Physical properties,biological applications and biocompatibility studies on biosynthesized single phase cobalt oxide (Co3O4) nanoparticles via Sageretia thea (Osbeck.)

Cobalt oxide nanoparticles were successfully biosynthesized by complete green process using aqueous leaf extracts of Sageretia thea as chelating agent. Diverse techniques were applied for characterization. Antibacterial (with and without UV illumination), antileishmanial, antioxidant and enzyme inhibition applications were assessed, while freshly isolated macrophages and red blood cells were used for biocompatibility studies. Good antibacterial nature and enhancement of bactericidal nature upon UV modulation is reported. Staphylococcus aureus and Escherichia coli are indicated as most susceptible bacterial strains. Significant cytotoxic potential is revealed with IC₅₀ calculated as 12.82 µg/ml and 3.16 µg/ml against the axenic leishmanial promastigote and amastigote cultures respectively. Biogenic cobalt oxide nanoparticles indicated DPPH free radical scavenging potential, while moderate antioxidant capacity and reducing power was demonstrated. Bioinspired cobalt oxide also demonstrated alpha amylase and protein kinase inhibition at higher concentrations. Biogenic cobalt oxide was found as more cytotoxic to macrophages (IC₅₀ = 58.55 µg/ml) then to RBC’s (IC₅₀ >200 µg/ml). Our results indicate green synthesis as an alternative, effective and eco-friendly method for the biosynthesis of cobalt oxide nanoparticles with numerous biological applications.     

Bioinspired synthesis of pure massicot phase lead oxide nanoparticles and assessment of their biocompatibility,cytotoxicity and in-vitro biological properties

Green and ecofriendly route for biosynthesis of lead oxide nanoparticles has been successfully demonstrated using aqueous leaf extracts of Sageretia thea (Osbeck.). Biosynthesized PbO (∼27 nm) nanoparticles were extensively characterized using XRD, FTIR, Raman, EDS etc. Morphology was studied through HR-TEM/SEM. As synthesized nanoparticles were investigated for their iv-vitro biological properties. Antibacterial activities revealed enhancement upon modulation by UV in a concentration dependent manner. Pseudomonas aeruginosa was found to be the most resistant strain (MIC = 250 µg/mL and MIC^uv = 31.25 µg/ml). MTT cytotoxicity on leishmania promastigotes and amastigotes revealed significant inhibition as indicated by their IC₅₀ values of 14.7 µg/mL and 11.95 µg/m respectively. Cytotoxicity was also confirmed using brine shrimp lethality (IC₅₀ = 27.7 µg/mL). Bio-compatibility evaluation indicated cytotoxicity to freshly isolated human macrophages (IC₅₀ = 57.1 µg/mL). Insignificant alpha-amylase inhibition and moderate protein kinase inhibition was revealed. Antioxidant activities indicated free radical scavenging activity (58 ± 2.45) at 200 µg/mL. Moderate total reducing power and total antioxidant activity was also indicated. Overall, we conclude lead oxide as a potential candidate for biological applications, however further studies are recommended on their in vitro and in vivo cytotoxicity.     

Ruellia prostrata Poir. activity evaluated by phytoconstituents,antioxidant, anti-inflammatory,antibacterial activity,and in silico molecular functions

Ruellia prostrata Poir. has been used historically as an anti-cancer, wound healing agent and to treat gonorrhea. We aimed to determine the phytochemicals present in ethyl acetate extract of R. prostrata Poir. (EAERP). We sought to determine the antioxidant, anti-inflammatory, and antibacterial activities in vitro, and toxicity properties in vivo. We also analyzed the Prediction of Activity Spectra for Substances (PASS), physicochemical, ADMET, and drug-likeness properties of phytochemicals in EAERP. To determine phytoconstituents, preliminary phytochemical screening and GC–MS were performed, while FT-IR was used to identify functional groups. The antioxidant activity was evaluated using a DPPH scavenging assay, whereas BSA denaturation and RBC hemolysis inhibition were used to assess anti-inflammatory activity. An agar-well-diffusion assay was performed to estimate the antibacterial activity. Brine shrimp lethality bioassay and oral delivery of EAERP of single-dose were performed to determine cytotoxicity and acute toxicity, respectively. The phytochemical screening revealed the presence of phenols, triterpenoids, saponins, steroids, amino acids, and fat and fixed oils. FT-IR analysis of EAERP showed the presence of many functional groups: alcohols/phenols, carboxylic acids, aldehydes, alkanes, esters, amines, amides, aromatic hydrocarbons, sulfoxides, and alkyl halides. GC–MS revealed the presence of 39 phytoconstituents including steroids, consistent with compounds and functional groups found in preliminary screening and FT-IR. EAERP showed dose-dependent antioxidant activity with an IC₅₀ value of 21.402 µg/mL and anti-inflammatory activity with an IC₅₀ value of 20.564 µg/mL in RBC hemolysis inhibition and 21.115 µg/mL in BSA denaturation assays. EAERP also exhibited dose-related antibacterial activity. EAERP exerted cytotoxicity with an LC₅₀ value of 17.619 μg/mL and acute toxicity with an LD₅₀ value of 4095.328 mg/kg without any adverse effects. The PASS server also predicted that the phytoconstituents of EAERP have antioxidant, anti-inflammatory, and antibacterial activities with probable activity (Pa) ranging from 0.310 to 0.717. Analysis of physicochemical, ADMET, and drug-likeness properties revealed the drug-able efficacy and safety of most compounds. The findings of this study indicated that R. prostrata Poir. contains phytoconstituents with potent antioxidant, anti-inflammatory, and antibacterial activities. Taken together, our measurements suggest that R. prostrata Poir. is a prime candidate for further exploration as a potential therapeutic agent.     

Chemical composition and larvicidal activity of Algerian Foeniculum vulgare seed essential oil

A laboratory study was conducted to determine the effect of three extraction parameters (soaking time, extraction time and the ratio of solid to liquid) on the yield and chemical composition of Foeniculum vulgare seeds essential oils. The bioactivity of the essential oil extracted for the optimum extraction parameters was assessed against Culex pipiens mosquito. F. vulgare essential oil composition included large amounts of phenylpropanoids. Through an extraction time of 6 h and a ratio solid to liquid of 300 g/L we can get over than 72% of trans-anethol without soaking the seeds. With bioassays, essential oils showed different activities on C. pipiens larvae and pupae. Results show that a concentration at 40 mg/L was sufficient to register 50% mortality for the second instars larvae and this, after 2 h exposition time. Moreover, concentration at 60 mg/L ensured after 4 h exposition time 90% mortality for the fourth instars larvae. However, pupae needed 24 h exposition time to show promising mortalities when using concentration at 200 mg/L. Even if laboratory bioassays are only the first step towards the use of essential oils in practical applications, these substances represent a potential alternative to chemical insecticides in some markets.     

Selective and rapid detection of triacetone triperoxide by double-step chronoamperometry

A selective detector for the improvised explosive, triacetone triperoxide is proposed. This is based on the rapid redox reaction of peroxides (hexamethylene triperoxide diamine, benzoyl peroxide, t-butyl peroxide, triacetone triperoxide and H₂O₂) with bromide at 55 °C. Consumption of bromide is indicative of the reduction of the R–O–O–R moiety, the appearance of Br₂ was found for all except for triacetone triperoxide. The latter was found to breakdown to acetone which rapidly reacts with Br₂ producing bromoacetones. The lack of Br₂ production is unique to triacetone triperoxide. Double step chronoamperometry (E₁ = 700 mV, E₂ = 960 mV (vs. Ag/AgCl)) allows for the quantitation of bromine (Br₂ + 2e^? ? 2Br^?) and bromide (2Br^? ? Br₂ + 2e^?) respectively. The results yielded a detection limit of 8.5 µM for triacetone triperoxide with a sensitivity of 0.026 µA µM^? 1. The detection limits of 16.3 µM and 14.9 µM were found respectively for HMTD and H₂O₂ based on the appearance of Bromine. These results indicate a possibility to develop a handheld sensor for TATP dermination.     

Comparative antioxidant activity,proteolysis and in vitro α-amylase and α-glucosidase inhibition of Allium sativum-yogurts made from cow and camel milk

The presence of extract of plant with medicinal properties during milk fermentation could enhance the therapeutical values of yogurt. In the present study, the effects of Allium sativum on the changes in post-acidification, total phenolic content (TPC), proteolysis by o-phthaldialdehyde (OPA) assay, antioxidant activity by (1,1-diphenyl-2-picrylhydrazyl radical (DPPH) inhibition) and capacity to inhibit in vitro α-amylase and α-glucosidase activities in cow or camel milk yogurt (MY) during 21 day refrigerated storage were investigated. The presence of A. sativum enhanced more pH reduction for camel-MY than for cow-MY compared to their respective controls during storage. The reverse was true for total titratable acid. TPC in camel-MY was higher (p < 0.05) than that in cow-MY. The presence of A. sativum in cow- and camel-MYs elevated (p < 0.05) the TPC, but these changed little during storage. Antioxidant activities (18–38% DPPH inhibition) were not different in both types of yogurts, either in the absence or in the presence of A. sativum. However, camel-MY had an increase (p < 0.05) in antioxidant activities (49–65%) during 7–21 days of storage. OPA values on day 0 was higher for camel-MY (368.2 ± 14.8 mg/g) than for cow-MY (80.1 ± 3.2 mg/g). The presence of A. sativum increased OPA values more for cow-MY than for camel-MY (3.0- and 1.3-folds, respectively). Higher inhibition (p < 0.05) of α-amylase by camel-MY compared to cow-MY occurred whereas α-glucosidase inhibition by cow-MY reduced (p < 0.05) as a result of refrigeration greater than 7 days. In general, the addition of A. sativum caused more antioxidant activities, proteolysis and enzymes (α-amylase and α-glucosidase) inhibition in camel-MY than in cow-MY.     

Gas Chromatography-Mass Spectroscopic,high performance liquid chromatographic and In-silico characterization of antimicrobial and antioxidant constituents of Rhus longipes (Engl)

Rhus longipes is one of those underutilized plant species with inherent values. Therefore, we conducted a phytochemical study and investigated the antioxidant and antimicrobial potentials of the plant extracts. Aqueous and ethanol extract was subjected to phytochemical analysis. Gas chromatography-mass spectroscopy was performed to identify the volatile compounds while high performance liquid chromatography was done to identify the phenolic and flavonoids in the ethanol extract. Bioactivity and molecular docking analysis was also done for the identification of the bioactive constituents. Tannins, flavonoids, phenolics, terpenoids, steroids, alkaloids, and saponins were identified both in the ethanol and in aqueous extracts of R. longipes. The extracts and ascorbic acid exhibited radical inhibition in a concentration dependent manner. The IC₅₀ values; 3.23, 4.13, 70.75 µg/mL (ABTS), 200.82, 103.63, 390.83 µg/mL (DPPH), 10.06, 93.46, 253.26 µg/mL (O₂), and 99.77, 109.23, 446.34 µg/mL (NO) for ascorbic acid, ethanol and aqueous extract respectively showed that ethanol extract exhibited better radical inhibition than the aqueous extract. 4-hydroxybenzoic and 4-hydroxycoumarin were the most abundant phenolics in the extract. The ethanol extract of R. longipes demonstrated broad-spectrum antibacterial activity with inhibition zone of 25.5 mm against S. aureus, 27.5 mm against E. coli, and 20.5 mm against P. aeruginosa. The identified phytochemicals demonstrated inhibitory potentials against bacterial glucosamine 6-phosphate synthase, penicillin-binding protein 3, DNA gyrase and β-lactamase. It is evident that R. longipes have some antioxidant and antibacterial properties and the plant contain important phytochemicals with ability to retard food oxidation and deterioration and thus could be annexed for various industrial and medicinal purposes.     

Ab initio calculations and mechanism of two proton migration reactions of ethoxy radical

We present a direct ab initio and density functional theory dynamics study of the thermal rate constants of the two H-migration reactions of C₂H₅O radical. MPW1K/6-31+G(d,p) methods were employed to optimize the geometries of all stationary points and to calculate the minimum energy path (MEP). The energies of all the stationary points were refined at the QCISD(T)/aug-cc-pVTZ level of theory. The thermal gas phase rate constants were evaluated based on the energetics from the QCISD(T)/aug-cc-pVTZ//MPW1K/6-31+G(d,p) level of theory using both microcanonical variational transition state theory (μVT) and canonical variational transition state theory (CVT) with the Eckart tunneling correction in the temperature range of 200–2500 K. The extended Arrhenius expression fitted from the μVT/Eckart rate constants of 1,2 H-shift and 1,3 H-shift reactions of C₂H₅O radical in the temperature range of 200–2500 K are k = 3.90 × 10⁻³¹T^12.4e^{(−2.13 × 103/T)} and k = 2.83 × 10⁻²⁹T^11.9e^{(−2.24 × 103/T)} s⁻¹, respectively. The two isomerization rate constants exhibited positive temperature dependence in the calculated temperature region. The variational effects for the two isomerizations of ethoxy radical are small and the tunneling effects are important in the low temperature range. The titled reactions are minor and not essential compared to the decomposition pathways of ethoxy radical.     

Strong intramolecular ferromagnetic couplings in nickel(II) and copper(II) complexes chelated with tert-butyl 5-methoxy-2-pyridyl nitroxide

We successfully isolated a new paramagnetic bidentate ligand tert-butyl 5-methoxy-2-pyridyl nitroxide (meopyNO). Complexation of nickel(II) and copper(II) perchlorates with meopyNO gave the corresponding ML₂-type bis-chelated compounds. The magnetic studies showed that they were ground high-spin molecules with 2J/k_B = +288(5) and +178(3) K for [M(meopyNO)₂(H₂O)₂] · (ClO₄)₂ (M = Ni and Cu, respectively), where the spin Hamiltonian is defined as H = ?2J(S₁ · S₂ + S₂ · S₃). From the crystallographic analysis, the torsion angles (?) around M–O–N–C_2py were 4.2(3)° and 6.87(19)°, respectively, being so small that the orthogonality between the magnetic radical π1 and the metal dσ orbitals would be guaranteed.     

Gamma irradiation induced enhancement of phenylalanine ammonia-lyase (PAL) and antioxidant activity in peach (Prunus persica Bausch,Cv. Elberta)

Effect of medium dose gamma irradiation on PAL and antioxidant activity of peach fruit was investigated. Peach fruit after harvest at commercial maturity was irradiated in the dose range 1.0–2.0 kGy, stored under refrigerated conditions (3±1 °C, RH 80%) and evaluated at intervals of 7 days. The antioxidant activity as determined by DPPH and FRAP methods revealed significant (p≤0.05) increase particularly in the dose range 1.6–2.0 kGy. During storage, maximum increase in both PAL and antioxidant activity was observed after 21 days. Positive correlation (r=0.75) existed between antioxidant activity and total phenols. EC₅₀ values as obtained from DPPH and FRAP experiments were significantly (p≤0.05) lower in irradiated fruits compared to control.     

Preferential crystallization in an unusual case of conglomerate with partial solid solutions

Ethanolamine mandelate (E.M.) crystallizes as a stable conglomerate and has been found to form partial solid solutions. The crystal structure of the pure enantiomer has been solved from single-crystal X-ray diffraction. In order to determine the extreme compositions of the partial solid solutions in equilibrium (87% ee), the isothermal ternary section in the system [(+)-E.M.–(−)-E.M.–(ethanol–water azeotropic mixture)] was established at 25 °C. Several consecutive preferential crystallization attempts (AS3PC method) were undertaken between T_B = 41 °C (starting temperature) and T_F = 25 °C (final temperature) on a 2-L scale.We initially expected to obtain crude crops whose enantiomeric purities would be close to that defined by the isothermal ternary phase diagram (T_F). In fact, the filtered solid phases are of lower enantiomeric excesses: ca. 62% ee. The monitoring of the mother liquor composition over the course of the entrainment shows that the enantiomeric composition of the filtered solid is related to the metastable equilibria involved in the preferential crystallization.     

Kinetic spectrophotometric method for trace determination of thiocyanate based on its inhibitory effect

A kinetic spectrophotometric method for the determination of thiocyanate, based on its inhibitory effect on silver(I) catalyzed substitution of cyanide ion, by phenylhydrazine in hexacyanoferrate(II) is described. Thiocyanate ions form strong complexes with silver(I) catalyst which is used as the basis for its determination at trace level. The progress of reaction was monitored, spectrophotometrically, at 488 nm (λ_max of [Fe(CN)₅PhNHNH₂]^3?, complex) under the optimum reaction conditions at: 2.5 × 10^?3 M [Fe(CN)₆]^4?, 1.0 × 10^?3 M [PhNHNH₂], 8.0 × 10^?7 M [Ag⁺], pH 2.8 ± 0.02, ionic strength (μ) 0.02 M (KNO₃) and temperature 30 ± 0.1 °C. A linear relationship obtained between absorbance (measured at 488 nm at different times) and inhibitor concentration, under specified conditions, has been used for the determination of [thiocyanate] in the range of 0.8–8.0 × 10^?8 M with a detection limit of 2 × 10^?9 M. The standard deviation and percentage error have been calculated and reported with each datum. A most plausible mechanistic scheme has been proposed for the reaction. The values of equilibrium constants for complex formation between catalyst–inhibitor (K_CI), catalyst–substrate (K_s) and Michaelis–Menten constant (K_m) have been computed from the kinetic data. The influence of possible interference by major cations and anions on the determination of thiocyanate and their limits has been investigated.     

Diazenyl schiff bases: Synthesis,spectral analysis,antimicrobial studies and cytotoxic activity on human colorectal carcinoma cell line (HCT-116)

A series of diazenyl schiff bases have been synthesized by reaction of salicylaldehyde containing azo dyes with various substituted aniline derivatives in the presence of acetic acid as catalyst. The structures of diazenyl derivatives were determined by FTIR, UV–vis, ¹H NMR, ¹³C NMR, CHN analysis, fluorimetric and mass spectroscopic studies. The synthesized derivatives were screened for their in vitro antimicrobial activity against various Gram-positive (S. aureus, B. subtilis, B. cereus), Gram-negative (S. typhi, S. enterica, E. coli, P. aeruginosa) bacterial and fungal (C. albicans, A. niger and A. fumigatus) strains, using cefadroxil (antibacterial) and fluconazole (antifungal) as standard drugs. The diazenyl schiff bases were also screened for their cytotoxicity against human colorectal carcinoma cell line (HCT-116) using 5-fluorouracil as standard drug by Sulforhodamine-B Stain (SRB) assay. The schiff bases exhibited significant activity toward both Gram-positive, Gram-negative bacterial and fungal strains. Most of the synthesized derivatives showed high activity against S. enterica. 4-((2,5-Dichlorophenyl)diazenyl)-2-((3-bromophenylimino)methyl)phenol (SBN-40) was found to be very active against S. aureus, B. cereus and E. coli, with MIC = 0.69 (µM/ml × 10²). The compound 4-((2-bromophenyl)diazenyl)-2-((4-nitrophenylimino)methyl)phenol (SBN-13) possessed comparable activity (IC₅₀ = 7.5 µg/ml) to the standard drug 5-fluorouracil (IC₅₀ = 3.0 µg/ml) against human colorectal carcinoma cell line (HCT-116).     

Papain incorporated chitin dressings for wound debridement sterilized by gamma radiation

Wound debridement is essential for the removal of necrotic or nonviable tissue from the wound surface to create an environment conducive to healing. Nonsurgical enzymatic debridement is an attractive method due to its effectiveness and ease of use. Papain is a proteolytic enzyme derived from the fruit of Carica papaya and is capable of breaking down a variety of necrotic tissue substrates. The present study was focused on the use of gamma radiation for sterilization of papain dressing with wound debriding activity. Membranes with papain were prepared using 0.5% chitin in lithium chloride/dimethylacetamide solvent and sterilized by gamma radiation. Fluid absorption capacity of chitin–papain membranes without glycerol was 14.30±6.57% in 6 h. Incorporation of glycerol resulted in significant (p<0.001) increase in the absorption capacity. Moisture vapour transmission rate of the membranes was 4285.77±455.61 g/m²/24 h at 24 h. Gamma irradiation at 25 kGy was found suitable for sterilization of the dressings. Infrared (IR) spectral scanning has shown that papain was stable on gamma irradiation at 25–35 kGy. The irradiated chitin–papain membranes were impermeable to different bacterial strains and also exhibited strong bactericidal action against both Gram-positive and Gram-negative bacteria. The fluid handling characteristics and the antimicrobial properties of chitin–papain membranes sterilized by gamma radiation were found suitable for use as wound dressing with debriding activity.     

Volatile components,antioxidant and antimicrobial activity of Citrus acida var. sour lime peel oil

Essential oil of Citrus acida Roxb. var. sour lime was analyzed by GC–MS. Out of 59 components 18 were identified from their fragmentation pattern. Among the identified constituents, o-cymene (16.62%) was found as a major component followed by α-cedrene (10.57%), decadienal (8.043%), bisabolene (5.066%) and β-humelene (4.135%). Citronellyl acetate (2.371%), linalool acetate (2.371%), carvone (1.806%), decanone (1.474%), isopulegol acetate (1.296%), farnesol (1.254%), 4′-methoxyacetophenone (1.207%), and Δ-carene (1.070%) were found in minor quantities whereas α-terpineole (0.607%), dihydroxylinalool acetate (0.650%), cis-nerone (0.574%), caryophyllene oxide (0.433%), and 2,2-dimethyl-3,4-octadienal (0.375%) were found in minute amounts.The antimicrobial activity of the essential oil of C. acida was determined by disc diffusion method, against different bacteria (Bacillus subtilis, Bacillus cereus, Staphylococcus aureus, Escherichia coli, Enterobacter aerogenes, Salmonella typhymurium) and fungi (Aspergillus ficuum, Aspergillus niger, Aspergillus fumigatus, Aspergillus flavis, Fusarium saloni, Fusarium oxysporum, Pencillium digitatum, Candida utilis). Maximum zone of inhibition was resulted against B. subtilis (22 mm) followed by C. utilis (20 mm) and B. cereus (19.8 mm), whereas the minimum zone of inhibition was shown by P. digitatum (10 mm). The inhibition zones, measured after 48 h and 96 h, showed that it is active against all tested bacteria and fungi. The results of antioxidant activity of essential oil of C. acida var. sour lime showed that it was able to reduce the stable radical DPPH to yellow-colored DPPH-H reaching 91.7% of DPPH scavenging effect comparative to ascorbic acid being a strong antioxidant reagent.     

Hypervalent iodine(III) catalyzed rapid and efficient access to benzimidazoles,benzothiazoles and quinoxalines: Biological evaluation of some new benzimidazole-imidazo[1,2-a]pyridine conjugates

A rapid, simple and highly efficient method for the synthesis of a variety of 2-aryl-benzimidazoles, 2-aryl-benzothiazoles and quinoxalines has been developed using Koser’s reagent [PhI(OH)OTs] as catalyst. The present work highlights the potential of Koser's reagent ([PhI(OH)OTs]) for the synthesis of benzimidazoles, benzothiazoles and quinoxalines, etc. Short reaction time, high yields, importantly low catalyst loading, broad substrate scope and scalability are the salient features of this methodology. Particularly, this method has been employed successfully to synthesize highly structured indole-benzimidazole and quinoxaline-6-carboxamide derivatives as well as biologically important benzimidazole-imidazo[1,2-a]pyridine conjugates in moderate to good yields. These remarkable features make the present methodology a valid contribution to the existing precedents for the synthesis of benzimidazoles, etc. In the MTT assay, benzimidazole-imidazo[1,2-a]pyridine conjugates 3s, 3t and 3v were found to be active on MCF-7 (IC₅₀ values of 5.10 ± 0.10, 8.23 ± 0.02, and 10.75 ± 0.03 µM, respectively) and MDA-MB-231 cell lines (IC₅₀ values of 10.83 ± 0.13, 7.68 ± 0.05, and 7.87 ± 0.24 µM, respectively). Flow-cytometry analysis revealed that the treatment of MCF-7 cells with compound 3s showed moderate effect on the progression of G0/G1 phase of the cell cycle.     

ATP- and redox-induced conformational changes in the activator of the radical enzyme 2-hydroxyisocaproyl-CoA dehydratase

A [4Fe–4S]¹⁺ cluster-containing protein activates 2-hydroxyisocaproyl-CoA dehydratase by an ATP-driven electron transfer. The activator has been proposed to change its conformation by MgATP similarly to nitrogenase Fe-protein. Iron chelation by bathophenanthroline removed the reduced [4Fe–4S]¹⁺ cluster from the activator in an ATP-dependent manner (rate, v = 0.128 ± 0.004 min⁻¹; K_m = 21 ± 1 μM); with ADP no chelation was observed (v < 0.001 min⁻¹). Chelation of the oxidised [4Fe–4S]²⁺ cluster occurred faster with ADP (v = 0.34 ± 0.05 min⁻¹) than with ATP (v = 0.132 ± 0.005 min⁻¹). The data indicate that reduction of the activator and binding of ATP induce conformational changes necessary to transfer the electron to the dehydratase. Interaction of both proteins promotes ATP hydrolysis (K_m = 0.5 ± 0.1 μM).     

Antioxidant activity and inhibition of key enzymes linked to type-2 diabetes and hypertension by Azadirachta indica-yogurt

Azadirachta indica is widely used in traditional medicine to treat diabetes and hypertension. In the present study A. indica-yogurt was prepared and refrigerated up to 28 days. pH of A. indica-yogurt was lower whereas total titratable acid (TTA) was higher than plain-yogurt during storage. The total phenolic content (TPC) and antioxidant capacity increased during storage. A. indica-yogurt had highest TPC (74.9 ± 5.1 μgGAE/ml; p < 0.05) on day 28 and DPPH inhibition (53.1 ± 5.0%; p < 0.05) on day 14 compared to plain-yogurt (29.6 ± 1.1 μgGAE/ml and 35.9 ± 5.2%, respectively). The OPA values increased between day 7 and 21 of storage but reduced on the 4th week of storage with values for A. indica-yogurt being higher (p < 0.05) than plain-yogurts. Maximum inhibition of α-amylase (47.4 ± 5.8%), α-glucosidase (15.2 ± 2.5%) and angiotensin-1 converting enzyme (ACE, 48.4 ± 7.2%) by plain-yogurt water extract occurred on day 7, 14 and 0, respectively. A. indica-yogurt water extract increased the inhibition to maximal values for α-glucosidase and ACE on day 14 of storage (15.9 ± 10.1% and 79.70 ± 11.2%, respectively) and for α-amylase on day 21 of storage (54.8 ± 3.2%). A. indica-yogurt has higher TPC, antioxidant activities and enzymes inhibitory effects than plain-yogurt. Thus A. indica-yogurt may have the potential to serve as enhanced functional yogurt with anti-diabetic and anti-hypertension activities.     

High-throughput investigation and characterization of strontium-phosphonatoethanesulfonates

Using the polyfunctional ligand 2-phosphonethanesulfonic acid (H₃L) a high-throughput (HT) study was started for the systematic investigation of the system SrCl₂/H₃L/NaOH/H₂O. The HT experiment comprising 48 individual reactions were performed to systematically investigate the influence of pH of the starting mixture as well as the molar ratio Sr²⁺:H₃L. Two new compounds SrH(O₃P–C₂H₄–SO₃) (1) and Sr₃(O₃P–C₂H₄–SO₃)₂(H₂O)₂ (2) were obtained and structurally characterized by single-crystal X-ray diffraction. The reaction products synthesized under hydrothermal conditions always contain traces of SrSO₄, which are due to the decomposition of small amounts of the ligand. While compound 2 could only be obtained under hydrothermal conditions, the synthesis of 1 could be accomplished under milder reaction conditions and a reaction scale-up could be performed. Compound 1 crystallizes in a monoclinic system with space group C2/c (no. 15), a = 534.73(11) pm, b = 1648.7(3) pm, c = 825.43(17) pm, β = 105.34(3)°, V = 701.8(2)–10⁶ pm³, Z = 4, R1 = 0.0268, and wR₂ = 0.0642 for I > 2σ(I). Compound 2 crystallizes in a triclinic system with space group P-1 (no. 2), a = 700.97(14) pm, b = 1008.5(2) pm, c = 1274.8(3) pm, α = 97.63(3)°, β = 92.03(3)°, γ = 92.03(3)°, V = 843.7(3)–10⁶ pm³, Z = 2, R1 = 0.0360, and wR₂ = 0.0896 for I > 2σ(I). In the structure of compound 1 the phosphorous and sulfur atoms cannot be distinguished due to identical crystallographic positions. Thus, an averaged structure was obtained which is built up by edge-sharing SrO₈ polyhedra that form infinite M–O–M chains. Compound 2 contains corner-, edge-, and face-sharing SrO₈ polyhedra which form inorganic M–O–M layers. These M–O–M chains (1) and layers (2) are connected to a three-dimensional network by the –CH₂CH₂– group of the ligand, respectively. Additional characterization by thermogravimetric analysis and IR-spectroscopy for compound 1 is also presented.