In the early 2000s, the first articles regarding the calculation of NMR parameters for natural products appeared in the literature. Since then, modelling ¹H and ¹³C chemical shifts and spin–spin coupling constants for this class of compounds has experienced a remarkable increase in precision, accessibility, and application, leading to considerable advances in the field. More recently, significant contributions from several authors have led to continuous growth in this research field, updating and broadening the simulation of NMR parameters, in particular with the application of new techniques for data treatment. Nowadays, such studies are routinely found in the high impact literature. In this review, we intend to cover the general guidelines and the main advances in NMR calculations of natural products published since 2012. We intend to address the bottlenecks of quantum chemical calculations of NMR parameters, including mathematical definitions, updates, and a discussion of relevant examples, and to highlight novel tools, for example DU8+, CP3, DP4, DP4+ and J-DP4. We will cover all aspects of NMR simulation focusing on natural products, from the fundamentals to the new computational toolboxes available, combining advanced quantum chemical calculations with complex upstream data processing and machine learning.

A new synthetic antimalarial drug, a salt derived from two antimalarial molecules, mefloquine (MQ) and artesunate (AS), here named MEFAS, has been tested for its pharmacological activity. Combinations of AS plus MQ hydrochloride are currently being used in areas with drug-resistant Plasmodium falciparum parasites; although AS clears parasitemia in shorter time periods than any other antimalarial drug, it does not cure infected patients; in addition, MQ causes side effects and is rather expensive, important problems considering that malaria affects mostly populations in poor countries. Here, we show that MEFAS is more effective than the combination of AS and MQ, tested in parallel at different mass proportions, against P. falciparum (chloroquine-resistant clone W2 and chloroquine-sensitive clone 3D7) in vitro and in mice infected with Plasmodium berghei , promoting cure of this infection. MEFAS tested against HepG2 hepatoma cells exhibited lower toxicity than the antimalarials AS and MQ alone or combined. Possible targets of MEFAS have been studied by confocal microscopy using fluorescent probes (Fluo-4 AM and BCECF-AM) in P. falciparum synchronous culture of W2-infected red blood cells. Dynamic images show that MEFAS exhibited intracellular action increasing cytoplasmic Ca ²⁺ at 1.0 ng/ml. This effect was also observed in the presence of tapsigargin, an inhibitor of SERCA, suggesting an intracellular target distinct from the endoplasmic reticulum. Trophozoites loaded with BCECF-AM, when treated with MEFAS, were still able to mobilize protons from the digestive vacuole (DV), altering the pH gradient. However, in the presence of bafilomycin A1, an inhibitor of the H ⁺ pump from acidic compartments of eukaryotic cells, MEFAS had no action on the DV. In conclusion, the endoplasmic reticulum and DV are intracellular targets for MEFAS in Plasmodium sp., suggesting two modes of action of this new salt. Our data support MEFAS as a candidate for treating human malaria.

According to the World Health Organization, half of the World’s population, approximately 3.3 billion people, is at risk for developing malaria. Nearly 700,000 deaths each year are associated with the disease. Control of the disease in humans still relies on chemotherapy. Drug resistance is a limiting factor, and the search for new drugs is important. We have designed and synthesized new 2-(trifluoromethyl)[1,2,4]triazolo[1,5-a]pyrimidine derivatives based on bioisosteric replacement of functional groups on the anti-malarial compounds mefloquine and amodiaquine. This approach enabled us to investigate the impact of: (i) ring bioisosteric replacement; (ii) a CF₃ group substituted at the 2-position of the [1,2,4]triazolo[1,5-a]pyrimidine scaffold and (iii) a range of amines as substituents at the 7-position of the of heterocyclic ring; on in vitro activity against Plasmodium falciparum. According to docking simulations, the synthesized compounds are able to interact with P. falciparum dihydroorotate dehydrogenase (PfDHODH) through strong hydrogen bonds. The presence of a trifluoromethyl group at the 2-position of the [1,2,4]triazolo[1,5-a]pyrimidine ring led to increased drug activity. Thirteen compounds were found to be active, with IC₅₀ values ranging from 0.023 to 20 µM in the anti-HRP2 and hypoxanthine assays. The selectivity index (SI) of the most active derivatives 5, 8, 11 and 16 was found to vary from 1,003 to 18,478.

Oral squamous cell carcinoma (OSCC) is one of the ten most common types of cancer worldwide. Plants of the genusPiper are used in traditional medicine to treat cancer, and they have a vast diversity of phytochemicals with cytotoxic potential. Purpose and Study Design: In this work, we analyzed the cytotoxic and selective potential of extracts and semipurified fractions of Piper mollicomum (PM), Piper truncatum (PT), Piper cernuum (PC), Piper arboreum (PA), and Piper cabralanum (PCa) using three different OSCC cell lines (SCC4, SCC9 and SCC25), and we measured their in vivo toxicities and conducted chemical analyses of their active fractions. The dichloromethane fractions of the crude methanolic extracts of the leaves of PM(-L-D), PC(-L-D) and PCa(-L-D) exhibited notable IC50 values of 94.2, 47.2 and 47.5 μg/mL, respectively, and all three of these extracts were more active than carboplatin (172.3 μg/mL). The most selective fraction was PC-L-D, which exhibited SI > 4.5; less than 5% hemolysis; and no significant alterations in in vivo acute toxicology. The major constituents in active fractions were lignans (PC-L-D and PCa-L-D) and chromenes (PM-L-D). PC-L-D demonstrated great potential for further development as an anticancer drug and could be the key to developing more effective and less toxic therapies against oral cancer.