Resumo em Inglês:

Pavonia malacophylla (Link & Otto) Garcke (Malvaceae sensu lato), commonly known as “malva-rosa” or “malva-veludo”, is traditionally used to treat flu, cough, and heart pain. The crude ethanolic extract (CEE) of P. malacophylla was obtained through maceration with ethanol, concentrated using a rotary evaporator, and subjected to vacuum liquid chromatography with silica gel 60 as the stationary phase. Hexane, ethyl acetate, and methanol were used as mobile phases in increasing polarity gradients, yielding nine fractions. Chromatographic fractionation led to the isolation and identification of 18 compounds, including one alcohol, three steroids, three triterpenes, four pheophytins, six flavonoids and one phenolic acid. Among these, compounds 1 (decanol), 4a (α-amyrin), 4b (β-amyrin), 11 (5,8-dihydroxy-7,4’-dimethoxyflavone) and 16 (methyl-4-hydroxycinnamate), were identified for the first time in the genus Pavonia. Microbiological assays of the CEE, fractions, and isolated compounds were conducted against Escherichia coli, Candida albicans, and Staphylococcus aureus, demonstrating antimicrobial activity at concentrations ranging from 250 to 400 µg mL-1.

Resumo em Inglês:

Cervical cancer is the fourth most common cancer in the world and the third most common in Brazilian women. The search for compounds with anticancer potential is important, since cancer is a public health problem, and some drugs may lead to side effects. In addition, cases of multidrug resistance may occur. Tabernaemontana species are considered a promising source of bioactive compounds. The antiproliferative potential of the crude extract and fractions of Tabernaemontana hystrix Steud. (Apocynaceae) root bark were evaluated through MTT assays using HeLa cells and NIH-3T3 cells. It was observed that EtOAc and BuOH fractions were selective against tumor cells, with IC50 (half maximal inhibitory concentration) values of 3.787 and 8.489 μg mL-1, respectively. The phytochemical investigation of both fractions was carried out, leading to the isolation of six monoterpene indole alkaloids (MIAs): olivacine (1), affinine (2), the mixture of alkaloids 1, janetine (3) and 3,14-dihydro-olivacine (4), and macusine B (5) from the EtOAc fraction. However, the BuOH fraction also provided compounds 1 and 3, and the new MIA, named as Nb-demethyl-18-formyl-affinine (6). Compounds 3 and 4 are being reported for the first time in the species. Further research is needed to evaluate the antiproliferative potential of these compounds.

Resumo em Inglês:

The fragmentation of four deprotonated plumeran indole alkaloids (PIAs), namely aspidospermidine (1), demethoxypalosine (2), aspidocarpine (3), and aspidolimine (4), previously isolated from Aspidosperma spruceanum has been investigated by electrospray ionization tandem mass spectrometry (ESI-MS/MS) in the negative ion mode. The fragmentation pathways have been established on the basis of accurate mass data. Our results demonstrated that the main product ions of deprotonated 1-4 result from remote hydrogen rearrangements. The most abundant product ion in the product ion spectrum of 2, 3, and 4 was the result of a ketene loss (methylketene for 2 and 3, and a ketene for 4) directly from the precursor ion. The product ion of m/z 183 was diagnostic for compound 2, whereas the radical loss of •CH3 occurred only for 3 and 4, which display an aromatic methoxyl group in their structures. These results indicated that ESI(-)-MS/MS could be also used for the identification of PIAs 1-4 in crude extracts using LC-ESI-MS/MS, especially when the extracts are more complex.

Resumo em Inglês:

Essential oils from the leaves and flowers of Thunbergia grandiflora, Thunbergia alata and Thunbergia erecta occurring in urban fragments of the Atlantic Forest in the state of Pernambuco, Brazil, were analyzed by GC-FID (gas chromatography with flame ionization detector) and GC-MS (gas chromatography mass spectrometry). A total of 76 compounds were identified, representing more than 95% of the oils. Differences in the chemical profile were found among the oils. Germacrene D (leaves: 0.61 ± 0.02 to 20.49 ± 0.78%; flowers: 0.84 ± 0.10 to 21.71 ± 0.77%) was the only sesquiterpene identified in abundance in all oils. The chemical compositions of the oils were compared using principal component analysis and hierarchical cluster analysis, which revealed significant differences. All three species exhibited antioxidant and cholinesterase activity. The oil from leaves of T. erecta achieved the best results on the DPPH (2,2-diphenyl-1-picrylhydrazyl) test and with the ABTS (2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) radical. The oil of T. erecta exerted a significant inhibition effect on the enzymes AChE (acetylcholinesterase), and BuChE (butyrylcholinesterase). Moreover, none of the oils tested showed toxicity against Artemia salina.

Resumo em Inglês:

Eriodictyon californicum is a species belonging to Boraginaceae family, popularly known as “yerba santa” and used in folk medicine to treat rheumatism, headaches, inflammation, and respiratory complications. In the present work, we performed phytochemical analyses of extracts from the leaves of E. californicum in order to isolate its chemical constituents. According to thin-layer chromatography (TLC) analyses, preliminary phytochemical screening indicated the presence of anthocyanins derivatives, flavonoids, condensed and hydrolysable tannins. Furthermore, classical chromatographic techniques (column chromatography, analytical and preparative thin-layer chromatography) led to the isolation of secondary metabolites. The compounds were elucidated by 1D and 2D nuclear magnetic resonance (NMR) (correlation spectroscopy (COSY), heteronuclear single quantum correlation (HSQC) and heteronuclear multiple bond correlation (HMBC)) analysis, Fourier transform infrared (FTIR) spectroscopy, mass spectrometry (MS) analysis, and comparison with literature data. In this study, seven metabolites were identified: sterubin (1), chrysoeriol (2), apigenin (3), hydroxygenkwanin (4), 5,4’-dihydroxy-7,3’-dimethoxyflavanone (5), ethyl cinnamate (6) and 5-hydroxy-7 methoxychromone (7). The compounds 1-5 were previously identified in this species, and the compounds 6 and 7 are being reported for the first time in the species E. californicum, as well as in Boraginaceae family. The 1H and 13C NMR data for some compounds have been reviewed. These results revealed that E. californicum is an important source of secondary metabolites, mainly flavonoids with chemophenetic relationships with Boraginaceae family.

Resumo em Português:

PHENYLPROPANOIDS WITH ANTI-Trypanosoma cruzi ACTION ISOLATED FROM LEAVES OF Piper crassinervium (Piperaceae). In the present work, the hexane extract from leaves of Piper crassinervium (Piperaceae) displayed activity against trypomastigotes of Trypanosoma cruzi (100% of parasite death at 200 μg mL−1) and was subjected to a bioactivity-guided fractionation. Using this approach, two free phenylpropanoids – methyl 2,3,4-trimethoxyphenylpropanoate (1) and methyl 3,4-dimethoxyphenylpropanoate (2) – one amide – 2α,3α-epoxy-1-piperidone (3) – and two phenylpropanoid imides – piplaroxide (4) and 4-hydroxy-3,5-dimethoxyphenylpropanoyl-2’α,3’α-epoxy-1’-piperidone (5) – were isolated. Compound 5 is an unreported metabolite and, except for 3, all other compounds are being described for the first time in P. crassinervium. Compounds 1-5 showed to be non-toxic against mammalian cells (NCTC 929 cells) with 50% cytotoxic concentration (CC50) > 200 μM and when evaluated against trypomastigotes, compounds 4 and 5 displayed higher potential with 50% effective concentration (EC50) values of 14.2 and 25.7 μM, respectively. Otherwise, compounds 1 and 2 exhibited moderate potential (EC50 = 45.7 and 38.3 μM) whereas 3 displayed reduced activity (EC50 = 97.9 μM). Altogether, these data suggested that the phenylpropanoid unit may play an important role in the potential against T. cruzi.

Resumo em Inglês:

Species of the genus Trichilia (Meliaceae) produce a significant variety of secondary metabolites. Limonoids, the largest part of these compounds, have attracted considerable attention from the scientific community, due to their structural diversity and biological activity. One species of this genus, Trichilia hirta Linneaus, has been the subject of several studies, highlighting its potential as a source of bioactive molecules, due to its varied biological activities, including insecticidal, anticancer, and antifungal properties. This suggests that T. hirta is a promising source of bioactive compounds. In the pursuit of isolating and identifying limonoids with bioactive potential, the T. hirta species was selected for a phytochemical investigation, using different liquid chromatography methods for the separation and purification of compounds (column chromatography, medium-pressure liquid chromatography and high-performance liquid chromatography), together with spectroscopic techniques, such as nuclear magnetic resonance and mass spectrometry, for structural elucidation. This approach led to the isolation and identification of a new cedrelone-class limonoid, designated as Hirtinol A (1), in addition to a mixture of 21α-melianone (2) and 21β-melianone (3), and the glycoside schumaniofioside A (4), the first chromone identified in a Trichilia species.

Resumo em Inglês:

Chemoenzymatic strategies to synthesize complex molecules have been developed by combining biocatalytic and synthetic methods in a multistep approach toward a target molecule. Dihydrobenzofuran neolignans (DBNs), a class of plant-derived natural compounds, display several biological activities. Oxidative coupling of phenylpropanoids is commonly used to obtain DBNs, but yields are low, and stereochemical control is poor. This study reports the novel eco-friendly and stereoselective conversion of methyl trans-ferulate (1) into DBN 2 ((±)-trans-dehydrodiferulate dimethyl ester) promoted by Trametes versicolor FC in 47% yield. Compared to Ag2O-promoted oxidative coupling, this biotransformation approach is enantioselective (66.7% ee of the main enantiomer) and affords DBN 2, as confirmed by chiral-HPLC (high-performance liquid chromatography) and NMR (nuclear magnetic resonance) data analyses. Our preliminary results highlighted the combination of biotransformation and traditional chemical processes as a promising starting point for obtaining DBNs from the corresponding phenylpropanoids enantioselectively.

Resumo em Inglês:

Fungi exhibits remarkable adaptability to diverse environments, making them widely distributed across ecosystems. Their vast diversity has driven extensive research into biotechnological applications, including biocatalysis mediated by whole cells or isolated enzymes. Among fungal biocatalysts, marine-derived strains have gained attention due to their unique enzymatic repertoire. In this study, whole cells of Penicillium citrinum CBMAI 1186 were employed to catalyze the selective reduction of α,β,γ,δ-unsaturated ketones into γ,δ-unsaturated ketones. The substrates were synthesized and characterized by nuclear magnetic resonance (NMR) and gas chromatography-mass spectrometry (GC-MS), while crystalline forms were further analyzed via X-ray diffraction. P. citrinum CBMAI 1186 exhibited high catalytic efficiency, achieving conversions exceeding 85% after six days. Fluorineand methyl-substituted compounds displayed faster conversion (1-3 days), suggesting substrate preference. In all cases, only the α,β double bond was reduced, confirming the selectivity of the microorganism for highly conjugated compounds. These discoveries indicate that P. citrinum CBMAI 1186 performs regioselective and chemoselective reductions with high efficiency, establishing its potential as a biocatalyst for selective bioreduction reactions. The exclusive transformation of α,β-unsaturated bonds underscores its applicability in biotechnological processes. Overall, this study highlights the potential of P. citrinum CBMAI 1186 in the development of novel sustainable bioprocesses for fine chemical synthesis.

Resumo em Português:

Solanum jabrense is an endemic species of Brazil, which occurs in high-altitude swamps in the Northeast, associated with rocky environments, exclusively in the states of Ceará, Paraíba, Pernambuco and Bahia. In previous studies, its pharmacological potential was demonstrated given the presence of flavonoids and steroid glycosides. In this work, three steroidal glycosides were isolated from the aerial part of S. jabrense, foliumin A and (22S,23R,25R)-3β,23-dihydroxyspirost-5-en-26-one 3-O-{α-L-rhamnopyranosyl-(1→2)-[α-L-rhamnopyranosyl-(1→4)]-β-D glucopyranoside}, a rare and a new saponin, respectively, in addition to an already known alkaloid, solamargine, all being the first record for the species. All structures were elucidated by spectroscopic data analysis (1D, 2D nuclear magnetic resonance (NMR) and high-resolution mass spectrometry (HRMS)) combined with polarimeter and infrared.

Resumo em Inglês:

This study investigated bioactive compounds isolated from the mangrove endophytic fungus Actinomucor elegans AcCC18.1A for the control of Xanthomonas axonopodis pv. passiflorae (Xap), the causal agent of bacterial spot disease in passion fruit. Through classical chromatographic techniques, we isolated four phenolic compounds: tyrosol (1), 4-hydroxyphenylacetic acid (2), 4-formylphenyl-2-phenylacetate (3), and phenylacetic acid (4), with their structures elucidated through nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Among the isolated compounds, compound 3 was characterized as a new natural product. Antimicrobial assays were performed using the broth microdilution method against four Xap strains (Xap1-Xap4), with amoxicillin (3.9 µg mL-1) and tetracycline (3.9 µg mL-1) as positive controls. All compounds exhibited inhibitory activity, with compound 2 showing the highest efficacy (7.8 µg mL-1). These results underscore the biotechnological potential of mangrove endophytic fungi as sources of bioactive molecules against agricultural phytopathogens, offering new insights for developing sustainable strategies to control bacterial spot in passion fruit cultivation.

Resumo em Inglês:

The reaction of (E)-2,3-dihydro-1H-inden-1-one oxime (3) with carboxylic acid anhydrides and fatty acids aiming at the formation of the respective esters unexpectedly produced imides [5a-5c and 5d-5k] (81-95% yields). This work proposes the formation of these imides from the oxime (3) through a mechanism using an oxaziridine as an intermediate, followed by a Beckmann-like rearrangement. However, in the presence of nucleophilic catalysts [dimethylaminopyridine (DMAP) and dicyclohexylcarbodiimide (DCC)] instead of electrophilic ones. Products were characterized by spectral analysis [NMR (1H / 13C) and MS (EIMS / HRMS)]. In the in silico study, the competition of some oxime derivatives was remarkable compared to galantamine (GNT) and its bioactive interactions with the main amino acid residues that are part of the site of interest of cholinesterase activity. The calculation of the physicochemical properties through molecular modeling also allowed us to understand the interaction between a ligand and its receptor, indicating the derivatives 5i, 5g, and 5h as promising acetylcholinesterase inhibitors.

Resumo em Inglês:

Peltogyne catingae is an Amazonian species with a purple heartwood that is highly resistant to attacks by xylophagous organisms. This antimicrobial property may be related to modified flavonoids known as peltogynoids. This study analyzed the composition of peltogynoids extracted from P. catingae wood residues using high performance liquid chromatography-mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR). Additionally, their antifungal activities were assessed against fungi isolated from Sporothrix schenckii (ATCC 32286) and Sporothrix brasiliensis (clinical isolate), which cause feline sporotrichosis. The isomers (+)-peltogynol (1) and (+)-mopanol (2) and their respective epimers (+)-peltogynol B (3) and (+)-mopanol B (4) were identified. The mixture of peltogynoids 1-4 showed promising results as a fungicidal agent against S. schenckii (MIC 31.25 µg mL–1) and a fungistatic effect against S. brasiliensis (MIC 62.50 µg mL–1). The 1D and 2D NMR spectroscopic results of epimers 3 and 4 are described here for the first time. The peltogynoids identified in this study are candidates for antifungals for the treatment of feline sporotrichosis.

Resumo em Inglês:

Mass spectrometry-based approaches constitute the primary strategy for the dereplication of isoquinoline-derived alkaloids, which are widely distributed in various genera of the Annonaceae family. On the other hand, although many species from the Annonaceae family have been studied regarding their alkaloid content, others remain largely unexplored, such as U. rufescens. In order to dereplicate isoquinoline-derived alkaloids from the trunk bark of U. rufescens, a liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis in positive ionization mode was conducted with its alkaloid fraction and the fragmentation data were subsequently interpreted manually. Based on the fragmentation pattern knowledge regarding isoquinoline-derived alkaloids, pallidine (1), along with the benzyltetrahydroisoquinolines coclaurine (2), N-methylcoclaurine (3), reticuline (5), norarmepavine (6), norjuziphine (7), and N-methylnorjuziphine (8); proaporphine stepharine (4); oxoaporphines liriodenine (10) and lysicamine (13); C-7 substituted aporphine norushinsunine (11); and the aporphines asimilobine (9), isopiline (12), nornuciferine (14), anonaine (15), and O-methylisopiline (16) were tentatively identified. In addition, a mixed fragmentation pathway was observed for isopiline (12), and a proposed fragmentation pathway for this compound was presented. Overall, this study expands the knowledge of U. rufescens, demonstrating the rich chemical diversity present in this species. Furthermore, it contributes to the research on the fragmentation patterns of isoquinoline-derived alkaloids.

Resumo em Inglês:

Piper tuberculatum Jacq. is known to be a promising source of amides, which have shown remarkable biological activities. In this study, a phytochemical investigation of the leaves of P. tuberculatum was conducted, leading to the isolation of the amides cis-piplartine (1), piplartine (2), and 4,5-dihydropiperlonguminine (3). The structures of the compounds were determined through the analysis of 1D and 2D nuclear magnetic resonance (NMR), mass spectrometry (MS), and high-resolution mass spectrometry (HRMS), as well as data comparison with the literature. The isolated amides were tested for acetylcholinesterase (AChE) inhibition assay and larvicidal activity against Aedes aegypti. The significant larvicidal activity of the isolated amides, along with the AChE inhibition results, indicate that the larvicidal activity is related to the inhibition of this enzyme. These results suggest that these amides are promising larvicidal compounds.

Resumo em Inglês:

A chemical investigation of the brown seaweed Dictyota mertensii (Hoyt) Schnetter, Hörning & Weber-Peukert, a member of the Dictyotaceae, was carried out. The ethyl acetate extract led to the isolation of two prenylated guaiane, including a new one (1) and the known dictyol H (2). In addition, the dolabellane diterpene 10,18-dihydroxy-dolabella-2,7-diene (3) and two benzalkonium chlorides (4-5) were also isolated. The structures of all compounds were elucidated by an extensive analysis of their one- and two-dimensional nuclear magnetic resonance data (1D and 2D NMR), and high-resolution electrospray ionization mass spectrometry (HRESIMS). The cell viability and the anti-inflammatory activity of diterpenes 1 and 2 were evaluated against lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophages.

Resumo em Inglês:

Bixa orellana L., known as annatto, is a plant in the Bixaceae family, widely used for its seeds rich in carotenoids, such as bixin (a natural dye) and geranylgeraniol (GGOH), an isoprenoid of interest for health and agriculture. This study evaluated the efficiency of annatto oil extraction using hydrodistillation, Soxhlet solvent extraction (conventional methods), and ultrasound-assisted extraction (modern method). Acetone, ethyl acetate, and hexane were used as extractor solvents. Gas chromatography coupled with flame ionization detection (GC-FID) and gas chromatography coupled with mass spectrometry (GC-MS) analyses revealed GGOH as the main compound in all methods, with concentration variations determined using 1-octadecanol as an external standard. Hydrodistillation showed the lowest yield (0.06%) but was more straightforward and sustainable. Extraction with organic solvents (Soxhlet and ultrasound) resulted in higher GGOH yields (1.35-2.01%), with hexane being the most efficient (0.250 mg mL–1). Soxhlet extraction with hexane is ideal for large quantities, while hydrodistillation is preferable for medicinal uses due to the absence of organic solvents.

Resumo em Inglês:

Eugenia uniflora L (EU), Myrtaceae, known as pitangueira, is recognized as a source of bioactive compounds, mainly polyphenols. Considering the complexity and variety of factors that influence the composition of their extracts, assigning antioxidant properties to specimens from distinct locations and environmental conditions is important. In this study, the composition profile (total phenolic content (TPC), total flavonoid content (TFC), gas chromatography-mass spectrometry (GC-MS), and ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) fingerprint) and antioxidant activity (by chelating effect, phosphomolybdenum, 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), hypochlorous acid (HOCl), ferric reducing antioxidant power (FRAP), and cupric reducing antioxidant capacity (CUPRAC) assays) of the extracts from three specimens of pitangueira (EU1, EU2, and EU3) obtained at different pH values were compared. The results indicated that extracts obtained with ethyl acetate (EA) at pH 4 had the highest effectiveness due to their elevated levels of phenolic compounds. Additionally, a significant occurrence of flavonoids in EU2 was observed, as demonstrated by the antioxidant activity of EA at pH 8 and EA/MeOH (1:3). This study provides valuable insights into the chemical variability of E. uniflora and its significant impact on antioxidant activities, highlighting the importance of extraction conditions to enhance the therapeutic efficacy of its bioactive compounds.

Resumo em Português:

In this study, the ultrasound-assisted extraction (UAE) technique was used to simultaneously optimize the yield and total phenolic content (TPC) of Lippia alba leaf extracts, evaluating the effect of ethanol concentration, extraction time and solvent-to-solid ratio with the aid of Box-Behnken design and response surface methodology. The L. alba extract obtained by UAE under the optimized condition (29% ethanol, 17.8 min and solvent-to-solid ratio of 71 mL g-1) resulted in a yield of 20.33% and TPC of 30.86 mg GAE g-1 dw. The extract obtained by UAE showed higher results of extraction yield, TPC, total flavonoid content (TFC) and antioxidant activities compared to the maceration and infusion extracts. Analysis performed by high-resolution mass spectrometry allowed the identification of several iridoids, phenolic acids, phenylpropanoids and flavonoids in the extracts of L. alba, which justified the antioxidant activities of its extracts, indicating that this species can be used as a source of economically important antioxidant compounds for the food, cosmetics and pharmaceutical industries.

Resumo em Português:

CHEMOSYSTEMATIC ANALYSIS OF THE MYRISTICACEAE FAMILY: THE MIXED PATHWAY (ACETATE/SHIKIMATE). The Myristicaceae family, belonging to the order Magnoliales, comprises of 21 genera and 1144 species distributed in the Americas, Africa and Asia. The phenolic chemical constituents of this taxon stand out, mainly in Myristica fragrans, which is known worldwide for its nutmeg spice. This study aimed to analyze and explore the chemical information obtained from micromolecules derived from the mixed pathway, contributing to the chemosystematics and chemometrics of the family. The methodology employed for the analysis of evolutionary parameters was that of Prof. Gottlieb. A bibliographical survey of the special metabolites of each genus was carried out, using Scifinder as a database, 3392 works published between 1945 and 2025. An occurrence number (ON) of 355 special metabolites from the mixed pathway was identified, distributed in only six genera: Horsfieldia (ON = 68), Iryanthera (ON = 120), Knema (ON = 76), Myristica (ON = 22), Pycnanthus (ON = 12) and Virola (ON = 57); bioproducers of arylflavans, aurones, chalcones, diarylpropanoids, dihydroflavonol, stilbenes, flavones, flavones, flavonones, isoflavonoids, and proanthocyanidins. These metabolic categories are mostly unprotected from phenolic protection. Chemometric analysis revealed that the genera can be grouped according to their chemical characteristics, showing a high degree of similarity within the taxa.

Resumo em Inglês:

Five diterpenoids were isolated from the hexane extract obtained from the roots of Annona vepretorum Mart. (Annonaceae). The chemical structures were determined as ent-3b-acetoxy-kaur-16-ene (1), 17-nor-kaur-16-one (2), ent-kaur-16-en-19-oic acid (3), ent-3b-hydroxy-kaur-16-ene (4) and ent-16b-hydro-kauran-17-oic acid (5). Their structures were identified by spectroscopic analyses (1D and 2D nuclear magnetic resonance (NMR) data) and comparison with literature data. This is the first report on the isolation of compound 2 in the Annonaceae family.

Resumo em Inglês:

Crinum scabrum Herb., a member of the Amaryllidaceae family, is native to Brazil and known for its diverse alkaloid content and biological potential. Previous studies identified crinamine, 6-hydroxycrinamine, and lycorine in this species. In this study, crude methanolic extracts from leaves and bulbs were prepared, followed by alkaloid enrichment via acid-base extraction. Electrospray ionization-linear trap quadrupole-cross-linking tandem mass spectrometry (ESI-LTQ-XL-MS/MS) analysis annotated crinamine, lycorine, and haemanthidine/6-epi-haemanthidine. Further separation using silica gel column chromatography and 1H nuclear magnetic resonance (NMR) analysis revealed the epimers mixture of haemanthidine/6-epi-haemanthidine (C1/2), crinamine (C3), and trisphaeridine (C4). Due to the high yield of C1/2 (24.4%), matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis was performed on the leaves, showing widespread distribution of ion peaks (m/z 318.144) corresponding to C1/2. These results underscore the significance of haemanthidine and its epimer, suggesting that Crinum scabrum leaves are a promising source of these alkaloids and facilitate further investigation of its potential biological activities.

Resumo em Inglês:

Zoantharians are benthic marine organisms widespread in Brazilian tropical shallow waters. Recent evidence suggests that the metabolism of these cnidarians may be influenced by diverse environmental factors. We have previously shown that two species of Palythoa found on the Brazilian coast share metabolomic similarities related to their location. Herein, through gas chromatography coupled with mass spectrometry (GC-MS) and liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis, along with molecular networking, we assessed polar and apolar extracts from 28 samples of Palythoa spp. and Zoanthus spp. collected at different Brazilian oceanic islands - Saint Peter and Saint Paul Archipelago, Fernando de Noronha Archipelago, Rocas Atoll and Trindade Island - to describe and compare their metabolome in such isolated regions, under reduced interference of anthropic actions. The chemical profiles of zoantharians from Brazilian oceanic islands include fatty acids and sterol derivatives, in apolar fractions, and ecdysteroids, phospholipids, ceramides, mycosporine-like amino acids, and alkaloids in polar fractions. These chemical classes are similar to those described for the continental zoanthids, previously assessed. The results presented herein reveal a preserved metabolome across the analyzed species, Palythoa caribaeorum, Palythoa variabilis and Zoanthus spp., and between island and continental organisms, suggesting core species-specific metabolites and a portion of an environmentally-driven chemical expression.

Resumo em Inglês:

Leishmaniasis is one of the six most important protozoal diseases worldwide. The potential antiprotozoal effect of pentacyclic triterpenes (TTPs), including friedelin (1), has been reported. Our goal is to create in silico models that can predict the effectiveness of TTPs against Leishmania species. We developed the Active-IT software to build these models using support-vector machine (SVM) and Naïve Bayes machine learning tools, high-quality datasets, and 3D compound structures. We synthesize N-derivatives (2-4) from friedelin to validate our theoretical results and evaluate their activity against the promastigote form of Leishmania amazonensis using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. Two compounds showed appreciable inhibitory effects on L. amazonensis. We found that friedelan-3-(2,4-dinitrophenylhydrazone) (2) had the most significant inhibitory activity and the lowest half-maximal inhibitory concentration (IC50) value, supporting our developed theoretical models. Our findings showed that theoretical models created from the 3D structures of active and inactive ligands (ligand-based drug design) can provide invaluable insights into complex biological processes.

Resumo em Inglês:

Orchidaceae family is a valuable source of bioactive compounds, particularly phenanthrenes and stilbenoids, which exhibit promising pharmacological properties. Cattleya nobilior Rchb. F. remains chemically and biologically unexplored, yet its potential bioactivity warrants investigation. This study aimed to identify phenanthrenes and stilbenoids from C. nobilior and evaluate their anti Trypanosoma cruzi and cytotoxic activities. Extracts from leaves, pseudobulbs, roots, and rhizomes were obtained using sequential solvent extraction by accelerated solvent extraction. Their biological effects were assessed against T. cruzi epimastigotes and cancer cell lines (Kasumi-1, CCRF-CEM, HCT-116, and MCF-7). Metabolomic profiling (liquid chromatography-diode array detection-mass spectrometry (LC-DAD-MS)) and multivariate analyses correlated chemical composition with bioactivity. Rhizome extracts (CnRz-DM5, CnRz-DM50) inhibited HCT-116 cells (> 80%), while CnBb-DM5, CnRz-DM5, and CnRo DM5 inhibited > 90% of leukemic cells. CnRo-DM5 also exhibited moderate anti-T. cruzi activity (half-maximal inhibitory concentration (IC50) = 33.3 µg mL-1). Metabolomic analysis suggested 67 phenanthrenes and stilbenoids associated with cytotoxicity. Guided by these findings, the most active extract was fractionated, leading to the isolation of gigantol and batatasin III. This study provides the first chemical and biological insights into C. nobilior, reinforcing its potential as a source of bioactive phenanthrenes and stilbenoids with anticancer and antiparasitic properties.

Resumo em Português:

Senna multijuga (Fabaceae) is a plant species native from Brazil and it has been used to recover degraded areas. There are a few reports about its chemical composition and biological activities. Therefore, this study aimed to conduct preliminary dereplication studies and evaluate the antioxidant activity by chemical and electrochemical methods of the ethanolic extract of S. multijuga (SM) leaves and its trypanocidal activity. High-performance liquid chromatography-electrospray ionization-ion trap-mass spectrometry (HPLC-ESI-IT-MS) based on molecular networking dereplication of the leaves and branches extracts led to annotation of one caffeoylquinic acid, one flavonol, two flavanones, and seven flavonol glycosides. Some of these metabolites are reported for the first time for this species. The leave extract showed significant radical scavenging properties. On the other hand, SM was more cytotoxic to 3T3 fibroblasts than to Trypanosoma cruzi epimastigotes (selectivity index (SI) = 0.23). Results showed a good agreement between the antioxidant power of extracts and their content of phenolic compounds.

Resumo em Inglês:

A phytochemical study of the latex from P. amapa and B. parinarioides has led to the isolation of nine compounds. From the latex of B. parinarioides, six compounds were isolated: lupeol acetate (1), butyrospermol (2), and its epimer, tirucalla-7,24-dien-3β-ol (3), cycloartenol (4), cycloeucalenol (5), obtusifoliol (6). This is the first report of their occurrence in B. parinarioides. From the latex of P. amapa isolated lupeol acetate (1), a mixture of acetylated triterpenes was identified, including α-amyrin acetate, β-amyrin, and lupeol (MIST-2). Additionally, two mixtures of hydroxylated and non-hydroxylated lupeol esters (MIST-3) and (MIST-1), were isolated and fully characterized using gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) techniques. A comparative study of the latex from both species has been conducted using high-performance liquid chromatography with ultraviolet detection using a diode array detector (HPLC-UV-DAD). This analysis has revealed common features, such as the presence of αand β-amyrin acetates and lupeol. However, the major distinction has been that the mixture of hydroxylated lupeol esters has been found exclusively in P. amapa, while cycloeucalenol and obtusifoliol have been observed only in B. parinarioides.

Resumo em Inglês:

Cafestol (1) is an ent-kaurane furanoditerpene found in the lipid fraction of coffee beans and is known for its hypercholesterolemic effect in humans. This adverse biological effect is particularly concerning when consuming non-filtered coffee beverages, such as Turkish and mocha coffees. In previous research, we investigated a wet postharvest process in coffee using three commercial Saccharomyces cerevisiae starter cultures (from bakery, white, and sparkling wines) capable of reducing lipid compounds. A reduction of cafestol (1) by approximately 54% was observed compared to a wet process without this yeast. The wet postharvest process is usually employed to obtain specialty coffees. In this work, we employed liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) to better understand the chemical transformations that cafestol underwent under commercial S. cerevisiae starter cultures fermentation conditions. Three metabolites derived from cafestol (1) oxidation at position C-17 (aldehyde isomers (6 and 7) and one hydroxymethyl furfural derivative (8)) were suggested because of coffee fermentation. This work opens perspectives for future studies since little is known about the biotransformation reactions of endogenous compounds in green coffee beans during wet processing.

Resumo em Português:

Plants of Remijia DC. (Rubiaceae) are widely distributed in South America and are often known by the popular names of “quinas” and “quinas-falsas” because of their similarity to the genus Cinchona L. This study consisted of a review of the reported substances and biological activities found in the Remijia genus. For this purpose, information was collected from SciFinder, ScienceDirect, PubMed and Google Scholar databases by entering the term “Remijia”. It was found that only four species have been chemically and biologically studied: R. ferruginea, R. peruviana, R. pedunculata and R. purdieana. Thirty-eight substances of different chemical classes were found, such as: quinoline alkaloids, indole alkaloids, flavonoids, phenolic acids, steroids, and a triterpene. Among the substances produced by these plants, quinoline alkaloids stood out, with 12 substances identified. In addition, the extracts and isolated substances from this genus showed antioxidant, anti-inflammatory activity of TNF-α (tumor necrosis factor alpha) inhibition, antiplasmodial, wound healing, cytotoxic, anti-Trypanosoma, antifeedant, antimalarial, antihyperlipidemic, antihyperglycaemic and ferriprotoporphyrin IX inhibition activities. This review demonstrates the chemical variability found in Remijia species and encourages further chemical studies. The great preference observed by the Remijia species studied to date to produce quinoline and indole alkaloids indicates that they are the chemosystematic markers of the genus.

Resumo em Português:

Humanity has historically turned to nature to treat diseases, with records dating back to the Neanderthals, who already used medicinal plants. To this date, biologically active natural products (NP) remain indispensable sources in drug development for several therapeutic areas, due to their vast structural diversity and unique ability to interact with specific biological targets. With the advancement of omics sciences, NP research has been revolutionized by omics approaches such as genomics, transcriptomics, proteomics, and metabolomics. These techniques are widely applied to identify biosynthetic pathways and search for new therapeutic targets, utilizing plants, microorganisms, and other natural sources. The integration of these approaches into multi-omics strategies has proven to be highly effective for the discovery of new NPs, offering significant advantages and avoiding the re-isolation of already known molecules. Furthermore, they provide a comprehensive view of the molecular mechanisms involved in NP production, enabling more targeted and efficient exploration. This combination of multidisciplinary approaches is crucial for the development of more selective and effective drugs, contributing to the advancement of safer and more innovative treatments. This review will contextualize the main omics techniques used in NP discovery, while providing examples of their use and new perspectives in NP discovery.

Resumo em Inglês:

Tuberculosis, caused by Mycobacterium tuberculosis, is the leading cause of death globally from an infectious agent. The search for new antituberculosis compounds is vital for developing effective drugs that reduce treatment duration and side effects, particularly for multidrug-resistant (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB). Natural products from plants, marine organisms, microorganisms, and animals have demonstrated antimycobacterial properties. Brazilian research on natural products is crucial, especially concerning antituberculosis activity, as Brazil is among the nations with the highest TB burden and possesses immense biodiversity. This study reviewed Brazilian research on antimycobacterial natural products, identifying promising compounds and extracts for antituberculosis studies. In summary, the most promising extracts reported were obtained from the plants Peschiera affinis, Plathymenia foliosa, Pouteria filipes, and Psychotria vellosiana, and the cyanobacterium Microcystis aeruginosa, showing minimum inhibitory concentration (MIC) values ≤ 1 µg mL-1. Among the isolated natural compounds, the alkaloid piperovatine (MIC 7.8 µg mL-1) and the neolignan eupomatenoid-5 (MIC 1.9 µg mL-1) stood out. Considering the results compiled and discussed in the present review, it is important to highlight the need to continue the studies with the most promising extracts, in order to identify the antimycobacterial compounds responsible for their activity. In the case of piperovatin and eupomatenoid-5, it is essential to perform advanced studies to complement the preclinical results, characterizing them as new candidates for antituberculosis drug development.

Resumo em Inglês:

Star fruit belongs to the Oxalidaceae family, originally from Asia and widely distributed worldwide as a food source. Traditional knowledge advises patients with kidney problems to avoid consuming this fruit. Bioguided studies have led to the isolation of a toxin with a structural core analogous to the amino acids phenylalanine and tyrosine. Mass spectrometry (MS) is the primary technique used for analyzing biological samples, as understanding the gas-phase decomposition reactions of target analytes enhances the efficiency of these analyses. In this study, we detail the mechanisms involved in the formation of the main ion fragments of caramboxin in electrospray ionization tandem mass spectrometry (ESI-MS/MS), supported by computational chemistry and mass spectral simulations.

Resumo em Inglês:

The nitroso (NO) and fluorine (F) groups are rarely addressed in electrophilic aromatic substitution (SEAr) reactions of undergraduate organic chemistry textbooks, and when they are, textbook misconceptions about their reactivity and regioselectivity often arise. Experimental data from the literature and molecular orbital calculations for nitrosobenzene and its dimer indicate that the nitroso group is deactivating and does not have significant reactivity. When nitrosobenzene undergoes SEAr, the reactive species responsible for its reactivity and regioselectivity is its dimer, containing the azodioxy group. This intermediate is ortho/para-directing and dissociates at the end of the reaction to yield the substituted nitrosobenzene. Therefore, describing the behavior of the NO group as simply deactivating and ortho/para-directing is inaccurate. The behavior of the fluorine group is more complex: it acts as an activating group at the para position through resonance, and as a deactivating group at the ortho and meta positions through its inductive effect. Similarly, simplifying the behavior of fluorine as deactivating and ortho/para-directing is also inaccurate. To rationalize the experimental behavior of fluorobenzene, one must consider the partial rate factors for each position of the monosubstituted benzene. The kinetic data should be normalized to reflect the actual reaction rate at each position, minimizing the influence of statistical factors and enabling analysis based on the energy term of the Eyring equation. The complexity of NO and F in SEAr, combined with discrepancies between experimental data and textbook, compromises the effective teaching of the reactivity and regioselectivity of nitrosobenzene, fluorobenzene, and their derivatives in undergraduate courses. It is recommended that the effects of NO and F be reserved for advanced courses, such as organic reaction mechanisms or advanced organic chemistry, to prevent the spread of misconceptions.