Search Results (61)

To develop a novel process to purify indole in wash oil with high efficiency, a previous study investigated the indole concentration in wash oil using a process combining methanol extraction and n-hexane re-extraction, which allowed the recovery of a raffinate phase containing 73.3 wt% indole-concentrated oil (ICO). In this study, model ICO, prepared based on the components and compositions present in ICO, and n-hexane were used as the raw material and solvent for the solute crystallization (SC) process, respectively, to examine the effect of SC experimental factors and conditions on the purification of indole. A Pyrex batch crystallizer with a jacket was used as the experimental apparatus. The purity and yield of indole in the generated crystals under optimal SC conditions (crystal washing, a crystallization temperature of 283 K, a crystallization time of 10 min, an impeller speed of 0 s⁻¹, and an initial volume ratio of the solvent to model ICO of 15.5) were 99.5 wt% and 57.5%, respectively. Furthermore, this study proposed a novel process for the highly efficient purification of indole contained in wash oil by utilizing the experimental data accumulated from processes in previous research and this study. Full article

Carbon quantum dots (CQD) are an emergent nanomaterial with unique optical and biological properties. However, the purification of CQD is one of the bottlenecks that makes it difficult to scale for application in different areas. In this work, we explore for the first time the potential of centrifugal partition chromatography (CPC) as an alternative preparative technology to achieve the purification of CQD at the gram scale. The hydrothermal method was used to synthesize CQD from avocado peels. After 6 h at 250 °C, a complex mix of strong blue-fluorescent CQDs were obtained and submitted to CPC fractionation without pretreatment. The best results were obtained with the solvent system n-hexane–ethyl acetate–methanol–water (1:2:1:2, v/v/v/v), in an elution-extrusion protocol. Nine fractions were obtained and were characterized by UV-VIS spectrophotometry, Fourier transform infrared (F-TIR), and field emission scanning electron microscopy (FESEM), confirming the presence of CQD of different sizes. CPC fractionations indicate that a polarity-based separation mechanism can be used to purify CQD. Interestingly, four fractions showed antibacterial and anti-biofilm effects on Pseudomonas putida and Listeria monocytogenes. Therefore, CPC allows for better refining of this type of nanomaterial, and in combination with other techniques, it would serve to obtain CQD of higher purity, facilitating the physicochemical and bioactivity characterization of these particles. CPC would also allow the use of waste, such as avocado peels, to obtain new materials. Full article

Commercial ascorbyl-6-O-esters (AEs) are composed of saturated fatty acids with relatively high melting points, resulting in limited solubility in lipophilic media. Therefore, a lipase-catalysed synthesis and purification method for ascorbyl-6-O-oleate (AO) was proposed in this study. The esterification synthesis (i.e., bonding of oleoyl group to ascorbic acid) rate was 19.7% using acetone as the reaction solvent. The transesterification synthesis (i.e., exchange of acyl group with oleic acid (OA) in ascorbyl-6-O-palmitate (AP)) rate increased to 73.8% (AP:OA = 1:3, molar ratio). The esterification product was purified sequentially by liquid–liquid extraction using ethyl acetate and water, followed by hexane and acetonitrile, resulting in 94.8 area% AO confirmed by HPLC. When acetonitrile was replaced with 90% methanol, AO achieved 97.2 area%. Similarly, the transesterification product showed 94.3 area% AEs (AP:AO = 8.9:91.1) after recrystallisation and liquid–liquid extraction. Finally, all purified AO revealed peaks corresponding to the hydroxyl groups at the C-2 and C-3 carbons (11.10 and 8.41 ppm, ¹H-NMR), whereas OA selectively esterified at the C-6 carbon (¹³C-NMR). FT-IR confirmed the presence of the ester bond (1733 cm⁻¹) and olefin structure (3006 cm⁻¹) of OA, and LC-ESI-MS/MS identified AO peaks at m/z 439.3. DSC analysis showed broad endothermic curves at 23.1–46.7 °C when the purified AO samples were pre-cooled at −25 °C. Full article

Chikungunya virus (CHIKV) is classified as a pathogen with the potential to cause a pandemic. This situation becomes more alarming since no approved drug exists to combat the virus. The present research aims to demonstrate the anti-CHIKV activity of molecules present in the latex of Euphorbia grandicornis. Therefore, a biodirected assay was carried out to find the molecules with anti-CHIKV activity. Extractions with hexane, dichloromethane, and methanol and subsequent purification by column chromatography were carried out to later evaluate cytotoxic activity by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay and antiviral activity by plaque assay. Our findings show that unlike the others, methanolic extract has a low cytotoxic effect and a good anti-CHIKV effect (EC₅₀ = 26.41 µg/mL), which increases when obtaining the purified active fraction (pAFeg1) (EC₅₀ = 0.4835 µg/mL). Time-of-addition suggests that the possible mechanism of action of pAFeg1 could be inhibiting any of the non-structural proteins of CHIKV. In addition, both the cytotoxic and anti-CHIKV activity of pAFeg1 demonstrate selectivity since it killed cancer cells and could not inhibit DENV2. Full article

This study employs Density Functional Theory (DFT) calculations and traditional all-atom Molecular Dynamics (MD) simulations to reveal atomistic insights into a task-specific Deep Eutectic Solvent (DES) supported by graphene oxide with the aim of mimicking its application in the natural gas desulfurization process. The DES, composed of N,N,N′,N′-tetramthyl-1,6-hexane diamine acetate (TMHDAAc) and methyldiethanolamine (MDEA) supported by graphene oxide, demonstrates improved efficiency in removing hydrogen sulfide from methane. Optimized structure and HOMO-LUMO orbital analyses reveal the distinct spatial arrangements and interactions between hydrogen sulfide, methane, and DES components, highlighting the efficacy of the DES in facilitating the separation of hydrogen sulfide from methane through DFT calculations. The radial distribution function (RDF) and interaction energies, as determined by traditional all-atom MD simulations, provide insights into the specificity and strength of the interactions between the DES components supported by graphene oxide and hydrogen sulfide. Importantly, the stability of the DES structure supported by graphene oxide is maintained after mixing with the fuel, ensuring its robustness and suitability for prolonged desulfurization processes, as evidenced by traditional all-atom MD simulation results. These findings offer crucial insights into the molecular-level mechanisms underlying the desulfurization of natural gas, guiding the design and optimization of task-specific DESs supported by graphene oxide for sustainable and efficient natural gas purification. Full article

Organic solvent nanofiltration (OSN) technology is advantageous for separating mixtures of organic solutions owing to its low energy consumption and environmental friendliness. Covalent organic frameworks (COFs) are good candidates for enhancing the efficiency of solvent transport and ensuring precise molecular sieving of OSN membranes. In this study, p-phenylenediamine (Pa) and 1,3,5-trimethoxybenzene (Tp) are used to construct, in situ, a TpPa COF skin layer via interfacial polymerization (IP) on a polyimide substrate surface. After subsequent crosslinking and activation steps, a kind of TpPa/polyimide (PI) OSN membrane is obtained. Under optimized fabrications, this OSN membrane exhibits an ethanol permeance of 58.0 LMH/MPa, a fast green FCF (FGF) rejection of 96.2%, as well as a pure n-hexane permeance of 102.0 LMH/MPa. Furthermore, the TpPa/PI OSN membrane exhibits good solvent resistance, which makes it suitable for the separation, purification, and concentration of organic solvents. Full article

The bioactive flavonoids pinostrobin (PN) and panduratin A (PA) from Boesenbergia rotunda are essential for research and therapeutic applications. This study introduces an innovative method utilizing ultrasound-assisted extraction with n-hexane pre-treatment, followed by one-step centrifugal partition chromatography (CPC) purification. Extraction efficiency was evaluated using ultra high-performance liquid chromatography (UHPLC), and the isolated compounds were characterized through ¹H-NMR and liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS), adhering to AOAC validation guidelines. Optimal extraction conditions comprised a particle size of 125 μm, a solid-to-liquid ratio of 1:30 g/mL, and a 10 min extraction time, yielding a crude extract of 6.96 ± 0.07%. Using an n-hexane/MeOH/water (5/3.4/1.6, v/v) solvent system in ascending mode, PN (2.16 mg, 98.78% purity) and PA (0.4 mg, 99.69% purity) were isolated from 67 mg of crude extract within 30 min. This streamlined approach enhances purification efficiency, allowing for faster extraction and higher purity, making it a suitable method for commercial applications. Full article

Athenaea fasciculata belongs to the Solanaceae family and is a promising source of cytotoxic withanolides known as aurelianolides A and B. In the last years, the pharmacological studies of these aurelianolides on different leukemia cell lines have stimulated new studies on their potential as alternative candidates for new lead anticancer drugs. However, the obtention of these two pure compounds by traditional preparative is a costly and long time-consuming process, which is performed in several steps. This study aimed to propose a straightforward approach for isolating aurelianolides A and B using high-speed countercurrent chromatography (HSCCC). In this study, among 10 different solvent systems, the system composed of n-hexane/ethyl acetate/methanol/water 3:6:2:1 (v/v/v/v) was chosen for optimization. This HEMWat system was optimized to 4:8:2:4 (v/v/v/v) and chosen for HSCCC separation in a tail-to-head elution mode. After the HSCCC scale-up procedure, a withanolides mixture (200.0 mg) was separated within 160 min in a single-step purification process. In total, 78.9 mg of aurelianolide A (up to 95.0% purity) and 54.3 mg of aurelianolide B (up to 88.5% purity) was obtained by this fast sequential liquid–liquid partition process. The isolated withanolides were identified by ¹H and ¹³C NMR spectroscopy (this method has proven to be faster and more efficient than classical procedures (CC and Prep-TLC)). Full article

Recent studies have shown that seagrasses could possess potential applications in the treatment of inflammatory disorders. Five seagrass species (Zostera muelleri, Halodule uninervis, Cymodocea rotundata, Syringodium isoetifolium, and Thalassia hemprichii) from the Great Barrier Reef (QLD, Australia) were thus collected, and their preliminary antioxidant and anti-inflammatory activities were evaluated. From the acetone extracts of five seagrass species subjected to 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging antioxidant assay, the extract of Z. muelleri had the highest activity (half minimal concentration of inhibition (IC₅₀) = 138 µg/mL), with the aerial parts (IC₅₀ = 119 µg/mL) possessing significantly higher antioxidant activity than the roots (IC₅₀ ≥ 500 µg/mL). A human peripheral blood mononuclear cells (PBMCs) assay with bacterial lipopolysaccharide (LPS) activation and LEGENDplex cytokine analysis showed that the aerial extract of Z. muelleri significantly reduced the levels of inflammatory cytokines tumour necrosis factor alpha (TNF-α), interleukin (IL)-1β, and IL-6 by 29%, 74%, and 90%, respectively, relative to the LPS treatment group. The aerial extract was thus fractionated with methanol (MeOH) and hexane fraction, and purification of the MeOH fraction by HPLC led to the isolation of 4-hydroxybenzoic acid (1), luteolin (2), and apigenin (3) as its major constituents. These compounds have been previously shown to reduce levels of TNF-α, IL-1β, and IL-6 and represent some of the major bioactive components of Z. muelleri aerial parts. This investigation represents the first study of the antioxidant and anti-inflammatory properties of Z. muelleri and the first isolation of small molecules from this species. These results highlight the potential for using seagrasses in treating inflammation and the need for further investigation. Full article

This study aimed to investigate the efficacy of supercritical CO₂ (SC-CO₂) extraction in enhancing the extraction rate, purity, and antioxidant activity of Indocalamus latifolius (Keng) McClure (Poaceae) leaf terpenoids (ILLTs). Crude extracts obtained from leaves were subjected to qualitative and quantitative analyses, revealing neophytadiene, phytol, β-sitosterol, β-amyrone, squalene, and friedelin as the primary terpenoid constituents, identified through gas chromatography–mass spectrometry (GC-MS). Compared with steam distillation extraction (SD), simultaneous distillation extraction (SDE), ultra-high pressure-assisted n-hexane extraction (UHPE-Hex), ultra-high pressure-assisted ethanol extraction (UHPE-EtOH), ultrasound-assisted n-hexane extraction (UE-Hex), and ultrasound-assisted ethanol extraction (UE-EtOH), SC-CO₂ exhibited a superior ILLT extraction rate, purity, and antioxidant activity. Scanning electron microscopy (SEM) observations of the residues further revealed more severe damage to both the residues and their cell walls after SC-CO₂ extraction. Under optimal parameters (4.5 h, 26 MPa, 39 °C, and 20% ethyl alcohol), the ILLT extraction rate with SC-CO₂ reached 1.44 ± 0.12 mg/g, which was significantly higher than the rates obtained by the other six methods. The subsequent separation and purification using WelFlash C18-l, BUCHI-C18, and Sephadex LH-20 led to an increase in the purity of the six terpenoid components from 12.91% to 93.34%. Furthermore, the ILLTs demonstrated cytotoxicity against HepG2 cells with an IC₅₀ value of 148.93 ± 9.93 μg/mL. Additionally, with increasing concentrations, the ILLTs exhibited an enhanced cellular antioxidant status, as evidenced by reductions in both reactive oxygen species (ROS) and malondialdehyde (MDA) levels. Full article

Bixin is the main carotenoid found in the outer portion of the seeds of Bixa orellana L., commercially known as annatto. This compound is industrially employed in pharmaceutical, cosmetic, and food formulations as a natural dye to replace chemical additives. This study aimed to extract bixin from annatto seeds and obtain encapsulated bixin in a powder form, using freeze-drying encapsulation and maltodextrin as encapsulating agent. Bixin was extracted from annatto seeds employing successive washing with organic solvents, specifically hexane and methanol (1:1 v/v), followed by ethyl acetate and dichloromethane for subsequent washes, to effectively remove impurities and enhance bixin purity, and subsequent purification by crystallization, reaching 1.5 ± 0.2% yield (or approximately 15 mg of bixin per gram of seeds). Bixin was analyzed spectrophotometrically in different organic solvents (ethanol, isopropyl alcohol, dimethylsulfoxide, chloroform, hexane), and the solvents chosen were chloroform (used to solubilize bixin during microencapsulation) and hexane (used for spectrophotometric determination of bixin). Bixin was encapsulated according to a 2² experimental design to investigate the influence of the concentration of maltodextrin (20 to 40%) and bixin-to-matrix ratio (1:20 to 1:40) on the encapsulation efficiency (EE%) and solubility of the encapsulated powder. Higher encapsulation efficiency was obtained at a maltodextrin concentration of 40% w/v and a bixin/maltodextrin ratio of 1:20, while higher solubility was observed at a maltodextrin concentration of 20% w/v for the same bixin/maltodextrin ratio. The encapsulation of this carotenoid by means of freeze-drying is thus recognized as an innovative and promising approach to improve its stability for further processing in pharmaceutical and food applications. Full article

In this paper, an environmentally friendly polyacrylonitrile-based (PAN-based) composite membrane with a Janus structure for wastewater treatment was successfully fabricated. To achieve the optimum adsorption of PAN-based Janus composite membrane, the asymmetric wettability was regulated through electrospinning, resulting in TiO₂ modifying PAN as the hydrophilic substrate layer, and PCL gaining a different thickness as the hydrophobic layer. The prepared Janus composite membrane (PAN/TiO₂-PCL20) showed excellent oil/water separation performance for diverse surfactant-stabilized oil-in-water emulsions. For n-hexane-in-water emulsion, the permeate flux and separation efficiency reached 1344 L m⁻² h⁻¹ and 99.52%, respectively. Even after 20 cycles of separation, it still had outstanding reusability and the separation efficiency remained above 99.15%. Meanwhile, the PAN/TiO₂-PCL20 also exhibited an excellent photocatalytic activity, and the removal rate for RhB reached 93.2%. In addition, the research revealed that PAN/TiO₂-PCL20 possessed good mechanical property and unidirectional water transfer capability. All results indicated that PAN/TiO₂-PCL20 with photocatalysis and oil/water separation performance could be used for practical complex wastewater purification. Full article

Using gas chromatography–tandem mass spectrometry and electrospun nanofibrous membrane, we developed and validated a simple, rapid, and sensitive methodology for quantifying eugenol residues in fish tissue and water samples. Fish tissue extract and water samples (315 samples) collected from three southeastern China provinces (Shanghai, Zhejiang, and Fujian), originating from eight provinces of Zhejiang, Jiangsu, Shandong, Guangdong, Fujian, Anhui, Shanghai, and Jiangxi, from April 2021 to April 2023 were filtered with an electrospun nanofiber membrane, extracted with trichloromethane/n-hexane, and directly concentrated to dry after simple purification. An internal standard of p-terphenyl in n-hexane and 5-µL injection volumes of the solutions was used to analyze eugenol via internal calibration with a minimum concentration of 0.5 µg/L in water samples and 0.1 µg/kg in aquatic product samples. The highest amount of eugenol was detected in Fujian province, possibly due to the higher temperature during transportation, while the lowest amount was found in Shanghai, which mainly uses temporary fish-culture devices. This is a fast, inexpensive, and effective method for testing large quantities of fish water and meat samples. Full article

Although membrane separation technology has been widely used in the treatment of oily wastewater, the complexity and high cost of the membrane preparation, as well as its poor stability, limit its further development. In this study, via the vacuum-assisted suction filtration method, polydopamine (PDA)-coated TiO₂ nanoparticles were tightly attached and embedded on both sides of laboratory filter paper (FP). The resultant FP possessed the typical wettability of high hydrophilicity in the air with the water contact angle (WCA) of 28°, superoleophilicity with the oil contact angle (OCA) close to 0°, underwater superoleophobicity with the underwater OCA greater than 150°, and superhydrophobicity under the water with the underoil WCA over 150° for five kinds of organic solvents (carbon tetrachloride, toluene, n-hexane, n-octane, and iso-octane). The separation efficiency of immiscible oil/water, oil-in-water, and water-in-oil emulsions using the modified FP is higher than 99%. After 17 cycles of emulsion separation, a high separation efficiency of 99% was still maintained for the FP, along with good chemical and mechanical stability. In addition, successful separation and purification were also realized for the oil-in-water emulsion that contained the methylene blue (MB) dye, along with the complete degradation of MB in an aqueous solution under UV irradiation. Full article

Wash oil, one of the by-products of coal tar distillation, contains useful nitrogen heterocyclic compounds (NHC) such as indole (IN), which is used as a raw material for perfume, essential amino acid, and pharmaceuticals. In this study, as a pre-treatment step for purification of IN, which is about 5.75% contained in wash oil, the enrichment of IN in wash oil was examined by combining formamide extraction (FE) and n-hexane re-extraction (HRE). The raw material for the re-extraction was a mixture of the preceding formamide extract phase acquired through batchwise 5-stage co-current extraction trial under fixed FE condition. As the 5-stage FE and HRE progressed, the IN yield based on IN in the wash oil was approximately 73.3%, and the IN concentration in the raffinate oil acquired from the re-extraction run was highly enriched to about 92.4%. In addition, the IN enrichment efficiency of the FE-HRE combined process (FHC) employed in this study was compared with methanol extraction (ME)-hexane re-extraction (HRE) combination (MHC). Full article