Pharmacologically Active Phytomolecules Isolated from Traditional Antidiabetic Plants and Their Therapeutic Role for the Management of Diabetes Mellitus

Diabetes mellitus is a chronic complication that affects people of all ages. The increased prevalence of diabetes worldwide has led to the development of several synthetic drugs to tackle this health problem. Such drugs, although effective as antihyperglycemic agents, are accompanied by various side effects, costly, and inaccessible to the majority of people living in underdeveloped countries. Medicinal plants have been used traditionally throughout the ages to treat various ailments due to their availability and safe nature. Medicinal plants are a rich source of phytochemicals that possess several health benefits. As diabetes continues to become prevalent, health care practitioners are considering plant-based medicines as a potential source of antidiabetic drugs due to their high potency and fewer side effects. To better understand the mechanism of action of medicinal plants, their active phytoconstituents are being isolated and investigated thoroughly. In this review article, we have focused on pharmacologically active phytomolecules isolated from medicinal plants presenting antidiabetic activity and the role they play in the treatment and management of diabetes. These natural compounds may represent as good candidates for a novel therapeutic approach and/or effective and alternative therapies for diabetes.     

A Simple and Efficient Electrochemical Sensor for Electrocatalytic Reduction of Nitrite Based on Poly(4‐aminoacetanilide) Film Using Carbon Paste Electrode

In this study, the electrochemical reduction of nitrite was investigated on poly(4‐aminoacetanilide) (PPAA) forming by cyclic voltammetry at the surface of carbon paste electrode. The electrochemical properties of the modified electrode have been studied by cyclic voltammetry and double potential step chronoamperometry. Results showed that in the optimum condition (pH = 0.00) the reduction of nitrite occurred at a potential about 667 mV more positive than that unmodified carbon paste electrode. This amount of electrocatalytic ability is high compared with other electrocatalysts. Using a chronoamperometric method, the catalytic rate constant (k) was calculated 8.4 × 10⁴ cm³ mol^‐1 s^‐1. Also, the electrocatalytic reduction peak currents was found to be linear with the nitrite concentration in the ranges of 5 × 10^‐4 M to 2.5 × 10^‐2 M and 2 × 10^‐5 M to 7 × 10^‐3 M with detection limits (2σ) were determined as 4.5 × 10^‐4 M and 1 × 10^‐5 M by cyclic voltammetry (CV) and hydrodynamic amperometry methods respectively. Recovery experiments exhibit the satisfactory results.     

Poly(ortho‐toluidine) Modified Carbon Paste Electrode: A Sensor for Electrocatalytic Reduction of Nitrite

The electrocatalytic reduction of nitrite has been studied by poly(ortho‐toluidine) films modified carbon paste electrode (P‐OT/MCPE). Cyclic voltammetry and chronoamperometry techniques were used to investigate the suitability of poly(ortho‐toluidine) as a mediator for the electrocatalytic nitrite reduction in aqueous solution with various pH. Results showed that pH 0.00 is the most suitable for this purpose. In the optimum pH, the reduction of nitrite occurs at a potential about 600 mV more positive than unmodified carbon paste electrode. The catalytic reaction rate constant, (k_h), was calculated 8.68×10² M^?1 s^?1 by the data of chronoamperometry. The catalytic reduction peak current was linearly dependent on the nitrite concentration and the linearity range obtained was 5.00×10^?4 M–1.90×10^?2 M. Detection limit has been found to be 3.38×10^?4 M (2σ). This method has been successfully employed for quantification of nitrite in real sample.     

Anti-cancer,anti-oxidant and molecular docking studies of thiosemicarbazone indole-based derivatives

Based on the structural elements of bioactive 3-substituted indoles, a new series of indole–thiosemicarbazone hybrid derivatives were designed, synthesized, and well-characterized using different spectral techniques. The intended scaffolds were screened for their in vitro anti-proliferative activities against breast cancer (MCF-7), lung cancer (A-549), and liver cancer (Hep-G2) cell lines, as well as their anti-oxidant properties. Cytotoxicity studies revealed that compound 6n was the most potent, at least threefold more potent than the commercially available reference drug etoposide, against A-549. In addition, morphological analysis by the acridine orange/ethidium bromide double staining test and flow cytometry analysis confirmed induction of apoptosis in the A-549 cells by compound 6n. In order to validate the experimental results, molecular studies were performed to achieve the possible binding interactions of the most potent compound (6n) and colchicine with tubulin as well as ANP with ATPase domain of topoisomerase IIα active sites. Moreover, the radical scavenging potential of the final derivatives was found to be excellent with the range of 0.015–0.630 µM, comparable to the standard ascorbic acid (0.655 µM).

     

Microwave-Assisted Green Synthesis of Non-Cytotoxic Silver Nanoparticles Using the Aqueous Extract of Rosa santana (rose) Petals and Their Antimicrobial Activity

Green methods using biological extracts, in particular plant-based solutions, have shown great potential for silver nanoparticle synthesis. A microwave-assisted single-step phytosynthesis of silver nanoparticles is described in the present study. The aqueous extract obtained from the Rosa santana (rose) petals was used for the first time in the synthesis. The synthesized nanoparticles obtained after optimized microwave conditions for time and temperature were analyzed by ultraviolet–visible spectroscopy (UV–Vis), Fourier-transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Zeta-size analysis. The results obtained from the characterization studies showed that the synthesized nanoparticles were nearly spherical in shape with sizes from 6.52?nm to 25.24?nm with an average particle size of 14.48?nm with a face-centered cubic structure. The antibacterial activities of the synthesized nanoparticles were evaluated and revealed that the silver nanoparticles displayed good inhibition against both Gram-negative and Gram-positive bacteria. Also, the cytotoxic effect of the silver nanoparticles on a mouse fibroblast cell line (L929) was studied by a cell viability assay. The results showed that phytosynthesized silver nanoparticles were nontoxic to the healthy normal cell line at all tested concentrations.     

Comparative study of Box–Behnken,central composite,and Doehlert matrix for multivariate optimization of Pb (II) adsorption onto Robinia tree leaves

A comparative study of Box–Behnken, central composite, and Doehlert matrix was performed on the adsorption of Pb (II) by Robinia tree leaves in a batch system. As a case study, uptake capacity (q) and removal efficiency (R) of Pb (II) biosorption have been evaluated with all theses approaches. The advantages and limitations of these different response surface techniques have been experimentally considered. The results show the different statistical predictability of Doehlert matrix and Box–Behnken design at 95% confidence level comparable with some extent with that of central composite design at some extreme conditions. An environmental and economical comparison was also carried out between individual and simultaneous optimization of removal efficiency (R) and uptake capacity (q) using desirability function. Optimization of q proves only to have advantages over R or simultaneous optimization of R and q in this particular biosorption process. Copyright © 2013 John Wiley & Sons, Ltd.     

A Natural Isolate Producing Shikimic Acid: Isolation, Identification, and Culture Condition Optimization

Shikimic acid has wide use in pharmaceuticals due to its application in the synthesis of drug Tamiflu used in the treatment of Swine flu. The high cost and limited availability of shikimic acid isolated from plants has impeded the use of this valuable building block of the drug. In this context, fermentation route to produce shikimic acid from renewable resources has become increasingly attractive. The present study was embarked upon isolation of wild-type microorganisms able to produce shikimic acid. Out of the 42 isolates obtained from the soil, isolate GR-21 was selected as the best with initial production of 0.54 g/L shikimic acid and later identified as Citrobacter sp. The process optimization resulted in 14-fold increase in the shikimic acid production, thereby claiming this process to be a sustainable alternative for the production of this important biomolecule. The process was further scaled up to 14 L bioreactor to validate the production of shikimic acid. Further, the product formed is shikimic acid was confirmed by FTIR analysis. The current studies suggest that the selected isolate could be used as a promising agent to fulfill the worldwide demand of shikimic acid.     

Spectrophotometric study of the effects of surfactants and ethanol on the acidity constants of fluorescein

In the present paper, a sensitive, fast and suitable method for the calculation of pK(a) values of fluorescein is proposed. The effects of sodium dodecyl sulfate (SDS) and Triton X-100 (TX-100) as a surface-active agent on the acidic and basic forms, and the spectral properties of fluorescein were studied by the spectrophotometric method. The study was performed in sub-micelle surfactant concentration, and absorption spectra at 300-550 nm intervals were recorded. Stepwise acidity constants of fluorescein at pH range 1.50-10.00 and at constant ionic strength 0.1M and 25 degrees C were determined using DATAN program using pH-spectrophotometric titration data. The method is efficient, however the component spectra showed intensive overlapping. The calculated acidity constants of fluorescein in water at ionic strength 0.1 are pK(a1)=2.20, pK(a2)=4.30 and pK(a3)=6.43. The acidity constants of the dye in ethanol-water solution were studied by the same procedure. Effect of surfactants and ethanol on acidity constants and pure spectrum of each component are also discussed.     

Gravitational luminosity of a hot plasma in $$R^{2}$$ gravity

The \(R^{2}\)-gravity contribution to the energy loss of a hot plasma due to gravitational bremsstrahlung is calculated in the linearized theory on the basis of classical Coulomb scattering of plasma constituents in small-angle scattering approximation. The explicit dependence of the gravitational luminosity on the plasma temperature is derived and its relevance to the Einstein gravity is demonstrated. The result, when applied to the Sun as a hot plasma, shows very good agreement with available data.