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One of the most popular one-pot glycosylation strategies is orthogonal one-pot synthesis, which was mainly based on thioglycosides. Despite its successful application, shortcomings of thioglycosides including aglycon transfers, interference of departing species and unpleasant odor restrict its application scope. Herein, we report a new and efficient orthogonal one-pot synthesis of oligosaccahrides based on glycosyl ortho-alkynylbenzoate, which solves the issues of thioglycoside-based orthogonal one-pot synthesis. Over a dozen of oligosaccharides have been efficiently synthesized by this method.

Euphordraculoates A (1) and B (2), featuring tigliane diterpenoids with two new carbon skeletons, were characterized as metabolites of Euphorbia dracunculoides and semisynthetic products, respectively. Their structures were determined by spectroscopic analyses and X-ray crystallography. The respective biosynthetic and chemical formation mechanisms for 1 and 2 from a known tigliane 3 was proposed. The detailed decarbonization mechanism from 3 to 2 was further explored by O-labeling experiment. Compound 2 could inhibit Wnt pathway in a dose- and time-dependent manner.

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The fruits ofLycium ruthenicum Murr have long been consumed as health food and used in folk medicine in China. Apart from the well-known polysaccharides, the active small molecular constituents in this fruit have not been fully studied. In this work, a systematic phytochemical study was carried out to investigate the small molecules and their potential health benefits. Nine new polyphenolic glycosides, lyciumserin A−I (1−9), together with 16 known compounds (10−25), were isolated and elucidated by high-resolution electrospray ionization mass spectrometry and comprehensive NMR analyses in combination with chemical hydrolysis. Compounds 1, 2, and 16 exhibited moderate inhibitory activity of monoamine oxidase B (MAO-B), while compounds 1 (50 μM) and 2 (100 μM) displayed significant neuroprotective effects (69.22 and 72.38% of cell viability, respectively) in the 6hydroxydopamine-induced injury of the PC12 cell model (54.41%), comparable to the positive drug rasagiline (70.45%). The neuroprotective effect of 1 and 2 was further evidenced by the observation of the morphological change and fluorescein diacetate/ propidium iodide staining. In addition, the levels of the major active compounds (1, 3, 5/6, and 16−18) vary from 21.5 to 892.3 μg/ g. This is the first report on phenolic glycosides from the fruits ofL. ruthenicum Murr that possess both significant MAO-B inhibitory and neuroprotective effects, indicating the promising potential of the fruits for the development of health care products and even therapeutic agents for the treatment of Parkinson's disease and other neurodegenerative diseases.

Introduction: As a famous traditional Chinese medicine, roots of Platycodon grandiflorus (Jacq.) A.DC. have shown multiple effects against neurodegenerative diseases. To investigate the components against Parkinson's disease (PD), the roots of P. grandiflora were selected as the research subject.Objective: Screening and identifying of monoamine oxidase B (MAO-B) inhibitors from the roots of P. grandiflorum via enzyme functionalised magnetic nanoparticles (MNPs)-based ligand fishing combined with high-performance liquid chromatography-mass spectrometry (HPLC-MS) analysis.Method: MAO-B functionalised MNPs have been synthesised for screening MAO-B inhibitors from the roots of P. grandiflorum. The ligands were identified by HPLC-MS and nuclear magnetic resonance (NMR) analysis, and their anti-PD activity was evaluated via MAO-B inhibition assay and cell viability assay in vitro.Results: Two MAO-B inhibitors were fished out and identified by HPLC-MS as protocatechuic aldehyde (1) and coumarin (2), with the half maximal inhibitory concentrations of 28.54 ± 0.39 and 25.39 ± 0.29 μM, respectively. Among them, 1 could also significantly increase the viability of 6-hydroxydopamine-damaged PC12 cells. Conclusion:The results are helpful to elucidate the anti-PD activity of the plant, and the ligand fishing method has shown good potential in discovery of MAO-B inhibitors.

A novel strategy of performing ligand fishing with enzyme-modified open tubular microchannel was proposed for screening bioactive components present in medicinal plants. Monoamine oxidase B was immobilized onto the surface of the microchannel for the first time to specifically extract its ligands when the plant's extracts solution flows through the channel. The thermal and the storage stability of immobilized monoamine oxidase B were significantly enhanced after immobilization. Crocin I and II were extracted from Crocus sativus, and tiliroside was extracted from Edgeworthia gardneri. All the three compounds were inhibitors of the enzyme with the half-maximal inhibitory concentration values of 26.70 ± 0.91, 19.88 ± 2.78, and 15.65 ± 0.85 μM, respectively. The enzyme inhibition kinetics and molecular docking were investigated. This is the first report on the inhibitory effects of tiliroside and crocin II. The novel ligand fishing method proposed in this work possesses advantages of rapidness, high efficiency, and tiny sample consumption compared to routine ligand fishing, with promising potential for screening active natural products in complex mixtures.

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