Vascular barrier protective effects of 3-N- or 3-O-cinnamoyl carbazole derivatives

Electrostatic Anchoring in RNA-Ligand Design─Dissecting the Effects of Positive Charges on Affinity, Selectivity, Binding Kinetics, and Thermodynamics

Targeting RNA with small molecules is an emerging field in medicinal chemistry. However, highly potent ligands are often challenging to achieve. One intuitive strategy to enhance ligand's potency is the implementation of positively charged moieties to interact with the negatively charged RNA phosphate backbone. We investigated the effect of such "electrostatic anchors" on binding affinity, kinetics, thermodynamics, and selectivity by MST, SPR, and ITC experiments, respectively, with the Ba SAM-VI riboswitch and the Tte preQ1 riboswitch aptamer model systems. RNA-ligand interactions were dominated by enthalpy, and electrostatic anchors had moderate effects on binding affinity driven by faster association rates for higher charged ligands. Despite the observations of loose binding interactions in SPR experiments with multibasic ligands, selectivity over structurally unrelated RNA off-targets was maintained. Therefore, the addition of positively charged moieties is no universal RNA-ligand design principle, but a purposefully implemented ionic RNA-ligand interaction can enhance potency without impairing selectivity.

Overview of piperlongumine analogues and their therapeutic potential

Natural products have long been an important source for discovery of new drugs to treat human diseases. Piperlongumine (PL) is an amide alkaloid isolated from Piper longum L. (long piper) and other piper plants and has received widespread attention because of its diverse biological activities. A large number of PL derivatives have been designed, synthesized and assessed in many pharmacological functions, including antiplatelet aggregation, neuroprotective activities, anti-diabetic activities, anti-inflammatory activities, anti-senolytic activities, immune activities, and antitumor activities. Among them, the anti-tumor effects and application of PL and its derivatives are most extensively studied. We herein summarize the development of PL derivatives, the structure and activity relationships (SARs), and their therapeutic potential on the treatments of various diseases, especially against cancer. We also discussed the challenges and future directions associated with PL and its derivatives in these indications.

Research progress in the biological activities of 3,4,5-trimethoxycinnamic acid (TMCA) derivatives

TMCA (3,4,5-trimethoxycinnamic acid) ester and amide are privileged structural scaffolds in drug discovery which are widely distributed in natural products and consequently produced diverse therapeutically relevant pharmacological functions. Owing to the potential of TMCA ester and amide analogues as therapeutic agents, researches on chemical syntheses and modifications have been carried out to drug-like candidates with broad range of medicinal properties such as antitumor, antiviral, CNS (central nervous system) agents, antimicrobial, anti-inflammatory and hematologic agents for a long time. At the same time, SAR (structure-activity relationship) studies have draw greater attention among medicinal chemists, and many of the lead compounds were derived for various disease targets. However, there is an urgent need for the medicinal chemists to further exploit the precursor in developing chemical entities with promising bioactivity and druggability. This review concisely summarizes the synthesis and biological activity for TMCA ester and amide analogues. It also comprehensively reveals the relationship of significant biological activities along with SAR studies.

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3,4,5-Trimethoxycinnamic acid (TMCA) derivatives show applications in different pathophysiological conditions due to its privileged structural scaffolds.

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Natural derived TMCA analogues and chemically modified TMCA ester and amide analogues and their bioactivities are focused in this review. Additionally, it also comprehensively summarized the relationship of significant biological activities along with SAR studies of synthetic TMCA derivatives.