Insight into the mechanism of adsorption and release of 11-nor-9-carboxy-Δ9-tetrahydrocannabinol in sewage by modeling regional suspended particles for evaluation of the influence on monitoring of cannabis illicit abuse.

The adsorption of 11-nor-9-carboxy-∆9-tetrahydrocannabinol (THC-COOH) by the suspended particles in sewage makes it fail to accurately monitor cannabis abuse. In this work, the model sewage sample was prepared through equivalent mixing the sewage from 10 different sewage treatment plants in Guangdong province of China and used as a comprehensive representative for investigating the adsorption and release behavior of THC-COOH on the suspended particles under different temperature and pH. The solid-liquid distribution of THC-COOH in sewage depended strongly on the adsorption and release properties which were susceptible to the temperature and pH, specially adjusting pH to 11.0 could release more than 90 % of THC-COOH from the suspended particles. By means of the kinetics models, pseudo-second-order kinetic and Weber-Morris models revealed the mechanism of adsorption and release of THC-COOH in sewage that was a relatively reversible and controllable process with multiple interactions, and then it was further confirmed by the validation experiment in a variety of actual sewage samples. According to the suggested pH, the modification of the existing detection protocol prior to high performance liquid chromatography-tandem triple quadrupole mass spectrometry (HPLC-TQ-MS/MS), was successfully applied to determination of THC-COOH in the stimulated positive samples, and the recoveries and RSDs were respectively 95.48-99.79 % and 4.0-5.6 %. The finding could greatly help improving the accuracy of not only the detection of THC-COOH in sewage but also the estimation data of the consumption level of cannabis in the related regions.

Combinatorial preparation and structural characterization of anthocyanins and aglycones from Purple-heart Radish for evaluation of physicochemical stability and pancreatic lipase inhibitory activity.

In this study, an efficient approach to preparation of different anthocyanins from Purple-heart Radish was developed by combining microwave-assisted extraction (MAE), macroporous resin purification (MRP) and ultrasound-assisted acid hydrolysis (UAAH) for evaluation of physicochemical stability and pancreatic lipase (PL) inhibitory activity. By optimization of MAE, MRP and UAAH processes, the anthocyanins reached the yield of 6.081 ± 0.106 mg/g, the purity of 78.54 ± 0.62 % (w/w) and the content of 76.29 ± 1.31 % (w/w), respectively. With high-resolution UHPLC-Q-Orbitrap/MS, 15 anthocyanins were identified as pelargonins with diverse glucosides and confirmed by pelargonidin standard. By glycosylation, pelargonins exhibited higher stability in different pH, temperature, light, metal ions environments than that of pelargonidin. However, PL inhibitory assay, kinetic analysis and molecular docking demonstrated that pelargonidin had higher PL inhibitory activity than pelargonins even though with similar binding sites and a dose-effect relationship. The above results revealed that the effect of glycosylation and deglycosylation on PL inhibitory activity and physicochemical stability.

Simultaneous separation and determination of several chiral antidepressants and their enantiomers in wastewater by online heart-cutting two-dimensional liquid chromatography.

A novel method for simultaneous separation and detection of the racemates and the enantiomers of common chiral antidepressants in wastewater matrix was developed by online heart-cutting two-dimensional liquid chromatography (2D-LC) coupled to solid-phase extraction (SPE). Screening of chiral stationary phases (CSPs) and chromatographic conditions was investigated for complete enantioseparation to be compatible with RP-HPLC in 1st D-LC. Using methanol-0.1 % (v/v) ammonia solution as mobile phase, a 2D-LC system was configured by reversed mode with a combination of C18 column and the serially CPS columns as 2D-LC stationary phases respectively. The target analytes could achieve satisfactory transformation between 2D-LCs with transfer rate of 90.57-98.58 %. By means of freeze-drying and SPE, three antidepressants in wastewater were greatly preconcentrated under the optimized conditions, improving the method performance. The racemates and the enantiomers of mirtazapine, bupropion and fluoxetine exhibited good linearity in the range of 0.10-30.00 ng/mL (R2≥0.9986), and LODs and LOQs ranged in 0.0183-0.0549 ng/mL and 0.0661-0.1831 ng/mL, respectively. By this way, the method was successfully applied to simultaneous determination of the racemates and the enantiomers of mirtazapine, bupropion and fluoxetine in wastewater samples. Among them, three samples contained bupropion at level of 0.401-0.822 ng/mL, and mirtazapine at level of 0.328 and fluoxetine at level of 0.381 ng/mL were detected respectively in the other two samples. The enantiomers were at level of 0.140-0.189 ng/mL for mirtazapine, 0.182-0.419 ng/mL for bupropion and 0.179-0.204 ng/mL for fluoxetine, respectively. The proposed method providing an efficient approach to monitoring chiral drugs and their enantiomers in wastewater, facilitating to pollution assessment of chiral drugs in the environment and regional survey of illicit abuse in drug control.

Screening and identification of lipase inhibitors extracted from Dioscorea nipponica Makino by UV-vis and HPLC coupled to UPLC-Q-TOF-MS/MS.

Dioscoreae nipponica Makino (D. nipponica) as the rhizome of dioscoreaceae rich in steroidal saponins, has been reported to have the hypolipidemic effects etc. However, it is still unclear which exact active components are primary responsible for the beneficial effects. This study was conducted to fish out the lipase inhibitors from D. nipponica, and evaluate the inhibitory activity on porcine pancreatic lipase (PPL) through in vitro kinetic assay using p-nitrophenyl palmitate as substrate. Accordingly, the ethanolic extract was subjected to D101 macroporous resin purification for spectrophotometric screening, high performance liquid chromatography (HPLC) separation and structural characterization by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. Through orlistat validation, the PPL inhibitory activity and IC50 value of the extract were respectively 68.34 ± 1.47 % and 107.05 µg/mL under the optimized inhibition conditions. From 6 steroidal saponins identified, the inhibitory components named the protodioscin, protogracillin, dioscin and gracillin were fished out by grouping separation and HPLC analysis. Furthermore, dioscin and gracillin with the parent structure of diogenin were confirmed as the major inhibitors by virtue of stability tests based on transformation of protodioscin and protogracillin. Finally, the inhibitory mechanism of the major inhibitors toward PPL was further clarified by kinetic analysis and molecular docking analysis. The proposed method not only revealed the PPL inhibitory components in D. nipponica, but also provided an effective approach to hierarchical screening of PPL inhibitors from natural plants.

Ultrasonic Enhancement of Aqueous Two-Phase Extraction and Acid Hydrolysis of Flavonoids from Malvaviscus arboreus Cav. Flower for Evaluation of Antioxidant Activity.

The ultrasonic-assisted aqueous two-phase extraction (UAATPE) of flavonoid glycosides from Malvaviscus arboreous Cav. flower (MACF) was developed using ethanol/ammonia sulfate systems, followed by the ultrasonic-assisted acid hydrolysis (UAAH) of the top extract with HCl solution. The optimization of UAATPE and UAAH processes was accomplished by single-factor experiments and response surface methodology. As a result, the flavonoid glycosides enriched in the top phase could achieve a maximum yield of 35.9 ± 1.1 mg/g by UAATPE and were completely hydrolyzed by UAAH deglycosylation. The flavonoid glycosides and their hydrolyzates were separated and characterized by high-performance liquid chromatography and ultra-high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. Ultrasonic enhancement of the extraction and hydrolysis was explored by comparative study. Furthermore, the in vitro activity of the flavonoid glycosides and the aglycones were comprehensively evaluated by antioxidant activity assays, including ferric-reducing antioxidant power and scavenging DPPH, hydroxyl, and superoxide radicals. All of the IC50 values suggest that the antioxidant activity of flavonoid aglycones was stronger than that of their glucosides and even vitamin C, revealing that the deglycosylated flavonoids from MACF were the more powerful antioxidants. This study provided an effective and eco-friendly strategy for the extraction, separation, and purification of flavonoids from MACF, as well as for the development of the potential flavonoid antioxidants.