Seven new abietane diterpenoids, comprising medusanthol A–G (1–3, 5, 7–9) and two previously identified analogs (4 and 6), were isolated from the hexane extract of the aerial parts of Medusantha ...martiusii. The structures of the compounds were elucidated by HRESIMS, 1D/2D NMR spectroscopic data, IR spectroscopy, NMR calculations with DP4+ probability analysis, and ECD calculations. The anti-neuroinflammatory potential of compounds 1–7 was evaluated by determining their ability to inhibit the production of nitric oxide (NO) and the proinflammatory cytokine TNF-α in BV2 microglia stimulated with LPS and IFN-γ. Compounds 1–4 and 7 exhibited decreased NO levels at a concentration of 12.5 µM. Compound 1 demonstrated strong activity with an IC50 of 3.12 µM, and compound 2 had an IC50 of 15.53 µM; both compounds effectively reduced NO levels compared to the positive control quercetin (IC50 11.8 µM). Additionally, both compounds significantly decreased TNF-α levels, indicating their potential as promising anti-neuroinflammatory agents.
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.
The skeleton of the helianane's family is an unsolved controversial topic. Recent synthetic studies and
13
C NMR structural analysis have demanded for an amendment of helianane to the open ring ...curcudiol. However, some authors argue that the original helianane structure, a benzofused eight-membered ether ring system, cannot be ruled out immediately without further spectral analyses of curcudiol and helianane. The fact that this compound is extremely rare, obtained only from marine organisms, makes remote the possibility of reisolation. Therefore, we decided to approach this problem computationally. Herein, we performed a complementary quantum mechanical study in order to provide more information about the helianane's actual skeleton. Our
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C NMR chemical shifts calculations suggests that the curcudiol structure is more likely to be the correct one. In addition, we simulated the formation pathways for both products starting from the known biosynthetic precursor. The results show that curcudiol is around 8.0 kcal mol
−1
more stable than the originally proposed helianane structure.
Comprehensive work suggesting the amendment of helianane to the open ring curcudiol by means of computational spectroscopy and thermodynamic reasons.
A new phenylpropanoid derivative, named euploic acid (1), was isolated from Euploca procumbens (Mill.) Diane & Hilger, Boraginaceae, along with lithospermic acid B (2), lithospermic acid (3), ...9’’-methyl lithospermate (4), and luteolin-7-O-glucoside (5). Compound structures were determined by mass spectrometry (MS), nuclear magnetic resonance (NMR) analysis and comparison with published data. Absolute configuration of 1 was established via electronic circular dichroism (ECD). Anti-inflammatory potential of euploic acid (1) was assessed by measuring its inhibition of cytokine and nitric oxide production in stimulated J774 macrophages. Compound 1 significantly reduced pro-inflammatory mediator production and release by stimulated macrophages at non-cytotoxic concentrations, comparable to the efficacy of dexamethasone. Our findings demonstrate the potential of euploic acid (1) as an effective anti-inflammatory agent. This study contributes to the structural elucidation of a new phenylpropanoid derivative and highlights its promising anti-inflammatory activity in the treatment of inflammatory disorders.
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•Theoretical prediction of the corrosion inhibition efficiencies.•Adsorption of the green synthetized molecules on alloy is of physicochemical type.•Anticorrosive efficiencies from ...83.5 up to 95.6% for mild steel in HCl 1 mol L−1.•Data crossing of the weight loss analysis and the electrochemical tests.•Polarization curves reveal that the three inhibitors act as mixed-type inhibitors.
Three phenylmethanimine derivatives (Schiff bases) were designed after a theoretical prediction of their corrosion inhibition efficiencies and a corroboration through the use of quantum chemical calculations. The molecules were then prepared using a classical condensation reaction between aldehydes and amines but taking in account the tenets of green chemistry. Their application as corrosion inhibitors for ASTM A36 steel in 1 mol L−1 hydrochloric acid media was explored by means of a weight loss analysis, electrochemical tests and a surface morphology analysis to physically evaluate the metallic sacrifice surfaces used. The results of the electrochemical tests revealed that the three compounds have a good anti-corrosion capacity and act as mixed-type corrosion inhibitors. In addition, cross-checking the data from weight loss analysis and electrochemical tests confirm Langmuir monolayer formation theory. The corrosion inhibition efficiencies found range between 83.5 and 95.6%.
A convenient synthesis under ultrasound (US) irradiation of 4-thiazolidinone, thiazole, dihydrothiazole, and thiazine hybrid compounds containing quinoline and indole nucleus is described. All the ...title compounds were characterized by NMR and HRMS. The synthetic protocol affords highly selective conversions, short reaction times, simple work-up procedures, and good yields compared with conventional methods. All the synthesized compounds were tested for in vitro cytotoxic activity against glioblastoma (SF-295), leukemia (HL-60), and prostate cancer (PC-3) cell lines. Three compounds ( 4c–e ) presented moderate to high activity against all cancer cell lines evaluated. Compound 4c stood out with its promising cytotoxicity activity against the HL-60 cell line with an IC 50 value of 2.41 μM and an SI of 10.5. The electrochemical behavior of 4c was studied using differential pulse voltammetry (DPV) on a glassy carbon electrode modified with dsDNA and with ssDNA in the solution. As a result, the pre-concentration of the compound on the dsDNA biosensor surface and modification of the oxidation currents of guanosine and adenosine bases in ssDNA experiments demonstrated an interaction between 4c and DNA. The affinity of 4c was evaluated against ctDNA by exploring spectroscopic techniques, showing that this compound acts preferentially as a groove binder. Molecular docking and dynamics simulations proposed that 4c interacts via groove binding and intercalation, corroborating the experimental results. The dominating interactions were conventional hydrogen bonds and van der Waals forces. Finally, our findings suggest the 4c derivative to be a potential anticancer prototype against HL-60.
Arthropod-borne viruses (arboviruses) are a severe public health problem worldwide, consisting of a significant part of all the emerging infectious diseases. It is estimated that arboviruses infect ...hundreds of millions of people globally each year, resulting in several thousand deaths. Despite their clear health threat, there are no prophylactic or pharmacological therapies available for most of them. Control of arbovirus infections is beyond pharmacological options; handling the larvae of mosquitos is an important and successful strategy, although currently available insecticides and larvicides are already associated with resistance. Therefore, searching for new strategies to prevent arbovirus infection is urgent and necessary. Marine organisms are an excellent source for structurally novel compounds due to their unique secondary metabolism, with outstanding antiviral and larvicidal activities. In the present review, we explored the ability of various marine natural products (MNPs) such as indole derivatives, diketopiperazines, scequinadoline A, cyclohexadepsipeptides, and others, to act as both antiviral and larvicidal, in an attempt to highlight their structure activity potential against the most relevant arboviruses affecting the human health.
Most studies evaluating insect communities along climatic gradients in mountain regions have overlooked the relevance of the contrasting effects of xeric and mesic habitats on species distribution ...and richness. Mesic zones in xeric ecosystems can provide more favorable conditions for the maintenance of some insects, including orchid bees (Apidae, Euglossini), which are known for their high species diversity in humid tropical forests.
For the first time, we sought to understand the distribution of Euglossini in xeric and mesic habitats during dry and wet seasons along an elevational gradient in Espinhaço mountains, southeastern Brazil.
The study collected 4873 orchid bees from three genera and 14 species. During the wet season, bee richness decreased with elevation in both xeric and mesic habitats. However, during the dry season, there was an increase in both bee richness and abundance at intermediate elevations. In the dry season, lower bee richness and abundance were recorded in xeric habitats compared with mesic habitats. Bee richness and abundance did not differ between the dry and wet seasons for mesic habitats, while lower richness and abundance were recorded in the dry season for xeric habitats. Species composition remained unchanged across habitats, and species turnover was identified as the primary driver of β‐diversity among elevations and seasons.
Orchid bees require high temperatures, but they cannot tolerate water stress in xeric habitats during the dry season. This highlights the importance of mesic habitats for maintaining these pollinators, which are essential for ecosystems in savanna and mountainous regions.
Euglossine richness decreases from lower to higher elevations on the mountains in mesic/xeric habitats, during the wet season. During the dry season, richness/abundance was higher at mid‐elevations in both habitats.
Richness and abundance were higher in mesic habitats than in xeric habitats during the dry season. These parameters did not differ between xeric and mesic habitats during the wet season.
In the dry seasons, euglossine richness and abundance in xeric habitats were lower than in the wet season. In mesic habitats, these parameters did not differ between seasons.
Several studies have demonstrated the cytotoxic potential of nor-β-lapachone derivative against cancer cells. Considering nor-β-lapachone as an important prototype, a set of new 3-substituted ...nor-β-lapachones was synthesized by a new synthetic route that involves the use of synthetic intermediate generated for coupling with several nucleophiles containing the carbohydrate and 2H-pyrazole substituent moieties. All the compounds were screened against four tumor cell lines. Two of the compounds showed moderate cytotoxicity, while the other compounds strongly inhibit all tested cancer cell lines.
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