In Silico and In Vitro Studies of Terpenes from the Fabaceae Family Using the Phenotypic Screening Model against the SARS-CoV-2 Virus.

In 2019, the emergence of the seventh known coronavirus to cause severe illness in humans triggered a global effort towards the development of new drugs and vaccines for the SARS-CoV-2 virus. These efforts are still ongoing in 2024, including the present work where we conducted a ligand-based virtual screening of terpenes with potential anti-SARS-CoV-2 activity. We constructed a Quantitative Structure-Activity Relationship (QSAR) model from compounds with known activity against SARS-CoV-2 with a model accuracy of 0.71. We utilized this model to predict the activity of a series of 217 terpenes isolated from the Fabaceae family. Four compounds, predominantly triterpenoids from the lupane series, were subjected to an in vitro phenotypic screening in Vero CCL-81 cells to assess their inhibitory activity against SARS-CoV-2. The compounds which showed high rates of SARS-CoV-2 inhibition along with substantial cell viability underwent molecular docking at the SARS-CoV-2 main protease, papain-like protease, spike protein and RNA-dependent RNA polymerase. Overall, virtual screening through our QSAR model successfully identified compounds with the highest probability of activity, as validated using the in vitro study. This confirms the potential of the identified triterpenoids as promising candidates for anti-SARS-CoV-2 therapeutics.

The effects of fraxetin and monnieriside A on Cultured L929 fibroblasts.

Skin lesions are considered a public health problem, compromising patients' quality of life. This work aimed to evaluate the effects of fraxetin and monnieriside A on Cultured L929 Fibroblasts through the scratch assay. Supernatants and cells from the fibroblast culture treated with the compounds were used to evaluate essential markers of the tissue repair process (IGF-1, VEGF, IL-8, IL-10, FGF-2, COL1A2, COL4A, PDGF) using ELISA and qRT-PCR. The results showed that fraxetin and MOA were non-cytotoxic and could stimulate cellular migration. Fraxetin induced IGF-1, VEGF, IL-8, and IL-10 expression, while MOA induced FGF2, COL1A2, and IL-10 expression. Altogether, these results set provides evidence that fraxetin and MOA have healing potential for tissue repair, paving the way for in vivo studies and clinical trials to validate the in vitro results.

In vitro Evaluation of Fungal Susceptibility and Inhibition of Virulence by Diosgenin.

Fungal infections are a public health problem that mainly affects immunosuppressed people, Candida spp. have been responsible for most sources of contamination and invasive fungal infections described around the world. The need arises to find new therapeutic approaches to combat growing infections. Plants and natural products have been considered a valuable source for discovering new molecules with active ingredients. Diosgenin is a sapogenin found in the families of Leguminosae and Dioscoreaceae, it is obtained mainly from the dioscin saponin through the hydrolysis method, it is a phytochemical that has been highlighted in the treatment of various diseases, as well as in combating microbial resistance. The present study aimed to evaluate the susceptibility of fungal strains to diosgenin, as well as verify the association with the reference drug and evaluate the inhibition of the virulence factor through morphological changes in the yeast state to the filamentous form of hyphae and pseudohyphae in strains of Candida albicans, Candida tropicalis and Candida krusei using the broth microdilution method and microculture technique. Antifungal assays revealed that diosgenin was not able to inhibit the growth of the tested strains. However, it was able to inhibit the fungal dimorphism of the strains evaluated, however further studies are recommended to verify its effectiveness against other virulence factors.

In vitro evaluation of the susceptibility of bacterial biofilms to hecogenin acetate.

Biofilms are a bacterial resistance strategy through which microorganisms organize themselves in the form of a colony fixed to a surface that is protected by a polymer matrix. Infectious diseases that result in biofilm formation have been considered a relevant public health problem due to the potential to increase patient morbidity and mortality, in addition to increasing the burden on health services. Such pathologies are treated with the use of antimicrobial drugs, the indiscriminate use of which has contributed to the process of bacterial resistance, demanding the need to invest in new alternatives to combat them. Based on this, the present work aimed to evaluate the anti-biofilm formation and eradication capacity of Hecogenin Acetate, a steroidal sapogenin of natural origin with important antibacterial properties. For this, we used strains of Streptococcus mutans INCQS 00,446 (ATCC 25,175), Enterococcus faecalis INCQS 00,018 (ATCC 14,506), Staphylococcus epidermidis INCQS 00,016 (ATCC 12,228), Staphylococcus aureus ATCC 25,923, Pseudomonas aeruginosa ATCC 9027 and Escherichia coli ATCC 259,223. The formation, formation inhibition and treatment assays were carried out in microdilution plates and revealed using the crystal violet method. Readings were carried out using absorbance at wavelengths of 492 nm. All tests were performed in triplicate and statistical analyzes were performed using Graphpad Prism v.5.0 software. It was observed that the bacterial strains used have a relevant capacity for biofilm formation, with the Gram positive ones identified in the present study as the best former. In the results of the analyzes with bacterial biofilm, it was identified that Hecogenin Acetate had a relevant antibiofilm capacity, and could therefore serve as a basis for further research into the development of new antimicrobial drugs.

Validation of an analytical method by HPLC for the quantification of yangambin from the Ocotea duckei species / Validación de un método analítico por HPLC para la cuantificación de yangambin de la especie Ocotea duckei

Ocotea duckei , known as Louro - de - cheiro, belongs to the Lauraceae family and presents lignoid yangambine (YAN) as the main plant marker. This work aimed to develop and validate an analytical method by high performance liquid chromatography for the quantification of YAN. The sample used was the crude eth anolic extract (CEE) obtained from aerial parts. In the developed method, a C18 column was used. The mobile phase was composed of acetonitrile and water (45:55), whereas the method parameters included mobile phase flow rate at 0.8 mL/min, oven temperature at 40°C, and monitoring at 205 nm. In the validation, the parameters of selectivity, linearity, precision, accuracy, robustness, limits of detection and quantification were evaluated. As a result, the developed method is in accordance with the guidelines f or validation of analytical methods and presented satisfactory chromatographic parameters for YAN determination. Thus, the present analytical methodology can be applied in the quality control of O. duckei raw materials.

Ocotea duckei , conocida como Louro - de - cheiro, pertenece a la familia Lauraceae y presenta la yangambina lignoide (YAN) como principal marcador vegetal. Este trabajo tuvo como objetivo desarrollar y val idar un método analítico por cromatografía líquida de alta resolución para la cuantificación de YAN. La muestra utilizada fue el extracto etanólico crudo (EEC) obtenido de partes aéreas. En el método desarrollado se utilizó una columna C18. La fase móvil c onsistió en acetonitrilo y agua (45:55), mientras los parámetros del método incluyeron el caudal de la fase móvil a 0,8 m L /min, la temperatura del horno a 40°C y la monitorización a 205 nm. En la validación se evaluaron los parámetros de selectividad, line alidad, precisión, exactitud, robustez, límites de detección y cuantificación. Como resultado, el método desarrollado está de acuerdo con las pautas para la validación de métodos analíticos y presentó parámetros cromatográficos satisfactorios para la deter minación de YAN. Por lo tanto, la presente metodología analítica se puede aplicar en el control de calidad de las materias primas de O. duckei.

Anticancer Activity of Chalcones and Its Derivatives: Review and In Silico Studies.

Chalcones are direct precursors in the biosynthesis of flavonoids. They have an α,ß-unsaturated carbonyl system which gives them broad biological properties. Among the biological properties exerted by chalcones, their ability to suppress tumors stands out, in addition to their low toxicity. In this perspective, the present work explores the role of natural and synthetic chalcones and their anticancer activity in vitro reported in the last four years from 2019 to 2023. Moreover, we carried out a partial least square (PLS) analysis of the biologic data reported for colon adenocarcinoma lineage HCT-116. Information was obtained from the Web of Science database. Our in silico analysis identified that the presence of polar radicals such as hydroxyl and methoxyl contributed to the anticancer activity of chalcones derivatives. We hope that the data presented in this work will help researchers to develop effective drugs to inhibit colon adenocarcinoma in future works.

Antimicrobial Potential of Betulinic Acid and Investigation of the Mechanism of Action against Nuclear and Metabolic Enzymes with Molecular Modeling.

Natural products have important pharmacological activities. This study sought to investigate the activity of the compound betulinic acid (BA) against different strains of bacteria and fungi. The minimum inhibitory concentration (MIC) was determined and then the minimum bactericidal concentration (MBC) and minimum fungicidal concentration (MFC). After performing the in vitro tests, molecular modeling studies were carried out to investigate the mechanism of action of BA against the selected microorganisms. The results showed that BA inhibited the growth of microbial species. Among the 12 species (Staphylococcus aureus, S. epidermidis, Pseudomonas aeruginosa, Escherichia coli, Mycobacterium tuberculosis, Candida albicans, C. tropicalis, C. glabrata, Aspergillus flavus, Penicillium citrinum, Trichophyton rubrum, and Microsporum canis) investigated, 9 (75%) inhibited growth at a concentration of 561 µM and 1 at a concentration of 100 µM. In general, the MBC and MFC of the products were between 561 and 1122 µM. In silico studies showed that BA presented a mechanism of action against DNA gyrase and beta-lactamase targets for most of the bacteria investigated, while for fungi the mechanism of action was against sterol 14α-demethylase (CYP51) targets and dihydrofolate reductase (DHFR). We suggest that BA has antimicrobial activity against several species.

Evaluation of the antibacterial and inhibitory activity of NorA and MepA efflux pumps from Staphylococcus aureus by diosgenin.

The increase in bacterial resistance to available antibiotics has driven several researchers to search for new agents with therapeutic properties. Diosgenin is a naturally occurring steroidal saponin that has demonstrated several pharmacological properties. In the present study, we report the antimicrobial activity of diosgenin against the standard and multidrug-resistant bacteria of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, in addition to the efflux pump inhibitory activity against Staphylococcus aureus strains carrying NorA and MepA pumps. For this purpose, the broth microdilution method was used, from which the value of the Minimum Inhibitory Concentration (MIC) was obtained, and this was associated with subinhibitory concentration (MIC/8) with antibiotic of clinical use and ethidium bromide for strains carrier by efflux pump. Diosgenin showed antimicrobial activity for standard S. aureus bacteria and potentiating activity in association with gentamicin and ampicillin for P. aeruginosa multidrug-resistant bacteria, it also showed potentiation in association with norfloxacin against the E. coli strain and gentamicin against the S. aureus strain. Antimicrobial activity against efflux pump-bearing strains revealed that saponin did not interfere with the efflux pump mechanism or intervened antagonistically. Thus, saponin has shown to be very promising against bacterial resistance in association with aminoglycoside, fluoroquinolones and beta-lactam, however additional studies should be carried out to better elucidate the mechanism of action of diosgenin.

In vitro leishmanicidal effect of Yangambin and Epi-yangambin lignans isolated from Ocotea fasciculata (Nees) Mez.

Introduction: Yangambin and epi-yangambin are the main lignans found in Louro-de-Cheiro [Ocotea fasciculata (Nees) Mez], a tree native to the Atlantic forests of northeastern Brazil whose leaves and bark are widely used in folk medicine. The present study investigated the leishmanicidal and immunomodulatory effects of both lignans in in vitro models of infection by Leishmania amazonensis or Leishmania braziliensis, both etiological agents of Cutaneous Leishmaniasis in Brazil. Methods: Bone marrow-derived mouse macrophages were infected with L. amazonensis or L. braziliensis and then treated for 48 h at varying concentrations of yangambin or epi-yangambin. Results: Yangambin and epi-yangambin were found to reduce the intracellular viability of either Leishmania species in a concentration-dependent manner, with respective IC50 values of: 43.9 ± 5 and 22.6 ± 4.9 µM for L. amazonensis, compared to IC50 values of 76 ± 17 and 74.4 ± 9.8 µM for L. braziliensis. In this context, epi-yangambin proved more selective and effective against in vitro infection by L. amazonensis. However, both lignans were found to distinctly modulate the production of inflammatory mediators and other cytokines by macrophages infected by either of the Leishmania species evaluated. While yangambin increased the production of IL-10 by L. braziliensis-infected macrophages, both compounds were observed to lower the production of NO, PGE2, IL-6 and TNF-α in both Leishmania species. Discussion: The present results serve to encourage the development of novel studies aimed at screening natural bioactive compounds with the hope of discovering new therapeutic options for the treatment of Cutaneous Leishmaniasis.

A Novel High-Content Screening-Based Method for Anti-Trypanosoma cruzi Drug Discovery Using Human-Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Chagas disease is caused by Trypanosoma cruzi infection and remains a relevant cause of chronic heart failure in Latin America. The pharmacological arsenal for Chagas disease is limited, and the available anti-T. cruzi drugs are not effective when administered during the chronic phase. Cardiomyocytes derived from human-induced pluripotent stem cells (hiPSC-CMs) have the potential to accelerate the process of drug discovery for Chagas disease, through predictive preclinical assays in target human cells. Here, we aimed to establish a novel high-content screening- (HCS-) based method using hiPSC-CMs to simultaneously evaluate anti-T. cruzi activity and cardiotoxicity of chemical compounds. To provide proof-of-concept data, the reference drug benznidazole and three compounds with known anti-T. cruzi activity (a betulinic acid derivative named BA5 and two thiazolidinone compounds named GT5A and GT5B) were evaluated in the assay. hiPSC-CMs were infected with T. cruzi and incubated for 48 h with serial dilutions of the compounds for determination of EC50 and CC50 values. Automated multiparametric analyses were performed using an automated high-content imaging system. Sublethal toxicity measurements were evaluated through morphological measurements related to the integrity of the cytoskeleton by phalloidin staining, nuclear score by Hoechst 33342 staining, mitochondria score following MitoTracker staining, and quantification of NT-pro-BNP, a peptide released upon mechanical myocardial stress. The compounds showed EC50 values for anti-T. cruzi activity similar to those previously described for other cell types, and GT5B showed a pronounced trypanocidal activity in hiPSC-CMs. Sublethal changes in cytoskeletal and nucleus scores correlated with NT-pro-BNP levels in the culture supernatant. Mitochondrial score changes were associated with increased cytotoxicity. The assay was feasible and allowed rapid assessment of anti-T. cruzi action of the compounds, in addition to cardiotoxicity parameters. The utilization of hiPSC-CMs in the drug development workflow for Chagas disease may help in the identification of novel compounds.

Is Riparin III a promising drug in the treatment for depression?

Stress is crucially related to the pathophysiology of mood disorders, including depression. Since the effectiveness and number of the current pharmacological options still presents significant limitations, research on new substances is paramount. In rodents, several findings have indicated that corticosterone administration induces the manifestation of behavioral and neurochemical aspects of depression. Recently, riparin III has shown antidepressant-like properties in trials performed on animal models. Thus, our goal was to investigate the effects of riparin III on behavioral tests, monoamines levels, oxidative stress and cytokines levels in chronic corticosterone-induced model of depression. To do this, female swiss mice were treated with subcutaneous administration of corticosterone for 22 days. In addition, for the last 10 days, riparin III or fluvoxamine were also administered per os in specific test groups. Control groups received subcutaneous saline injections or distilled water per os. At the end of the timeline, the animals were killed and their hippocampi, prefrontal cortex, and striatum dissected for neurochemical analysis. Brain changes following corticosterone administration were confirmed, and riparin III could reversed the most abnormal behavioral and neurochemical corticosterone-induced alterations. These results suggest the potential antioxidant, anti-inflammatory and antidepressant effects of riparin III after a chronic stress exposure.

In Silico Study Examining New Phenylpropanoids Targets with Antidepressant Activity.

BACKGROUND: Natural products, such as phenylpropanoids, which are found in essential oils derived from aromatic plants, have been explored during non-clinical psychopharmacology studies, to discover new molecules with relevant pharmacological activities in the central nervous system, especially antidepressant and anxiolytic activities. Major depressive disorder is a highly debilitating psychiatric disorder and is considered to be a disabling public health problem, worldwide, as a primary factor associated with suicide. Current clinically administered antidepressants have late-onset therapeutic actions, are associated with several side effects, and clinical studies have reported that some patients do not respond well to treatment or reach complete remission. OBJECTIVE: To review important new targets for antidepressant activity and to select phenylpropanoids with antidepressant activity, using Molegro Virtual Docker and Ossis Data Warris, and to verify substances with more promising antidepressant activity. RESULTS AND CONCLUSION: An in silico molecular modeling study, based on homology, was conducted to determine the three-dimensional structure of the 5-hydroxytryptamine 2A receptor (5- HT2AR), then molecular docking studies were performed and the predisposition for cytotoxicity risk among identified molecules was examined. A model for 5-HT2AR homology, with satisfactory results, was obtained indicating the good stereochemical quality of the model. The phenylpropanoid 4-allyl-2,6-dimethoxyphenol showed the lowest binding energy for 5-HT2AR, with results relevant to the L-arginine/nitric oxide (NO)/cGMP pathway, and showed no toxicity within the parameters of mutagenicity, carcinogenicity, reproductive system toxicity, and skin-tissue irritability, when evaluated in silico; therefore, this molecule can be considered promising for the investigation of antidepressant activity.

In vitro and in silico inhibitory effects of synthetic and natural eugenol derivatives against the NorA efflux pump in Staphylococcus aureus.

Staphylococcus aureus is a Gram-positive bacterium responsible for a number of diseases and has demonstrated resistance to conventional antibiotics. This study aimed to evaluate the antibacterial activity of eugenol and its derivatives allylbenzene, 4-allylanisole, isoeugenol and 4-allyl-2,6-dimethoxyphenol against the S. aureus NorA efflux pump (EP) in association with norfloxacin and ethidium bromide. The antibacterial activity of the compounds was assessed using the broth microdilution method to determine the minimum inhibitory concentration (MIC). A reduction in the MIC of ethidium bromide (a substrate for several efflux pumps) or norfloxacin was used as a parameter of EP inhibition. Molecular modeling studies were used to predict the 3D structure and analyze the interaction of selected compounds with the binding pocket of the NorA efflux pump. Except for 4-allylanisole and allylbenzene, the compounds presented clinically effective antibacterial activity. When associated with norfloxacin against the SA 1199B strain, 4-allyl-2,6-dimethoxyphenol eugenol and isoeugenol caused significant reduction in the MIC of the antibiotic, demonstrating synergistic effects. Similar effects were observed when 4-allyl-2,6-dimethoxyphenol, allylbenzene and isoeugenol were associated with ethidium bromide. Together, these findings indicate a potential inhibition of the NorA pump by eugenol and its derivatives. This in vitro evidence was corroborated by docking results demonstrating favorable interactions between 4-allyl-2,6-dimetoxypheno and the NorA pump mediated by hydrogen bonds and hydrophobic interactions. In conclusion, eugenol derivatives have the potential to be used in antibacterial drug development in strains carrying the NorA efflux pump.

Antifungal activity of farnesol incorporated in liposomes and associated with fluconazole.

Candida infections represent a threat to human health. Candida albicans is the main causative agent of invasive candidiasis, especially in immunosuppressed patients. The emergence of resistant strains has required the development of new therapeutic strategies. In this context, the use of liposomes as drug carrier systems is a promising alternative in drug development. Thus, considering the evidence demonstrating that sesquiterpene farnesol is a bioactive compound with antifungal properties, this study evaluated the activity farnesol-containing liposomes against different Candida strains. The IC50 of farnesol and its liposomal formulation was assessed in vitro using cultures of Candida albicans, Candida tropicalis, and Candida krusei. The Minimum Fungicidal Concentration (MFC) was established by subculture in solid medium. The occurrence of fungal dimorphism was analyzed using optical microscopy. The effects on antifungal resistance to fluconazole were assessed by evaluating the impact of combined therapy on the growth of Candida strains. The characterization of liposomes was carried out considering their vesicular size, polydispersion index, and zeta medium potential, in addition to electron microscopy analysis. Farnesol exerted an antifungal activity that might be associated with the inhibition of fungal dimorphism, especially in Candida albicans. The incorporation of farnesol into liposomes significantly increased its antifungal activity against C. albicans, C. tropicalis, and C. krusei. In addition, liposomal farnesol potentiated the action of fluconazole against C. albicans and C. tropicalis. On the other hand, the association of unconjugated farnesol with fluconazole resulted in antagonistic effects. In conclusion, farnesol-containing liposomes have the potential to be used in antifungal drug development. However, further research is required to investigate how the antifungal properties of farnesol are affected by the interaction with liposomes, contributing to the modulation of antifungal resistance to conventional drugs.

The Azoles in Pharmacochemistry: Perspectives on the Synthesis of New Compounds and Chemoinformatic Contributions.

Due to their versatile biological activity, Azoles are widely studied in pharmacochemistry. It is possible to use them in many applications and in studies aimed at discovering antiparasitic, antineoplastic, antiviral, antimicrobial compounds; and in the production of materials for treatment of varied pathologies. Based on their biological activity, our review presents several studies that involve this class of organic compounds. A bibliographic survey of this type can effectively contribute to pharmaceutical sciences, stimulating the discovery of new compounds, and structural improvements to biological profiles of interest. In this review, articles are discussed involving the synthesis of new compounds and chemoinformatic contributions. Current applications of azoles in both the pharmaceutical and agri-business sectors are well known, yet as this research highlights, azole compounds can also bring important contributions to the fight against many diseases. Among the heterocyclics, azoles are increasingly studied by research groups around the world for application against tuberculosis, HIV, fungal and bacterial infections; and against parasites such as leishmaniasis and trypanosomiasis. Our hope is that this work will help arouse the interest of research groups planning to develop new bioactives to fight against these and other diseases.

An investigation into the interaction between piplartine (piperlongumine) and human serum albumin.

Piplartines are alkaloid amides present in the roots and stems of different pepper species which have promising pharmacological properties including cancer prevention. Some recent studies have determined pharmacokinetic parameters of piplartine in rat blood plasma but without pointing to any molecular target or describing the physicochemical forces of the interaction. The present study investigated the interaction between piplartine and human serum albumin (HSA) the predominant protein in blood plasma. Fluorescence spectroscopy was utilized to observe the complex HSA-piplartine formation. Thermodynamic parameter analysis indicates that the process occurs spontaneously and is enthalpically driven; the affinity constant suggests that this interaction is reversible. This was reinforced by the binding density function method and by the displacement analysis that the piplartine binds on HSA at a single site, which was determined to be the IIA sub-domain. In silico analysis (molecular docking) identified the main residues involved in binding and the corresponding forces, which corroborates well with the experimental results.

2-Allylphenol Reduces IL-1ß and TNF-α, Promoting Antinociception through Adenosinergic, Anti-Inflammatory, and Antioxidant Mechanisms.

2-Allylphenol (2-AP) is a synthetic phenylpropanoid, structurally related to cardanol, thymol, and ortho-eugenol. Phenylpropanoids are described in the literature as being capable of promoting biological activity. Due to the similarity between 2-AP and other bioactive phenylpropanoids, the present research aims at evaluating the antioxidant, antinociceptive, and anti-inflammatory potential of 2-AP in silico, in vitro, and in vivo. At 30 min prior to the start of in vivo pharmacological testing, administration of 2-AP (25, 50, 75, and 100 mg/kg i.p.), morphine (6 mg/kg i.p.), dexamethasone (2 mg/kg s.c.), or vehicle alone was performed. In the acetic acid-induced abdominal writhing tests, pretreatment with 2-AP significantly reduced the number of abdominal writhes, as well as decreased licking times in the glutamate and formalin tests. Investigation of the mechanism of action using the formalin model led to the conclusion that the opioid system does not participate in its activity. However, the adenosinergic system is involved. In the peritonitis tests, 2-AP inhibited leukocyte migration and reduced releases of proinflammatory mediators TNF-α and IL-1ß. In vitro antioxidant assays demonstrated that 2-AP presents significant ability to sequester superoxide radicals. In silico docking studies confirmed interaction between 2-AP and the adenosine A2a receptor through hydrogen bonds with the critical asparagine 253 residues present in the active site. Investigation of 2-AP demonstrated its nociception inhibition and ability to reduce reactive oxygen species. Its interaction with A2a receptors may well be related to proinflammatory cytokines TNF-α and IL-1ß reduction activity, corroborating its antinociceptive effect.

ß-Lapachone and its iodine derivatives cause cell cycle arrest at G2/M phase and reactive oxygen species-mediated apoptosis in human oral squamous cell carcinoma cells.

ß-Lapachone is a natural naphthoquinone originally obtained from the bark of the purple Ipe (Tabebuia avellanedae Lor, Bignoniaceae) and its therapeutic potential in human cancer cells has been evaluated in several studies. In this study, we examined the effects of ß-lapachone and its 3-iodine derivatives (3-I-α-lapachone and 3-I-ß-lapachone) on cell proliferation, cell death, and cancer-related gene expression in human oral squamous cell carcinoma cells. ß-Lapachone and its 3-iodine derivatives showed potent cytotoxicity against different types of human cancer cell lines. Indeed, treatment with these compounds induced cell cycle arrest at G2/M phase, followed by internucleosomal DNA fragmentation, and caused significant increases in phosphatidylserine externalization, caspase-8 and -9 activation, mitochondrial membrane depolarization, reactive oxygen species (ROS) production, and apoptotic cell death morphology. The apoptosis induced by the compounds was prevented by pretreatment with a pan-caspase inhibitor (Z-VAD-FMK) and an antioxidant (N-acetyl-l-cysteine). In vivo, ß-lapachone and its 3-iodine derivatives significantly reduced tumor burden and did not alter any of the biochemical, hematological, or histological parameters of the animals. Overall, ß-lapachone and its 3-iodine derivatives showed promising cytotoxic activity due to their ability to induce cell cycle arrest at G2/M phase and promote caspase- and ROS-mediated apoptosis. In addition, ß-lapachone and its 3-iodine derivatives were able to suppress tumor growth in vivo, indicating that these compounds may be new antitumor drug candidates.

Spectral and computational features of the binding between riparins and human serum albumin.

The green Brazilian bay leaf, a spice much prized in local cuisine (Aniba riparia, Lauraceae), contains chemical compounds presenting benzoyl-derivatives named riparins, which have anti-inflammatory, antimicrobial and anxiolytic properties. However, it is unclear what kind of interaction riparins perform with any molecular target. As a profitable target, human serum albumin (HSA) is one of the principal extracellular proteins, with an exceptional capacity to interact with several molecules, and it also plays a crucial role in the transport, distribution, and metabolism of a wide variety of endogenous and exogenous ligands. To outline the HSA-riparin interaction mechanism, spectroscopy and computational methods were synergistically applied. An evaluation through fluorescence spectroscopy showed that the emission, attributed to Trp 214, at 346 nm decreased with titrations of riparins. A static quenching mechanism was observed in the binding of riparins to HSA. Fluorescence experiments performed at 298, 308 and 318 K made it possible to conduct thermodynamic analysis indicating a spontaneous reaction in the complex formation (ΔG<0). The enthalpy-entropy balance experiment with a molecular modeling calculation revealed that hydrophobic, hydrogen bond and non-specific interactions are present for riparin I-III with HSA. The set of results from fractional fluorescence changes obtained through Schatchard was inconclusive in establishing what kind of cooperativity is present in the interaction. To shed light upon the HSA-riparins complex, Hill's approach was utilized to distinguish the index of affinity and the binding constant. A correspondence between the molecular structures of riparins, due to the presence of the hydroxyl group in the B-ring, with thermodynamic parameters and index of affinity were observed. Riparin III performs an intramolecular hydrogen bond, which affects the Hill coefficient and the binding constant. Therefore, the presence of hydroxyl groups is capable of modulating the interaction between riparins and HSA. Site marker competitive experiments indicated Site I as being the most suitable, and the molecular modeling tools reinforced the experimental results detailing the participation of residues.

Computer-aided Drug Design Applied to Parkinson Targets.

BACKGROUND: Parkinson's disease (PD) is a progressive neurodegenerative disorder characterized by debilitating motor deficits, as well as autonomic problems, cognitive declines, changes in affect and sleep disturbances. Although the scientific community has performed great efforts in the study of PD, and from the most diverse points of view, the disease remains incurable. The exact mechanism underlying its progression is unclear, but oxidative stress, mitochondrial dysfunction and inflammation are thought to play major roles in the etiology. OBJECTIVE: Current pharmacological therapies for the treatment of Parkinson's disease are mostly inadequate, and new therapeutic agents are much needed. METHODS: In this review, recent advances in computer-aided drug design for the rational design of new compounds against Parkinson disease; using methods such as Quantitative Structure-Activity Relationships (QSAR), molecular docking, molecular dynamics and pharmacophore modeling are discussed. RESULTS: In this review, four targets were selected: the enzyme monoamine oxidase, dopamine agonists, acetylcholine receptors, and adenosine receptors. CONCLUSION: Computer aided-drug design enables the creation of theoretical models that can be used in a large database to virtually screen for and identify novel candidate molecules.