Rosmarinic acid and its derivative's duel as antitubercular agents: insights from computational prediction to functional response in vitro.

Tuberculosis is one of the most dreadful infectious diseases, afflicting global populations with anguish. With the emergence of multi-drug resistant strains of mycobacteria, the imperative for new anti-tuberculosis drugs has grown exponentially. Thus, the current study delves into evaluating the impact of Perovskia abrotanoides and its active metabolites-namely, rosmarinic acid and its derivatives-against strains of Mycobacterium tuberculosis (Mtb). Through the use of the CRI assay, the antimycobacterial potential of the high-altitude medicinal plant P. abrotanoides was gauged, while docking and molecular dynamics simulations unveiled plausible targets. Of these, the peak antimycobacterial effectiveness was observed in the P. abrotanoides ethyl acetate extract with 125 µg/mL as minimum inhibitory concentration against various strains of M. tuberculosis, encompassing H37Rv and strains resistant to multiple drugs. Following bioassay-guided fractionation and isolation, rosmarinic acid and rosmarinic acid methyl ester emerged as potent molecules against H37Rv and multidrug-resistant M. tuberculosis strains; minimum inhibitory concentration ranging from 15 to 32 µg/mL. Additionally, out of 22 targets explored, Mtb lipoamide dehydrogenase (PDB: 3II4) and Rv2623 (PDB: 3CIS) were forecasted as potential Mtb targets for rosmarinic acid and rosmarinic acid methyl ester, respectively, a supposition further affirmed by molecular simulations (100 ns). The stability of both complexes throughout the simulation was measured by protein backbone root-mean-square deviation, substantiating their roles as respective targets for antimycobacterial activities.Communicated by Ramaswamy H. Sarma.

The Abundant Phytocannabinoids in Rheumatoid Arthritis: Therapeutic Targets and Molecular Processes Identified Using Integrated Bioinformatics and Network Pharmacology.

The endocannabinoid system consists of several phytocannabinoids, cannabinoid receptors, and enzymes that aid in numerous steps necessary to manifest any pharmacological activity. It is well known that the endocannabinoid system inhibits the pathogenesis of the inflammatory and autoimmune disease rheumatoid arthritis (RA). To the best of our knowledge, no research has been done that explains the network-pharmacology-based anti-rheumatic processes by focusing on the endocannabinoid system. Therefore, the purpose of this study is to further our understanding of the signaling pathways, associated proteins, and genes underlying RA based on the abundant natural endocannabinoids. The knowledge on how the phytocannabinoids in Cannabis sativa affect the endocannabinoid system was gathered from the literature. SwissTarget prediction and BindingDB databases were used to anticipate the targets for the phytocannabinoids. The genes related to RA were retrieved from the DisGeNET and GeneCards databases. Protein-protein interactions (high confidence > 0.7) were carried out with the aid of the string web server and displayed using Cytoscape. The Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathway analysis was used to perform enrichment analyses on the endocannabinoid-RA common targets. ShinyGO 0.76 was used to predict the biological processes listed in the Gene Ontology (GO) classification system. The binding affinity between the ligand and the receptors was precisely understood using molecular docking, induced-fit docking, and a molecular dynamics simulation. The network pharmacology analyses predicted that processes like response to oxygen-containing compounds and peptodyl-amino acid modification are related to the potential mechanisms of treatment for RA. These biological actions are coordinated by cancer, neuroactive ligand-receptor interaction, lipids and atherosclerosis, the calcium signaling pathway, and the Rap1 signaling pathway. According to the results of molecular docking, in the context of RA, phytocannabinoids may bind to important target proteins such PIK3CA, AKT1, MAPK9, PRKCD, BRAF, IGF1R, and NOS3. This entire study predicted the phytocannabinoids' systemic biological characteristics. Future experimental research is needed, however, to confirm the results so far.

Structure-Based Identification of Potent Natural Product Chemotypes as Cannabinoid Receptor 1 Inverse Agonists.

Natural products are an abundant source of potential drugs, and their diversity makes them a rich and viable prospective source of bioactive cannabinoid ligands. Cannabinoid receptor 1 (CB1) antagonists are clinically established and well documented as potential therapeutics for treating obesity, obesity-related cardiometabolic disorders, pain, and drug/substance abuse, but their associated CNS-mediated adverse effects hinder the development of potential new drugs and no such drug is currently on the market. This limitation amplifies the need for new agents with reduced or no CNS-mediated side effects. We are interested in the discovery of new natural product chemotypes as CB1 antagonists, which may serve as good starting points for further optimization towards the development of CB1 therapeutics. In search of new chemotypes as CB1 antagonists, we screened the in silico purchasable natural products subset of the ZINC12 database against our reported CB1 receptor model using the structure-based virtual screening (SBVS) approach. A total of 18 out of 192 top-scoring virtual hits, selected based on structural diversity and key protein⁻ligand interactions, were purchased and subjected to in vitro screening in competitive radioligand binding assays. The in vitro screening yielded seven compounds exhibiting >50% displacement at 10 µM concentration, and further binding affinity (Ki and IC50) and functional data revealed compound 16 as a potent and selective CB1 inverse agonist (Ki = 121 nM and EC50 = 128 nM) while three other compounds-2, 12, and 18-were potent but nonselective CB1 ligands with low micromolar binding affinity (Ki). In order to explore the structure⁻activity relationship for compound 16, we further purchased compounds with >80% similarity to compound 16, screened them for CB1 and CB2 activities, and found two potent compounds with sub-micromolar activities. Most importantly, these bioactive compounds represent structurally new natural product chemotypes in the area of cannabinoid research and could be considered for further structural optimization as CB1 ligands.

Biological evaluation of novel substituted chloroquinolines targeting mycobacterial ATP synthase.

The ATP synthase of Mycobacterium tuberculosis is a validated drug target against which a diarylquinoline drug is under clinical trials. The enzyme is crucial for the viability both of actively replicating and non-replicating/dormant M. tuberculosis. Enzyme levels drop drastically as the bacilli enter dormancy and hence an inhibitor would make the dormant bacilli even more vulnerable. In this study, a set of 18 novel substituted chloroquinolines were screened against Mycobacterium smegmatis ATP synthase; 6 compounds with the lowest 50% inhibitory concentration (IC(50)) values (0.36-1.83 µM) were selected for further in vitro studies. All six compounds inhibited the growth of M. tuberculosis H37Rv in vitro, with minimum inhibitory concentrations (MICs) of 3.12 µg/mL (two compounds) or 6.25 µg/mL (four compounds). All of them were bactericidal to non-replicating M. tuberculosis H37Rv in hypoxic culture; three compounds caused a >2 log(10) reduction in CFU counts in 4 days at concentrations of 16× or 32× their MICs, compared with a 0.2 log(10) reduction by isoniazid and a >4 log(10) reduction by rifampicin at 100× their MICs. The compounds also contributed to a greater reduction in total cellular ATP of the bacilli compared with isoniazid and rifampicin during an exposure time of 18 h. The compounds at 100 µM caused only 5-35% inhibition of mouse liver mitochondrial ATP synthase, leading to selectivity indices ranging from >55-fold to >278-fold. In vitro cytotoxicity to the Vero cell line measured as the 50% cytotoxic concentration (CC(50)) of the compounds ranged between 55 µg/mL and >300 µg/mL.