetic resonance spectroscopy, and mass analysis. Cytotoxicity of isolated ß-sitosterol and 7-hydroxyfrullanolide were also determined. The IC(50) of SIP was calculated in the HL-60 cells and was found to be 53 µg/mL. Furthermore, SIP induced apoptosis in human leukemia HL-60 cells as measured by several biological end points. Cell cycle analysis and change in mitochondrial membrane potential was quantified by flow cytometry. Subsequently, using annexin V/PI assay, proportion of cells actively undergoing apoptosis was determined. Changes in DNA were observed by DNA ladder assay. RESULTS: SIP induced apoptotic bodies formation, induced DNA laddering, enhanced annexin-V-FITC binding of the cells, increased sub-G(0) DNA fraction, and induced loss of mitochondrial membrane potential (ΔΨm) in HL-60 cells. SIP also elevated the caspase 3 and caspase 9 levels in the HL-60 cells, which clearly indicates the involvement of the intrinsic proteins in inducing apoptosis. DISCUSSION: All the above parameters revealed that SIP induced apoptosis through the mitochondrial-dependent pathway in HL-60 cells. The criterion for anticancer activity in cytotoxicity assay was ≥70% growth inhibition at 100 µg/mL against at least 4 cell lines. As G lucidum and U dioica did not exhibit appreciable inhibitory activity against human cancer cell lines (less than 50%), they were not included in the study thereafter. The results established that SIP has apoptosis-inducing effect against HL-60 cells in vitro and is a promising candidate for further anticancer study. ß-Sitosterol and 7-hydroxyfrullanolide can be considered to be potent anticancer compounds isolated from SIP on the basis of present studies.

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In the present work, QSAR models for predicting the activities of ursolic acid analogs against human lung (A-549) and CNS (SF-295) cancer cell lines were developed by a forward stepwise multiple linear regression method using a leave-one-out approach. The regression coefficient (r(2)) and the cross-validation regression coefficient (rCV(2)) of the QSAR model for cytotoxic activity against the human lung cancer cell line (A-549) were 0.85 and 0.80, respectively. The QSAR study indicated that the LUMO energy, ring count, and solvent-accessible surface area were strongly correlated with anticancer activity. Similarly, the QSAR model for cytotoxic activity against the human CNS cancer cell line (SF-295) also showed a high correlation (r(2) = 0.99 and rCV(2) = 0.96), and indicated that dipole vector and solvent-accessible surface area were strongly correlated with activity. Ursolic acid analogs that were predicted to be active against these cancer cell lines by the QSAR models were semisynthesized and characterized on the basis of their (1)H and (13)C NMR spectroscopic data, and were then tested in vitro against the human lung (A-549) and CNS (SF-295) cancer cell lines. The experimental results obtained agreed well with the predicted values.

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A series of N-(2-anilino-pyridyl) linked 2-amino benzothiazoles (4a-n) and [1,2,4]triazolo [1,5-b]benzothiadiazine conjugates (5a-j) have been designed, synthesized and evaluated for their antiproliferative activity. Some of these compounds (4h-k, 4n, and 5e) have exhibited potent cytotoxicity specifically against human leukemia HL-60 cell lines with IC(50) values in the range of 0.08-0.70 µM. All these compounds were tested for their effects on the cell cycle perturbations and induction of apoptosis. Morphological evidences of apoptosis, including fragmentation of nuclei and inter nucleosomal DNA laddering formation were clearly observed after 24h exposure to compound 4i. Flow cytometry analysis revealed that compound 4i showed drastic cell cycle perturbations due to concentration dependant increase in the sub-G0 region which comprises of both the apoptotic and debris fraction, thus implying the extent of cell death. These compounds trigger the mitochondrial apoptotic pathway that results in the loss of mitochondrial membrane potential through activation of multiple caspases followed by activation of caspase-3, and finally cleavage of PARP. Further the mechanism of cell death was analysed by fluorescent microscopic analysis and also by scanning electron microscopy. The cytotoxicity of 4i correlated with induction of apoptosis, caspases activation and DNA damage and thus indicating the apoptotic pathway of anticancer effect of these compounds.

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Two series of compounds (5-14 and 15-23) based on the scaffolds of 2-(1,1-dioxido-4-phenyl-4Hbenzo[e][1,2,4]thiadiazin-3-yl)-N-(4-methoxyphenyl)hydrazinecarboxamide (5) and 2-((4-methoxyphenyl)amino)-10-phenyl-10H-benzo[e][1,2,4]triazolo[1,5-b][1,2,4]thiadiazine 5,5-dioxide (15) respectively, were designed and synthesized. These compounds were tested for anticancer activity against various cancer cell lines including lung, ovary, prostate, breast and colon cancers. They exhibited moderate to good inhibitory activity against the above cell lines and compound 9 was found to be the most active one from these two series. Further studies showed that cancer cell growth inhibition by compounds 22 and 23 could be in part due to the inhibition of tubulin polymerization, with the IC50 values of 4.70 and 5.25 µM, respectively.

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Although a number of chemicals have been isolated from Lantana camara, only a few have been evaluated for their biological significance. As part of our drug discovery program for cytotoxic agents from Indian medicinal plants, roots of L. camara L. were chemically investigated, which resulted in the isolation and identification of a cytotoxic agent, oleanolic acid (1b) as a major constituent. Oleanolic acid was converted into six semi-synthetic ester (2-7) and seven amide (8-14) derivatives. The ester derivatives (2-7) showed 3-6 times more selective activity than 1b against the human ovarian cancer cell line (IGR-OV-1), while amide derivatives 8-14 showed 16-53 times more selective activity against the human lung cancer cell line (HOP-62). Structure activity relationship within the ester (2-7) and amide (8-14) derivatives are discussed.

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