Andrographolide: A Diterpenoid from Cymbopogon schoenanthus Identified as a New Hit Compound against Trypanosoma cruzi Using Machine Learning and Experimental Approaches

American Trypanosomiasis, also known as Chagas disease, is caused by the protozoan Trypanosoma cruzi and exhibits limited options for treatment. Natural products offer various structurally complex metabolites with biological activities, including those with anti-T. cruzi potential. The discovery and development of prototypes based on natural products frequently display multiple phases that could be facilitated by machine learning techniques to provide a fast and efficient method for selecting new hit candidates. Using Random Forest and k-Nearest Neighbors, two models were constructed to predict the biological activity of natural products from plants against intracellular amastigotes of T. cruzi. The diterpenoid andrographolide was identified from a virtual screening as a promising hit compound. Hereafter, it was isolated from Cymbopogon schoenanthus and chemically characterized by spectral data analysis. Andrographolide was evaluated against trypomastigote and amastigote forms of T. cruzi, showing IC50 values of 29.4 and 2.9 μM, respectively, while the standard drug benznidazole displayed IC50 values of 17.7 and 5.0 μM, respectively. Additionally, the isolated compound exhibited a reduced cytotoxicity (CC50 = 92.8 μM) against mammalian cells and afforded a selectivity index (SI) of 32, similar to that of benznidazole (SI = 39). From the in silico analyses, we can conclude that andrographolide fulfills many requirements implemented by DNDi to be a hit compound. Therefore, this work successfully obtained machine learning models capable of predicting the activity of compounds against intracellular forms of T. cruzi.

Costic acid, a sesquiterpene from Nectandra barbellata (Lauraceae), attenuates sponge implant-induced inflammation, angiogenesis and collagen deposition in vivo

Sesquiterpenes are a class of metabolites derived from plant species with immunomodulatory activity. In this study, we evaluated the effects of treatment with costic acid on inflammation, angiogenesis, and fibrosis induced by subcutaneous sponge implants in mice. One sponge disc per animal was aseptically implanted in the dorsal region of the mice and treated daily with costic acid (at concentrations of 0.1, 1, and 10 μg diluted in 10 μL of 0.5% DMSO) or 0.5% DMSO (control group). After 9 days of treatment, the animals were euthanized, and the implants collected for further analysis. Treatment with costic acid resulted in the reduction of the inflammatory parameters evaluated compared to the control group, with a decrease in the levels of inflammatory cytokines and chemokines (TNF, CXCL-1, and CCL2) and in the activity of MPO and NAG enzymes. Costic acid administration altered the process of mast cell degranulation. We also observed a reduction in angiogenic parameters, such as a decrease in the number of blood vessels, the hemoglobin content, and the levels of VEGF and FGF cytokines. Finally, when assessing implant-induced fibrogenesis, we observed a reduction in the levels of the pro-fibrogenic cytokine TGF-β1, and lower collagen deposition. The results of this study demonstrate, for the first time, the anti-inflammatory, anti-angiogenic, and anti-fibrotic effects of costic acid in an in vivo model of chronic inflammation and reinforce the therapeutic potential of costic acid.

Evaluation of the anti-inflammatory activity of Acacia polyphylla and identification of a new apigenin-3-C- glycosylated type flavonoid

Owing to the potentially harmful adverse effects of current anti-inflammatory drugs, there is a need to identify new alternative substances. Thus, this study aimed to perform a phytochemical analysis of A. polyphylla to identify compounds responsible for its anti-inflammatory activity. Several fractions of the A. polyphylla extract were obtained and evaluated in an ex vivo anti-inflammatory assay using fresh human blood. Among the evaluated fractions, the BH fraction displayed the highest percentage of PGE2 inhibition (74.8%) compared to the reference drugs dexamethasone and indomethacin, demonstrating its excellent potential for anti-inflammatory activity. Astragalin (P1), a known 3-O-glucoside of kaempferol, was isolated from the A. polyphylla extract for the first time. In addition, a new compound (P2) was isolated and identified as the apigenin-3-C-glycosylated flavonoid. Astragalin showed moderate PGE2 activity (48.3%), whereas P2 was not anti-inflammatory. This study contributes to the phytochemical studies of A. polyphylla and confirms its anti-inflammatory potential.

Interaction of sakuranetin with unsaturated lipids forming Langmuir monolayers at the air-water interface: A biomembrane model

This study investigates the interaction between sakuranetin, a versatile pharmaceutical flavonoid, and monolayers composed of unsaturated phospholipids, serving as a surrogate for cell membranes. The phospholipids were 1-palmitoyl-2-oleoyl-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE). We conducted a series of experiments to comprehensively investigate this interaction, including surface pressure assessments, Brewster angle microscopy (BAM), and polarization-modulated infrared reflection-absorption spectroscopy (PM-IRRAS). Our findings unequivocally demonstrate that sakuranetin interacts with these phospholipids, expanding the monomolecular films. Notably, regarding POPC, the presence of sakuranetin led to a reduction in stability and a decline in surface elasticity, which can likely be attributed to intricate molecular rearrangements at the interface. The visual evidence of aggregations in BAM images reinforces the interactions substantiated by PM-IRRAS, highlighting sakuranetin's interaction with the polar and nonpolar regions of POPC. However, it is worth noting that these aggregations do not appear to contribute significantly to the viscosity of the mixed film, and our investigations did not reveal any substantial hysteresis. In contrast, when examining POPE, we observed a minor reduction in thermodynamic stability, indicative of fewer rearrangements within the monolayer. This notion was further reinforced by the limited presence of aggregations in the BAM images. Sakuranetin also increased the rigidity of the lipid monolayer; nevertheless, the monolayer remained predominantly elastic, facilitating easy re-spreading on the surface, especially for the first lipid. PM-IRRAS analysis unveiled interactions between sakuranetin and POPE's polar and nonpolar segments, compellingly explaining the observed monolayer expansion. Taken together, our data suggest that sakuranetin was more effectively incorporated into the monomolecular layer of POPE, indicating that membranes comprised of POPC might exhibit a greater degree of interaction in the presence of this pharmacologically active compound.

Potential anti-inflammatory biomarkers from Myrtaceae essential oils revealed by untargeted metabolomics

Many species from Myrtaceae have traditionally been used in traditional medicine as anti-inflammatory, antimicrobial, antidiarrheal, antioxidant and antirheumatic, besides in blood cholesterol reduction. In the present work, the anti-inflammatory activity of essential oils from eighteen Myrtaceae spp. were evaluated according to their ex-vivo anti-inflammatory activity in human blood, and the corresponding biomarkers were determined using untargeted metabolomics data and multivariate data analysis. From these studied species, six displayed anti-inflammatory activity with percentage rates of inhibition of PGE2 release above 70%. Caryophyllene oxide (1), humulene epoxide II (2), β-selinene (3), α-amorphene (4), α-selinene (5), germacrene A (6), β-bisabolene (7), α-muurolene (8), α-humulene (9), β-gurjunene (10), myrcene (11), β-elemene (12), α-cadinol (13), α-copaene (14), E-nerolidol (15) and ledol (16) were annotated as potential anti-inflammatory biomarkers. The results obtained in this study point to essential oils from species of the Myrtaceae family as a rich source of anti-inflammatory agents.

Therapeutic Activity of a Topical Formulation Containing 8-Hydroxyquinoline for Cutaneous Leishmaniasis

Cutaneous leishmaniasis exhibits a wide spectrum of clinical manifestations; however, only a limited number of drugs are available and include Glucantime® and amphotericin B, which induce unacceptable side effects in patients, limiting their use. Thus, there is an urgent demand to develop a treatment for leishmaniasis. Recently, it was demonstrated that 8-hydroxyquinoline (8-HQ) showed significant leishmanicidal effects in vitro and in vivo. Based on that, this work aimed to develop a topical formulation containing 8-HQ and assess its activity in experimental cutaneous leishmaniasis. 8-HQ was formulated using a Beeler base at 1 and 2% and showed an emulsion size with a D50 of 25 and 51.3 µm, respectively, with a shear-thinning rheological behaviour. The creams were able to permeate artificial Strat-M membranes and excised porcine skin without causing any morphological changes in the porcine skin or murine skin tested. In BALB/c mice infected with L. (L.) amazonensis, topical treatment with creams containing 1 or 2% of 8-HQ was found to reduce the parasite burden and lesion size compared to infected controls with comparable efficacy to Glucantime® (50 mg/kg) administered at the site of the cutaneous lesion. In the histological section of the skin from infected controls, a diffuse inflammatory infiltrate with many heavily infected macrophages that were associated with areas of necrosis was observed. On the other hand, animals treated with both creams showed only moderate inflammatory infiltrate, characterised by few infected macrophages, while tissue necrosis was not observed. These histological characteristics in topically treated animals were associated with an increase in the amount of IFN-γ and a reduction in IL-4 levels. The topical use of 8-HQ was active in decreasing tissue parasitism and should therefore be considered an interesting alternative directed to the treatment of leishmaniasis, considering that this type of treatment is non-invasive, painless, and, importantly, does not require hospitalisation, improving patient compliance by allowing the treatment to be conducted.

An In Vivo Assessment of the Effect of Hexane Extract from Endlicheria paniculata Branches and Its Main Compound, Methyldehydrodieugenol B, on Murine Sponge-Induced Inflammation

The present study aims to explore the anti-inflammatory potential activity of the hexane extract from branches (HEB) of Endlicheria paniculata (Lauraceae) and its main compound, methyldehydrodieugenol B, in the inflammatory response induced by a murine implant sponge model. HPLC-ESI/MS analysis of HEB led to the identification of six chemically related neolignans, with methyldehydrodieugenol B as the main compound. An in silico analysis of the pharmacokinetic parameters of the identified compounds suggested moderate solubility but good absorption and biodistribution in vivo. Thus, the treatment of mice with HEB using in vivo assays indicated that HEB promoted pro-inflammatory, antiangiogenic, and antifibrogenic effects, whereas treatment with methyldehydrodieugenol B caused anti-inflammatory, antifibrogenic, and antiangiogenic effects. The obtained results shown the therapeutic potential of HEB and methyldehydrodieugenol B in the treatment of pathologies associated with inflammation and angiogenesis, including chronic wounds.

Biseugenol from Ocotea cymbarum (Lauraceae) attenuates inflammation, angiogenesis and collagen deposition of sponge-induced fibrovascular tissue in mice

Several species of the genus Ocotea are used in traditional medicine due to their anti-inflammatory and analgesic properties. In this work we sought to investigate the effects of biseugenol, the main component of the hexane extract from the leaves of Ocotea cymbarum (Lauraceae), during a chronic inflammatory process induced by polyester-polyurethane sponge in mice. In addition to the inflammatory component, sponge discs also allowed us to evaluate parameters associated with the formation of new blood vessels and the deposition and organization of the extracellular matrix, processes that are related to the chronification of the inflammatory response. Daily treatment with biseugenol (0.1, 1 or 10 µg in 10 µl of 0.5% DMSO) inhibited the synthesis of inflammatory cytokines (TNF-α, CXCL-1 and CCL2) and the neutrophil and macrophage infiltrate into to the implants, indirectly evaluated by the activity of myeloperoxidase and N-acetyl-β-D-glycosaminidase enzymes, respectively. In implants treated with biseugenol, we observed a reduction in angiogenesis, assessed through histological quantification of mean number of blood vessels, the levels of the pro-angiogenic cytokines FGF and VEGF and the activity of metalloproteinases. Except for VEGF levels, all mentioned parameters showed significant reductions after treatment with biseugenol. Finally, the administration of the compound also reduced TGF-β1 levels, collagen synthesis and deposition, in addition to modifying the organization of the newly formed matrix, presenting a potential anti-fibrotic effect. Therefore, our results demonstrate the potential therapeutic use of biseugenol for the treatment of a series of pathological conditions, where parameters associated with inflammation, angiogenesis and fibrogenesis are deregulated.

Exploring functional and structural features of chemically related natural prenylated hydroquinone and benzoic acid from Piper crassinervium (Piperaceae) on bacterial peroxiredoxin inhibition

Multiple drug resistance (MDR) bacterial strains are responsible by 1.2 million of human deaths all over the world. The pathogens possess efficient enzymes which are able to mitigate the toxicity of reactive oxygen species (ROS) produced by some antibiotics and the host immune cells. Among them, the bacterial peroxiredoxin alkyl hydroperoxide reductase C (AhpC) is able to decompose efficiently several kinds of hydroperoxides. To decompose their substrates AhpC use a reactive cysteine residue (peroxidatic cysteine-CysP) that together with two other polar residues (Thr/Ser and Arg) comprise the catalytic triad of these enzymes and are involved in the substrate targeting/stabilization to allow a bimolecular nucleophilic substitution (SN2) reaction. Additionally to the high efficiency the AhpC is very abundant in the cells and present virulent properties in some bacterial species. Despite the importance of AhpC in bacteria, few studies aimed at using natural compounds as inhibitors of this class of enzymes. Some natural products were identified as human isoforms, presenting as common characteristics a bulk hydrophobic moiety and an α, β-unsaturated carbonylic system able to perform a thiol-Michael reaction. In this work, we evaluated two chemically related natural products: 1,4-dihydroxy-2-(3',7'-dimethyl-1'-oxo-2'E,6'-octadienyl) benzene (C1) and 4-hydroxy-2-(3',7'-dimethyl-1'-oxo-2'E,6'-octadienyl) benzoic acid (C2), both were isolated from branches Piper crassinervium (Piperaceae), over the peroxidase activity of AhpC from Pseudomonas aeruginosa (PaAhpC) and Staphylococcus epidermidis (SeAhpC). By biochemical assays we show that although both compounds can perform the Michael addition reaction, only compound C2 was able to inhibit the PaAhpC peroxidase activity but not SeAhpC, presenting IC50 = 20.3 μM. SDS-PAGE analysis revealed that the compound was not able to perform a thiol-Michael addition, suggesting another inhibition behavior. Using computer-assisted simulations, we also show that an acidic group present in the structure of compound C2 may be involved in the stabilization by polar interactions with the Thr and Arg residues from the catalytic triad and several apolar interactions with hydrophobic residues. Finally, C2 was not able to interfere in the peroxidase activity of the isoform Prx2 from humans or even the thiol proteins of the Trx reducing system from Escherichia coli (EcTrx and EcTrxR), indicating specificity for P. aeruginosa AhpC.

Effect of partial O-methylation in dehydrodieugenol on its antitrypanosomal activity - correlation with the toxicity using cell membrane models

Biseugenol (1), a neolignan with antiprotozoal activity against Trypanosoma cruzi, was partially methylated, and the compound obtained - methyl biseugenol (2) - had its activity evaluated against the extracellular (trypomastigotes) and intracellular (amastigotes) forms of T. cruzi. It was observed that both compounds 1 and 2 exhibited similar effects against trypomastigotes (IC₅₀ of 11.7 and 16.2 μM, respectively), whereas compound 2 displayed higher activity against amastigotes (IC₅₀ = 8.2 μM) in comparison with biseugenol (IC₅₀ = 15.4 μM). Additionally, reduced toxicity against NCTC cells for compound 2 was observed (CC₅₀ > 200 μM), differently from compound 1 with CC₅₀ = 58.0 μM. Aiming to understand better the molecular mechanism of the biological action of compound 2, the prodrug was incorporated into cellular membrane models constituted of Langmuir monolayers of the lipids dipalmitoylphosphatidylcholine (DPPC), dipalmitoylphosphatidylethanolamine (DPPE), dipalmitoylphosphatidylserine (DPPS), and dipalmitoylphosphatidylglycerol (DPPG). The lipid-drug interaction was inferred through tensiometry, surface potential, infrared spectroscopy (PM-IRRAS), and Brewster angle microscopy (BAM). The prodrug expanded DPPC and DPPG monolayers and condensed DPPE ones, as well as presented characteristic behaviors regarding the chemical structure of the lipid considering expansion-compression curves, surface potential-area isotherms, and stability of previously compressed monolayers to relevant-biological surface pressures. PM-IRRAS indicated a molecular disorder for DPPC and DPPS alkyl chains in the presence of the drug. BAM revealed the presence of domains in the DPPG and DPPE monolayers, which was probably induced by the prodrug. These data suggest, in general, that the lipid composition modulates the interaction of compound 2, whose results are expected to correlate to its trypanocidal activity, which involves the plasma membrane of T. cruzi as the primary target, i.e., the first barrier that the compound should encounter to interact with the microorganism.

Identification of inhibitors as drug candidates against Chagas disease

Chagas disease, after more than a century after its discovery, is still a major public health problem. It is estimated that approximately 10 million people worldwide are infected with T. cruzi. However, the situation is more critical in Latin America and other regions where the disease is endemic. The largest number of cases occurs in Brazil, Argentina, and Mexico as more than 100 million people in these regions are located in areas with a high risk of contamination by the vector. The need for new therapeutic alternatives is urgent, as the available drugs have severe limitations such as low efficacy and high toxicity. From this scenario, in this work, we employed the virtual screening technique using cruzain and BDF2 as key biological targets for the survival of the parasite. Our objective was to identify potential inhibitors of T. cruzi trypomastigotes, which could be considered drug candidates against Chagas disease. For this, we employed different in silico methodologies and the obtained results were corroborated using in vitro biological assays. For the VS studies, a database containing synthetic compounds was simulated at the binding site of cruzain and BDF2. In addition, pharmacophoric models were constructed in the initial phases of VS, as well as other advanced analyses (molecular dynamics simulations, calculations of binding free energy, and ADME prediction) were carried out and the results allowed the selection of potential inhibitors of T. cruzi. Based on the obtained data, 32 different compounds commercially available were subjected to biological tests against the trypomastigote form of T. cruzi. As result, 11 of those compounds displayed significant activity against T. cruzi and can be considered potential candidates for the treatment of Chagas disease.

Cytotoxic effects of neolignans from Saururus cernuus (Saururaceae) against prostate cancer cells

In this study, five neolignans were isolated from Saururus cernuus-threo-dihydroguaiaretic acid (1), threo-austrobailignan-6 (2), threo-austrobailignan-5 (3), verrucosin (4), and saucernetin (5)-and have their cytotoxic effects evaluated in prostate cancer cell lines (PC3 and DU145). Initially, using an in silico approach, tested compounds were predicted to be absorbed by the gastrointestinal tract, be able to permeate the blood-brain barrier and did not show any alert in PAINS (pan-assay structures interference). In vitro assays showed that compounds 2, 4, and 5 reduced cell viability of DU145 cell line at 100 μmol/L after 48 h while compounds 1 and 3 showed to be inactive at the same conditions. Furthermore, compounds 4 and 5 reduced cell number as early as in 24 h at 50 μmol/L and compound 2 showed effects at 100 μmol/L in 24 h against both cancer cell lines PC3 and DU145. Studies using flow cytometry were conducted and indicated that compound 4 induced strong necrosis and apoptosis whereas compound 5 induced strong necrosis. Otherwise, less active compound 2 did not show evidence of induction of apoptosis or necrosis, suggesting that its mechanism of action involves inhibition of cell proliferation. In conclusion, compounds 4 and 5 have been shown to be promising cytotoxic agents against prostate cancer cell lines and can be used as a starting point for the development of new drugs for the treatment of prostate cancer.

Supplementation with okra combined or not with exercise training is able to protect the heart of animals with metabolic syndrome

The metabolic syndrome (MetS) is a clinical manifestation strongly associated with cardiovascular disease, the main cause of death worldwide. In view of this scenario, many therapeutic proposals have appeared in order to optimize the treatment of individuals with MetS, including the practice of exercise training (ET) and the consumption of okra (O). The aim of the present study was to evaluate the effect of O consumption and/or ET in animals with MetS. In all, 32 male Zucker rats (fa/fa) at 10 weeks old were randomly distributed into four groups of 8 animals each: MetS, MetS+O, MetS+ET and MetS+ET+O, and 8 lean Zucker rats (fa/ +) comprised the control group. Okra was administered by orogastric gavage 2x/day (morning and night, 100 mg/kg), 5 days/week, for 6 weeks. The ET was performed on a treadmill 1x/day (afternoon), 5 days/week, 60 min/day, in an intensity of 70% of maximal capacity, for the same days of O treatment. It was found that, O consumption alone was able to promote improved insulin sensitivity (MetS 93.93 ± 8.54 mg/dL vs. MetS+O 69.95 ± 18.7 mg/dL, p ≤ 0.05, d = 1.65, CI = 50.32 -89.58, triglyceride reduction (MetS 492.9 ± 97.8 mg/dL vs. MetS+O 334.9 ± 98.0 mg/dL, p ≤ 0.05, d = 1.61, CI = 193.2-398.7). In addition, it promoted a reduction in systolic blood pressure (MetS 149.0 ± 9.3 mmHg vs. MetS+O 132.0 ± 11.4 mmHg, p ≤ 0.05, d = 1.63, CI = 120-140), prevented an increase in cardiac collagen (MetS 12.60 ± 2.08% vs. MetS+O 7.52 ± 0.77%, p ≤ 0.05, d = 3.24, CI = 6.56-8.49). When associated with ET, the results were similar. Thus, we conclude that O consumption combined or not with aerobic ET can have a protective effect on the cardiac tissue of rats with MetS.

Sakuranetin interacting with cell membranes models: Surface chemistry combined with molecular simulation

Sakuranetin, a natural compound with activity in lipidic biointerfaces, was isolated from Baccharis retusa and studied with two models of lipid membranes: Langmuir monolayers and Molecular Simulation. For that, the mammalian lipid DPPC was chosen. Sakuranetin condensed the monolayers at high surface pressures, decreased the surface compressional modulus, reduced the molecular order of the acyl chains (diminution of all-trans/gauche conformers ratio), and increased the heterogeneity of the interface, forming aggregates. Molecular simulation data gave information on the bioactive compound's most favorable thermodynamic positions along the lipid monolayer, which was the lipid-air interface. These combined results lead to the conclusion that this lipophilic compound may interact with the lipidic layers, preferentially at the lipid-air interface, to minimize the free energy, and reaches this conformation disturbing the thermodynamic, structural, mechanical, rheological, and morphological properties of the well-packed DPPC monolayer.

Sakuranetin exerts anticonvulsant effect in bicuculline-induced seizures

Epilepsy is a chronic neurological disorder characterized by an abnormal, spontaneous, and synchronized neuronal hyperactivity. Therapeutic approaches for controlling epileptic seizures are associated with pharmacoresistance and side effects burden. Previous studies reported that different natural products may have neuroprotector effects. Sakuranetin (SAK) is a flavanone with antiparasitic, anti-inflammatory, antimutagenic, antiallergic, and antioxidant activity. In the present work, the effect of SAK on seizures in a model of status epilepticus induced by bicuculline (BIC) in mice was evaluated. Male Swiss mice received an intracerebroventricular injection (i.c.v.) of SAK (1, 10, or 20 mg/kg-SAK1, SAK10, or SAK20). Firstly, animals were evaluated in the open field (OF; 20 min), afterwards in the elevated plus maze (EPM) test (5 min). Next, 30 min prior the administration of BIC (1 mg/kg), mice received an injection of SAK (1 or 10 mg/kg, i.c.v.) and were observed in the OF (20 min) for seizures assessment. After behavioral procedures, immunohistochemical analysis of c-Fos was performed. Our main results showed that the lowest doses of SAK (1 and 10 mg/kg) increased the total distance traveled in the OF, moreover protected against seizures and death on the BIC-induced seizures model. Furthermore, SAK treatment reduced neuronal activity on the dentate gyrus of the BIC-treated animals. Taken together, our results suggest an anticonvulsant effect of SAK, which could be used for the development of anticonvulsants based on natural products from herbal source.

Adenanthin Is an Efficient Inhibitor of Peroxiredoxins from Pathogens, Inhibits Bacterial Growth, and Potentiates Antibiotic Activities

The emergence and re-emergence of bacterial strains resistant to multiple drugs represent a global health threat, and the search for novel biological targets is a worldwide concern. AhpC are enzymes involved in bacterial redox homeostasis by metabolizing diverse kinds of hydroperoxides. In pathogenic bacteria, AhpC are related to several functions, as some isoforms are characterized as virulence factors. However, no inhibitor has been systematically evaluated to date. Here we show that the natural ent-kaurane Adenanthin (Adn) efficiently inhibits AhpC and molecular interactions were explored by computer assisted simulations. Additionally, Adn interferes with growth and potentializes the effect of antibiotics (kanamycin and PMBN), positioning Adn as a promising compound to treat infections caused by multiresistant bacterial strains.

Bioprospecting as a strategy for conservation and sustainable use of the Brazilian Flora

Abstract In Brazil, research with natural products had a strong impulse when FAPESP supported the creation of the Laboratory of Chemistry of Natural Products of the Institute of Chemistry of USP (1966). In 1999, FAPESP launched the Research Program in the Characterization, Conservation, Restoration and Sustainable Use of Biodiversity (BIOTA-FAPESP), which intensified the sustainable exploitation of biodiversity, and which evolved to form the Biota Network for Bioprospection and Bioassays (BIOprospecTA), which integrates groups from all over the country, optimizing the use of the skills already installed for the bioprospecting of microorganisms, plants, invertebrates, vertebrates and marine organisms. Of the 104 projects related to plant sciences, 35 carried out bioprospection of Brazilian flora, belonging to the areas of Chemistry, Botany, Genetics, Plant Physiology, Plant Morphology, Plant (Chemo)taxonomy, Ecosystem Ecology, Plant Genetics. Physical Sciences, Forest Resources, Forestry Engineering, Agronomy, leading to thousands of publications, engagement of hundreds of students and a deeper understanding of natural products in different biological models through macromolecules analysis aided by computational and spectrometric strategies, in addition to pharmacological evaluations. The development of omics approaches led to a more comprehensive view of the chemical profile of an organism, and enabled integrated and concomitant studies of several samples, and faster annotation of known molecules, through the use of hyphenated and chemometric techniques, and molecular networking. This also helped to overcome the lack of information on the safety and efficacy of herbal preparations, in projects dealing with the standardization of herbal products, according to international standards. The BIOTA-FAPESP program has also focused on environmental aspects, in accordance with the principles of Green Chemistry and has had positive effects on international collaboration, on the number and impact of scientific publications and on partnership with companies, a crucial step to add value and expand the production chain of bioproducts. Also, the compilation, systematization and sharing of data were contemplated with the creation of the NUBBEDB database, of free access, and that integrates with international databases (ACD/labs, American Chemical Society – ACS), helping researchers and companies in the development from different areas of science, technology, strengthening the bioeconomy and subsidizing public policies.

α-zingiberene, a sesquiterpene from essential oil from leaves of Casearia sylvestris, suppresses inflammatory angiogenesis and stimulates collagen deposition in subcutaneous implants in mice

α-zingiberene is a phytochemical of the sesquiterpenes class, the major constituent of the essential oil from the leaves of Casearia sylvestris, a plant widely used in traditional medicine for the treatment of inflammatory diseases, tumours, and bacterial infections. In the present study, we evaluated the effects of daily administration of α-zingiberene (0.01, 0.1 and 1 μg diluted in 10 μl of 0.5% DMSO) on the inflammatory, angiogenic, and fibrogenic components, induced by subcutaneous sponge implants in an animal model. Treatment with sesquiterpene resulted in a reduction in macrophage activation, as well as in mean blood vessels and in the activity of metalloproteinases 2 and 9. Furthermore, it resulted in an increase in collagen deposition near the implants. These results show the therapeutic potential of α-zingiberene in the treatment of pathologies, in which processes such as inflammation and angiogenesis are exacerbated, or even for the treatment of chronic wounds.

In vivo anti-inflammatory activity of Fabaceae species extracts screened by a new ex vivo assay using human whole blood

INTRODUCTION

Plants have been considered a promising source for discovering new compounds with pharmacological activities. The Fabaceae family comprises a large variety of species that produce substances with diverse therapeutic potential, including anti-inflammatory activity. The limitations of current anti-inflammatories generate the need to research new anti-inflammatory structures with higher efficacy as well as develop methods for screening multiple samples, reliably and ethically, to assess such therapeutic properties.

OBJECTIVE

Validate and apply a quantification method for prostaglandin E₂ (PGE₂ ) production from an ex vivo assay in human blood in order to screen anti-inflammatory activity present in many Fabaceae species extracts.

METHODS

Human blood was incubated with extracts from 47 Fabaceae species. After lipopolysaccharide (LPS)-induced inflammation, PGE₂ was quantified in the plasma by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The extracts that presented PGE₂ production inhibition were further assessed through in vivo assay and then chemically characterised through an analysis of ultra-performance liquid chromatography electrospray ionisation quadrupole time-of-flight tandem mass spectrometry (UPLC-ESI-QTOF-MS² ) data.

RESULTS

The new ex vivo anti-inflammatory assay showed that five out of the 47 Fabaceae species inhibited PGE₂ production. Results from an in vivo assay and the metabolic profile of the active extracts supported the anti-inflammatory potential of four species.

CONCLUSION

The quantification method for PGE₂ demonstrated fast, sensitive, precise, and accurate results. The new ex vivo anti-inflammatory assay comprised a great, reliable, and ethical approach for the screening of a large number of samples before an in vivo bioassay. Additionally, the four active extracts in both ex vivo and in vivo assays may be useful for the development of more efficient anti-inflammatory drugs.

Ginkgo biloba Extract (GbE) Restores Serotonin and Leptin Receptor Levels and Plays an Antioxidative Role in the Hippocampus of Ovariectomized Rats

Since Ginkgo biloba extract (GbE) was reported to improve the hypothalamic serotonergic system of ovariectomized (OVX) rats, the present study aimed to verify the GbE effects on hippocampal oxidative stress, inflammation, and levels of the serotonin transporter (5-HTT), and both the serotonin (5-HT1A, 5-HT1B) and leptin receptors of OVX rats. Two-month-old female Wistar rats had their ovaries surgically removed (OVX) or not (SHAM). After 60 days, OVX rats were gavaged daily with GbE 500 mg kg-1 (OVX+GbE), while SHAM and OVX groups received saline 0.9% (vehicle) for 14 days. Rats were then euthanized, and hippocampi were collected. Both 5-HT1A and 5-HT1B levels were significantly reduced in OVX rats compared to SHAM rats, while 5-HT1A was higher in OVX+GbE rats in comparison to OVX rats. Similarly, LepR levels were increased in OVX+GbE rats compared to OVX rats, reaching similar levels to SHAM rats. Superoxide dismutase activity increased in OVX rats in relation to SHAM rats, which was restored to SHAM levels by GbE treatment. Additionally, GbE significantly increased the glutathione peroxidase activity in comparison to the SHAM group. No differences were observed either in catalase activity or in the levels of 5-HTT, PKCα, TLR-4, NF-κBp50, ERK, and CREB. In summary, our results show a potential effect of GbE on hippocampal pathways involved in feeding behavior, and thus, they suggest that GbE activity might improve menopausal-related hippocampal disorders, offering an alternative therapeutic tool particularly for women to whom hormone replacement therapy may be contraindicated.

New perspectives on natural flavonoids on COVID-19-induced lung injuries

The SARS-CoV-2 virus, responsible for COVID-19, spread rapidly worldwide and became a pandemic in 2020. In some patients, the virus remains in the respiratory tract, causing pneumonia, respiratory failure, acute respiratory distress syndrome (ARDS), and sepsis, leading to death. Natural flavonoids (aglycone and glycosides) possess broad biological activities encompassing antiinflammatory, antiviral, antitumoral, antiallergic, antiplatelet, and antioxidant effects. While many studies have focused on the effects of natural flavonoids in experimental models, reports based on clinical trials are still insufficient. In this review, we highlight the effects of flavonoids in controlling pulmonary diseases, particularly the acute respiratory distress syndrome, a consequence of COVID-19, and their potential use in coronavirus-related diseases. Furthermore, we also focus on establishing a relationship between biological potential and chemical aspects of related flavonoids and discuss several possible mechanisms of action, pointing out some possible effects on COVID-19.

Sesquiterpene Polygodial from Drimys brasiliensis (Winteraceae) Down-Regulates Implant-Induced Inflammation and Fibrogenesis in Mice

Drimys brasiliensis (Winteraceae) has been investigated in traditional medicine for its anti-inflammatory properties to treat gastric ulcers and allergic and respiratory system diseases as well as for cancer treatment. In this work, we investigate the ability of the sesquiterpene polygodial, isolated from D. brasiliensis stem barks, to modulate the chronic inflammatory response induced by polyester-polyurethane sponge implants in C57BL/6J mice. Daily treatment with polygodial inhibited the macrophage content in the implants as determined by the activity of the N-acetyl-β-d-glucosaminidase enzyme as well as decreased the levels of CXCL1/KC and CCL2/JE/MCP-1 pro-inflammatory chemokines and the presence of mast cells along the formed fibrovascular tissue. Similarly, the deposition of a new extracellular matrix (total collagen and type I and III collagen fibers) as well as the production of the TGF-β1 cytokine were attenuated in implants treated with polygodial, showing for the first time its antifibrogenic capacity. The hemoglobin content, the number of newly formed vessels, and the levels of VEGF cytokine, which were used as parameters for the assessment of the neovascularization of the implants, did not change after treatment with polygodial. The anti-inflammatory and antifibrogenic effects of polygodial over the components of the granulation tissue induced by the sponge implant indicate a therapeutic potential for the treatment of inflammatory diseases associated with the development of fibrovascular tissue.

Dehydrodieugenol B and hexane extract from Endlicheria paniculata regulate inflammation, angiogenesis, and collagen deposition induced by a murine sponge model

The present study reports the evaluation of hexane extract from Endlicheria paniculata and its main metabolite dehydrodieugenol B in the inflammatory response induced by a murine implant sponge model. As a result, a reduction in the inflammatory markers (myeloperoxidase and N-acetyl-β-D-glucosaminidase) and number of mast cells were observed in comparison to the control group. All doses were also able to reduce angiogenic parameters evaluated in fibrovascular tissue. In implants treated with dehydrodieugenol B a reduction in total collagen deposition and types I and III collagen fibers were observed, while an increased in total collagen deposition and types I and III collagen fibers were observed in the treatment with hexane extract. Docking studies into cyclooxygenase-2 active site revealed that the dehydrodieugenol B had binding modes and energies comparable with celecoxib, diclofenac and ibuprofen. Therefore, dehydrodieugenol B was able to alter key components of chronic inflammation, resulting in a reduced inflammatory response and also presenting antifibrogenic and antiangiogenic effects. However, treatment with hexane extract resulted in a reduced inflammatory response with antiangiogenic effects, but caused fibrogenic effects.

Electrospray mass-spectrometry guided target isolation of neolignans from Nectandra leucantha (Lauraceae) by high performance- and spiral-coil countercurrent chromatography

Nectandra leucantha (Lauraceae) is a tree indigenous to the tropical Atlantic forests of Brazil, one of the most biodiverse flora hotspots worldwide. This plant species contains high concentrations of neolignan and dehydrodieugenol derivatives that express significant in-vitro activities against various parasite strains. These activities are however responsible for severe tropical human infections, such as Leishmaniasis (Leishmania spp.) and Chagas disease (Trypanosoma cruzi), which have been classified by the World Health Organization (WHO) as Neglected Tropical Diseases (NTDs). In order to optimize the isolation process for these target metabolites, n-hexane extract of the leaves was separated by means of semi-preparative high performance countercurrent chromatography (HPCCC) and scale-up spiral-coil countercurrent chromatography (sp-CCC) systems. Several biphasic solvent mixtures were evaluated for their partitioning effects on neolignans, resulting in the selection of an optimized system n-hexane - ethylacetate - methanol - water (7:3:7:3, v/v/v/v). The chromatographic experiments on the HPCCC and sp-CCC were run in the head-to-tail mode with 500 mg and 16 g injections, respectively. For specific and multiple metabolite detection, the recovered CCC-fractions were off-line injected, in the sequence of recovery, to an electrospray mass-spectrometry (ESI-MS/MS) device. A projection of the single ion traces of the target compounds, in the positive ionization mode at a scan range of m/z 100-1500, located chromatographic areas where the co-elution effects occurred and pure target metabolites were present. Five major target neolignans were specifically detected, which enabled the accurate pooling of CCC-fractions for an optimum recovery of the metabolites. The direct comparison of the performance characteristics of the two CCC-devices, with very different mechanical designs was achieved by the conversion of the time axis into a partition ratio (K_D) separation scale. As a result, the compound specific K_D-elution values of the target neolignan were determined in high precision, while the comparison of the calculated separation factor (α) and resolution factor (R_S) values revealed a superior separation performance for the HPCCC system. Also, the reproducibility of detected metabolites in the two CCC experiments was confirmed by small variations (ΔK_D ±0.1). Neolignan target compounds with anti-parasite activities were successfully isolated in the 100 mg to 4 g range in a single lab-scale countercurrent chromatographic process step.

Conventional Versus Natural Alternative Treatments for Leishmaniasis: A Review

Leishmaniasis is a neglected disease caused by protozoan belonging to the Leishmania genus. There are at least 16 pathogenic species for humans that are able to cause different clinical forms, such as cutaneous or visceral leishmaniasis. In spite of the different species and clinical forms, the treatment is performed with few drug options that, in most cases, are considered outdated. In addition, patients under classical treatment show serious side effects during drug administration, moreover parasites are able to become resistant to medicines. Thus, it is believed and well accepted that is urgent and necessary to develop new therapeutic options to overpass these concerns about conventional therapy of leishmaniasis. The present review will focus on the efficacy, side effects and action mechanism of classic drugs used in the treatment of leishmaniasis, as well as the importance of traditional knowledge for directing a rational search toward the discovery and characterization of new and effective molecules (in vivo assays) from plants to be used against leishmaniasis.

Combined treatment with caffeic and ferulic acid from Baccharis uncinella C. DC. (Asteraceae) protects against metabolic syndrome in mice

Fractionation of the EtOH extract from aerial parts of Baccharis uncinella C. DC. (Asteraceae) led to isolation of caffeic and ferulic acids, which were identified from spectroscopic and spectrometric evidence. These compounds exhibit antioxidant and anti-inflammatory properties and have been shown to be effective in the prevention/treatment of metabolic syndrome. This study investigated whether the combined treatment of caffeic and ferulic acids exhibits a more significant beneficial effect in a mouse model with metabolic syndrome. The combination treatment with caffeic and ferulic acids was tested for 60 days in C57 mice kept on a high-fat (40%) diet. The data obtained indicated that treatment with caffeic and ferulic acids prevented gain in body weight induced by the high-fat diet and improved hyperglycemia, hypercholesterolemia and hypertriglyceridemia. The expression of a number of metabolically relevant genes was affected in the liver of these animals, showing that caffeic and ferulic acid treatment results in increased cholesterol uptake and reduced hepatic triglyceride synthesis in the liver, which is a likely explanation for the prevention of hepatic steatosis. In conclusion, the combined treatment of caffeic and ferulic acids displayed major positive effects towards prevention of multiple aspects of the metabolic syndrome and liver steatosis in an obese mouse model.

Flavonone treatment reverses airway inflammation and remodelling in an asthma murine model

BACKGROUND AND PURPOSE

Asthma is an inflammatory disease that involves airway hyperresponsiveness and remodelling. Flavonoids have been associated to anti-inflammatory and antioxidant activities and may represent a potential therapeutic treatment of asthma. Our aim was to evaluate the effects of the sakuranetin treatment in several aspects of experimental asthma model in mice.

EXPERIMENTAL APPROACH

Male BALB/c mice received ovalbumin (i.p.) on days 0 and 14, and were challenged with aerolized ovalbumin 1% on days 24, 26 and 28. Ovalbumin-sensitized animals received vehicle (saline and dimethyl sulfoxide, DMSO), sakuranetin (20 mg kg(-1) per mice) or dexamethasone (5 mg kg(-1) per mice) daily beginning from 24th to 29th day. Control group received saline inhalation and nasal drop vehicle. On day 29, we determined the airway hyperresponsiveness, inflammation and remodelling as well as specific IgE antibody. RANTES, IL-5, IL-4, Eotaxin, IL-10, TNF-α, IFN-γ and GMC-SF content in lung homogenate was performed by Bioplex assay, and 8-isoprostane and NF-kB activations were visualized in inflammatory cells by immunohistochemistry.

KEY RESULTS

We have demonstrated that sakuranetin treatment attenuated airway hyperresponsiveness, inflammation and remodelling; and these effects could be attributed to Th2 pro-inflammatory cytokines and oxidative stress reduction as well as control of NF-kB activation.

CONCLUSIONS AND IMPLICATIONS

These results highlighted the importance of counteracting oxidative stress by flavonoids in this asthma model and suggest sakuranetin as a potential candidate for studies of treatment of asthma.

The mystery of the 'resin-of-canuaru': a medicine used by caboclos river-dwellers of the Amazon, Amazonas, Brazil

ETHNOPHARMACOLOGICAL RELEVANCE

'Resin-of-canuaru' is a medicine utilized by caboclos living in the Amazon Region, Brazil. There is a mystery regarding its origin because the caboclos maintain that this substance is derived only from animal secretions (from a frog called canuaru), whereas the historic literature claims that 'resin-of-canuaru' is derived solely from a plant exudate (resin). Based on our ethnographic studies, we hypothesized that this substance is a combination of both. Because the past reports on this resiniferous material in the literature are based solely on observations, we aimed to present ethnographic, zoological and chemical data to try to elucidate the origin of the 'resin-of-canuaru'.

MATERIALS AND METHODS

Ethnographic techniques and methods were applied, including participant observation, the use of field diaries and informal and unstructured interviews. The canuaru frog (Trachycephalus resinifictrix Goeldi, 1907) and 'resin-of-canuaru' were collected for taxonomic identification and chemical analysis, respectively. The resiniferous 'resin-of-canuaru' was extracted using MeOH and then analyzed by silica gel TLC and NMR.

RESULTS

Canuaru frogs live in tree cavities and secrete a large amount of substances during spawning, resulting in a resiniferous material. NMR analysis of the MeOH extract of this crude material showed peaks assigned to 3,4-secofriedel-4(23)-en-3-oic acid (putranjuvic acid) and its methyl ester derivative (methyl putranjivate) and to biogenetic precursor of these two compounds (a lactone derivative), which is formed by the oxidation of friedelin. Based on evidence that Protium species accumulate primarily tetracyclic/pentacyclic triterpenoids and that the co-occurrence of the compounds listed above is rarely described in plant species, we suggest that these compounds could be products of the biotransformation of friedelin by the frog.

CONCLUSIONS

According to our data, the 'resin-of-canuaru' seems to have both animal and vegetal origins.

The potential of secondary metabolites from plants as drugs or leads against protozoan neglected diseases - part II

Infections with protozoan parasites are a major cause of disease and mortality in many tropical countries of the world. Diseases caused by species of the genera Trypanosoma (Human African Trypanosomiasis and Chagas Disease) and Leishmania (various forms of Leishmaniasis) are among the seventeen "Neglected Tropical Diseases" (NTDs) defined by the WHO. Furthermore, malaria (caused by various Plasmodium species) can be considered a neglected disease in certain countries and with regard to availability and affordability of the antimalarials. Living organisms, especially plants, provide an innumerable number of molecules with potential for the treatment of many serious diseases. The current review attempts to give an overview on the potential of such plant-derived natural products as antiprotozoal leads and/or drugs in the fight against NTDs. In part I, a general description of the diseases, the current state of therapy and need for new therapeuticals, assay methods and strategies applied in the search for new plant derived natural products against these diseases and an overview on natural products of terpenoid origin with antiprotozoal potential were given. The present part II compiles the current knowledge on natural products with antiprotozoal activity that are derived from the shikimate pathway (lignans, coumarins, caffeic acid derivatives), quinones of various structural classes, compounds formed via the polyketide pathways (flavonoids and related compounds, chromenes and related benzopyrans and benzofurans, xanthones, acetogenins from Annonaceae and polyacetylenes) as well as the diverse classes of alkaloids. In total, both parts compile the literature on almost 900 different plant-derived natural products and their activity data, taken from over 800 references. These data, as the result of enormous efforts of numerous research groups world-wide, illustrate that plant secondary metabolites represent an immensely rich source of chemical diversity with an extremely high potential to yield a wealth of lead structures towards new therapies for NTDs. Only a small percentage, however, of the roughly 200,000 plant species on earth have been studied chemically and only a small percentage of these plants or their constituents has been investigated for antiprotozoal activity. The repository of plant-derived natural products hence deserves to be investigated even more intensely than it has been up to present.

Nepeta cataria L. var. citriodora (Becker) increases penile erection in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Nepeta cataria (NC), catnip, induces pleasure in cats and humans.

AIM OF THE STUDY

Because sexual behavior is involved in pleasure, the effect of NC on sexual behavior and penile erection was evaluated in male rats that were acutely fed chow enriched with 10% NC leaves. Further, yawning was monitored because we previously demonstrated that NC modifies dopaminergic-related behaviors and that sexual behavior is closely linked with the dopaminergic system. The general activity and the motor coordination were examined to investigate the possible motor and emotional interferences of the sexual performance.

MATERIAL AND METHODS

Male rats of the NC group received for a 4h period the chow enriched with 10% NC leaves while the control groups received regular chow. Fifteen min after the end of the 4h period of NC feeding the sexual behavior, apomorphine-induced penile erection and motor coordination were observed; the general activity in the open field was assessed 0, 15, 30 and 60 min after treatment.

RESULTS

NC treatment increased male rat's penile erection. A slightly facilitation on male rat sexual behavior and a decreased in general activity of NC treated rats were observed. No effects on motor coordination and yawning episodes were detected by the NC treatment.

CONCLUSIONS

It was suggested that NC increases penile erection and slightly improves male rat sexual behavior by an action on dopaminergic systems.

Psychoactive plants described in a Brazilian literary work and their chemical compounds

Ethnopharmacological research investigates the plants and other medicinal and toxic substances utilized by different traditional populations. One approach in this field is a literature search of the available publications on medicinal plants. The purpose of the current study was to select plants with psychoactive effects described in a Brazilian literary work written by Pio Correa in 1926. Those mentioned plants were classified in accordance with their indications for use as stimulants and depressors of the central nervous system. For the phytochemical study herein, we researched these species via a database search, and all the obtained information was compiled into a new database to analyze possible correlations between the chemical compounds and the psychoactive categories. Of the 813 plants searched in the literary work, 104 presented chemical data in the scientific periodicals consulted. Seventy-five of them belong to the stimulant category, while 31 are depressors and two of them belong to both categories. Phenols and flavonoids were the main compounds observed in plants of both categories, though at different frequencies. Monoterpenes (29.9%) and sesquiterpenes (28.6%) were also observed in plants from the stimulant category, while 25.8% of plants from the depressor category were comprised of carotenoids and 22.6% of steroids. The main specific compounds were identified as ferulic acid, α-pinene, limonene, α-humulene and kaempferol among the stimulant plants. Otherwise, in depressor plants were characterized caffeic acid, kaempferol, quercetin, β-carotene, physalins and withanolides as specific compounds. The association between ethnopharmacological and chemotaxonomic data, as presented in this study, could support plant selection in further investigations by research groups whose studies focus on psychoactive plants as potential therapeutics.

Evaluation of a methylation procedure to determine cyclopropenoids fatty acids from Sterculia striata St. Hil. Et Nauds seed oil

Cyclopropenoids fatty acids (CPFA) from Sterculia striata seed oil were characterized by gas chromatography/mass spectrometry (GC/MS) and quantified by gas chromatography-flame ionization detector (GC-FID) after derivation to fatty acid methyl esters using a cold base-catalyzed procedure. 1H nuclear magnetic resonance (NMR) analysis were done in oil and fatty acid methyl esters derivatives to quantify CPFA and verify artifacts formation during the base-catalyzed reaction. Similar quantities of CPFA were found in S. striata and Sterculia foetida seed oils before and after a base-catalyzed methylation by NMR analysis, with no artifact formation. These results were compatible with those obtained by GC-FID analysis. Transmethylation with KOH in methanol was an appropriated method to prepare cyclopropenoids fatty acids methyl esters and quantify them by GC and NMR analysis.