Correction: Analysis of canthin-6-one alkaloids derived from Eurycoma spp. by micellar liquid chromatography and conventional high-performance liquid chromatography: a comparative evaluation.

[This corrects the article DOI: 10.1039/D2RA07034K.].

Immunochromatographic assay for miroestrol and deoxymiroestrol, its cross-reactivity, and application in Pueraria mirifica (white Kwao Krua) analysis.

INTRODUCTION: Miroestrol (Mi) and deoxymiroestrol (Dmi) are trace, yet potent, phytooestrogens found in white Kwao Krua [Pueraria candollei var. mirifica (Airy Shaw & Suvat.) Niyomdham, PM]. However, the analysis of these substances is difficult because of complex matrix effects and their various analogues. In addition, alteration in the cross-reactivity of a gold nanoparticle (AuNP)-based immunochromatographic assay (ICA) resulting from the electrostatic adsorption between antibodies and AuNPs has not yet been evaluated. OBJECTIVES: This study aims to develop, characterise, and validate ICA with a monoclonal antibody exhibiting similar reactivity against Mi and Dmi (MD-mAb). MATERIALS AND METHODS: The ICA performance was validated for cross-reactivity and performance in comparison with those of indirect competitive enzyme-linked immunosorbent assays (icELISAs) with MD-mAb and mAb exhibiting specificity against Mi (Mi-mAb). RESULTS: The ICA showed a limit of detection (LOD) at 1 and 16 µg/mL for Mi and Dmi, respectively. The cross-reactivity of the ICA with Dmi was lower (6.25%) than that observed with the icELISA (120%). Cross-reactivity of ICA against other compounds of the PM was also correlated with those of icELISA; no false-positive/negative results were observed. The repeatability and reproducibility of the ICA were confirmed. The results obtained using ICA in samples of PM are correlated with the concentrations determined through icELISAs. CONCLUSION: An ICA with MD-mAb was constructed and validated. However, direct conjugation via the electrostatic adsorption of mAb-AuNPs was expected to alter the cross-reactivity of ICA, especially that of the analyte analogue Dmi.

Extraction of curcuminoids and ar-turmerone from turmeric (Curcuma longa L.) using hydrophobic deep eutectic solvents (HDESs) and application as HDES-based microemulsions.

The extraction of curcuminoids and aromatic (ar)-turmerone from Curcuma longa L. using organic solvents produces chemical waste, and is therefore incompatible with food applications. To address this issue, this study presents the design of hydrophobic deep eutectic solvents (HDESs) and HDES-based microemulsions. Using the response surface methodology (RSM), the optimal extraction conditions were identified as follows: HDES = OA:menthol (1:3.6 M ratio), solid-to-liquid ratio = 10:1 (mg/mL), and extraction duration = 90 min (prediction accuracy ≥ 85 %). Under these conditions, the HDES extraction yields of bisdemethoxycurcumin, demethoxycurcumin, curcumin, and ar-turmerone were 2.49 ± 0.25, 5.61 ± 0.45, 9.40 ± 0.86, and 3.83 ± 0.19 % (w/w, dry basis), respectively, while those obtained using the HDES-based microemulsion were 2.10 ± 0.18, 6.31 ± 0.48, 12.6 ± 1.20, and 2.58 ± 0.19 % (w/w, dry basis), respectively. The HDES and its microemulsions are more effective and environmentally friendly than conventional organic solvents for the extraction of curcuminoids and ar-turmerone, and these solvents are also compatible with food and pharmaceutical formulations.

Transformation of Pueraria candollei var. mirifica phytoestrogens using immobilized and free ß-glucosidase, a technique for enhancing estrogenic activity.

Pueraria candollei var. mirifica (PM) has a significant beneficial effect on postmenopausal symptoms associated with estrogen deficiency. However, the estrogenic activity and intestinal absorption of isoflavonoid glycosides derived from PM, such as daidzin and genistin, are significantly lower than those of their aglycones. To enhance the estrogenic activity of the PM extract, we developed ß-glucosidase and its immobilized form to increase the PM aglycone content (daidzein and genistein). The enzyme immobilization was done by alginate beads, and the resulting ß-glucosidase alginate beads have a diameter of about 0.20 cm. Response surface methodology (RSM) was used to optimize certain parameters, such as the pH, temperature, and ethanol concentration. The optimal conditions of ß-glucosidase for daidzein and genistein production were pH of 4.8-4.9, a temperature in the range 46.3-49.1 °C, and ethanol concentration of 10.0-11.0%. The ANOVA results indicated that the design experiment involving free and immobilized ß-glucosidase was the best fit by quadratic models, which had adjusted R 2 values between 0.8625 and 0.9318. Immobilized ß-glucosidase can be reused up to nine times and maintained efficacy of greater than 90%. Treatment of the PM extract with ß-glucosidase increased the estrogenic activity of the PM extract by 8.71- to 23.2-fold compared to that of the untreated extract. Thus, ß-glucosidase has a high potential for enhancing the estrogenic activity of PM constituents, and it can be applied on an industrial scale to increase the utility of these natural products.

Development of a colorless Centella asiatica (L.) Urb. extract using a natural deep eutectic solvent (NADES) and microwave-assisted extraction (MAE) optimized by response surface methodology.

This study outlines a green process for Centella asiatica (L.) Urb. (CA) extraction. Natural deep eutectic solvents (NADESs) and microwave-assisted extraction (MAE) were combined to provide a high bioactive compound yield and high antioxidant activity. Among the NADESs evaluated, the combination of acetylcholine chloride : malic acid : water (1 : 2 : 2): water (40 : 60) was the best for extraction. These conditions provide high madecassoside (MS) (21.7 mg g-1 dry weight) and asiaticoside (AS) (12.7 mg g-1 dry weight) yields, with greater than 80% (v/v) EtOH (13.3 mg g-1 MS and 7.80 mg g-1 AS). In addition, the extracts from this process showed higher antioxidant activity (IC50 = 0.26 mg mL-1) than the CA aqueous EtOH and water extracts. Moreover, the color of the extract products was less green than that of the extracts prepared using EtOH and aqueous EtOH as solvents, which are suitable for cosmeceutical products. Response surface methodology (RSM) was used for MAE optimization. The ANOVA data from the central composition design (CCD) of RSM were fitted with quadratic models yielding acceptable R 2 (>0.93), adjusted R 2 (>0.87), predicted R 2 (>0.81), and nonsignificant lack of fit (p > 0.05) values. The quadratic model was validated using optimal conditions (30 s, power 300 W, and a liquid to solid ratio 20 mL g-1), and the model validation showed more than 80% accuracy in both MS and AS yields. This research presented an effective green process for CA extraction, which resulted in an environmentally friendly CA extract requiring little energy consumption and no organic solvents.

Biocompatible natural deep eutectic solvent-based extraction and cellulolytic enzyme-mediated transformation of Pueraria mirifica isoflavones: a sustainable approach for increasing health-bioactive constituents.

The presence of specific gut microflora limits the biotransformation of Pueraria mirifica isoflavone (PMI) glycosides into absorbable aglycones, thus limiting their health benefits. Cellulolytic enzyme-assisted extraction (CAE) potentially solves this issue; however, solvent extraction requires recovery of the hydrophobic products. Here, we established the simultaneous transformation and extraction of PMIs using cellulolytic enzymes and natural deep eutectic solvents (NADESs). The NADES compositions were optimized to allow the use of NADESs as CAE media, and the extraction parameters were optimized using response surface methodology (RSM). The optimal conditions were 14.7% (v/v) choline chloride:propylene glycol (1:2 mol ratio, ChCl:PG) at 56.1 °C for the cellulolytic enzyme (262 mU/mL) reaction in which daidzin and genistin were extracted and wholly transformed to their aglycones daidzein and genistein. The extraction of PMIs using ChCl:PG is more efficient than that using conventional solvents; additionally, biocompatible ChCl:PG enhances cellulolytic enzyme activity, catalyzing the transformation of PMIs into compounds with higher estrogenicity and absorbability.

A miniaturized monolith-MWCNTs-COOH multi-stir-rod microextractor device for trace parabens determination in cosmetic and personal care products.

A portable and simple microextractor device was constructed by aligning six miniaturized multi-stir-rod microextractors. Each microextractor was prepared from rod-like multiwalled carbon nanotubes functionalized with a carboxylic group (MWCNTs-COOH) in composite monoliths that were bundled together and connected to a small DC motor. Using six of these microextractors, the device could extract six samples at the same time. A scanning electron microscope (SEM) showed the MWCNTs-COOH well distributed throughout the highly porous structure of the monolith-MWCNTs-COOH-stir-rod. This miniaturized multi-stir-rod microextractor device was used for the extraction of four parabens, methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP). Under optimized conditions, good linearities were obtained in the concentration range of 1.0 ng mL-1 to 1.0 µg mL-1 for MP and EP and 2.0 ng mL-1 to 1.0 µg mL-1 for PP and BP. The limits of detection were low, 636.2 ±â€¯7.6 pg mL-1 for MP, 675.5 ±â€¯6.0 pg mL-1 for EP, 676.6 ±â€¯8.6 pg mL-1 for PP and 803.4 ±â€¯9.6 pg mL-1 for BP. The developed microextractor could be used up to 15 times (%RSDs from 1.5 to 5.2) and also provided good preparation reproducibility (%RSD from 1.3 to 5.8, n = 6). The % RSDs of intra-day (n = 6) and inter-day (n = 6) precisions were obtained from 1.10-7.79 and 1.96-7.55, respectively. This developed device coupled with high performance liquid chromatography-diode array detector (HPLC-DAD) was applied for the extraction and preconcentration of four parabens in personal care products and cosmetics. The recoveries were studied by spiking the standard solution of parabens in real samples. Good recoveries were obtained in the range of 89.0 ±â€¯2.7 to 102.7 ±â€¯1.8% for MP, 88.09 ±â€¯6.4 to 102.5 ±â€¯1.0% for EP, 83.4 ±â€¯6.4 to 102.9 ±â€¯1.5% for PP and 83.5 ±â€¯3.6 to 102.3 ±â€¯2.0% for BP. This developed device might be easily applied for the extraction and preconcentration of other trace organic compounds in sample matrices.

A polypyrrole-chitosan cryogel stir-bead micro-solid phase extractor for the determination of phthalate esters in contact lenses storage solutions and in artificial saliva in contact with baby teethers.

Phthalate esters (PAEs), especially dimethyl phthalate (DMP), diethyl phthalate (DEP), dibutyl phthalate (DBP), di-2-ethylhexyl phthalate (DEHP) are widely used as plasticizers in plastics and polymers. They are not chemically bound and can easily migrate into food and human tissue that comes into contact with these materials. The method developed in this work was applied for the preconcentration and determination of these four phthalate esters that might leach from contact lenses and baby teethers. A novel stir-bead micro-solid phase extractor of chitosan cryogel composited with polypyrrole with a steel wire core was evaluated for the extraction of DMP, DEP, DBP and DEHP before analysis by high performance liquid chromatography (HPLC). Scanning electron micrographs of the polypyrrole-chitosan cryogel beads revealed a high porosity with large surface area. Under the optimum conditions, the developed method provided a good linearity in a concentration range from 10 to 750 ng mL-1 for DMP and from 5.0 to 750 ng mL-1 for DEP, DBP and DEHP. The limits of detection (LOD) were 6.07 ± 0.22 ng mL-1, 4.358 ± 0.097 ng mL-1, 4.408 ± 0.099 ng mL-1 and 3.916 ± 0.053 ng mL-1 for DMP, DEP, DBP and DEHP, respectively, and the method reproducibility was good (n = 6, % RSD < 6.0). DBP and DEHP were detected in two original storage solutions of contact lenses from 13.2 ± 1.1 ng mL-1 to 15.4 ± 1.9 ng mL-1 and from 21.3 ± 1.6 ng mL-1 to 23.5 ± 1.5 ng mL-1, respectively. In the artificial saliva in contact with baby teether samples only DEHP was found, from 4.91 ± 0.31 ng mL-1 to 6.78 ± 0.23 ng mL-1, with good recoveries ranging from 81.3 ± 8.4% to 106.3 ± 5.2%.

A novel miniaturized zinc oxide/hydroxylated multiwalled carbon nanotubes as a stir-brush microextractor device for carbamate pesticides analysis.

A novel miniaturized "stir-brush microextractor" was prepared using a zinc oxide/hydroxylated multiwalled carbon nanotubes (ZnO/MWCNTs-OH) coated stainless steel brush connected to a small dc motor. The synthesized zinc oxide on each strand of stainless steel had a flower-like nanostructure when observed by a scanning electron microscope (SEM). This structure produced a large surface area before it was coated with the hydroxylated multiwalled carbon nanotubes sorbent. Under optimal conditions, the developed device provided a good linearity for the extraction of carbofuran and carbaryl, in the range of 25-500 ng mL(-1) and 50-500 ng mL(-1), respectively, with low limits of detection of 17.5 ± 2.0 ng mL(-1) and 13.0 ± 1.8 ng mL(-1). It also provided a good stir-brush-to-stir-brush reproducibility (% relative standard deviation < 5.6%, n = 6). The device was applied for the extraction and preconcentration of carbamate pesticides in fruit and vegetable samples prior to analysis with a gas chromatograph coupled with a flame ionization detector (GC-FID). Carbofuran was found at 9.24 ± 0.93 ng g(-1) and carbaryl was detected at 7.05 ± 0.61 ng g(-1) with good recoveries in the range of 73.7 ± 10.0% to 108.4 ± 2.6% for carbofuran and 75.7 ± 10.0% to 111.7 ± 5.7% for carbaryl.

Development of magnetic micro-solid phase extraction for analysis of phthalate esters in packaged food.

A novel, simple and low cost magnetic multi-walled carbon nanotubes-poly (vinyl alcohol) cryogel-micro-solid phase extraction (magnetic-MWCNTs-PVA cryogel-µ-SPE) sorbent was synthesized by incorporating magnetic particles and MWCNTs into a PVA cryogel. The magnetic-MWCNTs-PVA cryogel-µ-SPE sorbent developed, with a large surface area and macro-porous structure, provided good sorbent-to-sorbent reproducibility (%RSD<8) and each sorbent could be used up to 30 times (%RSD<6). This sorbent was applied for the extraction of dibutyl phthalate (DBP) and di-2-(ethylhexyl) phthalate (DEHP) in packaged food prior to analysis by gas chromatograph coupled with flame ionisation detector (GC-FID). The concentration of DBP and DEHP in hot-water samples from plastic bags were found in the range 0.04-0.15 µg mL(-1) and 0.03-0.20 µg mL(-1), respectively, but only DEHP was found in clear chicken soup samples in the range 0.02-0.07 µg mL(-1).