Three quinolizidine dimers from the seeds of Sophora alopecuroides and their hepatoprotective activities

Discovery of hepatoprotective activity components from Thymus quinquecostatus celak. by molecular networking, biological evaluation and molecular dynamics studies

Thymus quinquecostatus Celak. is an edible herb that widely cultivated in Asia and possesses hepatoprotective activity, but the underlying non-volatile components of this protective activity are not well studied. In this study, combining molecular networking visualization and bioassay-guided fractionation strategies, a pair of novel skeleton diterpenoid enantiomers, (+)- and (-)-thymutatusone A [(+)- and (-)-1], along with one new and one known biogenetically related compounds (2-3) and 16 other known compounds (4-19), were identified from T. quinquecostatus. Their structures were exhaustively characterized by comprehensive spectroscopic data, X-ray diffraction analysis, and ECD calculations. Compounds (±)-1, (-)-1, and (+)-1, with a rare tricyclo [7.3.1.02,7] tridecane skeleton, exhibited potent hepatoprotective activity in HepG2 cells injured by acetaminophen, with EC50 values of 11.5 ± 2.8, 8.4 ± 1.9, and 12.2 ± 0.3 μM respectively. They were more potent than positive drug bifendate (EC50 15.2 ± 1.3). Further, the underlying mechanism for the hepatoprotective activity of compound (-)-1 related to activating the Nrf 2 signaling pathway. What's more, molecular docking and molecular dynamics simulation analysis showed that compound (-)-1 could dock with the active site of Nrf 2 protein and form a stable system through hydrogen bonding. These results suggest that T. quinquecostatus can be used as a valuable source of hepatoprotective activity compounds.

Quinolizidine-Type Alkaloids: Chemodiversity, Occurrence, and Bioactivity

Quinolizidine alkaloids (QAs) are nitrogen-containing compounds produced naturally as specialized metabolites distributed in plants and animals (e.g., frogs, sponges). The present review compiles the available information on the chemical diversity and biological activity of QAs reported during the last three decades. So far, 397 QAs have been isolated, gathering 20 different representative classes, including the most common such as matrine (13.6%), lupanine (9.8%), anagyrine (4.0%), sparteine (5.3%), cytisine (6.5%), tetrahydrocytisine (4.3%), lupinine (12.1%), macrocyclic bisquinolizidine (9.3%), biphenylquinolizidine lactone (7.1%), dimeric (7.1%), and other less known QAs (20.9%), which include several structural patterns of QAs. A detailed survey of the reported information about the bioactivities of these compounds indicated their potential as cytotoxic, antiviral, antimicrobial, insecticidal, anti-inflammatory, antimalarial, and antiacetylcholinesterase compounds, involving favorable putative drug-likeness scores. In this regard, research progress on the structural and biological/pharmacological diversity of QAs requires further studies oriented on expanding the chemical space to find bioactive scaffolds based on QAs for pharmacological and agrochemical applications.

Research Progress of Natural Matrine Compounds and Synthetic Matrine Derivatives

Matrine is a quinoline alkaloid extracted and separated from the dried root, fruit, and other parts of the plant Sophora flavescens using an organic solvent. Matrine exhibits a variety of biological activities and is widely used in pharmacy, agronomy, and other fields. Due to its low bioavailability, poor chemical stability, and toxicity to the central nervous system, a large number of researchers have searched for matrine derivatives with higher biological activity and safety by modifying its structure. In this review article, the research progress of matrine derivatives obtained using two methods (extraction from Sophora flavescens and structural modifications) from 2018 to 2022 in terms of pharmacological activity, mechanism of action, and structure-activity relationship are presented. The modification of matrine over the past five years has been mainly on the D-ring. Many new matrine alkaloids have been extracted from natural products, some of which have good pharmacological activity, which broadens the strategy for matrine structural modification in the future.

Sophflarine A, a novel matrine-derived alkaloid from Sophora flavescens with therapeutic potential for non-small cell lung cancer through ROS-mediated pyroptosis and autophagy

BACKGROUND

Novel compounds and more efficient treatment options are urgently needed for the treatment of non-small cell lung cancer (NSCLC). The decoction of Sophora flavescens has been used to treat NSCLC in the clinic, and matrine-type alkaloids are generally considered to be the key pharmacodynamic material basis. But the previous study showed that common matrine-type alkaloids exhibit significant cytotoxicity only when at concentrations close to the millimolar (mM) level. The key antitumor alkaloids in S. flavescens seem to have not yet been revealed.

PURPOSE

The aim of this study was to screen water-soluble matrine alkaloid with novel skeleton and enhanced activity from S. flavescens, and to reveal the pharmacological mechanism of its therapeutic effect on NSCLC.

METHODS

Alkaloid was obtained from S. flavescens by chromatographic separation methods. The structure of alkaloid was determined by spectroscopic methods, and single-crystal X-ray diffraction. The mechanism of anti-NSCLC in vitro with cellular models was evaluated by MTT assay, western blotting, cell migration and invasion assay, plate colony-formation assay, tube formation assay, immunohistochemistry assay, hematoxylin and eosin staining. The antitumor efficacy in vivo was test in NSCLC xenograft models.

RESULTS

A novel water-soluble matrine-derived alkaloid incorporating 6/8/6/6 tetracyclic ring system, named sophflarine A (SFA), was isolated from the roots of S. flavescens. SFA had significantly enhanced cytotoxicity compared with the common matrine-type alkaloids, having an IC₅₀ value of 11.3 μM in A549 and 11.5 μM in H820 cells at 48 h. Mechanistically, SFA promoted NSCLC cell death by inducing pyroptosis via activating the NLRP3/caspase-1/GSDMD signaling pathway, and inhibited cancer cell proliferation by increasing the ROS production to activate autophagy via blocking the PI3K/AKT/mTOR signaling pathway. Additionally, SFA also inhibited NSCLC cell migration and invasion by suppressing EMT pathway, and inhibited cancer cell colony formation and human umbilical vein endothelial cell angiogenesis. In concordance with the above results, SFA treatment blocked tumor growth in an A549 cell-bearing orthotopic mouse model.

CONCLUSION

This study revealed a potential therapeutic mechanism of a novel matrine-derived alkaloid, which not only described a rational explanation for the clinical utilization of S. flavescens, but also provided a potential candidate compound for NSCLC treatment.

Gold-catalyzed endo-selective cyclization of alkynylcyclobutanecarboxamides: synthesis of cyclobutane-fused dihydropyridones

Cyclobutane-fused dihydropyridones can be efficiently synthesized by a completely endo-selective gold-catalyzed cyclization of alkynylcyclobutanes bearing an appended amide, which proceeds under mild conditions. The observed selectivity, which is reversed from that previously observed for the cyclization of related alcohols and acids, is supported by DFT calculations.

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A personal selection of 32 recent papers is presented covering various aspects of current developments in bioorganic chemistry and novel natural products such as hyperispirone A from Hypericum beanii.