Antiproliferative Noscapinoids Bearing an Amidothiadiazole Scaffold as Apoptosis Inducers: Design, Synthesis and Molecular Docking.

Noscapine an FDA-approved antitussive agent. With low cytotoxicity with higher concentrations, noscapine and its derivatives have been shown to have exceptional anticancer properties against a variety of cancer cell lines. In order to increase its potency, in this study, we synthesized a series of new amido-thiadiazol coupled noscapinoids and tested their cytotoxicity in vitro. All of the newly synthesised compounds demonstrated potent cytotoxic potential, with IC50 values ranging from 2.1 to 61.2 µM than the lead molecule, noscapine (IC50 value ranges from 31 to 65.5 µM) across all cell lines, without affecting normal cells (IC50 value is>300 µM). Molecular docking of all these molecules with tubulin (PDB ID: 6Y6D, resolution 2.20 Å) also revealed better binding affinity (docking score range from -5.418 to -9.679 kcal/mol) compared to noscapine (docking score is -5.304 kcal/mol). One of the most promising synthetic derivatives 6aa (IC50 value ranges from 2.5 to 7.3 µM) was found to bind tubulin with the highest binding affinity (ΔGbinding is -28.97 kcal/mol) and induced apoptosis in cancer cells more effectively.

Kinesin-3 motors are fine-tuned at the molecular level to endow distinct mechanical outputs.

BACKGROUND: Kinesin-3 family motors drive diverse cellular processes and have significant clinical importance. The ATPase cycle is integral to the processive motility of kinesin motors to drive long-distance intracellular transport. Our previous work has demonstrated that kinesin-3 motors are fast and superprocessive with high microtubule affinity. However, chemomechanics of these motors remain poorly understood. RESULTS: We purified kinesin-3 motors using the Sf9-baculovirus expression system and demonstrated that their motility properties are on par with the motors expressed in mammalian cells. Using biochemical analysis, we show for the first time that kinesin-3 motors exhibited high ATP turnover rates, which is 1.3- to threefold higher compared to the well-studied kinesin-1 motor. Remarkably, these ATPase rates correlate to their stepping rate, suggesting a tight coupling between chemical and mechanical cycles. Intriguingly, kinesin-3 velocities (KIF1A > KIF13A > KIF13B > KIF16B) show an inverse correlation with their microtubule-binding affinities (KIF1A < KIF13A < KIF13B < KIF16B). We demonstrate that this differential microtubule-binding affinity is largely contributed by the positively charged residues in loop8 of the kinesin-3 motor domain. Furthermore, microtubule gliding and cellular expression studies displayed significant microtubule bending that is influenced by the positively charged insert in the motor domain, K-loop, a hallmark of kinesin-3 family. CONCLUSIONS: Together, we propose that a fine balance between the rate of ATP hydrolysis and microtubule affinity endows kinesin-3 motors with distinct mechanical outputs. The K-loop, a positively charged insert in the loop12 of the kinesin-3 motor domain promotes microtubule bending, an interesting phenomenon often observed in cells, which requires further investigation to understand its cellular and physiological significance.

Bisphenol A exposure induces neurobehavioral deficits and neurodegeneration through induction of oxidative stress and activated caspase-3 expression in zebrafish brain.

Bisphenol A (BPA) is noted for its adversative effects by inducing oxidative stress, carcinogenicity, neurotoxicity, inflammation, etc. However, the likely act of BPA in inducing neurodegenerative phenotypes remains elusive in the available literature. Hence, the present study was conducted to decipher the neurodegenerative potential of BPA in inducing Parkinson's disease like phenotypes in zebrafish. Zebrafish were subjected to chronic waterborne exposure to BPA for 56 days. Locomotor activities and neurobehavioral response were assessed by the NTDT (novel tank diving test), OFT (open field test), and LDPT (light-dark preference test). The oxidative stress markers and histopathological observation for pyknosis and chromatin condensation were carried out. Immunohistochemistry for activated caspase-3 and targeted proteins expression study was performed. The basic findings reveal that chronic BPA exposure significantly induces locomotor dysfunction through a significant decline in mean velocity and total distance traveled. As a measure of pyknosis and chromatin condensation, pyknotic and Hoechst positive neurons in telencephalon and diencephalon significantly increased by BPA exposure. A higher concentration of BPA adversely affects the neurobehavioral response, antioxidant status, and neuromorphology in zebrafish. Parkinson-relevant targeted protein expression viz. alpha-synuclein and LRRK2, were significantly upregulated, whereas tyrosine hydroxylase, NeuN, and Nurr1 were significantly downregulated in the zebrafish brain. As an indicator of cell death by apoptosis, the expression of activated caspase-3 was significantly increased in the BPA-exposed zebrafish brain. These basic results of the current study indicate that chronic waterborne exposure to BPA induces neuropathological manifestation leading to the development of motor dysfunction and Parkinsonism-like neurodegenerative phenotypes in zebrafish.

Synthesis and biological evaluation of novel biaryl type α-noscapine congeners.

Natural α-noscapine, a known antitussive drug, is also now known to possess weak anticancer efficacy with relatively safe toxicity profile. In this study, we report synthesis and evaluation of novel biaryl type α-noscapine congeners designed by adding aryl unit to the tetrahydroisoquinoline part of natural α-noscapine core. Palladium catalyzed Suzuki cross coupling of 9-bromo α-noscapine with aryl boronic acids was employed using mild and inexpensive reagents to attain desired noscapinoids 5a-g in excellent yields. Screening anti-proliferative activity for new noscapinoids 5b-g, on human cancer cell lines resulted three compounds 5b, 5d and 5f as potent analogues, active against human breast epithelial (MCF-7), human cervix cancer (HeLa) and human lung adenocarcinoma epithelial (A549) cell lines.

Molecular insight of isotypes specific ß-tubulin interaction of tubulin heterodimer with noscapinoids.

Noscapine and its derivatives bind stoichiometrically to tubulin, alter its dynamic instability and thus effectively inhibit the cellular proliferation of a wide variety of cancer cells including many drug-resistant variants. The tubulin molecule is composed of α- and ß-tubulin, which exist as various isotypes whose distribution and drug-binding properties are significantly different. Although the noscapinoids bind to a site overlapping with colchicine, their interaction is more biased towards ß-tubulin. In fact, their precise interaction and binding affinity with specific isotypes of ß-tubulin in the αß-heterodimer has never been addressed. In this study, the binding affinity of a panel of noscapinoids with each type of tubulin was investigated computationally. We found that the binding score of a specific noscapinoid with each type of tubulin isotype is different. Specifically, amino-noscapine has the highest binding score of -6.4, -7.2, -7.4 and -7.3 kcal/mol with αßI, αßII, αßIII and αßIV isotypes, respectively. Similarly 10 showed higher binding affinity of -6.8 kcal/mol with αßV, whereas 8 had the highest binding affinity of -7.2, -7.1 and -7.2 kcal/mol, respectively with αßVI, αßVII and αßVIII isotypes. More importantly, both amino-noscapine and its clinical derivative, bromo-noscapine have the highest binding affinity of -46.2 and -38.1 kcal/mol against αßIII (overexpression of αßIII has been associated with resistance to a wide range of chemotherapeutic drugs for several human malignancies) as measured using MM-PBSA. Knowledge of the isotype specificity of the noscapinoids may allow for development of novel therapeutic agents based on this class of drugs.

Islet Dimensions and Its Impact on the Cellular Composition and Insulin-Secreting Capacity: Insights Into the Role of Non-beta Cells.

Studies have underscored the significance of islet dimensions, encompassing i) the necessity for islets to maintain an optimal diameter to sustain functional activity; ii) larger islets exhibit an intermingled architecture of alpha and beta cells, enhancing functional activity through paracrine effects; iii) non-alpha/beta (NAB) cells play a significant role in regulating beta cells; and iv) there is a preferential loss of larger islets in cases of type 2 diabetes mellitus. To delve deeper into these aspects, the authors documented the cellular composition in islets of various dimensions and regions of the pancreas, along with their secreting capacity, using the expression of the myosin Va motor protein in nine non-diabetic adult human pancreases. The proportion of NAB cells was found to be higher in intermediate islets and significantly lower in smaller and larger islets. By comparing the differences in islet composition, where NAB cells increase from smaller to intermediate islets, leading to a decrease in the proportion of alpha and beta cells, and in larger islets, there is a higher proportion of beta and alpha cells similar to smaller islets, we propose the hypothesis that NAB cells proliferate as islets increase in size. Furthermore, in larger islets, these NAB cells convert into alpha and beta cells, resulting in the scattered, intermingled arrangement observed in larger islets. The higher intensity of myosin Va expression in the islets of the tail region, along with a similar proportion of NAB cells in intermediate islets of the tail region compared to larger islets, leads to decreased inhibitory stimuli to beta cells and an increased insulin-secreting capacity.

Probabilistic modelling is superior to deterministic approaches in the human health risk assessment: an example from a tribal stretch in central India.

This case drew national attention in 2018. About 100 people died and more than 300 hospitalized in a span of few years in a village of 1200 people in a tribal stretch in central India. Medical teams visiting the area reported severe renal failure and blamed the local eating and drinking habits as causative factors. This human health assessment based on geochemical investigations finds nitrate (NO3-) and fluoride (F-) pollution as well in village's groundwater. Both deterministic and probabilistic techniques are employed to decipher the contamination pathways and extent of contamination. Source apportionments of NO3- and F- and their relationship with other ions in groundwater are carried out through chemometric modelling. Latent factors controlling the hydrogeochemistry of groundwater too are explored. While hazard quotients ([Formula: see text]) of the chemical parameters ([Formula: see text] and [Formula: see text]) identify ingestion as the prominent pathway, the calculated risk certainty levels (RCL) of the hazard index (HI) values above unity are compared between the deterministic and probabilistic approaches. Deterministic model overestimates the HI values and magnify the contamination problems. Probabilistic model gives realistic results that stand at infants ([Formula: see text] = 34.03%, [Formula: see text] = 24.17%) > children ([Formula: see text] = 23.01%, [Formula: see text] = 10.56%) > teens ([Formula: see text] = 13.17%, [Formula: see text] = 2.00%) > adults ([Formula: see text] = 11.62%, [Formula: see text] = 1.25%). Geochemically, about 90% of the samples are controlled by rock-water interaction with Ca2+-Mg2+-HCO3- (~ 56%) as the dominant hydrochemical facies. Chemometric modelling confirms Ca2+, Mg2+, HCO3-, F-, and SO42- to originate from geogenic sources, Cl- and NO3- from anthropogenic inputs and Na+ and K+ from mixed factors. The area needs treated groundwater for human consumption.

Substrate-directed Synthesis of Isocoumarin and 3-Ylidenephthalide Conjugated Noscapinoids and their Antiproliferative Activities.

A series of new noscapinoids designed; synthesized and assessed whether its 3-ylidenephthalide and isocoumarin conjugates improved cytotoxicity. Cu-catalysed Sonogashira coupling of N-propargyl noscapine with 2-bromobenzoic acids followed by in-situ substrate-directed 5-exo-dig or 6-endo-dig cyclization produced 3-ylidenephthalide 6 a-6 f and isocoumarin 7 a-7 h analogues in very good yields. In comparison to the lead drug, noscapine, all the newly synthesised derivatives exhibited strong cytotoxic potential in vitro with IC50 ranging from 5.4 µM to 39.5 µM across the evaluated panel of cancer cell lines, without harming normal cells (IC50 >300 µM).

Rational design of novel microtubule targeting anticancer drugs N-imidazopyridine noscapinoids: Chemical synthesis and experimental evaluation based on in vitro using breast cancer cells and in vivo using xenograft mice model.

We present N-imidazopyridine-noscapinoids, a new class of noscapine derivatives that bind to tubulin and exhibit antiproliferative activity against triple positive (MCF-7) and triple negative (MDA-MB-231) breast cancer cells. The N-atom of the isoquinoline ring of noscapine scaffold was altered in silico by coupling the imidazo [(Ye et al., 1998; Ke et al., 2000) 1,21,2-a] pyridine pharmacophore to rationally develop a series of N-imidazopyridine-noscapinoids (7-11) with high tubulin binding affinity. The predicted ΔGbinding of the N-imidazopyridine-noscapinoids 7-11 varied from -27.45 to -36.15 kcal/mol, a much lower value than noscapine with ΔGbinding -22.49 kcal/mol. The cytotoxicity of N-imidazopyridine-noscapinoids was evaluated using hormone dependent MCF-7, triple negative MDA-MB-231 breast cancer cell lines and primary breast cancer cells. The cytotoxicity of these compounds (represented as IC50 concentration) ranges between 4.04 and 33.93 µM against breast cancer cells without affecting normal cells (IC50 value > 952 µM). All the compounds (7-11) perturbed the cell cycle progression at G2/M phase and triggered apoptosis. Among all the N-imidazopyridine-noscapinoids, N-5-Bromoimidazopyridine-noscapine (9) showed promising antiproliferative activity and was selected for detailed investigation. The onset of apoptosis treated with 9 using MDA-MB-231 revealed morphological changes like cellular shrinkage, chromatin condensation, membrane blebbing, and apoptotic bodies formation. Along with elevated reactive oxygen species (ROS), there was a loss of mitochondrial membrane potential, suggesting induction of apoptosis to cancer cells. Compound 9 was also found to significantly regress the implanted tumour in nude mice as xenografts of MCF-7 cells without any apparent side effects after drug administration. We conclude that N-imidazopyridine-noscapinoids possess excellent potential as a promising drug for treating breast cancers.

Copper(I) mediated facile synthesis of potent tubulin polymerization inhibitor, 9-amino-α-noscapine from natural α-noscapine.

Facile synthesis of natural α-noscapine analogue, 9-amino-α-noscapine, a potent inhibitor of tubulin polymerization for cancer therapy, is achieved via copper(I) iodide mediated in situ aromatic azidation and reduction of 9-bromo-α-noscapine (obtained by bromination of natural α-noscapine) with NaN(3) in DMSO at 130°C in the presence of L-proline as an amino acid promoter. The protocol developed here avoided isolation of 9-azido-α-noscapine and did not cleave the sensitive C-C bond between two heterocyclic phthalide and isoquinoline units.

In silico inspired design and synthesis of a novel tubulin-binding anti-cancer drug: folate conjugated noscapine (Targetin).

Our screen for tubulin-binding small molecules that do not depolymerize bulk cellular microtubules, but based upon structural features of well known microtubule-depolymerizing colchicine and podophyllotoxin, revealed tubulin binding anti-cancer property of noscapine (Ye et al. in Proc Natl Acad Sci USA 95:2280-2286, 1998). Guided by molecular modelling calculations and structure-activity relationships we conjugated at C9 of noscapine, a folate group-a ligand for cellular folate receptor alpha (FRα). FRα is over-expressed on some solid tumours such as ovarian epithelial cancers. Molecular docking experiments predicted that a folate conjugated noscapine (Targetin) accommodated well inside the binding cavity (docking score -11.295 kcal/mol) at the interface between α- and ß-tubulin. The bulky folate moiety of Targetin is extended toward lumen of microtubules. The binding free energy (ΔG (bind)) computed based on molecular mechanics energy minimization was -221.01 kcal/mol that revealed favourable interaction of Targetin with the receptor. Chemical synthesis, tubulin-binding experiments, and anti-cancer activity in vitro corroborate fully well with the molecular modelling experiments. Targetin binds tubulin with a dissociation constant (K (d) value) of 149 ± 3.0 µM and decreases the transition frequencies between growth and shortening phases of microtubule assembly dynamics at concentrations that do not alter the total polymer mass. Cancer cells in general were more sensitive to Targetin compared with the founding compound noscapine (IC(50) in the range of 15-40 µM). Quite strikingly, ovarian cancer cells (SKOV3 and A2780), known to overexpress FRα, were much more sensitive to targetin (IC(50) in the range of 0.3-1.5 µM).

Utilization of intron-flanking EST-specific markers in the genetic characterization of Artemisia annua genotypes from the trans-Himalayan region of Ladakh, India.

Genetic variation was assessed utilizing intron-flanking EST-specific markers among genotypes of Artemesia annua collected from two sampling sites viz. Nubra (9,600 ft) and Leh (11,500 ft) valleys of the trans-Himalayan region, Ladakh, India. The available ESTs (3,60,906) sequences of A. annua were aligned with the genomic sequences of Arabidopsis to developed 'intron-flanking' EST-PCR based primers. These primers anneal with the conserved region of exon (flanking to the intron) and amplified the introns. Out of the 39 primers selected and tested on 20 genotypes of A. annua, we successfully exploited 81 codominant intron length polymorphism (ILP) markers, with an average of 2.08 markers per primer and 92.04% polymorphism detection. Clustering of genotypes revealed distribution of genotypes into 2 distinct clusters with respect to their site of collection. Significantly, this study demonstrates that Arabidopsis genome sequence can be useful in developing gene-specific PCR-based markers for other non-model plant species like A. annua in the absence of genome sequences.

Single-Molecule Analysis of Sf9 Purified Superprocessive Kinesin-3 Family Motors.

A complex cellular environment poses challenges for single-molecule motility analysis. However, advancement in imaging techniques have improved single-molecule studies and has gained immense popularity in detecting and understanding the dynamic behavior of fluorescent-tagged molecules. Here, we describe a detailed method for in vitro single-molecule studies of kinesin-3 family motors using Total Internal Reflection Fluorescence (TIRF) microscopy. Kinesin-3 is a large family that plays critical roles in cellular and physiological functions ranging from intracellular cargo transport to cell division to development. We have shown previously that constitutively active dimeric kinesin-3 motors exhibit fast and superprocessive motility with high microtubule affinity at the single-molecule level using cell lysates prepared by expressing motor in mammalian cells. Our lab studies kinesin-3 motors and their regulatory mechanisms using cellular, biochemical and biophysical approaches, and such studies demand purified proteins at a large scale. Expression and purification of these motors using mammalian cells would be expensive and time-consuming, whereas expression in a prokaryotic expression system resulted in significantly aggregated and inactive protein. To overcome the limitations posed by bacterial purification systems and mammalian cell lysate, we have established a robust Sf9-baculovirus expression system to express and purify these motors. The kinesin-3 motors are C-terminally tagged with 3-tandem fluorescent proteins (3xmCitirine or 3xmCit) that provide enhanced signals and decreased photobleaching. In vitro single-molecule and multi-motor gliding analysis of Sf9 purified proteins demonstrate that kinesin-3 motors are fast and superprocessive akin to our previous studies using mammalian cell lysates. Other applications using these assays include detailed knowledge of oligomer conditions of motors, specific binding partners paralleling biochemical studies, and their kinetic state.

Development of 1,3-diynyl derivatives of noscapine as potent tubulin binding anticancer agents for the management of breast cancer.

We developed 1,3-diynyl derivatives of noscapine (an opium alkaloid) through in silico combinatorial approach and screened out a panel of promising derivatives that bind tubulin and display anticancer activity. The selected derivatives such as 9-4-tBu-Ph-Diyne (20p), 9-3,4-Di-Cl-Diyne (20k) and 9-3,4-Di-F-Diyne (22s) noscapinoids revealed improved predicted binding energy of -6.676 kcal/mol for 20p, -7.294 kcal/mol for 20k and -7.750 kcal/mol for 20s respectively in comparison to noscapine (-5.246 kcal/mol). These 1,3-diynyl derivatives (20p, 29k and 20s) were strategically synthesized in high yields by regioselective modification of noscapine scaffold and HPLC purified (purity is >96%). The decrease in intrinsic fluorescence of purified tubulin to 8.39%, 17.39% and 25.47% by 20p, 20k and 20s respectively, compared to control suggests their binding capability to tubulin. Their cytotoxicity activity was validated based on cellular studies using two human breast adenocarcinoma (MCF-7 and MDA-MB-231), a panel of primary breast tumor cells and one normal human embryonic kidney cell (293 T). The 1,3-diynyl noscapinoids, 20p, 20k and 20s inhibited cellular proliferation in all the cancer cells that ranged between 6.2 and 38.9 µM, without affecting the normal healthy cells (cytotoxicity is <5% at 100 µM). Further, these novel derivatives arrest cell cycle in the G2/M-phase, followed by induction of apoptosis to cancer cells. Thus, we conclude that 1,3-diynyl-noscapinoids have great potential to be a novel therapeutic agent for breast cancers.Communicated by Ramaswamy H. Sarma.

Folate receptor-targeted PLGA-PEG nanoparticles for enhancing the activity of genistein in ovarian cancer.

Genistein (GEN), a natural isoflavone possesses a wide range of pharmacological properties and nutraceutical applications. GEN has been studied for its anticancer activity against different types of cancers, but its use in clinical practice is limited due to its low water solubility, rapid metabolism and excretion, lack of cancer cell targeting and poor bioavailability. In the present study, we investigated folate receptor-targeted and PEGylated poly(lactide-co-glycolide) nanoparticles (PLGA-PEG-FA NPs) containing GEN for targeted delivery to ovarian cancer cells. PLGA-PEG and PLGA-PEG-FA polymer conjugates were synthesized and characterized. Nano-precipitation method was employed for the fabrication of NPs of PLGA, PLGA-PEG and PLGA-PEG-FA containing GEN. GEN containing PLGA-PEG and PLGA-PEG-FA NPs prepared were small (104.17 ± 1.61 and 125.41 ± 3.11 nm, respectively) and exhibited sustained release of GEN for around six days. Folate-decorated PLGA-PEG NPs showed increased cellular uptake in comparison to non-targeted PLGA-PEG NPs. The GEN containing PLGA-PEG-FA NPs showed superior anticancer activity than non-targeted PLGA and PLGA-PEG NPs in folate receptor-overexpressing ovarian cancer cell line, SKOV-3. The IC50 of GEN, GEN encapsulated NPs of PLGA, PLGA-PEG and PLGA-PEG-FA were 51.48, 26.70, 23.43 and 11.98 µg/ml, respectively. Folate-targeted PLGA nanoparticles could be developed for potential target-specific delivery of GEN in the treatment of ovarian cancer.

In silico design of novel tubulin binding 9-arylimino derivatives of noscapine, their chemical synthesis and cellular activity as potent anticancer agents against breast cancer.

We present a series of 9-arylimino derivatives of noscapine (an antitussive plant alkaloid) that binds to tubulin and displaying anticancer activity against a panel of breast cancer cells. These compounds were rationally designed by coupling of Schiff base containing imine groups at position-9 of the isoquinoline ring of noscapine. Based on a combination of Glide docking and free energy of binding (FEB) calculation, we have screened a panel of three 9-compounds, 12-14 with improved binding affinity with tubulin compared to noscapine. The predicted FEB is -6.166 kcal/mol for 12, -6.411 kcal/mol for 13 and -7.512 kcal/mol for 14. In contrast, the predicted FRB of noscapine is -5.135 kcal/mol. These novel derivatives were strategically synthesized and validated their anticancer activity based on cellular studies using two human breast adenocarcinoma, MCF-7 and MDAMB-231, as well as with a panel of primary breast tumor cells isolated from patients. Interestingly, all these derivatives inhibited cellular proliferation in all the cancer cells that ranged between 3.6 and 26.4 µM, which is 11.02-2.03 fold lower than that of noscapine. Unlike previously reported derivatives of noscapine that arrest cells in the S-phase, these novel derivatives effectively inhibit proliferation of cancer cells, arrest the cell cycle in the G2/M-phase and induced apoptosis. Thus, we conclude that 9-arylimino derivatives of noscapine have great potential to be a novel therapeutic agent for breast cancers.Communicated by Ramaswamy H. Sarma.

Rational design, synthesis and biological evaluations of amino-noscapine: a high affinity tubulin-binding noscapinoid.

Noscapine and its derivatives are important microtubule-interfering agents shown to have potent anti-tumor activity. The binding free energies (ΔG (bind)) of noscapinoids computed using linear interaction energy (LIE) method with a surface generalized Born (SGB) continuum solvation model were in agreement with the experimental ΔG (bind) with average root mean square error of 0.082 kcal/mol. This LIE-SGB model guided us in designing a novel derivative of noscapine, amino-noscapine [(S)-3-((R)-9-amino-4-methoxy-6-methyl-5,6,7,8-tetrahydro [1, 3] dioxolo[4,5-g]isoquinolin-5-yl)-6,7-dimethoxy isobenzo-furan-1(3H)-one] that has higher tubulin binding activity (predicted ΔG (bind) = -6.438 kcal/mol and experimental ΔG (bind) = -6.628 kcal/mol) than noscapine, but does not significantly change the total extent of the tubulin subunit/polymer ratio. The modes of interaction of amino-noscapine with the binding pocket of tubulin involved three hydrogen bonds and are distinct compared to noscapine which involved only one hydrogen bond. Also the patterns of non-bonded interactions are albeit different between both the lignads. The 'blind docking' approach (docking of ligand with different binding sites of a protein and their evaluations) as well as the reasonable accuracy of calculating ΔG (bind) using LIE-SGB model constitutes the first evidence that this class of compounds binds to tubulin at a site overlapping with colchicine-binding site or close to it. Our results revealed that amino-noscapine has better anti-tumor activity than noscapine.

Rational design of novel N-alkyl amine analogues of noscapine, their chemical synthesis and cellular activity as potent anticancer agents.

The scaffold structure of noscapine (an antitussive plant alkaloid) was modified by inducting N-aryl methyl pharmacophore at C-9 position of the isoquinoline ring to rationally design and screened three novel 9-(N-arylmethylamino) noscapinoids, 15-17 with robust binding affinity with tubulin. The selected 9-(N-arylmethylamino) noscapinoids revealed improved predicted binding energy of -6.694 kcal/mol for 15, -7.118 kcal/mol for 16 and -7.732 kcal/mol for 17, respectively in comparison to the lead molecule (-5.135 kcal/mol). These novel derivatives were chemically synthesized and validated their anticancer activity based on cellular studies using two human breast adenocarcinoma, MCF-7 and MDA-MB-231, as well as with a panel of primary breast tumor cells. These derivatives inhibited cellular proliferation in all the cancer cells that ranged between 3.2 and 32.2 µM, which is 11.9 to 1.8 fold lower than that of noscapine. These novel derivatives effectively arrest the cell cycle in the G2/M phase followed by apoptosis and appearance of apoptotic cells. Thus, we conclude that 9-(N-arylmethyl amino) noscapinoids, 15-17 have a high probability to be a novel therapeutic agent for breast cancers.

A new indexing approach for evaluating heavy metal contamination in groundwater.

Three indexing methods, namely heavy metal pollution index (HPI), contamination index (Cd) and heavy metal evaluation index (HEI), are commonly used for heavy metal evaluation in groundwater. These methods have several limitations. In HPI, 14 out of 15 groundwater samples collected in the study area of Nalagarh valley, Himachal Pradesh, India qualify for drinking purposes with their values varying between 10.73 and 107.50 (critical limit = 100), while in Cd, the same number of samples (>90%) are rejected as their values (Cd = 1.31-37.87) exceed the critical limit of 3. HEI varies from 10.31 to 46.87 with a mean of 26.06, but since it does not have a defined critical limit, quality assessment depends on worker's discretion. It thus becomes very confusing as to which indexing method to use. To overcome this dilemma, a very simple indexing method called 'heavy metal contamination index (HCI)' has been developed on the basis of assigning weight to each heavy metal parameter. A new classification system with six distinct water classes of different uses too has been proposed considering the regulatory limits, human health risk and toxicity of the violator parameters. Regression analysis confirms that HCI has larger number of significantly correlated key parameters compared to the other three indices. Chemometric techniques confirm that Cr, Cu, Fe, Mn and Zn are derived from lithogenic inputs and As, Cd, Ni and Pb from anthropogenic sources. HCI when integrated with Cluster Analysis gives the best possible results in identifying factors that influence the various water classes.

Correspondence of ISSR and RAPD markers for comparative analysis of genetic diversity among different apricot genotypes from cold arid deserts of trans-Himalayas.

The phylogenetic relationships of 36 locally grown Prunus armeniaca genotypes which are collected from nine sampling sites from two valleys viz. Nubra (9,600 ft) and Leh (11,500 ft) of trans-Himalayan region were analyzed using 31 PCR markers (20 RAPDs and 11 ISSRs). This is the first report of molecular genetic diversity studies in apricot from this region of the world. RAPD analysis yielded 139 fragments, of which 136 were polymorphic, with an average of 6.8 polymorphic fragments per primer. ISSR analysis produced 58 bands, of which 56 were polymorphic, with an average of 5.09 polymorphic fragments per primer. The primers based on (CT)n produced maximum number of bands (nine) while, (AT)n and many other motifs gave no amplification. RAPD markers were found more efficient with regards to polymorphism detection, as they detected 97.84 % as compared to 96.5 % for ISSR markers. Clustering of genotypes within groups was not similar when RAPD and ISSR derived dendrogram were compared, whereas the pattern of clustering of the genotypes remained more or less the same in RAPD and combined data of RAPD + ISSR. The results of PCA analysis were comparable to the cluster analysis. These analyses, allowed us to identify the groups corresponding to the two apricot collection sites.