Isolation and Purification of Condensed Tannin from the Leaves and Branches of <Emphasis Type="Italic">Prunus cerasifera</Emphasis> and Its Structure and Bioactivities

Prunus cerasifera has a rich resource and a weak utilization rate and its biological functions have been investigated. We found that the contents of total phenol (TP) in leaves and branches of Prunus cerasifera were 117.8 ± 8.8 and 100.04 ± 0.9 mg/g, respectively; the contents of soluble condensed tannin (SCT) were 73.95 ± 0.9 and 78.65 ± 4.1 mg/g, respectively; the structure of SCT containing afzelechin/epiafzelechin, catechin/epicatechin, and atechin/epicatechin as the main units and the SCT from leaves and branches exhibited better anti-tyrosinase and antioxidant activities. This study could clarify Prunus cerasifera condensed tannin resource availability and lay a theoretical foundation for its development as a natural antioxidant and tyrosinase inhibitor.     

Investigation of phytochemicals and antioxidant capacity of selected <Emphasis Type="Italic">Eucalyptus</Emphasis> species using conventional extraction

Eucalyptus species have found their place in traditional medicine and pharmacological research and they have also been shown to possess a large number of phenolic compounds and antioxidants. The present study sought to implement conventional extraction to yield maximal total phenolic content (TPC), total flavonoid content (TFC), proanthocyanidins, antioxidants, and saponins from E. robusta using different solvents. The most suitable extraction solvent was further employed for extracting phytochemicals from E. saligna, E. microcorys, and E. globulus to select the Eucalyptus species with the greatest bioactive compound content. The results emphasised the efficiency of water in extracting TPC ((150.60 ± 2.47) mg of gallic acid equivalents per g), TFC ((38.83 ± 0.23) mg of rutin equivalents per g), proanthocyanidins ((5.14 ± 0.77) mg of catechin equivalents per g), and antioxidants ABTS ((525.67 ± 1.99) mg of trolox equivalents (TE) per g), DPPH ((378.61 ± 4.72) mg of TE per g); CUPRAC ((607.43 ± 6.69) mg of TE per g) from E. robusta. Moreover, the aqueous extract of E. robusta had the highest TPC, TFC and antioxidant values among the other Eucalyptus species tested. These findings highlighted the efficiency of conventional extraction in extracting natural bioactive compounds from Eucalyptus species for pharmaceutical and nutraceutical applications.     

Effect of <Emphasis Type="Italic">Rol</Emphasis> Genes on Polyphenols Biosynthesis in <Emphasis Type="Italic">Artemisia annua</Emphasis> and Their Effect on Antioxidant and Cytotoxic Potential of the Plant

Flavonoids are famous for their antioxidant capacity and redox potential. They can combat with cell aging, lipid peroxidation, and cancer. In the present study, Artemisia annua hybrid (Hyb8001r) was subjected to qualitative and quantitative analysis of flavonoids through HPLC. Rol genes transgenics of A. annua were also evaluated for an increase in their flavonoid content along with an increase in antioxidant and cytotoxic potential. This was also correlated with the expression level of flavonoids biosynthetic pathway genes as determined by real-time qPCR. Phenylalanine ammonia-lyase and chalcone synthase genes were found to be significantly more highly expressed in rol B (four to sixfold) and rol C transgenics (3.8–5.5-fold) than the wild-type plant. Flavonoids detected in the wild-type A. annua through HPLC include rutin (0.31 mg/g DW), quercetin (0.01 mg/g DW), isoquercetin (0.107 mg/g DW) and caffeic acid (0.03 mg/g DW). Transgenics of the rol B gene showed up to threefold increase in rutin and caffeic acid, sixfold increase in isoquercetin, and fourfold increase in quercetin. Whereas, in the case of transgenics of rol C gene, threefold increase in rutin and quercetin, 5 fold increase in isoquercetin, and 2.6-fold increase in caffeic acid was followed. Total phenolics and flavonoids content was also found to be increased in rol B (1.5-fold) and rol C (1.4-fold) transgenics as compared to the wild-type plant along with increased free radical scavenging activity. Similarly, the cytotoxic potential of rol gene transgenics against MCF7, HeLA, and HePG2 cancer cell lines was found to be significantly enhanced than the wild-type plant of A. annua. Current findings support the fact that rol genes can alter the secondary metabolism and phytochemical level of the plant. They increased the flavonoids content of A. annua by altering the expression level of flavonoids biosynthetic pathway genes. Increased flavonoid content also enhanced the antioxidant and cytotoxic potential of the plant.     

Stinging Nettle (Urtica dioica L.) as a Functional Component in Durum Wheat Pasta Production: Impact on Chemical Composition,In Vitro Glycemic Index,and Quality Properties

Stinging nettle (Urtica dioica L.) is a good source of biologically active compounds with proven beneficial health effects. This study aimed to investigate the effect of nettle herb supplementation on chemical composition, including the content of selected minerals and pigments, the in vitro glycemic response, and the cooking and sensory quality of extruded pasta. Tagliatelle-shaped pasta was produced under semi-technical scale by partial replacement of durum wheat semolina with 0, 1, 2, 3, 4, and 5% of lyophilized nettle. The partial substitution with freeze-dried nettle caused a statistically significant (p ≤ 0.05) increase in the content of minerals, especially calcium, iron, potassium, and magnesium in the products. The calcium content in the pasta fortified with 5%-addition of stinging nettle was 175.9 mg 100 g⁻¹ and this concentration was 5.8 times higher than in the control sample. At the same time, high content of chlorophylls and carotenoids (237.58 µg g⁻¹ and 13.35 µg g⁻¹, respectively) was noticed. Enriching pasta with a 0–5% addition of stinging nettle resulted in a statistically significant (p ≤ 0.05) increase in the content of the total dietary fiber (TDF) (from 5.1 g 100 g⁻¹ to 8.82 g 100 g⁻¹) and the insoluble dietary fiber (IDF) (from 2.29 g 100 g⁻¹ to 5.63 g 100 g⁻¹). The lowest hydrolysis index of starch (HI = 17.49%) and the lowest glycemic index (GI = 49.31%) were noted for the pasta enriched with 3% nettle.     

Determination of Hg isotopic compositions in certified reference material NIES No. 13 Human Hair by cold vapor generation multi-collector inductively coupled plasma mass spectrometry

Hg isotopic ratios of NIES CRM No. 13 Human Hair were analyzed using cold vapor generation coupled to multi-collector inductively coupled plasma mass spectrometer to meet the growing demand for better understanding of Hg exposure routes by using Hg isotopic compositions in human hair samples. To validate and assure the accuracy of our analytical method, (1) the reproducibility of the Hg isotopic measurement was monitored and (2) the Hg isotopic compositions of four secondary reference materials—IAEA-085, IAEA-086, and CRPG-RL24H—were measured. Our results for NIES CRM No. 13 show the mass-dependent fractionation values of δ ¹⁹⁹Hg = (2.13 ± 0.07) ‰, δ ²⁰⁰Hg = (0.98 ± 0.08) ‰, δ ²⁰¹Hg = (2.77 ± 0.10) ‰, δ ²⁰²Hg = (1.89 ± 0.10) ‰, and δ ²⁰⁴Hg = (2.76 ± 0.16) ‰ (2SD, n = 11) and the mass-independent fractionation values of Δ ¹⁹⁹Hg = (1.65 ± 0.06) ‰, Δ ²⁰⁰Hg = (0.04 ± 0.04) ‰, Δ ²⁰¹Hg = (1.36 ± 0.07) ‰, and Δ ²⁰⁴Hg = (?0.04 ± 0.11) ‰ (2SD, n = 11). Interlaboratory comparison of the CRM performed at the University of Pau showed good agreement with the values obtained at NIES.     

Determination of phenolic compounds in medicinal plants from the Lamiaceae family

A procedure for the determination of Phenolic compounds in extracts from the medicinal plants of the Lamiaceae family—garden sage (Salvia officinalis L.), creeping thyme (Thymus serpyllum L.), wild marjoram (Origanum vulgare L.), and common balm (Melissa officinalis L.)—obtained under different extraction conditions was developed. The identification of the extracted compounds was performed and their qualitative and quantitative composition was established by HPLC with diode array and mass-spectrometric detection with consideration for the obtained characteristics of the standard samples of individual components. The test samples of medicinal herbs contained caffeic acid (0.19–0.62 mg/g) and rosmaric acid (4–23 mg/g); the highest rosmaric acid content (23 mg/g) was found in wild marjoram, and the lowest content (4 mg/g), in creeping thyme. The extracts of wild marjoram contained the greatest amounts of Phenolic compounds; rosmaric acid and luteolin-7-O-β-D-glucuronide were major components, whereas protocatechuic, 3-O-caffeoylquinic, and caffeic acids were minor components.     

A Novel 2-Keto-<Emphasis Type="SmallCaps">d</Emphasis>-Gluconic Acid High-Producing Strain <Emphasis Type="Italic">Arthrobacter globiformis</Emphasis> JUIM02

2-Keto-d-gluconic acid (2KGA) is mainly used for industrial production of erythorbic acid, a food antioxidant. In this study, a 2KGA producing strain JUIM02 was firstly identified as Arthrobacter globiformis by morphological observation and 16S rDNA sequencing. The 2KGA synthetic capacity of A. globiformis JUIM02 was evaluated by both fermentation and bioconversion, with 180 g/L dextrose monohydrate as substrates, in shake flasks and 5 L fermenters. For fermentation, 2KGA titer, yield, molar yield, and productivity of JUIM02 reached 159.05 g/L, 0.97 g/g, 90.18%, and 6.63 g/L/h in 24 h. For non-sterile and buffer-free bioconversion by free resting cells (~?3.2 g/L dry cell weight) of JUIM02, these data were 172.96 g/L, 1.06 g/g, 98.07%, and 5.41 g/L/h in 32 h. Moreover, JUIM02 resting cells could be repeatedly used. Resting cells stored at 4 °C within 30 days showed stable bioconversion capacity, with 2KGA titers ≥?171.50 g/L, yields ≥?1.04 g/g, and molar yields ≥?97.24%. The 2KGA synthetic pathway in A. globiformis, which was rarely reported, was also speculated similar to Pseudomonas and verified preliminarily. In conclusion, A. globiformis JUIM02 is a promising 2KGA industrial-producing strain suitable for various production methods and a suitable object for 2KGA metabolism research of A. globiformis.     

The Influence of Different Strategies for the Saccharification of the Banana Plant Pseudostem and the Detoxification of Concentrated Broth on Bioethanol Production

Pseudostem of the Musa cavendishii banana plant was submitted to chemical pretreatments with acid (H₂SO₄ 2%, 120 °C, 15 min) and with alkali (NaOH 3%, 120 °C, 15 min), saccharified by commercial enzymes Novozymes® (Cellic CTec2 and HTec2). The influences of the pretreatments on the degradation of the lignin, cellulose and hemicellulose, porosity of the surface, particle crystallinity, and yield in reducing sugars after saccharification (Y _RS), were established. Different concentrations of biomass (70 and 100 g/L in dry matter (dm)), with different physical differences (dry granulated, crushed wet bagasse, and whole pseudostem), were used. The broth with the highest Y _RS among the different strategies tested was evaporated until the concentration of reducing sugars (RS) was to the order of 100 g/L and fermented, with and without prior detoxification with active carbon. Fermentation was carried out in Erlenmeyer flasks, at 30 °C, initial pH 5.0, and 120 rpm. In comparison to the biomass without chemical pretreatment and to the biomass pretreated with NaOH, the acid pretreatment of 70 g/L of dry granulated biomass enabled greater digestion of hemicellulose, lower index of cellulose crystallinity, and higher Y _RS (45.8 ± 0.7%). The RS increase in fermentation broth to 100 g/L, with posterior detoxification, presented higher productivity ethanol (Q _P = 1.44 ± 0.02 g/L/h) with ethanol yield (Y _P/RS) of 0.41 ± 0.02 g/g. The value of Q _P was to the order of 75% higher than Q _P obtained with the same broth without prior detoxification.     

Biochemical and Molecular Study of <Emphasis Type="Italic">Carpobrotus edulis</Emphasis> Bioactive Properties and Their Effects on <Emphasis Type="Italic">Dugesia sicula</Emphasis> (Turbellaria,Tricladida) Regeneration

The traditional medicinal properties of Carpobrotus edulis are well recognized, particularly in Tunisia where it is used for wound healing. Thus, in this study, biochemical and molecular properties of its leaves’ bioactive aqueous-acetone extract were investigated. The total phenolic content (TPC) of the extract was estimated to be 184 ± 5 mg/100 g of fresh matter (FM). The qualitative and quantitative polyphenolic profile was determined by ultra performance liquid chromatography with diode array detection (UPLC-DAD) and showed that chlorogenic acid was the major compound (43.7%). The extract exhibits potent antioxidant capacities with IC50 = 56.19 and 58.91 μg/ml, as accessed via the anionic DPPH and cationic ABTS radical scavenging assays, respectively. The extract has high antibacterial properties, especially against the Gram+ Staphylococcus aureus and Bacillus cereus strains. To investigate the extract effect on regeneration, the flatworm Dugesia sicula Lepori, 1948, was used as a model. The macroscopic analysis of planarian cultures in ordinary medium containing phenolic extract at non-toxic concentrations illustrated that the extract caused morphological changes. Additionally, the molecular study through the fluorescence-activated cell sorting (FACS) technique showed that C. edulis polyphenols can harm the stem cells’ development. These results emphasize the ecotoxicological impact of phenolic rejections in the environment on flatworms’ physiology.     

Regeneration-Based Quantification of Coumarins (Scopoletin and Scoparone) in <Emphasis Type="Italic">Abutilon indicum</Emphasis> In Vitro Cultures

Abutilon indicum exploited for its immense value has been propagated successfully through multiple shoot induction and somatic embryogenesis. Direct regeneration (8.20?±?0.83 shoots) was achieved from nodal explants using 0.5 mg/l kinetin (Kn) in MS media. The basal callus from nodal explants turned embryogenic on subsequent introduction of 0.2 mg/l TDZ into the Kn-supplemented media, giving rise to somatic embryos. The embryogenic potential of calli expressed in terms of embryo-forming capacity (EFC) increased from 8.15 EFC to 20.95 EFC after plasmolysis. The phytochemical analysis (HPLC) for the presence of scopoletin and scoparone has revealed a unique accumulation pattern, with higher levels of scopoletin during the earlier stages and scoparone in the later stages of development. The embryogenic calli contained the highest amount of coumarins (99.20?±?0.97 and 61.03?±?0.47 μg/gFW, respectively) followed by regenerated plant (9.43?±?0.20 and 36.36?±?1.19 μg/gFW, respectively), obtained via somatic embryogenesis. Rapid multiplication of A. indicum equipped with two potent coumarins is important in order to meet the commercial demand for combat against dreadful diseases, thereby providing a new platform for plant-based drugs and their manufacture on a commercial scale.     

Growth of Cyanobacteria: Optimization for Increased Carbohydrate Content

Growths of Lyngbya limnetica and Oscillatoria obscura were investigated at varying pH, light intensity, temperature, and trace element concentration with a view to optimize these parameters for obtaining the maximum carbohydrate content. The maximum growth for both strains was obtained at pH 9.0 and temperature 20 ± 3 °C using a light intensity of 68.0 μmol m^?2 s^?1 with continuous shaking. Growth under the nitrogen starvation condition affected the carbohydrate content more compared to the phosphorus starvation, and maximum concentrations were found as 0.660 and 0.621 g/g of dry biomass for L. limnetica and O. obscura, respectively. Under the optimized nitrogen-rich conditions, the specific growth rates for the two strains were found to be 0.187 and 0.215 day^?1, respectively. The two-stage growth studies under nitrogen-rich (stage I) followed by nitrogen starvation (stage II) conditions were performed, and maximum biomass and carbohydrate productivity were found as 0.088 and 0.423 g L^?1 day^?1 for L. limnetica. This is the first ever attempt to evaluate and optimize various parameters affecting the growth of cyanobacterial biomass of L. limnetica and O. obscura as well as their carbohydrate contents.     

Enzymatic Hydrolysis of Black Liquor Xylan by a Novel Xylose-Tolerant,Thermostable β-Xylosidase from a Tropical Strain of <Emphasis Type="Italic">Aureobasidium pullulans</Emphasis> CBS 135684

From three cell-associated β-xylosidases produced by Aureobasidium pullulans CBS 135684, the principal enzyme was enriched to apparent homogeneity and found to be active at high temperatures (60–70 °C) over a pH range of 5–9 with a specific activity of 163.3 units (U) mg^?1. The enzyme was thermostable, retaining over 80% of its initial activity after a 12-h incubation at 60 °C, with half-lives of 38, 22, and 10 h at 60, 65, and 70 °C, respectively. Moreover, it was tolerant to xylose inhibition with a K _i value of 18 mM. The K _m and V _max values against p-nitrophenyl-β-d-xylopyranoside were 5.57 ± 0.27 mM and 137.0 ± 4.8 μmol min^?1 mg^?1 protein, respectively. When combining this β-xylosidase with xylanase from the same A. pullulans strain, the rate of black liquor xylan hydrolysis was significantly improved by up to 1.6-fold. The maximum xylose yield (0.812 ± 0.015 g g^?1 dry weight) was obtained from a reaction mixture containing 10% (w/v) black liquor xylan, 6 U g^?1 β-xylosidase and 16 U g^?1 xylanase after incubation for 4 h at 70 °C and pH 6.0.     

Chitosan-Based Surface Molecularly Imprinted Polymer Microspheres for Sustained Release of Sinomenine Hydrochloride in Aqueous Media

The surface molecular imprinting technique has been proposed as a prospective strategy for template molecule recognition and separation by devising the recognition sites on the surface of imprinted materials. The purpose of this study was to establish a novel drug delivery system which was developed by surface molecular imprinting method using β-cyclodextrin (β-CD)-grafted chitosan (CS) (CS-g-β-CD) microspheres as matrix and sinomenine hydrochloride (SM) as the template molecule. By adjusting the amount of functional monomer and cross-linking agent, we got the more excellent adsorption of CS-g-β-CD molecularly imprinted polymers (MIPs-CS-g-β-CD). When the amount of functional monomer was 6 mmol and cross-linking agent was 20 mmol, the maximum binding capacity of MIPs and non-imprinted polymers (NIPs) was 55.9 mg/g and 37.2 mg/g, respectively. The results indicated that the recognition of SM with MIPs was superior to NIPs. The adsorption isotherms of MIPs-CS-g-β-CD indicated that the adsorption behavior fitted better to the Langmuir model, which showed that the adsorption process of polymer was monomolecular layer. In in vitro drug release studies, the accumulative release amount of MIPs-CS-g-β-CD was up to 78% within 24 h. MIPs exhibited an excellent controlled SM release profile without burst release and the mechanism of SM release was shown to conform to non-Fick diffusion. Therefore, MIPs-CS-g-β-CD were successfully applied to extraction of SM and used as the materials for drug delivery system.     

Influence of drying methods on chemical compositions,antioxidant and antibacterial activity of essential oil from lemon peel

The influence of natural, hot-air and infrared drying on chemical composition and bioactivity of lemon peel essential oil are investigated in this study. The results showed that drying resulted in losses or increases of some components or production of some new substances, but the d-limonene (59.52–70.01%) was found as the main component of essential oil. Drying brought about decreases in the yield, antioxidant and antibacterial activity of essential oil. However, the natural drying had little effect, while the hot-air and infrared drying resulted in significant decreases in these parameters, especially at the higher temperature. The yield was the lowest under hot-air drying (60 °C) and decreased by 78%, while infrared drying (60 °C) sample exhibited the lowest antioxidant and antibacterial activities. Infrared drying was easier to lead to the decrease in bioactivity than hot-air drying at the same temperature. These results provided the theoretical basis for drying lemon peel.     

Quantitative Analysis of Phenolic Acids in Extracts Obtained from the Fruits of Peucedanum alsaticum L. and Peucedanum cervaria (L.) Lap

Peucedanum alsaticum L. and Peucedanum cervaria (L.) Lap. are, in common with all species belonging to the Apiaceae family, rich in coumarins and essential oils. Phenolic acids also present in the plant are very important pharmacologically, because of their broad spectrum of biological activity. A simple high-performance liquid chromatographic method has been developed for separation and quantitative analysis of the major phenolic acids in extracts obtained from the fruits of P. alsaticum and P. cervaria. Soxhlet extraction, ultrasound extraction, and accelerated solvent extraction under different conditions were used to find the most efficient extraction conditions. Optimum chromatographic performance was obtained with a C₁₈ column and acetonitrile—1% (v/v) aqueous acetic acid as mobile phase. Ferulic, p-coumaric, caffeic, vanillic, syringic, p-hydroxybenzoic, protocatechuic, chlorogenic, and gallic acids were investigated in the fruits of the plants. For all calibration plots linearity was good (R ² > 0.9991) in the ranges tested. The highest yields of most of the phenolic acids were achieved by use of accelerated solvent extraction. The predominant phenolic acid in the fruits of both plants was chlorogenic acid. The amounts, which depended on the method of extraction, were approximately 146 ± 1.616 and 109.92 ± 3.405 mg per 100 g dry weight for P. cervaria and P. alsaticum, respectively.     

Calculating the Ionization Constant of Functional Groups of Carboxyl Ion Exchangers

The potentiometric titration of a weakly basic carboxyl cation exchanger, obtained via alkaline hydrolysis of an acrylonitrile copolymer with divinyl benzene (degree of crosslinking, 12%) in a wide range of variation in a solution of рН (2–12) and NaCl (concentration 0.01, 0.1, 0.5, 1 М), is considered. The maximum ion-exchange capacity of the ion exchanger for Na⁺ is determined (10.10 ± 0.088 mmol/g of the dry mass) and found to be independent of the solution’s ionic strength. It is established that in the investigated range of NaCl concentrations and рН, the acid–base balance is adequately described by Gregor’s equation. The parameters of this equation are calculated as a function of the NaCl concentration: рK_а = 8.13 ± 0.04, n = 1.50 ± 0.02 for 0.01 М; рK_а = 6.56 ± 0.04, n = 2.60 ± 0.07 for 0.1 М; and рK_а = 5.66 ± 0.6, n = 2.62 ± 0.06 for 0.5 and 1 М. It is shown that to describe the acid–base balance correctly within the proposed model we must estimate the adequacy of the experimental and calculated values of the ion exchanger’s capacity at each рН value according to the calculated parameters of Gregor’s equation.     

Adsorptive recovery of geniposidic acid from gardenia yellow pigment extraction wastewater by anion exchange: equilibrium,thermodynamics and mechanism modeling and simulation

For many years, the traditional process of gardenia yellow pigment extraction has produced wastewater containing significant quantities of Geniposidic acid (GSA), a substance that could be put to pharmacological uses if it could be effectively recovered. This study aimed to provide an efficient adsorption material, D08, for recycling GSA. Batch experiments showed that adsorption capacity depends on initial concentration and temperature. The maximal adsorption capacity of GSA onto an anionic exchanger reached 310 mg/g. The pK _a value of GSA was determined to be 4.21. Pore diffusion coefficients (D _p) of GSA for 283, 298 and 313 K were 3.274 × 10^?10, 5.069 × 10^?10 and 7.356 × 10^?10 m²/s, respectively. Recovery efficiency of GSA was achieved to 99.81 %. In comparison with pseudo first-order and pseudo second-order equations, the PDM model demonstrated the best fit to the kinetics data of GSA adsorption. Adsorption/desorption experiments proved that D08 offers great adsorption capacity, high adsorption rate and good repeatability. In order to help us to accurately comprehend the mass transfer process, numerical simulation and post-processing to variables c(r, t) and q(r, t) were performed to clarify the adsorption process.     

Modelling of proton and metal exchange in the alginate biopolymer

Acid–base behaviour of a commercial sodium alginate extracted from brown seaweed (Macrocystis pyrifera) has been investigated at different ionic strengths (0.1≤I/mol l^?1≤1.0) and in different supporting electrolytes (Et₄NI, NaCl, KCl, LiCl, NaCl+MgCl₂), with the aim of examining the influence of ionic medium on the proton-binding capacity and of quantifying the strength of interaction with light metal ions in the perspective of speciation studies in natural aqueous systems. Potentiometric ([H⁺]-glass electrode) and titration calorimetric data were expressed as a function of the dissociation degree (α) using different models (Henderson–Hasselbalch modified, Högfeldt three parameters and linear equations). The dependence on ionic strength of the protonation constants was taken into account by a modified specific interaction theory model. Differences among different media were explained in terms of the interaction between polyanion and metal cations of the supporting electrolytes. Quantitative information on the proton-binding capacity, together with the stabilities of different species formed, is reported. Protonation thermodynamic parameters, at α=0.5, are log K ^H=3.686±0.005, ΔG ⁰=?21.04±0.03 kJ mol^?1, ΔH ⁰=4.8±0.2 kJ mol^?1 and TΔS ⁰=35.7±0.3 kJ mol^?1, at infinite dilution. Protonation enthalpies indicate that the main contribution to proton binding arises from the entropy term. A strict correlation between ΔG and TΔS was found, TΔS=?9.5–1.73 ΔG. Results are reported in light of building up a chemical complexation model of general validity to explain the binding ability of naturally occurring polycarboxylate polymers and biopolymers. Speciation profiles of alginate in the presence of sodium and magnesium ions, naturally occurring cations in natural waters, are also reported.     

Synthesis,SAR and in vitro therapeutic potentials of thiazolidine-2,4-diones

Background

Thiazolidinedione is a pentacyclic moiety having five membered unsaturated ring system composed with carbon, oxygen, nitrogen and sulfur molecules at 1 and 3 position of the thiazole ring and widely found throughout nature in various form. They favourably alter concentration of the hormones secreted by adipocytes, particularly adiponectin. They also increase total body fat and have mixed effects on circulating lipids. Thiazolidinedione nucleus is present in numerous biological moieties and has different pharmacological activities likes, e.g. antimalarial, antimicrobial, antimycobacterial, anticonvulsant, antiviral, anticancer, anti-inflammatory, antioxidant, anti-HIV (human immunodeficiency virus) and antituberculosis.

Results and discussion

The synthesized compounds were screened for their in vitro antimicrobial potential against Gram (positive and negative) bacterial and fungal strains by tube dilution technique. In this series, compound 10 exhibited significant antimicrobial activity against B. subtilis and S. aureus with MIC?=?4.2?×?10^?2 µM/ml, compound 15 showed significant activity against K. pneumonia with MIC?=?2.60?×?10^?2 µM/ml and compound 4 displayed potent antibacterial activity against E. coli with MIC?=?4.5?×?10^?2 µM/ml. Compound 10 had most potent antifungal activity against C. albicans and A. niger with MIC?=?4.2?×?10^?2 µM/ml. Compounds 12 and 15 were found as most active antidiabetic agents having IC₅₀?=?27.63 μg/ml and 22.35 μg/ml, respectively, using DPPH assay. Antioxidant activity results indicated that compounds 3 and 9 displayed good antioxidant agent with IC₅₀?=?29.04 μg/ml and 27.66 μg/ml respectively, using α amylase assay.

Conclusion

All the synthesized derivatives exhibited good antimicrobial, antidiabetic and antioxidant activities using specific methods then compared with mentioned standard drugs. Especially, compounds 3, 4, 9, 10, 12 and 15 displayed highest activity. Structure activity relationship demonstrated that presence of electron withdrawing group (o-NO₂, p-Cl, p-Br) enhanced the antibacterial activity against E. coli as well as increased the antioxidant activity while the presence of electron releasing group (o/p-OCH₃, 3,4,5-trimethoxy) enhanced the antibacterial activity against S. aureus, B. subtilis, S. typhi, K. pneumonia, C. albicans and A. niger as well as the antidiabetic activity.

     

Chemical composition,antioxidant and antimicrobial potential of essential oils from different parts of <Emphasis Type="Italic">Daphne mucronata</Emphasis> Royle

This research work was executed to determine chemical composition, anti-oxidant and anti-microbial potential of the essential oils extracted from the leaves and stem of Daphne mucronata Royle. From leaves and stem oils fifty-one different constituents were identified through GC/MS examination. The antioxidant potential evaluated through DPPH free radical scavenging activity and %-inhibition of peroxidation in linoleic acid system. The stem’s essential oil showed the good antioxidant activity as compared to leaves essential oil. Results of Antimicrobial activity revealed that both stem and leaves oils showed strong activity against Candida albicans with large inhibition zone (22.2?±?0.01, 18.9?±?0.20 mm) and lowest MIC values (0.98?±?0.005, 2.44?±?0.002 mg/mL) respectively. Leaves essential was also active against Escherichia coli with inhibition zone of 8.88?±?0.01 mm and MIC values of 11.2?±?0.40 mg/mL. These results suggested that the plant’s essential oils would be a potential cradle for the natural product based antimicrobial as well as antioxidant agents.

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