Tuning anion binding properties of Bis(indolyl)methane Receptors: Effect of substitutions on optical responses

Novel Insights in the Hypertension Treatment & Type 2 Diabetics Induced by Angiotensin Receptor Blockers: MD Simulation Studies & Molecular Docking of Some Promising Natural Therapies

Angiotensin receptor blockers (ARBs) are commonly used to treat hypertension that target the hormonal system (renin-angiotensin system (RAS)), which regulates various physiological functions in the body. ARBs work by blocking the binding of angiotensin II to its receptor, thereby preventing a rise in blood pressure. These drugs not only normalize the overactivation of RAS but also provide protective effects against cardiovascular, renal, and type 2 diabetic patients. Inappropriate RAS activity has been linked to insulin resistance of type 2 diabetes. Olmesartan, as an ARB, was found to have a beneficial role in reducing postprandial glucose levels in type 2 diabetes. However, ARBs can cause side effects, prompting a search for new compounds that have fewer adverse effects. This study explores the potential of natural metabolites, specifically eugenol, gallic acid, myricetin, p-cymene, quercetin, and kaempferol, as ARB inhibitors compared to the current standard, olmesartan. Using in silico studies, the binding affinity of these natural substances to the ARB receptor was evaluated. The results showed that myricetin and kaempferol had affinities higher than those of olmesartan, suggesting that they could serve as promising ARB inhibitors for hypertension treatment. These natural compounds could provide an alternative approach to conventional antihypertensive drugs, which may have fewer side effects. However, more research is needed to validate the efficacy and safety of these natural compounds as antihypertensive drugs. Further in vitro and in vivo studies are needed to confirm their effectiveness and safety. This study provides a promising starting point for future investigations into the potential of natural metabolites as alternative treatments for hypertension. The findings also highlight the importance of exploring natural alternative treatments for hypertension and the protective effects of ARBs on early stage type-2 diabetics.

Selective and Effective Sensing of Cyanide Ion with no Interference in Water by Phenothiazine-indolium Fused Optical Sensor

The sensor with electron donor phenothiazine-2-carbaldehyde and electron acceptor indolium carboxylic acid, is developed with an intramolecular charge transfer transition between them. The synthesized molecule senses cyanide ion in water. The cyanide ion reacts with the molecule via nucleophilic addition in the indolium ring with a noticeable purple to colorless change in the solution observed. Also with the cyanide ion interaction, the sensor exhibits change in UV-visible absorption and fluorescence spectra. While the other ion does not show spectral and visual changes when interacts with the sensor molecule. Also the interference study reveals that the molecule is highly selective towards cyanide ion. Different source of water samples confirms the CN- ion sensing efficiency of the molecule. 1:1 interaction between the molecule PTI and cyanide ion is confirmed from the results of Jobs plot, 1H NMR and HRMS. Paper strips were prepared and this can act as a simple tool to sense cyanide ion in various water samples.

Small-molecule fluorogenic probes based on indole scaffold

Indoles are the most versatile organic N-heterocyclic compounds widely present in bioactive natural products and used in different fields such as coordination chemistry, pharmacy, dyes, and medicine, as well as in the biology and polymer industries. More recently, the indole scaffold has been widely used in analytical chemistry for the design and development of small-molecule fluorescent chemosensors in the fields of molecular recognition and molecular imaging. The indole-based chemosensor derivatives contain heteroatoms like N-, O-, and S-, through which they interact with analytes (cations, anions, and neutral species), producing measurable analytical signals that can be used for the fluorimetric and colorimetric detection of different analytes in biological, agricultural and environmental samples. This review focuses on indole-based small-molecule fluorimetric and colorimetric chemosensors for detecting cations, anions, and neutral species in a comprehensive manner. Furthermore, the recognition mechanisms are discussed in detail, which could help researchers design and develop more powerful and efficient fluorescent chemosensors in the near future.

Tuning sensing efficacy of anthraimidazoledione-based charge transfer dyes: nitro group positioning impact

Anthraimidazoledione-based optical sensors have been designed by varying the position of the nitro functional group. All three positional isomers showed highly colored, photostable optical signals owing to intramolecular charge transfer interactions. Despite having the same anion-binding site (imidazole unit), the selectivity and sensitivity of the compounds depend on the positioning of the nitro group. The selectivity was fairly good for the meta isomer, followed by the ortho and para isomers, respectively. In contrast, the sensitivity towards anions followed a completely opposite trend, with the para isomer being the most sensitive one towards anions. Interestingly, the color changing response along the turn-on fluorescence signal was observed only with CN- ions in a semi-aqueous environment. Though the introduction of water as a co-solvent could improve the selectivity, the sensitivity was found to be slightly less than that observed in pure organic medium. Mechanistic studies indicated hydrogen bonding interactions between the imidazole -NH proton and cyanide, which further facilitated the extent of intramolecular charge transfer.

Oxidized Bisindolyl-Based Amphiphilic Probe for Dual Mode Analysis of Heavy Metal Pollutants in Aqueous Medium

The oxidized bisindolyl-based amphiphilic, chromogenic probe has been synthesized that can form nanoscopic aggregates in the aqueous medium. Along with solvent polarity and pH of the medium, it was observed that the addition of heavy metal pollutants, like Hg2+ can cause significant alteration in the charge transfer state. This resulted in the immediate change in the solution color from yellow to orange. Additionally, we could excite either the monomer species or the aggregates of the probe by choosing the proper excitation wavelength. Upon exciting at 390 nm, the compound exhibited a broad fluorescence spectrum with maxima at 450 nm, presumably due to twisted state charge transfer. On the contrary, the aggregated species (λex = 465 nm) displayed a comparatively weaker fluorescence band centered at 565 nm. Interestingly, the fluorescence intensity at the 450 nm band experience fluorescence quenching in the presence of Hg2+ ion, while the aggregate emission band remained unaffected. Finally, the present system was utilized for detection of mercury ions in natural water samples.

Differential response for multiple ions: a smart probe to construct optically tunable molecular logic systems

A rhodamine-based optical probe has been designed through a one-pot synthetic protocol involving phenanthroline as a binding motif. The compound showed a bright pink coloration specifically upon the addition of Cu²⁺ and Hg²⁺ ions. However, the appearance of bright red fluorescence was observed only in the presence of Hg²⁺. Considering both, we can detect and discriminate these two ions even at ppb level concentration. Furthermore, these in situ generated metal complexes were utilized for the selective recognition of CN^- and I^- ions. Pre-coated TLC plates were developed for rapid on-site detection of these toxic ions even in remote places. Finally, on a single molecular probe based on differential opto-chemical interactions with different ions (Cu²⁺, Hg²⁺, CN^- and I^-), we were able to design numerous trivial (OR, NOR) and non-trivial (INHIBIT, IMPLICATION, COMPLEMENT, TRANSFER, NOT-TRANSFER) logic gates. Most fascinatingly, we can switch the logic response from one type to another by simply tuning only the optical output channel.