13C NMR Dereplication Using MixONat Software: A Practical Guide to Decipher Natural Products Mixtures

Natural Products Dereplication: Databases and Analytical Methods

The development of efficient methods for dereplication has been critical in the re-emergence of the research in natural products as a source of drug leads. Current dereplication workflows rapidly identify already known bioactive secondary metabolites in the early stages of any drug discovery screening campaign based on natural extracts or enriched fractions. Two main factors have driven the evolution of natural products dereplication over the last decades. First, the availability of both commercial and public large databases of natural products containing the key annotations against which the biological and chemical data derived from the studied sample are searched for. Second, the considerable improvement achieved in analytical technologies (including instrumentation and software tools) employed to obtain robust and precise chemical information (particularly spectroscopic signatures) on the compounds present in the bioactive natural product samples. This chapter describes the main methods of dereplication, which rely on the combined use of large natural product databases and spectral libraries, alongside the information obtained from chromatographic, UV-Vis, MS, and NMR spectroscopic analyses of the samples of interest.

Vasorelaxant Activity of Salvia hispanica L.: Involvement of the Nitric Oxide Pathway in Its Pharmacological Mechanism

Salvia hispanica L., commonly known as chía, and its seeds have been used since ancient times to prepare different beverages. Due to its nutritional content, it is considered a dietary ingredient and has been reported with many health benefits. Chia seed components are helpful in cardiovascular disease (CVD) by reducing blood pressure, platelet aggregation, cholesterol, and oxidation. Still, its vasodilator effects on the vascular system were not reported yet. The hexanic (HESh), dichloromethanic (DESh), and methanolic (MESh) extracts obtained from chía seeds were evaluated on an aortic ring ex-vivo experimental model. The vasorelaxant efficacy and mechanism of action were determined. Also, phytochemical data was obtained through 13C NMR-based dereplication. The MESh extract showed the highest efficacy (Emax = 87%), and its effect was partially endothelium-dependent. The mechanism of action was determined experimentally, and the vasorelaxant curves were modified in the presence of L-NAME, ODQ, and potassium channel blockers. MESh caused a relaxing effect on KCl 80 mM-induced contraction and was less potent than nifedipine. The CaCl2-induced contraction was significantly decreased compared with the control curve. Phytochemical analysis of MESh suggests the presence of mannitol, previously reported as a vasodilator on aortic rings. Our findings suggest NO-cGMP pathway participation as a vasodilator mechanism of action of S. hispanica seeds; this effect can be attributed, in part, to the mannitol presence. S. hispanica could be used in future research focused on antihypertensive therapies.

Antibacterial Potency of an Active Compound from Sansevieria trifasciata Prain: An Integrated In Vitro and In Silico Study

Sansevieria trifasciata Prain holds great potential as a valuable asset in pharmaceutical development. In this study, our focus is to explore and assess the antibacterial activity of various components derived from this plant, including extracts, fractions, subfractions, and isolates, explicitly targeting two common bacteria: Escherichia coli and Streptococcus aureus. The isolated compound, identified as a derivative pyridone alkaloid (5-methyl-11-(2-oxopyridin-1(2H)-yl)undecaneperoxoicacid), demonstrates notable antibacterial effects. The extracts, fractions, subfractions, and isolates reveal significant bacterial growth reductions (p < 0.05). The minimum inhibitory concentration (MIC) values for Escherichia coli were 1.95 ppm, 3.9 ppm, 15.62 ppm, and 7.81 ppm, respectively, while the MIC values for Streptococcus aureus were 1.95 ppm, 1.95 ppm, 15.62 ppm, and 7.81 ppm, respectively. Computational analysis showed the isolates' interaction with key residues on the active site of β-ketoacyl-ACP synthase from Escherichia coli and TyrRS from Streptococcus aureus. The findings indicate that the isolates exhibit a strong affinity for specific residues, including His333, Cys163, and Phe392 in β-ketoacyl-ACP synthase, as well as Arg88, His117, Glu160, and Gln213 in TyrRS. Comparative energy calculations using MMPBSA demonstrate the isolates' favorable binding energy (-104,101 kJ/mol for β-ketoacyl-ACP synthase and -81,060 kJ/mol for TyrRS) compared to ciprofloxacin. The elucidated antibacterial activity and molecular interactions of the isolates present valuable knowledge for future in vitro studies, facilitating the development of novel antibacterial agents targeting diverse bacterial strains.

Advanced Methods for Natural Products Discovery: Bioactivity Screening, Dereplication, Metabolomics Profiling, Genomic Sequencing, Databases and Informatic Tools, and Structure Elucidation

Natural Products (NP) are essential for the discovery of novel drugs and products for numerous biotechnological applications. The NP discovery process is expensive and time-consuming, having as major hurdles dereplication (early identification of known compounds) and structure elucidation, particularly the determination of the absolute configuration of metabolites with stereogenic centers. This review comprehensively focuses on recent technological and instrumental advances, highlighting the development of methods that alleviate these obstacles, paving the way for accelerating NP discovery towards biotechnological applications. Herein, we emphasize the most innovative high-throughput tools and methods for advancing bioactivity screening, NP chemical analysis, dereplication, metabolite profiling, metabolomics, genome sequencing and/or genomics approaches, databases, bioinformatics, chemoinformatics, and three-dimensional NP structure elucidation.