The alkaloid cryptolepine as a source of polyadenylate targeting therapeutic agent: Induction of self-assembly in the polyadenylate moiety.

RNAs have become a well-known target for chemotherapeutic agents in the recent years. The tails of most eukaryotic m-RNA are characterized by the presence of a long polyadenylate sequence which plays an important role in its growth and maturation. This lays emphasis on development of molecular probes that target the polyadenylate sequence.

Comparative binding studies on the interaction of the indoloquinoline alkaloid cryptolepine with the B and the non-canonical protonated form of DNA: A spectroscopic insight.

Background: Low pH induced nucleic acid polymorphism and the interaction of naturally occurring small molecules with different polymorphic forms of DNA have been the focus in developing new drugs. Recent studies have revealed that low pH plays an active role in growth and development of cancer cells. Our target is to find whether and how the indoloquinoline alkaloid cryptolepine (CRP) interact with different polymorphic forms of natural DNA, in hope to explore this group of alkaloids as new therapeutics.

Influence of position of hydroxyl group of flavonoids on their binding with single stranded polyriboadenylic acid: A spectroscopic evaluation.

Single stranded polyriboadenylic acid [poly (rA)] has been accepted widely as a suitable drug target owing to its vital role in the development of cancer since it controls gene expression during cell growth and differentiation. The biological properties of poly (rA) depend on its structural morphology. Pharmacologically active flavonoids can act as suitable binders to poly (rA) and significantly change its biophysical properties.

In-depth investigation of the binding of flavonoid taxifolin with bovine hemoglobin at physiological pH: Spectroscopic and molecular docking studies.

The use of bioactive flavonoids as drugs has long mesmerized the scientific world. Their small size and planar structure enables them to interact with limitless substrates especially biomolecules. Taxifolin is a flavonoid well known for its anti-oxidizing and metal chelating properties.

Elucidation of the association of potential chemotherapeutic alkaloid chelerythrine with bovine hemoglobin by experimental probing and molecular docking simulation.

Chelerythrine (CHL) is a pharmacologically important molecule that appears in positively charged iminium and neutral alkanolamine form on varying the pH. Association of bovine hemoglobin (BHb) with iminium and alkanolamine forms of CHL is explored employing several spectroscopic and theoretical tools. Our results revealed that iminium form of CHL shows greater binding affinity than the neutral alkanolamine form, with nearly one binding site on the protein for both forms.

Molecular insight into the binding aspects of benzo[c]phenanthridine alkaloid nitidine with bovine hemoglobin: A biophysical exploration.

The association of a putative bioactive alkaloid nitidine (NIT) with blood protein bovine hemoglobin (BHb) was investigated by employing various biophysical and molecular docking techniques. NIT binding to BHb was first characterized by hypochromic effect on the Soret band absorption of BHb from spectrophotometric studies. Spectrofluorimetric titration and unchanged fluorescence lifetime of BHb confirmed ground state complexation followed by the static nature of the emission quenching mechanism of the protein induced by NIT.

Spectroscopic, photophysical and theoretical insight into the chelation properties of fisetin with copper (II) in aqueous buffered solutions for calf thymus DNA binding.

Fisetin (FTN) and its metal chelates are critically important since this bioflavonoid possesses wide range of pharmacological properties. Usually, metal binding property enhances the pharmaceutical activity of FTN. Thus in this report, we investigated the complexation of FTN with biologically essential metal ion Cu and further examined the effect of such complexation on calf thymus DNA (CT DNA) binding in comparison with free FTN.

Structural alteration of low pH, low temperature induced protonated form of DNA to the canonical form by the benzophenanthridine alkaloid nitidine: Spectroscopic exploration.

Polymorphism of DNA plays a very important part of research relating to the drug-DNA interactions. Here main focus of our investigation is to monitor the interaction of the benzophenanthridine plant alkaloid, nitidine (NIT) with two different forms of DNA i.e.

Domain-Specific Association of a Phenanthrene-Pyrene-Based Synthetic Fluorescent Probe with Bovine Serum Albumin: Spectroscopic and Molecular Docking Analysis.

In this report, the interaction between a phenanthrene-pyrene-based fluorescent probe (PPI) and bovine serum albumin (BSA), a transport protein, has been explored by steady-state emission spectroscopy, fluorescence anisotropy, far-ultraviolet circular dichroism (CD), time-resolved spectral measurements, and molecular docking simulation study. The blue shift along with emission enhancement indicates the interaction between PPI and BSA. The binding of the probe causes quenching of BSA fluorescence through both static and dynamic quenching mechanisms, revealing a 1:1 interaction, as delineated from Benesi-Hildebrand plot, with a binding constant of ∼10 M, which is in excellent agreement with the binding constant extracted from fluorescence anisotropy measurements.

Targeting human telomeric DNA quadruplex with novel berberrubine derivatives: insights from spectroscopic and docking studies.

Study on bioactive molecules, capable of stabilizing G-Quadruplex structures is considered to be a potential strategy for anticancer drug development. Berberrubine (BER) and two of its analogs bearing alkyl phenyl and biphenyl substitutions at 13-position were studied for targeting human telomeric G-quadruplex DNA sequence. The structures of berberrubine and analogs were optimized by density functional theory (DFT) calculations.

Role of hydroxyl groups in the B-ring of flavonoids in stabilization of the Hoogsteen paired third strand of Poly(U).Poly(A)*Poly(U) triplex.

We have reported the interaction of two flavonoids namely quercetin (Q) and morin (M) with double stranded poly(A).poly(U) (herein after A.U) and triple stranded poly(U).

Multispectroscopic and Theoretical Exploration of the Comparative Binding Aspects of Bioflavonoid Fisetin with Triple- and Double-Helical Forms of RNA.

The interactions of RNA triplex (U.A*U) and duplex (A.U) with naturally occurring flavonoid fisetin (FTN) have been examined at pH 7.

Self-structure assembly in single stranded polyriboadenylic acid by benzophenanthridine alkaloid: Spectroscopic and calorimetric exploration.

Present study allows us a better understanding of the interaction of nitidine, a benzophenanthridine alkaloid with single stranded polyriboadenylic acid [ss-poly (rA)]. The interaction leads to self-structure induction in ss-poly (rA) under the experimental condition of pH 7.0.

Third strand stabilization of poly(U)·poly(A)* poly(U) triplex by the naturally occurring flavone luteolin: A multi-spectroscopic approach.

Naturally occurring flavonoid luteolin (LTN) was found to interact with double stranded poly(A).poly(U) and triple stranded poly(U)·poly(A)*poly(U) with association constants of the order of 10M. The association was monitored by various spectroscopic and viscometric techniques.

Spectroscopic study on the binding of chelerythrine with duplex poly (rA): A model of RNA intercalation.

Here we have reported a detail study on the interaction of the benzophenanthridine alkaloid chelerythrine (CHL) with double stranded polyriboadenylic acid [ds poly (rA)] by exploiting various spectroscopic techniques. The alkaloid shows high binding affinity (binding constant is 1.10×10M) towards the double stranded RNA as revealed from Scatchard plot.

Inhibitory effects of the dietary flavonoid quercetin on the enzyme activity of zinc(II)-dependent yeast alcohol dehydrogenase: Spectroscopic and molecular docking studies.

A multispectroscopic exploration was employed to investigate the interaction between the metallo-enzyme alcohol dehydrogenase (ADH) from yeast with bioflavonoid quercetin (QTN). Here, we have characterized the complex formation between QTN and Zn in aqueous solution and then examined the effect of such complex formation on the enzymatic activity of a zinc(II)-dependent enzyme alcohol dehydrogenase from yeast. We have observed an inhibition of enzymatic activity of ADH in presence of QTN.

Micelle assisted structural conversion with fluorescence modulation of benzophenanthridine alkaloids.

In this study we have reported the anionic surfactant (Sodium dodecyl sulfate, SDS) driven structural conversion of two benzophenanthridine plant alkaloids namely Chelerythrine (herein after CHL) and Sanguinarine (herein after SANG). Both the alkaloids exist in two forms: the charged iminium and the neutral alkanolamine form. The iminium form is stable at low pH (<6.

An overview on the interaction of phenazinium dye phenosafranine to RNA triple and double helices.

Triple helical nucleic acids or triplex are formed from the combination of three oligonucleotides. In the double stranded form the base pairs are joined through Watson-Crick base pairing while the third strand of the triplex is joined through Hoogsteen base pairing. The Hoogsteen base paired strands are less stable compare to the Watson-Crick strands.

Molecular Aspects of the Interaction of Iminium and Alkanolamine Forms of the Anticancer Alkaloid Chelerythrine with Plasma Protein Bovine Serum Albumin.

The interaction between a quaternary benzophenanthridine alkaloid chelerythrine (herein after, CHL) and bovine serum albumin (herein after, BSA) was probed by employing various spectroscopic tools and isothermal titration calorimetry (ITC). Fluorescence studies revealed that the binding affinity of the alkanolamine form of the CHL is higher compared to the iminium counterpart. This was further established by fluorescence polarization anisotropy measurement and ITC.

Exploring the comparative binding aspects of benzophenanthridine plant alkaloid chelerythrine with RNA triple and double helices: a spectroscopic and calorimetric approach.

A comparative study on the interaction of a benzophenanthridine alkaloid chelerythrine (CHL) with RNA triplex poly(U).poly(A)*poly(U) (hereafter U.A*U, .

Deciphering the Positional Influence of the Hydroxyl Group in the Cinnamoyl Part of 3-Hydroxy Flavonoids for Structural Modification and Their Interaction with the Protonated and B Form of Calf Thymus DNA Using Spectroscopic and Molecular Modeling Studies.

Studies on the interaction of naturally occurring flavonoids with different polymorphic forms of nucleic acid are helpful for understanding the molecular aspects of binding mode and providing direction for the use and design of new efficient therapeutic agents. However, much less information is available on the interactions of these compounds with different polymorphic forms of DNA at the molecular level. In this report we investigated the interaction of two widely abundant dietary flavonoids quercetin (Q) and morin (M) with calf thymus (CT) DNA.