On the traditional medicinal plants and plant-derived natural drugs used by indigenous people of Nagaland, India

An ethnobotanical documentation on the medicinal plants used by local people of Nagaland (North-east India) has been presented here. The study explored 33 plant species (with their local names, indigenous applications, sources/origins, parts of plants used, bioactive compounds present, process of preparing medicines from the plants) belonging to 28 families have been reviewed thoroughly. Some examples are, Catharanthus roseus (Tsuinrinaro, Periwinkle), Acacia pennata (Chakrangaing, Ballikhadira), Adhatoda vasica (Kicharangnaro, Malabar-nut), Ageratum conzyoides (Imchenriza, Billy-goat-weed,/Tropical-white-weed), Alstonia scholaris (Lazarongpang, Blackboard), Rauvolfia serpentina (Per-mozutong, Indian-snakeroot), etc. Plant based drugs are very popular and effective in Nagaland from ancient times but thorough-documentation with scientific-background of effectiveness, active chemical-compounds present, their action-mechanism, etc., are still scanty. Such review can be of useful for pharmacologist, phyto-chemists to a broad group of researchers and may lead to discovery of new sources of novel medicines through traditional therapeutic knowledge.

Targeting aloe active compounds to c-KIT promoter G-quadruplex and comparative study of their anti proliferative property

Small molecules targeting G-quadruplex of oncogene promoter is considered as a promising anticancer therapeutics approach. Natural aloe compounds aloe emodin, and its glycoside derivative aloe emodin-8-glucoside and aloin have anticancer activity and also have potential DNA binding ability. These three compounds have promising binding ability towards quadruplex structures particularly c-KIT G-quadruplex. Here, this study demonstrates complete biophysical study of these compounds to c-KIT quadruplex structure. Aloe emodin showed highest binding stabilization with c-KIT which has been proved by absorbance, fluorescence, dye displacement, ITC and SPR studies. Moreover, comparative study of these compounds with HCT 116 cells line also agreed to their anti proliferative property which may be helpful to establish these aloe compounds as potential anticancer drugs. This study comprises a complete biophysical study along with their anti proliferative property and demonstrates aloe emodin as a potent c-KIT binding molecule.

Mechanistic investigation into the binding property of Yohimbe towards natural polymeric DNAs

DNA interactions with multivalent ligand(s) have increasingly become the subject of substantial research. For several small molecules with therapeutic potential, nucleic acids serve as their primary molecular target. Such interaction has been shown to affect transcription or replication, ultimately leading to apoptotic cell death. As a result, researchers are becoming increasingly interested in understanding how small molecules interact with DNA making it possible to develop new, DNA-specific drugs. The bioactive indole alkaloid, Yohimbe (Yohimbine; Yh) has been broadly studied in pharmacological properties while its binding mode to DNA has not been explicated so far. This study adopted molecular modelling and multi-spectroscopic methods to investigate the interaction between Yohimbine and herring testes (HT DNA) in physiological conditions. Minor hypochromic and bathochromic shifts of fluorescence intensity were observed, suggesting the binding of Yh to HT DNA. The Scatchard plot analyses using the McGhee-von Hipple method revealed non-cooperative binding and affinities in the range of 105 M-1. The thermodynamic parameters suggested exothermic binding, which was favoured by negative enthalpy and positive entropy changes from temperature-dependent fluorescence experiments. Salt-dependent fluorescence suggested that the interaction between the ligand and DNA was governed by non-polyelectrolytic forces. The results of iodide quenching, urea denaturation assay, dye displacement, and in silico molecular docking, suggested groove binding of Yh to HT DNA. Thus, the groove binding mechanism of interaction was validated by both biophysical and computational techniques. The structural elucidation and energetic profiling of Yh's interaction with naturally occurring polymeric DNA can be useful to the development of DNA-targeted therapeutics.

Structural Insight into Groove Binding of Yohimbine with Calf Thymus DNA: A Spectroscopic, Calorimetric, and Computational Approach

A variety of anticancer and antibacterial drugs target DNA as one of their primary intracellular targets. Understanding ligand-DNA interactions and developing new, promising bioactive molecules for clinical use are greatly aided by elucidating the interaction between small molecules and natural polymeric DNAs. Small molecules' ability to attach to and inhibit DNA replication and transcription provides more information on how drugs impact the expression of genes. Yohimbine has been broadly studied in pharmacological properties, while its binding mode to DNA has not been explicated so far. In this study, an attempt was made to explore the interaction between Yohimbine (YH) and calf thymus (CT-DNA) by using varying thermodynamics and in silico approaches. Minor hypochromic and bathochromic shifts of fluorescence intensity were observed, suggesting the binding of YH to CT-DNA. The Scatchard plot analysis using the McGhee-von Hipple method revealed noncooperative binding and affinities in the range of 10⁵ M^-1. The binding stoichiometry value is 2:1 (2 molecules of YH were span by 1 base pair) and was determined by Job's plot. The thermodynamic parameters suggested exothermic binding, which was favored by negative enthalpy and positive entropy changes from both isothermal titration calorimetry and temperature-dependent fluorescence experiment. Salt-dependent fluorescence suggested that the interaction between the ligand and DNA was governed by nonpolyelectrolytic forces. Kinetics experiment confirmed the static type of quenching. The results of iodide quenching, urea denaturation assay, dye displacement, DNA melting, and in silico molecular docking (MD) suggested groove binding of YH to CT-DNA. Circular dichroism spectra confirmed minimal perturbation of CT-DNA with YH binding via groove region. Therefore, the groove binding mechanism of interaction was validated by biophysical techniques and in silico, MD approaches. The findings supported here may contribute to the development of new YH therapeutics possessing better efficacy and lesser side effects.

PROTEIN BINDING CHARACTERISTICS OF YOHIMBINE, A NATURAL INDOLE ALKALOID BASED DRUG FOR ERECTILE DYSFUNCTION

Even to this day, talking about sexual-dysfunctions largely remains a taboo. Hence less studies were recorded and fewer remedies given. Erectile dysfunction (ED) is one of the most commonly treated psychological disorders which leads to major distress, interpersonal limitation and reduces the quality of life & marriage. This study aimed to assess a plant-derived molecule, Yohimbine (Yoh, a β-carboline indole-alkaloid; often used for ED treatment) and its potential binding phenomenon with hemoglobin (Hb). Successful binding of the Yoh with Hb is evident from spectroscopic and molecular-docking results. Yoh quenched the fluorescence of Hb efficiently through static mode. The binding affinity was in the order of 10⁵ M^-1 with 1:1 stoichiometry. Thermodynamic analyses concluded that the protein-ligand association to be spontaneous and attributed by entropy-driven exothermic-binding. Non-polyelectrolytic factor was the core, dominating factor. The structural aspects have been deciphered through infra-red spectroscopy and computational-methods. The giant 3D-protein moiety was significantly perturbed through drug-binding. Hydrophobic forces and hydrogen bonding participation were stipulated by molecular modeling data. This study reveals the detailed interaction pattern and molecular mechanism of Hb-Yoh binding; correlating the structure-function relationship for the first time; therefore, holds enormous importance from the standpoint of rational and efficient drug-designing & development.

Biophysical and molecular modeling evidences for the binding of sulfa molecules with hemoglobin

The molecular mechanism of the heme protein, hemoglobin (Hb) interaction with sulfa molecule, sulfadiazine (SDZ) has been investigated through spectroscopic, neutron scattering and molecular modeling techniques. Absorption and emission spectroscopic studies showed that SDZ molecules were bound to Hb protein, non-cooperatively. The binding affinityof SDZ-Hb complex at standard experimental condition was evaluated to be around (4.2 ± 0.07) ×10⁴, M^-1with 1:1 stoichiometry. Drug induced structural perturbation of the 3 D protein moiety was confirmed through circular dichroism (CD), synchronous fluorescence and small angle neutron scattering methods. From the temperature dependent spectrofluorometric studies, the negative standard molar Gibbs energy change suggested the spontaneity of the reaction. The negative enthalpy and positive entropy change(s) indicated towards the involvement of both electrostatic and hydrophobic forces during the association process. Salt dependent fluorescence study revealed major contributions from non-poly-electrolytic forces. Molecular modeling studies determined the probable binding sites, types of interaction involved and the conformational alteration of the compactness of the Hb structure upon interaction with SDZ molecule. Overall, the study provides detailed insights into the binding mechanism of SDZ antibiotics to Hb protein.Communicated by Ramaswamy H. Sarma.

Targeting Natural Polymeric DNAs with Harmane: An Insight into Binding and Thermodynamic Interaction Through Biophysical Approach

DNA is one of the major molecular targets for a broad range of anticancer drugs. Hence, interaction studies involving cellular DNA and small molecules can be highly beneficial as they often lead to rational and efficient drug design. In this study, the binding interaction of Harmane (a naturally occurring, bioactive indole alkaloid) with two natural polymeric DNAs, that is, Calf thymus (CT) DNA and Herring testis (HT) DNA has been elucidated using biophysical techniques. A ground state, 1:1 complexation, was revealed by steady-state fluorescence spectroscopy. The thermodynamic profile and energetics of the associated reaction were evaluated by temperature-dependent fluorescence spectroscopy. The spontaneity of the binding was confirmed by the negative ΔG° values in both cases. Negative enthalpy change, along with stronger positive entropic contribution, indicated the dominant electrostatic nature of the interaction and finally the entropy-driven exothermic binding process throughout. Salt-dependent studies further demonstrated the significant contribution of electrostatic interactions in ligand binding toward DNA. Infrared data substantiated the structural information of the said interactions, leading to the exploration of the structure-function relationship.