Solvent Water Research Articles

Epicatechin Isolated from Litchi chinensis Sonn. (Litchi) Fruit Peel Ethyl Acetate Extract Modulated Glucose Uptake in Chang Cells and Suppressed ROS Production in RAW 264.7 Macrophages.

Bioactive flavonoid epicatechin has been reported in the peel of litchi fruit but isolated from its hydroalcoholic extracts. This study isolated epicatechin with cellular glucose uptake modulatory and ROS production inhibitory properties from the ethyl acetate (EtOAc) extract using a bioassay-guided approach. The fruit peel was defatted with hexane and sequentially extracted using dichloromethane (DCM), EtOAc, methanol (MeOH) and water. In vitro phytochemical models, namely antioxidant (Fe3+ reducing, radical scavenging and anti-linoleic acid peroxidative) and glycaemic control (α-glucosidase and α-amylase inhibitory and glucose uptake modulatory), were employed for the bioassay-guided isolation, while the isolated compound was characterised using NMR and mass spectrometry and assessed for dose-dependent inhibition of α-glucosidase and lipopolysaccharide (LPS)-induced cellular ROS production, as well as modulation of cellular glucose uptake. Relative to the other extracts, the EtOAc extract had appreciable phenol and flavonoid contents, which perhaps influenced its potent anti-lipid peroxidative (65.0%) and α-glucosidase inhibitory (52.4%) effects. The α-glucosidase inhibitory potency of the fractions (1-8) from the EtOAc extracts correlated with their flavonoid contents, with fraction 5 outperforming other fractions. The fraction comprised a pool of fractions obtained from the DCM:MeOH:water (7:3:0.281 v/v/v) solvent system. LC-MS revealed the predominant presence of epicatechin in fraction 5, which was later isolated from one of the sub-fractions (sub-fraction 4) of fraction 5. This sub-fraction had stronger anti-lipid peroxidative (65.5%), α-glucosidase inhibitory (65.8%) and glucose uptake modulatory (38.2%) effects than the other sub-fractions from fraction 5, which could have been influenced by the isolated epicatechin. Moreover, the isolated epicatechin inhibited α-glucosidase (IC50 = 35.3 µM), modulated cellular glucose uptake (EC50 = 78.5 µM) and inhibited LPS-induced ROS production in RAW 264.7 macrophages in a dose-dependent fashion [IC50 = 18.9 µM; statistically comparable (p > 0.05) to ascorbic acid, IC50 = 9.57 µM]. Epicatechin from litchi peel EtOAc extract could potentiate glucose uptake modulatory, α-glucosidase inhibitory and ROS suppressive capacities, which could be influential in the use of litchi fruit peel for managing diabetes and associated oxidative damage.

PH‐sensitive size/surface charge‐adaptive quaternary ammonium salt copolymer micelles for antibiofilm activity against Staphylococcus aureus

AbstractThe low penetration of antibacterial materials within biofilms results in a 1000‐fold decrease in bactericidal efficiency, complicating the complete removal of biofilms and potentially leading to persistent and recurrent bacterial infections that significantly impact human health. In this study, we present a multifunctional pH‐responsive antibacterial material based on random copolymers poly(dimethylaminoethyl methacrylate decyl ammonium bromide‐co‐polyethylene glycol methacrylate) copolymer (PQACs10‐co‐PEGMA10). The PQACs10‐co‐PEGMA10 copolymers could self‐assemble into micelles in selective solvent water. With the stealth function of polyethylene glycol (PEG), the PQACs10‐co‐PEGMA10 micelles can rapidly penetrate biofilms in a physiological environment and exhibit excellent antibacterial activity by exposing the quaternary ammonium salt (QACs) in an acidic microenvironment to eliminate biofilm. Furthermore, PQACs10‐co‐PEGMA10 micelles were applied as coatings using a dropwise method. The PEG chain formed hydration layer and the QACs chain for sterilization can hinders bacterial adhesion and proliferation, thereby preventing biofilm formation. The results show that the minimal inhibit concentration values and minimum biofilm eradication concentrations of the PQACs10‐co‐PEGMA10 micelles against Gram‐positive Staphylococcus aureus were 64 and 128 μg/mL, respectively. The antifouling and antibacterial rates of micelle coating against S. aureus were more than 99.99%. Taken together, the pH‐responsive PQACs10‐co‐PEGMA10 micelles demonstrate a good ability to clear and prevent biofilms, holding promise for complete biofilm removal and a reduction in biofilm‐related infections.

In vitro antioxidant and antibacterial activities of Ajuga integrifolia leaf extracts obtained with different solvents

BackgroundMany diseases are increasingly recognized as public health concerns worldwide because of the increasing incidence of multidrug-resistant bacteria. Recently, interest in the use of indigenous medicinal plants to treat infectious illnesses has increased, highlighting the need to find new bioactive phytochemicals. Ajuga integrifolia is a plant commonly utilized in traditional drugs to treat a wide range of diseases, although its effectiveness has not been scientifically validated. The present study aimed to evaluate the total phenolic and flavonoid contents and assess the biological activities of A. integrifolia leaf extracts produced via different solvent systems.MethodsSoxhlet extraction was employed to obtain crude extracts from different solvents (methanol, ethanol and water). The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric-reducing power assays were used to measure the antioxidant activity, and the antibacterial activity of the extract was evaluated on the basis of its minimum inhibitory concentration (MIC) against two gram-negative bacteria (Escherichia coli (ATCC-25922) and Pseudomonas aeruginosa (ATCC-43495)) and two gram-positive bacteria (Staphylococcus aureus (ATCC-25923) and Streptococcus pyogenes (ATCC-19615)) via the agar disk-diffusion technique.ResultsA significant amount of total phenolic content (TPC) and flavonoid content (TFC) were present in all the extracts. The extracts presented powerful antioxidant activity in all the assays. The disc diffusion and MIC results revealed the ability of the methanol and ethanol extracts of A. integrifolia leaves to inhibit S. aureus growth at a concentration of 3.125 mg/mL. However, the water extracts were ineffective against E. coli and P. aeruginosa.ConclusionsThese findings indicate that A. integrifolia leaf extracts have reasonable biological activities. These findings underscore the importance of A. integrifolia leaves as a source of health benefits.

Pharmacological Potential and Electrochemical Characteristics of Typha angustifolia Pollen

Typha angustifolia L. (TA) pollen has been utilized as a traditional Chinese medicine for treating various internal and external traumas. Moreover, bioactive compounds possess diverse pharmacological activities. This study aims to evaluate the antiviral properties of TA based on its ability to generate bioenergy, capable of inhibiting viruses. TA pollens were extracted using water and ethanol solvents. These extracts were utilized to identify the phytochemical contents and correlate with the antioxidant activity via 2,2-diphenyl-1-picrylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays. HPLC analysis was conducted to identify its electron-shuttling compositions. The bioenergy-generating characteristics were determined via microbial fuel cells. The water extract (TA-W) showed higher antioxidant activity due to a higher phenolic and flavonoid content compared to the ethanol extract (TA-E). Quercetin-3-O-(2G-α-L-rhamnosyl)-rutinoside, quercetin-3-O-neohesperidoside, and quercetin are the electron shuttles (ES) identified out of the 11 compounds. TA obtained a 1.39 ± 0.10 amplification factor of power generation that indicates potential bioenergy-generating and associated antiviral characteristic properties. The findings may provide a foundation for developing antiviral medications specifically designed to target virus-related diseases, while minimizing the risk of drug toxicity and reducing the costs of drug development.

Ionising and ultraviolet radiation induce the secretion of melanin in Tetrahymena pyriformis

ABSTRACT The objective of this study was to determine the effect of ionising and ultraviolet radiation on stimulating melanin secretion in Tetrahymena pyriformis. Cell cultures were exposed to different doses of radiation for 48, 72 and 96 h. After incubation, melanin was extracted and analysed. Our results showed that melanin concentration increased with increasing irradiation dose and exposure duration. Melanin was insoluble in water and organic solvents but soluble in alkaline and acidic solutions. A linear correlation between the logarithm of melanin absorbance and wavelength ranging from 400 to 600 nm was observed. The HPLC chromatograms of melanin degradation products by the alkaline hydrogen peroxide oxidation method revealed the existence of four peaks. The natural melanin standard extracted from the cuttlefish Sepia officinalis was used as a reference compound of eumelanin markers. These markers were detected in control cells, irradiated cells and black human hair but with different intensities.

In Silico Analysis of Vitamin D Interactions with Aging Proteins: Docking, Molecular Dynamics, and Solvation Free Energy Studies

Aging is a natural process that is also influenced by some factors like the food someone eats, lifestyle decisions, and impacts on general health. Despite the recognized role of nutrition in modulating the molecular and cellular mechanisms underlying aging, there is a lack of comprehensive exploration into potential interventions that can effectively mitigate these effects. In this study, we investigated the potential anti-aging properties of vitamin D by examining its interactions with key molecular targets involved in aging-related pathways. By using molecular docking and dynamics techniques, we evaluate the interactions and stability of vitamins D2 and D3 with key proteins involved in aging pathways, such as SIRT1, mTOR, AMPK, Klotho, AhR, and MAPK. Our results reveal promising binding affinities between vitamin D and SIRT1 forms, with energy values of −48.33 kJ/mol and −45.94 kJ/mol for vitamins D2 and D3, respectively, in aqueous environments. Moreover, molecular dynamics simulations revealed that the vitamin D3–SIRT1 complex exhibited greater stability compared with the vitamin D2–SIRT1 complex. The study calculated the solvation free energy to compare the solubility of vitamins D2 and D3 in water and various organic solvents. Despite their strong interactions with water, both vitamins exhibited low solubility, primarily due to the high energy cost associated with cavity formation in the aqueous environment. Compared with other solvents, water demonstrated particularly low solubility for both vitamins. This suggested that vitamins D2 and D3 preferred binding to aging receptors over dissolving in bulk aqueous environments, supporting their strong therapeutic interactions with these receptors. These findings shed light on the molecular mechanisms underlying vitamin D’s potential anti-aging effects and lay the groundwork for developing nutraceuticals targeting aging and associated diseases. Understanding these mechanisms holds promise for future interventions aimed at promoting healthy aging and enhancing overall well-being.

Comparative analysis of phytochemical constituents in different parts of Aspilia africana: A potential medicinal plant for therapeutic applications

BackgroundAmong the diverse array of plants used in traditional medicine, Aspilia africana is highly valued due to its high efficacy against many ailments and its well-noted potential for wound healing. The plant has been widely used to cure illnesses in traditional medicine, which is practiced throughout much of Africa, where an estimated about 80 % of the population gets their main healthcare from this source. PurposeThis study aimed to qualitatively screen the phytochemical constituents of Aspilia africana to confirm its therapeutic properties and generate scientific proof that justifies its usage in traditional medicine. Study designAspilia africana stem, roots, and leaves were screened qualitatively for phytochemical components using pet-ether extracts and distilled water, and qualitative data was generated. MethodExtraction of phytochemicals was done by using the cold maceration method, 150 g of each of the dried parts were taken and packed into 3 separate glass jars containing 500 ml of each solvent (distilled water and pet-ether solvents) and allowed to stand for 24 h. ResultsThis study found 15 phytochemicals which include tannins, phlobatannins, alkaloids, terpenoids, flavonols, glycosides, phenols, steroids, anthraquinones, saponins, phytosterols, proteins and amino acids, coumarins, cardiac glycosides, and flavonoids in A. africana. The occurrence of the therapeutic components in the aqueous extract of roots, leaves, and stem were nine (9), nine (9), and eight (8) respectively, and that of the pet-ether extract were nine (9), eight (8), and seven (7) in roots, leaves, and stem respectively. ConclusionThe presence of these phytochemicals indicates prospective uses in the pharmaceutical and nutraceutical industries, as well as supports the use of Aspilia africana in traditional medicine. To completely understand and make use of the plant's medicinal qualities, further investigations are required on its anti-microbial activities.

Effect of solvent polarity on yield extract, antioxidant and antibacterial activities of phytochemicals from Andrographis paniculata leaves

ABSTRACT In this study, the impact of solvent polarity on the extraction yield, antibacterial activity and antioxidant characteristics of phytochemical compounds derived from Andrographis paniculata leaves was investigated. The simplicia of A. paniculata was macerated in different organic solvents with raising polarity (n-Hexane, ethyl acetate, dichloromethane, ethanol, methanol, methanol–water) at room temperature for 24 h. Preliminary screening revealed that the yield extract, phytochemical composition, antibacterial activity and antioxidant properties were influenced by the polarity of the solvent used for extraction. The optimum yield extract was obtained using a methanol–water solvent (50:50, v/v) of 15.46%. The most active antibacterial activity against biofilm-forming bacteria (Pseudomonas aeruginosa) was obtained using ethyl acetate and dichloromethane with a minimum inhibition concentration (MIC) value of 312.5 µg mL−1. Meanwhile, the antioxidant properties of A. paniculata leaf extract with all solvents shows a very weak level. The antibacterial activity and antioxidant properties of A. paniculata leaf extracts are related to the phytochemical content in the extract. This result is evident in the extract with ethyl acetate solvents with the highest total phenolic and flavonoid values. However, GC-MS analysis of A. paniculata extract revealed 20 components, with Supraene having the greatest compounds.

The morphology and thermo-regulating properties of electrospun PVA/PEG/Ag nanofibers of water and formic acid solvents

The solvent utilized in the electrospinning solution significantly impacts the morphology and thermal properties of PVA/PEG/Ag nanofibers. To prevent leakage of PEG, solid-liquid phase change, a suitable encapsulation method involves utilizing a combined single-phase electrospinning that incorporates PEG and supporting polymer of PVA. This study aims to investigate the production of thermal-regulating nanofibers from a solution containing PEG 6000, PVA, and AgNO3 precursor using electrospinning method. The influence of water and formic acid as a solvent on the morphology of the nanofibers was examined using SEM. The selected nanofiber characteristics and thermal performance were evaluated through FE-SEM, FT-IR, XRD, DSC, PCM leakage, and DTG tests. SEM images revealed that the formic acid-based nanofibers, consisting of two polymers and two polymer/Ag NPs, exhibited a nanoporous membrane, possibly due to enhanced cross-linking compared to water-based nanofibers. The results of the DSC indicated that fusion and solidification enthalpies of the selected water-based nanofibers were measured as 70.09 and −85.43 J/g, respectively. Unexpectedly, the DSC results indicated higher enthalpies compared to unheated samples. SEM image after thermal cycles, leakage results, and DTG of water-based nanofibers demonstrated their production with thermal stability, reliability, and the potential for creating shape-stable, thermally regulating fabricated nanofibers for various applications.

Solution and Surface Solvation of Nitrate Anions with Iron(III) and Aluminum(III) in Aqueous Environments: A Raman and Vibrational Sum Frequency Generation Study.

Hydrated trivalent metal nitrate salts, Fe(NO3)3·9H2O and Al(NO3)3·9H2O, in both solid and aqueous phases are investigated. Raman and surface-selective vibrational sum frequency generation (SFG) spectroscopy, are used to shed light on ion-ion interactions and hydration in several spectral regions spanning low frequency (440-550 cm-1) to higher frequency modes of nitrate and water (720, 1050, 1250-1450, and 2800-3750 cm-1). These frequencies span the metal-water mode, nitrate in-plane deformation, nitrate symmetric and asymmetric modes, and the OH stretch of condensed phase water molecules. Comparison to NaNO3, and in some cases KNO3, is also shown, providing insight. Splitting and frequency shifts are observed and discussed for both the solid state and solution phase. The Lewis acidity of Fe3+ and Al3+ ions plays a significant role in the observed spectra, in particular for the nitrate asymmetric band splitting and frequency shift. The spectral response from water solvation for iron and aluminum nitrates is nonlinear as compared to linear for sodium nitrate, suggesting significantly different solvation environments that are limited by water hydration capacity at higher concentrations. Moreover, a non-hydrogen bonded OH, dangling OH, from hydrating water molecules is observed spectroscopically for Al and Fe nitrate solutions. Furthermore, aluminum nitrate perturbs the surface water structure more than iron nitrate despite aluminum being a weaker Lewis acid. The surface water structure is thus found to be unique for the Al(NO3)3 solutions as compared to both Fe(NO3)3 and NaNO3, such that surface solvation is more pronounced. This observation exemplifies the nature of the Fe(III) and Al(III) ions and their substantial influence on the surface water structure.

Adsorption of polyelectrolytes in the presence of varying dielectric discontinuity between solution and substrate.

We examine the interactions between polyelectrolytes (PEs) and uncharged substrates under conditions corresponding to a dielectric discontinuity between the aqueous solution and the substrate. To this end, we vary the relevant system characteristics, in particular the substrate dielectric constant ɛs under different salt conditions. We employ coarse-grained molecular dynamics simulations with rodlike PEs in salt solutions with explicit ions and implicit water solvent with dielectric constant ɛw = 80. As expected, at low salt concentrations, PEs are repelled from the substrates with ɛs < ɛw but are attracted to substrates with a high dielectric constant due to image charges. This attraction considerably weakens for high salt and multivalent counterions due to enhanced screening. Furthermore, for monovalent salt, screening enhances adsorption for weakly charged PEs, but weakens it for strongly charged ones. Meanwhile, multivalent counterions have little effect on weakly charged PEs, but prevent adsorption of highly charged PEs, even at low salt concentrations. We also find that correlation-induced charge inversion of a PE is enhanced close to the low dielectric constant substrates, but suppressed when the dielectric constant is high. To explore the possibility of a PE monolayer formation, we examine the interaction of a pair of like-charged PEs aligned parallel to a high dielectric constant substrate with ɛs = 8000. Our main conclusion is that monolayer formation is possible only for weakly charged PEs at high salt concentrations of both monovalent and multivalent counterions. Finally, we also consider the energetics of a PE approaching the substrate perpendicular to it, in analogy to polymer translocation. Our results highlight the complex interplay between electrostatic and steric interactions and contribute to a deeper understanding of PE-substrate interactions and adsorption at substrate interfaces with varying dielectric discontinuities from solution, ubiquitous in biointerfaces, PE coating applications, and designing adsorption setups.

Very-Large-Scale GPU-Accelerated Nuclear Gradient of Time-Dependent Density Functional Theory with Tamm-Dancoff Approximation and Range-Separated Hybrid Functionals.

Modern graphics processing units (GPUs) provide an unprecedented level of computing power. In this study, we present a high-performance, multi-GPU implementation of the analytical nuclear gradient for Kohn-Sham time-dependent density functional theory (TDDFT), employing the Tamm-Dancoff approximation (TDA) and Gaussian-type atomic orbitals as basis functions. We discuss GPU-efficient algorithms for the derivatives of electron repulsion integrals and exchange-correlation functionals within the range-separated scheme. As an illustrative example, we calculate the TDA-TDDFT gradient of the S1 state of a full-scale green fluorescent protein with explicit water solvent molecules, totaling 4353 atoms, at the ωB97X/def2-SVP level of theory. Our algorithm demonstrates favorable parallel efficiencies on a high-speed distributed system equipped with 256 Nvidia A100 GPUs, achieving >70% with up to 64 GPUs and 31% with 256 GPUs, effectively leveraging the capabilities of modern high-performance computing systems.

A first-principles adsorption study of functionalized carbon, boron nitride, silicon carbon nanotubes with ifosfamide as vehicles for drug delivery: Thermal analysis

We investigated the adsorption of ifosfamide (IFS) on the outer surface of zigzag (10, 0) carbon nanotubes (CNT), boron nitride nanotubes (BNNT), and silicon carbon nanotubes (SiCNT), using density functional theory (DFT) calculations at the PBE-D3 level in a water solvent phase. Based on zero-point corrected binding energies (Ebin), IFS exhibits chemisorption through its O-head and Cl-head on CNT (−1.05 eV) compared to BNNT (−0.93 eV), characterized by covalent interaction. In contrast, IFS undergoes physisorption via its O-head on SiCNT with binding energy of −0.68 eV as the most stable model this interaction is driven by electrostatic forces. The formation of complexes between the drug and nanotubes is influenced by charge transfer dynamics. Our thermodynamic analysis demonstrates the Gibbs free energy (ΔG) and enthalpy energy (ΔH) for all models are exothermic and spontaneous. The observed decrease in binding energy for BNNT and CNT correlates with changes in their energy gap, dipole moment, and charge transfer upon IFS adsorption. Notably, SiCNT exhibits a different response with a significant energy gap change leading to an increase in dipole moment and charge transfer. These findings suggest that these nanotubes demonstrate promising sensitivity to the presence of IFS and could be explored as potential drug delivery systems for this drug.

Enhancing the conductivity and dispersion properties of polyaniline using ethyl orange

In our research, we developed a novel one-step synthesis method for polyaniline (PANI) using the organic dye Ethyl Orange (EO). This method facilitated the formation of PANI nanorods and significantly enhanced their electrical conductivity, achieving up to 13.5 S cm−1. The structural interaction between EO and PANI was confirmed through Fourier-transform infrared (FTIR) and UV–visible (UV-Vis) spectroscopy. Notably, the inclusion of EO improved PANI's dispersion properties, resulting in a zeta potential of 34 mV in water and excellent dispersibility in various organic solvents. These attributes significantly enhance the application potential of PANI nanorods, especially in protective coatings. Electrochemical impedance spectroscopy (EIS) analysis revealed that EO-PANI/WPU coatings (0.5 wt% EO-PANI) exhibited exceptional electrochemical stability and corrosion resistance in a 3.5 wt% NaCl solution. Specifically, the initial impedance magnitude (Zf=0.01 Hz, 1010 ohms) of EO-PANI/WPU coatings was approximately two orders of magnitude higher than that of traditional WPU coatings (108 ohms). Over time, the EO-PANI coatings demonstrated higher phase angles and impedance, indicating superior electrochemical stability and protective performance.

Quality and noodle-making performance of wheat flour with varied gluten strengths altered by addition of various arabinoxylans.

This study examined the effects of adding different types of arabinoxylans (AXs) to wheat flour with varying gluten strengths on flour quality and noodle-making performance, with the aim of utilizing AXs as health-enhanced ingredients. Three flours (Goso, Hojoong, and Joongmo) with low, medium, and high gluten strengths were used, along with two water-extractable AXs (E1 and E2) and one water-unextractable AX (U) with diverse molecular weights and viscosities. The addition of 2% AXs increased the water and sucrose solvent retention capacity values and decreased the gluten performance index values for all flours, with a notable effect on Goso flour by U. The dough development time was prolonged in all flours, necessitating more water for development. The sodium dodecyl sulfate sedimentation volume increased with the addition of AXs, especially with E2 and U. Pasting properties remained unaffected, suggesting a minimal impact on starch-related properties. However, noodles made with E2 and U showed deteriorated quality in terms of fresh noodle texture, weight gain, cooking water turbidity, and cooked noodle texture, in contrast to noodles made with E1 alone. Additionally, adjusting the water amount when adding U altered the textural properties, approaching that of noodles without added AXs. Overall, the impact of AXs on flour and noodle quality varied depending on their molecular weights, viscosities, and the gluten strength of the flour. Additionally, AXs could be successfully utilized by adjusting the water amount for the production of health-enhancing noodles. PRACTICAL APPLICATION: Arabinoxylans, as health-promoting ingredients, can be utilized in noodle production by optimizing the water amount and mixing time.

Leveraging analog quantum computing with neutral atoms for solvent configuration prediction in drug discovery

We introduce an approach to sampling equilibrium solvent water molecule configurations within proteins that leverages analog quantum computing. We present a complete end-to-end study from the molecular biology application to the development of the quantum algorithm to the implementation on a neutral atom quantum processing unit (QPU). To do so, we combine a quantum placement strategy to the 3D Reference Interaction Site Model, an approach capable of predicting continuous solvent distributions. The intrinsic quantum nature of such coupling guarantees molecules not to be placed too close to each other, a constraint usually imposed by hand in classical approaches. We present first a full quantum adiabatic evolution model that uses a local Rydberg Hamiltonian to cast the general problem into an antiferromagnetic Ising model. Its solution is embodied into a Rydberg atom array QPU. Following a classical emulator implementation, a QPU portage allows to experimentally validate the algorithm performances on an actual quantum computer. As a perspective of use on next generation devices, we emulate a second hybrid quantum-classical version of the algorithm. Such a variational quantum approach uses a classical Bayesian minimization routine to find the optimal laser parameters. Overall, these Quantum-3D-RISM algorithms open a route towards the application of analog quantum computing in molecular modeling and drug design. Published by the American Physical Society 2024

Extraction and Concentration of Spirulina Water-Soluble Metabolites by Ultrafiltration.

Spirulina (Arthospira platensis) is known for its rich content of natural compounds like phycocyanin, chlorophylls, carotenoids, and high protein levels, making it a nutrient-dense food. Over the past decade, research has aimed to optimize the extraction, separation, and purification of these valuable metabolites, focusing on technologies such as high-pressure processing, ultrasound-assisted extraction, and microwave-assisted extraction as well as enzymatic treatments, chromatographic precipitation, and membrane separation. In this study, various extraction methods (conventional vs. ultrasound-assisted), solvents (water vs. phosphate buffer), solvent-to-biomass ratios (1:5 vs. 1:10), and ultrafiltration (PES membrane of MWCO 3 kDa, 2 bar) were evaluated. The quantities of total protein, phycocyanin (PC), chlorophyll a (Cla), and total carotenoids (TCC) were measured. The results showed that ultrasound-assisted extraction (UAE) with phosphate buffer at a 1:10 ratio yielded a metabolite-rich retentate (MRR) with 37.0 ± 1.9 mg/g of PC, 617 ± 15 mg/g of protein, 0.4 ± 0.2 mg/g of Cla, and 0.15 ± 0.14 mg/g of TCC. Water extraction in the concentration process achieved the highest concentrations in MRR, with approximately 76% PC, 92% total protein, 62% Cla, and 41% TCC. These findings highlight the effective extraction and concentration processes to obtain a metabolite-rich retentate from Spirulina biomass, reducing the volume tenfold and showing potential as a functional ingredient for the food, cosmetic, and pharmaceutical industries.

Ion Association and Hydration of Some Heavy-Metal Nitrate Salts in Aqueous Solution.

Aqueous solutions of four heavy-metal nitrate salts (AgNO3, TlNO3, Cd(NO3)2 and Pb(NO3)2) have been studied at 25 °C using broadband dielectric relaxation spectroscopy (DRS) at frequencies 0.27 ≤ ν/GHz ≤ 115 over the approximate concentration range 0.2 ≲ c/mol L-1 ≲ 2.0 (0.08 ≲ c/mol L-1 ≲ 0.4 for the less-soluble TlNO3). The spectra for AgNO3, TlNO3, and Pb(NO3)2 were best described by assuming the presence of three relaxation processes. These consisted of one solute-related Debye mode centered at ∼2 GHz and two higher-frequency solvent-related modes: one an intense Cole-Cole mode centered at ∼18 GHz and the other a small-amplitude Debye mode at ∼500 GHz. These modes can be assigned, respectively, to the rotational diffusion of contact ion pairs (CIPs), the cooperative relaxation of solvent water molecules, and its preceding fast H-bond flip. For Cd(NO3)2 solutions an additional solute-related Debye mode of small-amplitude, centered at ∼0.5 GHz, was required to adequately fit the spectra. This mode was consistent with the presence of small amounts of solvent-shared ion pairs. Detailed analysis of the solvent modes indicated that all the cations are strongly solvated with, at infinite dilution, effective total hydration numbers (Zt0 values) of irrotationally bound water molecules of ∼5 for both Ag+ and Tl+, ∼10 for Pb2+, and ∼20 for Cd2+. These results clearly indicate the presence of a partial second hydration shell for Pb2+(aq) and an almost complete second shell for Cd2+(aq). However, the hydration numbers decline considerably with increasing solute concentration due to ion-ion interactions. Association constants for the formation of contact ion pairs indicated weak complexation that varies in the order: Tl+ < Ag+ < Pb2+ < Cd2+, consistent with the charge/radius ratios of the cations and their Gibbs energies of hydration. Where comparisons were possible the present constants mostly agreed well with the rather uncertain literature values.

B-156 Extraction strategy for therapeutic drug monitoring of sirolimus and tacrolimus using volumetric absorptive microsampling

Abstract Background Following organ transplantation, patients are placed on immunosuppressant drugs (ISDs) to minimize the risk of rejection. Sirolimus and tacrolimus are two of the most widely used ISDs, however, due to their narrow therapeutic indices, patients require frequent therapeutic drug monitoring (TDM). Recurrent venipuncture can become uncomfortable and disruptive, especially in the pediatric population. Therefore, we describe an extraction method using dried whole blood from volumetric absorptive microsampling (VAMS) devices for the detection of sirolimus and tacrolimus by turbulent flow liquid chromatography tandem mass spectrometry (TFC-MS/MS). The use of VAMS in the clinical laboratory will provide ISD patients with a convenient alternative to traditional blood draws. Methods MassTrak immunosuppressant calibrators based on a whole blood matrix (Waters) were applied to 30 μL VAMS Mitra devices (Neoteryx) and dried overnight. To extract the whole blood off of VAMS tip, we tested various methanol:water solvent ratios, of which 30 μL was added to the device. Tips were extracted using ultrasonication (30 min), vortexing (5 min), and centrifugation. Once extracted from the tip, 25 mM zinc sulfate was added to whole blood extract at a 1:1 (v/v) ratio. An acetonitrile and methanol extraction reagent was then added to the whole blood/zinc sulfate solution at a 2:1 (v/v) ratio. After brief vortexing, samples were centrifuged at 16,060 × g (10 min) and tested using an established TFC-MS/MS method which deploys a TLX-2 system for sample preparation coupled to a Q-Trap tandem mass spectrometer (AB Sciex 5500). Results A 80:20 (v/v) water:methanol extraction solvent yielded the greatest extraction efficacy for both sirolimus and tacrolimus from the VAMS tips compared to other tested ratios. We established a 5-point calibration curve to correlate the measured values of ISDs with known MassTrak calibration standard concentrations. The resulting average calibration curve from 3 independent experiments was highly linear for both sirolimus (R2= 0.992; slope= 1.1; intercept= 0.94) and tacrolimus (R2= 0.996; slope= 1.1; intercept = 0.8819). Our VAMS whole blood extraction strategy was correlated to the established neat whole blood protocol, which utilized all of the sample preparation steps outlined above except the initial extraction from the VAMS tip. The average extraction efficacy was 89.1% for sirolimus with an average coefficient of variation (CV%) of 12.1% across 3 independent experiments. For tacrolimus, we demonstrated an average extraction efficacy of 100.1% with an average CV% of 8.4%, again across 3 independent experiments. Conclusions We demonstrate the feasibility of using a VAMS approach to TDM of sirolimus and tacrolimus. Our results demonstrate favorable recoveries for both of the tested drugs, evidenced by high recoveries of the external calibration standards. Additionally, our method exhibited high extraction efficacy and low variability. Further validation studies, including the utilization of clinical samples is necessary to confirm our preliminary findings.

Electronic structure, global reactivity descriptors and nonlinear optical properties of glycine interacted with ZnO, MgO and CaO for bacterial detection

Modern laboratory medicine relies on analytical instruments for bacterial detection, focusing on biosensors and optical sensors for early disease diagnosis and treatment. Thus, Density Functional Theory (DFT) was utilized to study the reactivity of glycine interacted with metal oxides (ZnO, MgO, and CaO) for bacterial detection. Total dipole moment (TDM), frontier molecular orbitals (FMOs), FTIR spectroscopic data, electronic transition states, chemical reactivity descriptors, nonlinear optical (NLO) characteristics, and molecular electrostatic potential (MESP) were all investigated at the B3LYP/6–31G(d, p) level using DFT and Time-Dependent DFT (TD-DFT). The Coulomb-attenuating approach (CAM-B3LYP) was utilized to obtain theoretical electronic absorption spectra with the 6-31G(d, p) basis set to be more accurate than alternative quantum chemical calculation approaches, showing good agreement with the experimental data. The TDM and FMO investigation showed that glycine/CaO model has the highest TDM (10.129Debye) and lowest band gap (1.643 eV). The DFT computed IR and the experimental FTIR are consistent. The calculated UV-vis spectra showed a red shift with an increase in polarity following an increase in the absorption wavelength due to the interaction with ZnO, MgO, and CaO. Among the five solvents of water, methanol, ethanol, DMSO and acetone, the water and DMSO enhances the UV-Vis absorption. Glycine/CaO model showed high linear polarizability (14.629 × 10−24esu) and first hyperpolarizability (23.117 × 10−30esu), indicating its potential for nonlinear optical applications. The results showed that all model molecules, particularly glycine/CaO, contribute significantly to the development of materials with potential NLO features for sensor and optoelectronic applications. Additionally, MESP confirmed the increased electronegativity of the studied structures. Additionally, glycine/ZnO nanocomposite was synthesized and characterized using IR and UV-visible spectroscopy to determine their structural and spectroscopic features. It was discovered that there was good agreement between the DFT computed findings and the related experimental data. The antibacterial activity of glycine/ZnO nanocomposites against Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa were studied in terms of concentration and time. The results showed that increasing the concentration of glycine/ZnO nanocomposite significantly enhanced its antibacterial efficacy by lowering optical density. Notably, Pseudomonas aeruginosa exhibited lower susceptibility to the nanocomposite compared to S. aureus, requiring higher concentrations for effective bactericidal action. In summary, this study contributes novel insights into the dual functionality of glycine-metal oxide complexes, with significant implications as optical biosensor for microbial detection.