Computer-aided drug design and virtual screening of targeted combinatorial libraries of mixed-ligand transition metal complexes of 2-butanone thiosemicarbazone.

The present paper deals with in silico evaluation of 32 virtually designed transition metal complexes of 2-butanone thiosemicarbazone and N,S,O containing donor hetero-ligands namely py, bpy, furan, thiophene, 2-picoline, 1,10-phenanthroline, piperazine and liquid ammonia. The complexes were designed with a view to assess their potential anticancer, antioxidant and antibacterial activity. The absorption, distribution, metabolism, excretion and toxicity (ADMET) properties of the chosen ligands were calculated by admetSAR software. Metabolic sites of different ligands likely to undergo metabolism were predicted using Metaprint 2D. The proposed complexes were also evaluated for their drug-like quality based on Lipinski's, Veber, Ghose and leadlikeness filters. Druglikeness and toxicity potential were predicted by OSIRIS property explorer. The pharmacokinetic properties and bioactivity scores were calculated by Molinspiration tool. Bioactivity scores of the complexes were predicted for drug targets including enzymes, nuclear receptors, kinase inhibitors, G-protein coupled receptor ligands and ion channel modulators. Molecular docking of selected Fe(II) mixed-ligand complexes was performed using AutoDock version 4.2.6 and i-GEMDOCK version 2.1 with two target proteins namely Ribonucleotide reductase (RR) and Topoisomerase II (Topo II). The results were compared with three standard reference drugs viz. Doxorubicin HCl, Letrozole (anticancer) and Tetracycline (antibiotic). Multivariate data obtained were analyzed using principal component analysis (PCA) for visualization and projection as scatter and 3D plots. Positive results obtained for hetero-ligands using admetSAR version 1.0 indicated good absorption and transport kinetics of the hetero-ligand complexes through the human intestine and blood-brain barrier. The hetero-ligands were predicted to have no associated mutagenic effect(s) also. However, none of the hetero-ligands was predicted to be Caco-2 (human colon cancer cell line) permeable. Most of the hetero-ligands and the parent ligand (2-butanone thiosemicarbazone) were predicted to undergo Phase-I metabolism prior to excretion using MetaPrint2D software. Pharmacokinetic evaluation of the proposed complexes revealed that all complexes displayed drug-like character and were predicted to have no apparent toxic side-effects. All the proposed complexes showed moderate to good biological activity scores (-5.0 to 0.0). Mixed complexes with bpy, 2-picoline and 1,10-phenanthroline showed significant bioactivity scores (as enzyme inhibitors) in the range 0.02-0.13. Likewise, good docking scores were obtained for Fe (II) complexes with the same ligands. [FeL(2-pic)2] displayed the lowest binding energy (-6.47 kcal/mol) with respect to Topo II followed by [FeL(py)2] (-6.14 kcal/mol) as calculated by AutoDock version 4.2.6. With respect to binding with RR, [FeL(2--pic)2] again displayed the lowest binding energy (-7.21 kcal/mol) followed by [FeL(py)2] (-5.96 kcal/mol). On the basis of docking predictions and various other computational evaluations, four mixed-ligand complexes of Fe in +2 oxidation state with py, bpy, 2--picoline and 1,10-phenanthroline were synthesized with 2-butanone thiosemicarbazone. All the synthesized Fe complexes were characterized using various spectroscopic techniques and tested for their potential anticancer activity in vitro against human breast carcinoma cell line MDA-MB 231 and human lung carcinoma cell line A549 cell line using MTT assay. [FeL(2-pic)2], [FeL(bpy)], and [FeL(py)2] were found to exhibit significant antiproliferative activity with IC50 values in the range of 80-100 µM against breast and lung cancer cells. The synthesized Fe complexes also displayed mild antioxidant activities. The synthesized and studied Fe complexes have the potential for development into future anticancer agents if analyzed and modified further for improvement of their ADMET, solubility and permeability criteria set for potential drug-candidates.

ROS mediated pro-apoptotic effects of Tinospora cordifolia on breast cancer cells.

The inevitable development of chemoresistance and unmanageable side effects are the major therapeutic challenges in management of breast cancer imposing an urgent need for identification of novel therapeutic agents. In the present investigation, we report anti-proliferative activity of chloroform fraction of Tinospora cordifolia (TcCF), an Ayurvedic medicinal plant, on breast cancer cells. We found that TcCF inhibited growth of breast cancer cells, MDA-MB-231 and MCF-7. More interestingly, we observed TcCF treatment increased intra-cellular ROS levels, altered expression of pro and anti-apoptotic genes, decreased colony formation ability and induced apoptosis in breast cancer cells. We also found that inhibition of ROS abrogated TcCF induced apoptosis in breast cancer cells, emphasizing the role ROS in TcCF induced breast cancer cell death. Furthermore, we identified the presence of pharmacologically active compounds like rutin and quercetin which account for the anti-cancer property of TcCF against breast cancer cells. These data show TcCF is a promising anti-cancer agent against breast cancer cells.

Anticancer and Antioxidant activity of Zingiber officinale Roscoe rhizome.

Dietary components present in foods, spices and herbs are source of natural compounds viz. phenols, flavonoids, tocopherols, ascorbic acid and carotenoids with potential benefits. Ginger is one such herb commonly used throughout the world as a spice for dietary as well as medicinal purpose since ancient period. Here, we investigated the methanolic extract of Zingiber officinale rhizome (ZOME) for anticancer activity against human cervical cancer HeLa cells and breast cancer MDA-MB-231 cells and antioxidant activity using 1,1-diphenyl-2-picryl hydroxyl (DPPH) scavenging assay, 2,2'-azinobis-3-ethylbenzothiozoline-6-sulfonic acid (ABTS) cation decolorization test. Antiproliferative activity was substantiated by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) and colony formation assay for cell viability and cell proliferation, Hoechst staining was performed to examine apoptosis. Our results demonstrated that ZOME inhibited the proliferation and colony formation in HeLa and MDA-MB-231 cells, in a dose- and time-dependent manner and induced typical changes in nuclear morphology, chromatin condensation and fragmentation, membrane shrinkage and blebbing in both cells indicated apoptotic property of Z. officinale. ZOME exhibited potent antiradical activity against DPPH and ABTS. On the basis of the results of the present study, it may be suggested that Z. officinale has promising anticancer and antioxidant properties. Since, Z officinale has been commonly used throughout the world as a spice for dietary as well as for medicinal purposes since prehistoric times. Therefore, enriched use of Z. officinale as dietary material could be recommended in ethno-medicine for the management of cervical and breast cancers. Moreover, further studies are needed to isolate and characterize the potent compounds for further adjuvant therapy against such malignancies.

Identification of Anticancer and Antioxidant phytoconstituents from chloroform fraction of Solanum nigrum L. berries using GC-MS/MS analysis.

Solanum nigrum is a traditional Indian plant acclaimed for its medicinal properties since antiquity. Among all plant parts fruit berries have shown to be most pharmacologically active part. In the present investigation, we tried to characterize the bioactive principles of chloroform fraction of S. nigrum (CFSn) fruit berries using GC-MS analysis. We could identify 29 compounds belonging to different chemical classes viz. alkaloids, flavonoids, carbohydrates, glycosides, phytosterols, proteins, phenolic compounds, and saponins. More specifically, we found two novel phenolic compounds, benzoiisovanillin and syringic acid (4-hydroxy-3, 5-dimethoxybenzoic acid), which may be responsible for its pharmacological properties. Our phytochemical investigation of CFSn was well supported by its total phenolic content and antioxidant activity which we evaluated subsequently. Further, we investigated the anticancer activity against breast cancer cell lines (MDA-MB-231 and MCF-7) as well. Our in vitro results indicated that CFSn exhibited significant antiproliferative activity against both these cell lines and due induction of cancer cell death through apoptosis. Our study emphasizes the need for isolation and characterization of specific bioactive compounds of CFSn and determination of their mechanism of action responsible for its anticancer activity in breast cancer cells.

Simultaneous Quantification of Syringic Acid and Kaempferol in Extracts of Bergenia Species Using Validated High-Performance Thin-Layer Chromatographic-Densitometric Method.

A rapid, sensitive, selective and robust quantitative densitometric high-performance thin-layer chromatographic method was developed and validated for separation and quantification of syringic acid (SYA) and kaempferol (KML) in the hydrolyzed extracts of Bergenia ciliata and Bergenia stracheyi. The separation was performed on silica gel 60F254 high-performance thin-layer chromatography plates using toluene : ethyl acetate : formic acid (5 : 4: 1, v/v/v) as the mobile phase. The quantification of SYA and KML was carried out using a densitometric reflection/absorption mode at 290 nm. A dense spot of SYA and KML appeared on the developed plate at a retention factor value of 0.61 ± 0.02 and 0.70 ± 0.01. A precise and accurate quantification was performed using linear regression analysis by plotting the peak area vs concentration 100-600 ng/band (correlation coefficient: r = 0.997, regression coefficient: R(2) = 0.996) for SYA and 100-600 ng/band (correlation coefficient: r = 0.995, regression coefficient: R(2) = 0.991) for KML. The developed method was validated in terms of accuracy, recovery and inter- and intraday study as per International Conference on Harmonisation guidelines. The limit of detection and limit of quantification of SYA and KML were determined, respectively, as 91.63, 142.26 and 277.67, 431.09 ng. The statistical data analysis showed that the method is reproducible and selective for the estimation of SYA and KML in extracts of B. ciliata and B. stracheyi.