We present a facile approach for the direct attachment of cross-linked poly(2-thiopheneacetic acid) onto the surface of magnetite nanoparticles with one single carbon layer (Fe 3 O 4 @1C NPs) via self-assembly oxidative polymerization. The functional Fe 3 O 4 @1C NPs combined with poly(2-thiopheneacetic acid) [Fe 3 O 4 @1C@ poly(Th) NPs] was successfully prepared and used for magnetic solid-phase extraction (MSPE). The influence of the preparation conditions and extraction conditions were investigated in detail. The morphology and size distribution of the monolithic materials were characterized by transmission electron microscopy. Under the optimized experimental conditions, the prepared Fe 3 O 4 @1C@ poly(Th) NPs showed good extraction efficiency for canthin-6-one alkaloids. Furthermore, the results indicated that the binding specificity and selectivity of the Fe 3 O 4 @1C@ poly(Th) NPs might be attributed to electrostatic interactions and pore structure. A MSPE–HPLC method was also developed for quantitative analysis of canthin-6-one alkaloids. The developed method showed good linearity, low limit of detections, low limit of quantifications, and good reproducibility over a wide linear range. To further prove the utility, Fe 3 O 4 @1C@ poly(Th) NPs-MSPE was also used to extract canthin-6-one alkaloids from Eurycoma longifolia stems, with a recovery rate of 87.9–114%. Thus, this method is potentially applicable for the extraction of similar alkaloid compounds from medicinal herb samples.
Alzheimer disease (AD), a prevalent neurodegenerative disorder, is one of the leading causes of dementia. However, there is no effective drug for this disease to date. Picrasma quassioides (D.Don) Benn, a Chinese traditional medicine, was used mainly for the treatment of inflammation, fever, microbial infection and dysentery. In this paper, we reported that the EtOAc extract of Picrasma quassioides stems showed potential neuroprotective activities in l -glutamate-stimulated PC12 and Aβ 25-35 -stimulated SH-SY5Y cell models, as well as improved memory and cognitive abilities in AD mice induced by amyloid-β peptide. Moreover, it was revealed that the anti-AD mechanism was related to suppressing neuroinflammatory and reducing Aβ 1-42 deposition using ELISA assay kits. To clarify the active components of the EtOAc extract of Picrasma quassioides stems, a systematic phytochemistry study led to isolate and identify six β-carboline alkaloids ( 1 – 6 ), seven canthin-6-one alkaloids ( 7 – 13 ), and five quassinoids ( 14 – 18 ). Among them, four β-carbolines ( 1 – 3 , and 6 ) and six canthin-6-ones ( 7 – 11 , and 13 ) exhibited potential neuroprotective activities in vitro . Based on these date, the structure-activity relationships of alkaloids were discussed. Furthermore, molecular docking experiments showed that compounds 2 and 3 have high affinity for both of dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYPKIA) and butyrylcholinesterase (BuChE).
危险品化学品经营许可证（带存储）