Restoring homeostasis in persistent inflammation requires suppressing the inflammatory response and promoting resolution. Currently, no clinically used small molecules intentionally achieve both effects. Endogenous long-chain vitamin E metabolites (LCMs) address inflammation at multiple sites, including pro-inflammatory leukotriene production and cytokine release, thus limiting inflammation. Among LCMs, we here identified ω-carboxylates and ω-alcohols that suppress leukotriene biosynthesis while enhancing the biosynthesis of prostaglandin E2 and specialized pro-resolving mediators, specifically protectins or isomers, proposed to promote inflammation resolution. These LCMs induce a lipid mediator class switch in activated and non-activated human innate immune cells and in a mouse model of self-resolving peritonitis and inhibit ferroptosis. Changes in lipid mediator classes are tightly coordinated between local and systemic sites and follow different kinetics. Mechanistically, LCMs induce polyunsaturated fatty acid release and translocate 15-lipoxygenase-1, a key enzyme in protectin biosynthesis, to particulate locales while also engaging other mechanisms, partially involving cyclooxygenase-2, to increase protectin production. The LCMs also inhibit soluble epoxide hydrolase, reducing the degradation of anti-inflammatory epoxyeicosatrienoic acids, and increase levels of endocannabinoids and dihydroceramides with immunomodulatory and stress-protective functions. These findings provide insights into immunoregulation by tocotrienol metabolites and offer promising lead structures for redirecting lipid mediator profiles from inflammation toward resolution.

Inhibition of the Unfolded Protein Response (UPR) pathway of phytopathogenic fungi represents a promising strategy for the discovery of natural products capable of attenuating fungal resistance to plant defense metabolites. Polyprenylated xanthones isolated from Clusiaceae and Calophylaceae have recently been identified as inhibitors of this fungal resistance pathway whereas Garcinia parvifolia (Miq.) Miq. is known for its high xanthone content. Consequently, systematic phytochemical investigation of the latex and bioguided fractionation based on anti-UPR cell-based assay were conducted. A total of sixteen compounds were isolated, including one previously unreported terpenophenol with an original structure (2) and three previously undescribed xanthones (12-14), the latter obtained through bioguided fractionation. Among the isolated compounds, demethylrubraxanthone (12) exhibited notable anti-UPR activity, with an IC50 value of 8.0 ± 0.3 μM. To address the limited availability of (12) in the latex, a semisynthesis from rubraxanthone (1) was eventually conducted.

Presently it is estimated that many of the approximately 4000 new natural products isolated every year following complicated, long, and expensive isolation processes are already known; because of this, developing new strategies for locating secondary metabolites of interest in complex extracts or fractions is important. Currently, chromatographic and spectroscopic techniques are being used to optimize the isolation and identification of natural products. In this investigation we have used 13C NMR dereplication analyses for the quick identification of a number of triterpenes (friedelin, lupeol, betulinic acid), sterols (euphol, β-sitosterol) and fatty acids (palmitic acid) present in semipurified fractions obtained from the stem bark extract of Clusia flava and to assist in the isolation of the bioactive metabolites trapezifolixanthone and paralycolin A. The complete and correct assignment of the 1H and 13C NMR spectroscopic data for paralycolin A is reported for the first time and the antioxidant and antiAGEs activity of both metabolites is described.

The emergence and reappearance of a growing number of diseases, together with the loss of biodiversity, have restructured bioprospecting methodologies when studying secondary metabolites, which continue to play a key role in the discovery of natural products with pharmacological activity. In this investigation, a combined approach using chemometric analyses of 1H-NMR and HPLC metabolic and chromatographic profiles, respectively, and 13C-NMR dereplication analysis has been used to identify inhibitors of virulence factors in bacteria as part of a new approach in the fight against antimicrobial resistance. Multivariate statistical analysis was used to correlate the 1H-NMR metabolic and HPLC chromatographic profiles of the root crude extract and semipurified fractions from Colubrina yucatanensis (M.C.Johnst.) G.L.Nesom, Rhamnaceae, with the results from their inhibition of the production of pyocyanin, proteases, and biofilm formation in a model of Pseudomonas aeruginosa. The methodology used allowed the identification of activity-associated signals and components in the 1H-NMR metabolic and HPLC chromatographic profiles of the bioactive extract and semipurified fractions, respectively. 13C-NMR dereplication analysis of the semipurified bioactive fractions using the MixONat software confirmed that one of the activity-associated signals detected in the 1H-NMR profile belonged to 3-O-acetyl-ceanotic acid. Purification and evaluation of the pure ceanotane confirmed its identification as one of the bioactive metabolites produced by C. yucatanensis. This is the first report of 3-O-acetyl-ceanotic acid as a natural inhibitor of bacterial virulence factors.

The unfolded protein response (UPR) is a key component of fungal virulence. The prenylated xanthone gamma-mangostin isolated from Garcinia mangostana (Clusiaceae) fruit pericarp, has recently been described to inhibit this fungal adaptative pathway. Considering that Calophyllum caledonicum (Calophyllaceae) is known for its high prenylated xanthone content, its stem bark extract was fractionated using a bioassay-guided procedure based on the cell-based anti-UPR assay. Four previously undescribed xanthone derivatives were isolated, caledonixanthones N-Q ( 3, 4, 8, and 12), among which compounds 3 and 8 showed promising anti-UPR activities with IC50 values of 11.7 +/- 0.9 and 7.9 +/- 0.3 mu M, respectively.

INTRODUCTION:Propolis is a resinous natural substance collected by honeybees from buds and exudates of various trees and plants; it is widely accepted that the composition of propolis depends on the phytogeographic characteristics of the site of collection.OBJECTIVES:The aim of this study was to determine the phytochemical composition of ethanolic extracts from eight propolis batches collected in different regions of Benin (north, center, and south) and Congo, Africa.MATERIAL AND METHODS:Characterization of propolis samples was performed by using different hyphenated chromatographic methods combined with carbon-13 nuclear magnetic resonance (13 C NMR) dereplication with MixONat software. Their antioxidant or anti-advanced glycation end-product (anti-AGE) activity was then evaluated by using diphenylpicrylhydrazyl and bovine serum albumin assays, respectively.RESULTS:Chromatographic analyses combined with 13 C NMR dereplication showed that two samples from the center of Benin exhibited, in addition to a huge amount of pentacyclic triterpenes, methoxylated stilbenoids or phenanthrenoids, responsible for the antioxidant activity of the extract for the first one. Among them, combretastatins might be cytotoxic. For the second one, the prenylated flavanones known in Macaranga-type propolis were responsible for its significant anti-AGE activity. The sample from Congo was composed of many triterpene derivatives belonging to Mangifera indica species.CONCLUSION:Therefore, propolis from the center of Benin seems to be of particular interest, due to its antioxidant and anti-AGE properties. Nevertheless, as standardization of propolis is difficult in tropical zones due to its great chemodiversity, a systematic phytochemical analysis is required before promoting the use of propolis in food and health products in Africa.

The identification of bioactive constituents from complex mixtures of Natural Products (NPs) is an important field of applied chemometrics. It requires the thorough chemical analysis of sample material, which is generally facilitated by liquid chromatography coupled to high-resolution tandem mass spectrometry (LC-MS2). Providing a simple and time efficient complementary approach, the current work presents the use of matrix free laser desorption ionization mass spectrometry (LDI-MS) within a chemometric model that allows the identification of activity markers in complex mixtures. As a working example the correct prediction and consecutive isolation of NPs with notable anti-AGEs effects from crude bark extracts of Garcinia parvifolia is discussed. Results were thoroughly compared to those obtained by a concurrently performed LC-MS2 analyses. In addition, the 13C NMR dereplication tool MixONat was successfully used to confirm the structures of high yield activity markers directly from complex mixtures prior to their isolation. Overall LDI-MS yielded comparable results to LC-MS2 and should be considered as complementary technique in applied chemometrics.

Gemmotherapy, a natural therapy based on bud macerates, has recently gained importance in the field of food supplements. However, two coexisting extraction methods employ a glycerin-based solvent, either in a binary or ternary solvent mixture. The absence of an official method for bud preparation leads to non-standardized bud macerates. Given this context, this study aimed to (i) assess the influence of solvent composition on the chemical profile of olive young shoot macerates obtained using glycerin-based solvents or using different solvent extractions and (ii) to compare the two coexisting traditional bud extraction methods described by Dr Pol Henry and by the European Pharmacopoeia. A comprehensive phytochemical analysis of all macerates was conducted using HPLC-DAD-ELSD-MS2, identifying 50 metabolites divided into 7 classes through dereplication. The extracts obtained with the solvent described by the European Pharmacopoeia (ethanol/glycerin) and by Dr Pol Henry (water/ethanol/glycerin) appeared to be the most diversified in terms of metabolite distribution and possessed higher rates of secondary metabolites. These observations reinforce the interest in a glycerin-based solvent mixture for bud extraction in gemmotherapy. In addition, the difference in composition between the two traditional solvents was highlighted. Indeed, iridoids were predominant in both macerates, representing about 50% of the chemical composition, but differences were observed from one macerate to another regarding the proportions of the other chemical classes. This emphasizes the necessity for standardized gemmotherapy macerates.

Discovering new solutions for crop protection is a major challenge for the next decades as a result of the ecotoxicological impact of classical fungicides, the emergence of fungicide resistances, and the consequence of climate change on pathogen distribution. Previous work on fungal mutants deficient in the unfolded protein response (UPR) supported that targeting this pathway is a promising plant disease control strategy. In particular, we showed that the UPR is involved in fungal virulence by altering cell protection against host defense compounds, such as phytoalexins and phytoanticipins. In this study, we evaluated natural products targeting fungal IRE1 protein (UPR effector) and consequently increasing fungal susceptibility to plant defenses. Developing an in vitro cell-based screening assay allowed for the identification of seven potential IRE1 inhibitors with a focus on polyhydroxylated prenylated xanthones. Inhibition of hac1 mRNA splicing, which is mediated by IRE1, was then validated for the most active compound, namely, γ-mangostin 3. To study the mode of interaction between the binding site of IRE1 and active xanthones, molecular docking was also undertaken, revealing similar and novel interactions between the known inhibitor and the binding site. Eventually, active xanthones applied at subtoxic doses induced a significant reduction in necrosis size for leaves of Brassica oleracea inoculated with Alternaria brassicicola and Botrytis cinerea.

A bio-assay guided fractionation strategy based on cholinesterase assay combined with 13C NMR-based dereplication was used to identify active metabolites from the bark of Mesua lepidota. Eight compounds were identified with the aid of the 13C NMR-based dereplication software, MixONat, i.e., sitosterol (1), stigmasterol (2), alpha-amyrin (3), friedelin (6), 3 beta-friedelinol (7), betulinic acid (9), lepidotol A (10) and lepidotol B (11). Further bio-assay guided isolation of active compounds afforded one xanthone, pyranojacareubin (12) and six coumarins; lepidotol A (10), lepidotol B (11), lepidotol E (13), lepidotin A (14), and lepidotin B (15), including a new Mammea coumarin, lepidotin C (16). All the metabolites showed strong to moderate butyrylcholinesterase (BChE) inhibition. Lepidotin B (15) exhibited the most potent inhibition towards BChE with a mix-mode inhibition profile and a Ki value of 1.03 mu M. Molecular docking and molecular dynamics simulations have revealed that lepidotin B (15) forms stable interactions with key residues within five critical regions of BChE. These regions encompass residues Asp70 and Tyr332, the acyl hydrophobic pocket marked by Leu286, the catalytic triad represented by Ser198 and His438, the oxyanion hole (OH) constituted by Gly116 and Gly117, and the choline binding site featuring Trp82. To gauge the binding strength of lepidotin B (15) and to pinpoint pivotal residues at the binding interface, free energy calculations were conducted using the Molecular Mechanics Generalized Born Surface Area (MM-GBSA) approach. This analysis not only predicted a favourable binding affinity for lepidotin B (15) but also facilitated the identification of significant residues crucial for the binding interaction.

Propolis is used by corbiculated bees to protect the bee hive; it is mostly used to seal cracks, to reduce or prevent microbial growth and to embalm invaders. Different factors have been reported to influence the chemical composition of propolis, including bee species and the flora surrounding the hive. Nevertheless, the majority of the studies are focused on propolis produced by Apis mellifera, while studies on the chemical composition of propolis produced by stingless bees are still limited. In this investigation, the chemical composition of 27 propolis samples collected in the Yucatan Peninsula from A. mellifera beehives, together with 18 propolis samples from six different species of stingless bees, were analyzed by GC-MS. Results showed that lupeol acetate and β-amyrin were the characteristic triterpenes in propolis samples from A. mellifera, while grandiflorenic acid and its methyl ester were the main metabolites present in samples from stingless bees. Multivariate analyses were used to explore the relationship between bee species and botanical sources on the chemical composition of the propolis samples. Differences in body size and, therefore, foraging abilities, as well as preferences for specific botanical sources among bee species, could explain the observed variation in propolis chemical composition. This is the first report on the composition of propolis samples from the stingless bees Trigona nigra, Scaptotrigona pectoralis, Nannotrigona perilampoides, Plebeia frontalis and Partamona bilineata.

Concentrated bud macerates (CBMs) are obtained from meristematic tissues such as buds and young shoots by maceration in a solvent composed of glycerin, water and ethanol (1/1/1/, v/v). Their traditional utilization in gemmotherapy has gained interest in the past years, and the knowledge of their chemical characterization can provide commercial arguments, particularly to secure their quality control. Therefore, an optimized method for phytochemical analysis including glycerol removal by a preliminary solid phase extraction (SPE) followed by compound identification using high performance liquid chromatography coupled with ultra-violet and tandem mass detectors (HPLC-UV-MS2) was developed. This method was applied on 5 CBMs obtained from Alnus glutinosa, Ribesnigrum, Rosmarinus officinalis, Rosa canina and Tilia tomentosa in order to determinate their chemical composition. Their antioxidant effects were also investigated by radical scavenging activity assays (DPPH and ORAC). Glycerol removal improved the resolution of HPLC chemical profiles and allowed us to perform TLC antioxidant screening. Our approach permitted the identification of 57 compounds distributed in eight major classes, three of them being common to all macerates including nucleosides, phenolic acids and glycosylated flavonoids. Quantification of the later class as a rutin equivalent (RE) showed a great disparity between Rosa canina macerate (809 mg RE/L), and the other ones (from 175 to 470 mg RE/L). DPPH and ORAC assays confirmed the great activity of Rosa canina (4857 and 6479 μmol TE/g of dry matter, respectively). Finally, phytochemical and antioxidant analysis of CBMs strengthened their phytomedicinal interest in the gemmotherapy field.

The isoquinoline alkaloids (IAs) represent a large and diverse subfamily of phytochemicals in terms of structures and pharmacological activities, including ion channel inhibition. Several IAs, such as liriodenine (an oxoaporphine) and curine (a bisbenzylisoquinoline (BBIQ), inhibit the L-type voltage-gated Ca2+ channels (LTCC). In this study, we aimed to search for new blockers of LTCC, which are therapeutic targets in neurological and cardiovascular diseases. We set up a screening assay using the rat pituitary GH3b6 cell line, which expresses two LTCC isoforms, CaV1.2 and CaV1.3. Both LTCC subtypes can be indirectly activated by KCl concentration elevation or directly by the dihydropyridine (DHP), BAY K8644, leading to an increase in the intracellular Ca2+ concentration ([Ca2+]i). These Ca2+ responses were completely blocked by the selective LTCC DHP inhibitor, nifedipine. Thereby, 16 selected IAs were tested for their ability to inhibit KCl and BAY K8644-induced Ca2+ responses. We then identified three new potent LTCC blockers, namely, oxostephanine, thaliphyline, and thalmiculine. They inhibited LTCC with IC50 values in the micromolar range through interaction to a binding site different to that of dihydropyridines. The two subfamilies of IAs, oxoaporphine with oxostephanine, and BBIQs with both thalyphilline and thalmiculine, constitute interesting pharmacophores for the development of future therapeutic leads for neurological and cardiovascular diseases.

Thirty-three natural products were isolated from the aerial parts of Antidesma bunius, Euphorbiaceae, a plant used in Vietnamese traditional medicine against rheumatoid arthritis. All compounds were reported the first time for this species, and nine constituents resembled undescribed natural products, noticeably three coumarinolignans with 2,2-dimethyl-1,3-dioxolane moiety, two cyclopeptides, and two furofuran-type lignans connected with a phenylpropanoid moiety. The individual structures were elucidated by combining NMR and MS data, and their configuration was established by NOESY and ECD experiments and NMR calculations. Compounds with sufficient amount were analyzed for their inhibition of advanced glycation endproducts (AGEs) formation, metabolites involved in many diseases like Alzheimer, joint diseases or diabetes. With IC50 values below 0.2 mM rutin and p-hydroxyphenethyl trans-ferulate showed to be moderately active, both still being 10-times more active than the positive control aminoguanidine.

Naturally occurring substances are valuable resources for drug development. In this respect, chalcones are known to be antiproliferative agents against prostate cancer cell lines through various mechanisms or targets. Based on the literature and preliminary results, we aimed to study and optimise the efficiency of a series of chalcones to inhibit androgen-converting AKR1C3, known to promote prostate cancer. A total of 12 chalcones with different substitution patterns were synthesised. Structure–activity relationships associated with these modifications on AKR1C3 inhibition were analysed by performing enzymatic assays and docking simulations. In addition, the selectivity and cytotoxicity of the compounds were assessed. In enzymatic assays, C-6′ hydroxylated derivatives were more active than C-6′ methoxylated derivatives. In contrast, C-4 methylation increased activity over C-4 hydroxylation. Docking results supported these findings with the most active compounds fitting nicely in the binding site and exhibiting strong interactions with key amino acid residues. The most effective inhibitors were not cytotoxic for HEK293T cells and selective for 17β-hydroxysteroid dehydrogenases not primarily involved in steroid hormone metabolism. Nevertheless, they inhibited several enzymes of the steroid metabolism pathways. Favourable substitutions that enhanced AKR1C3 inhibition of chalcones were identified. This study paves the way to further develop compounds from this series or related flavonoids with improved inhibitory activity against AKR1C3.

Chalcones are a well-known family of natural flavonoids, renowned for a variety of pharmacological activities such as their anti-inflammatory, anti-bacterial and also anti-cancer properties. We investigated synthetic and semi-synthetic derivatives of MF-15, a benzylated dihydrochalcone isolated from Melodorum fruticosum leaves, in an in silico profiling approach and discovered several distinct bioactivities on individual protein targets. One or a combination of these activities lead to in vitro anti-proliferative activity on different cancer cell lines, previously published in [1] and [2].