In silico Study of Acetylcholinesterase and Beta-secretase Inhibitors: Potential Multitarget Anti-Alzheimer's Agents.

BACKGROUND: Alzheimer's disease is a progressive neurodegenerative process with multifactorial characteristics. This disease follows the natural aging process, affecting mainly people over 65 years. Pharmacotherapeutic treatment currently combats symptoms related to cognitive function. Several targets have begun to attract the interest of the scientific community to develop new drug candidates which have better pharmacokinetic and lower toxicity parameters. OBJECTIVE: The present study aims to design new candidates for acetylcholinesterase/ß-secretase (AChE/BACE1) multitarget inhibitor drugs. METHODS: 17 natural products were selected from the literature with anticholinesterase activity and 1 synthetic molecule with inhibitory activity for BACE1. Subsequently, the molecular docking study was performed, followed by the derivation of the pharmacophoric pattern and prediction of pharmacokinetic and toxicological properties. Finally, the hybrid prototype was designed. RESULTS: All selected molecules showed interactions with their respective target enzymes. Derivation of the pharmacophoric pattern from molecules that interacted with the AChE enzyme resulted in 3 pharmacophoric regions: an aromatic ring, an electron-acceptor region and a hydrophobic region. The molecules showed good pharmacokinetic and toxicological results, showing no warnings of mutagenicity and/or carcinogenicity. After the hybridization process, three hybrid molecules were obtained, which showed inhibitory activity for both targets. CONCLUSION: It is concluded that research in the field of medicinal chemistry is advancing towards the discovery of new drug candidates that bring a better quality of life to patients with AD.

Chromatographic profile, in silico and in vivo study of the pharmacokinetic and toxicological properties of major constituent present in kefir, the kefiran.

Kefiran is a polysaccharide present in kefir grains that have been widely explored due to its potential health benefits. The objective of this work was to characterize and quantify the components present in the ethanolic extract of milk kefir grains; to study its pharmacokinetic and toxicological properties in silico and evaluate the acute toxicity of the kefiran in zebrafish. The prediction of pharmacokinetic properties was performed by QikProp software. In silico toxicity assessment was performed using the DEREK (deductive estimate of risk from existing knowledge) software. In the chromatographic, kefiran was identified as the major component. Results showed that the kefiran had low human oral absorption and intestinal absorption its due poor solubility profile; low logP value, indicating its lipophilicity and the low MDCK and Caco-2 cells permability, and unable to cross the blood-brain barrier. Kefiran did not present any structural warning for in silico toxicity. In zebrafish, the dose of 2,000 mg/kg of kefiran produced nonsignificant alterations in the analyzed organs. It can be said then that kefiran has an acceptable degree of safety for use in the development of drugs or functional foods. Further research such as in vivo testing to confirm its pharmacological potential is currently underway.

Potential of the Compounds from Bixa orellana Purified Annatto Oil and Its Granules (Chronic®) against Dyslipidemia and Inflammatory Diseases: In Silico Studies with Geranylgeraniol and Tocotrienols.

Some significant compounds present in annatto are geranylgeraniol and tocotrienols. These compounds have beneficial effects against hyperlipidemia and chronic diseases, where oxidative stress and inflammation are present, but the exact mechanism of action of such activities is still a subject of research. This study aimed to evaluate possible mechanisms of action that could be underlying the activities of these molecules. For this, in silico approaches such as ligand topology (PASS and SEA servers) and molecular docking with the software GOLD were used. Additionally, we screened some pharmacokinetic and toxicological parameters using the servers PreADMET, SwissADME, and ProTox-II. The results corroborate the antidyslipidemia and anti-inflammatory activities of geranylgeraniol and tocotrienols. Notably, some new mechanisms of action were predicted to be potentially underlying the activities of these compounds, including inhibition of squalene monooxygenase, lanosterol synthase, and phospholipase A2. These results give new insight into new mechanisms of action involved in these molecules from annatto and Chronic®.

Design of Multitarget Natural Products Analogs with Potential Anti-Alzheimer's Activity.

BACKGROUND: Alzheimer's disease (AD) is a neurodegenerative condition and the most common type of dementia among the elderly. The enzymes acetylcholinesterase (AChE) and nitric oxide synthase (NOS) have a pivotal role in the pathophysiology of this disease. OBJECTIVE: This study aimed to select medicinal plant-derived molecules with reported inhibition of AChE and design optimized molecules that could inhibit not only AChE, but also NOS, potentially increasing its efficacy against AD. METHODS: 24 compounds were selected from the literature based on their known AChE inhibitory activity. Then, we performed molecular orbital calculations, maps of electrostatic potential, molecular docking study, identification of the pharmacophoric pattern, evaluation of pharmacokinetic and toxicological properties of these molecules. Next, ten analogs were generated for each molecule to optimize their effect where the best molecules of natural products had failed. RESULTS: The most relevant correlation was between HOMO and GAP in the correlation matrix of the molecules' descriptors. The pharmacophoric group's derivation found the following pharmacophoric features: two hydrogen bond acceptors and one aromatic ring. The studied molecules interacted with the active site of AChE through hydrophobic and hydrogen bonds and with NOS through hydrogen interactions only but in a meaningful manner. In the pharmacokinetic and toxicological prediction, the compounds showed satisfactory results. CONCLUSION: The design of natural products analogs demonstrated good affinities with the pharmacological targets AChE and NOS, with satisfactory pharmacokinetics and toxicology profiles. Thus, the results could identify promising molecules for treating Alzheimer's disease.

Hypoglycemic Activity of Aqueous Extract of Latex from Hancornia speciosa Gomes: A Study in Zebrafish and In Silico.

Hancornia speciosa Gomes is a tree native to Brazil and has therapeutic potential for several diseases. Ethnopharmacological surveys have reported that the plant is used as a hypoglycemic agent and to lose weight. This study aimed to evaluate the effects of the aqueous extract from H. speciosa latex (LxHs) in a zebrafish model of diabetes. The extract was evaluated through high-performance thin-layer chromatography (HTPLC), nuclear magnetic resonance (NMR), and Fourier-transform infrared spectroscopy (FT-IR). We then tested treatments with LxHs (500, 1000, and 1500 mg/kg) by assessing blood glucose levels in alloxan-induced diabetic animals, and metformin was used as a control. The toxicity was evaluated through histopathology of the pancreas and biochemical assessment of serum levels of AST, ALT, creatinine, and urea. The extract was also assessed for acute toxicity through several parameters in embryos and adult animals. Finally, we performed in silico analysis through the SEA server and docking using the software GOLD. The phytochemical study showed the compounds cornoside, dihydrocornoide, and 1-O-methyl-myoinositol (bornesitol). The treatment with all doses of LxHs significantly decreased alloxan-induced hyperglycemia without any significant histological or biochemical abnormalities. No significant frequency of teratogenesis was observed in the embryos exposed to the extract, and no significant behavioral changes or deaths were observed in adult animals. In silico, the results showed a potential interaction between inositol and enzymes involved in carbohydrates' metabolism. Overall, the results show a hypoglycemic activity of the extract in vivo, with no apparent toxicity. The computational studies suggest this could be at least partially due to the presence of bornesitol, since inositols can interact with carbohydrates' enzymes.

Fatty ethanolamide of Bertholletia excelsa triglycerides (Brazil nuts): anti-inflammatory action and acute toxicity evaluation in Zebrafish (Danio rerio).

Fatty amides (N-alkylamides) are bioactive lipids that are widely distributed in microorganisms, animals, and plants. The low yield in the extraction process of spilantol, a fatty amide, which is mainly related to its diverse biological effects, compromises its application on a large scale. Thus, this study proposes an alternative method to synthesise fatty amides from Bertholletia excelsa (AGBe) oil, with a chemical structure similar to that of spilantol. Carrageenan-induced abdominal oedema in vivo models were used in zebrafish (Danio rerio). In in vivo studies, oral AGBe produced no signs of toxicity. In the histopathological study, AGBe did not cause significant changes in the main metabolising organs (liver, kidneys, and intestines). All doses of AGBe (100 mg/kg, 500 mg/kg, and 750 mg/kg) were effective in reducing oedema by 65%, 69%, and 95%, respectively, producing a dose-response effect compared to the control group, and spilantol-inhibited oedema by 48%. In the in silico study, with the use of molecular docking, it was observed that among the AGBe, the molecules 18:1, ω-7-ethanolamine, and 18:1, ω-9-ethanolamine stood out, with 21 interactions for COX-2 and 20 interactions for PLA2, respectively, surpassing the spilantol standard with 15 interactions for COX-2 and PLA2. The anti-inflammatory action hypothesis was confirmed in the in silico study, demonstrating the involvement of AGBe in the process of inhibiting the enzymes COX-2 and PLA2. Therefore, based on all the results obtained and the fact that until the dose of 1000 mg/kg was administered orally in zebrafish, it was not possible to determine the LD50; it can be said that AGBe is effective and safe for anti-inflammatory activity.

Identification of known drugs as potential SARS-CoV-2 Mpro inhibitors using ligand- and structure-based virtual screening.

Background: The new coronavirus pandemic has had a significant impact worldwide, and therapeutic treatment for this viral infection is being strongly pursued. Efforts have been undertaken by medicinal chemists to discover molecules or known drugs that may be effective in COVID-19 treatment - in particular, targeting the main protease (Mpro) of the virus. Materials & methods: We have employed an innovative strategy - application of ligand- and structure-based virtual screening - using a special compilation of an approved and diverse set of SARS-CoV-2 crystallographic complexes that was recently published. Results and conclusion: We identified seven drugs with different original indications that might act as potential Mpro inhibitors and may be preferable to other drugs that have been repurposed. These drugs will be experimentally tested to confirm their potential Mpro inhibition and thus their effectiveness against COVID-19.

Perillyl alcohol decreases the frequency and severity of convulsive-like behavior in the adult zebrafish model of acute seizures.

This research aimed to assess the effect of perillyl alcohol (PA) on convulsive behavior in vivo using adult zebrafish (Danio rerio, both sexes). The seizures were induced with pentylenetetrazole (PTZ) intraperitoneally at 170 mg/kg, and diazepam (DZP) was used as the control anticonvulsant (2 mg/kg, oral); PA was tested at 10, 50, and 100 mg/kg orally. The groups had ten animals per group (total n = 60), observed for 10 minutes after seizure induction. We manually appraised typical seizure phenotypes for quantification and used an animal tracking software (Toxtrac) to assess the motor parameters. Next, we sought to find a mechanism of action for PA anticonvulsant activity in silico using a structure-based activity prediction server and molecular docking. The results show that PTZ induced seizure-like behavior in all untreated animals with hyperlocomotion episodes, seizure itself, posture loss, and immobility. DZP inhibited the seizures in all animals of the positive control group. PA, in turn, inhibited the occurrence of seizures in a dose-dependent manner, with frequencies of 90%, 70%, and 40% (for 10, 50, and 100 mg/kg, respectively). The PA treatments also decreased several seizure endpoints in a dose-dependent manner. Also, the difference of the group treated with highest dose of PA was statistically significant compared with the negative control group for all the endpoints assessed (p < 0.05, Kruskal-Wallis). The in silico analyses suggested that PA can affect the GABAergic system, which might be involved in its anticonvulsant activity, but other mechanisms cannot be ruled out. Overall, our results suggest an anticonvulsant potential in perillyl alcohol.

Molecular Docking, Physicochemical Properties, Pharmacokinetics and Toxicity of Flavonoids Present in Euterpe oleracea Martius.

BACKGROUND: Euterpe oleracea Martius, popularly known as açaí, is a fruit rich in α- tocopherols, fibers, lipids, mineral ions, and polyphenols. It is believed that the high content of polyphenols, especially flavonoids, provides several health-promoting effects to the açaí fruit, including anti-inflammatory, immunomodulatory, antinociceptive and antioxidant properties. Most of the flavonoids are antioxidant molecules of plant origin that act as a trap for free radicals, reacting and neutralizing them, thus offering perspectives in preventing oxidative damage. OBJECTIVE: In this study, we aim to perform an in silico evaluation of flavonoids present in the pulp and the oil of Euterpe oleracea Martius, evaluating their potential to serve as antioxidant agents. METHODS: Firstly, we selected 16 flavonoids present in Euterpe oleracea Martius pulp and oil, and then their physicochemical properties were analyzed concerning the Lipinski's Rule of Five. Moreover, we evaluated their pharmacokinetic properties using the QikProp module of the Schrödinger software as well as their toxicity profile, using the DEREK software. Docking simulations, using the GOLD 4.1 software, as well as pharmacophoric hypotheses calculation of molecules were also performed. RESULTS: Flavonoids present in the açaí pulp including catechin, epicatechin, luteolin, chrisoeriol, taxifolin, apigenin, dihydrokaempferol, isovitexin, and vitexin presented good oral bioavailability. Regarding the pharmacokinetic properties, the compounds catechin, epicatechin, isovitexin, luteolin, chrisoeriol, taxifolin, and isorhamnetin rutinoside presented the best results, besides high human oral absorption. Regarding the prediction of toxicological properties, compounds isorhamnetin rutinoside and rutin presented mutagenicity for hydroxynaphthalene or derivate, and regarding the docking simulations, all the compounds investigated in this study presented key interactions with the corresponding targets. CONCLUSION: The flavonoids catechin, chrysoeriol, and taxifolin presented the best results according to the evaluation conducted in this study. These computational results can be used as a theoretical basis for future studies concerning the development of drug candidates, as well as to enlighten biological tests in vitro and in vivo, which can contribute to the treatment of neurodegenerative diseases, such as Alzheimer's disease, Parkinson's disease, and Huntington's disease.

Antioxidant Effect of Flavonoids Present in Euterpe oleracea Martius and Neurodegenerative Diseases: A Literature Review.

INTRODUCTION: Neurodegenerative diseases (NDDs) are progressive, directly affecting the central nervous system (CNS), the most common and recurrent are Alzheimer's disease (AD) and Parkinson's disease (PD). One factor frequently mentioned in the etiology of NDDs is the generation of free radicals and oxidative stress, producing cellular damages. Studies have shown that the consumption of foods rich in polyphenols, especially those of the flavonoid class, has been related to the low risk in the development of several diseases. Due to the antioxidant properties present in the food, a fruit that has been gaining prominence among these foods is the Euterpe oleracea Mart. (açaí), because it presents in its composition significant amounts of a subclass of the flavonoids, the anthocyanins. METHODS: In the case review, the authors receive a basic background on the most common NDDs, oxidative stress and antioxidants. In addition, revisiting the various studies related to NDDs, including flavonoids and consumption of açaí. RESULTS: Detailed analysis of the recently reported case studies reveal that dietary consumption of flavonoid-rich foods, such as açaí fruits, suggests the efficacy to attenuate neurodegeneration and prevent or reverse the age-dependent deterioration of cognitive function. CONCLUSION: This systematic review points out that flavonoids presenting in açaí have the potential for the treatment of diseases such as PD and AD and are candidates for drugs in future clinical research. However, there is a need for in vitro and in vivo studies with polyphenol that prove and ratify the therapeutic potential of this fruit for several NDDs.

Alzheimer's Disease: A Review from the Pathophysiology to Diagnosis, New Perspectives for Pharmacological Treatment.

Dementia is characterized by the impairment of cognition and behavior of people over 65 years. Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder in the world, as approximately 47 million people are affected by this disease and the tendency is that this number will increase to 62% by 2030. Two microscopic features assist in the characterization of the disease, the amyloid plaques and neurofibrillary agglomerates. All these factors are responsible for the slow and gradual deterioration of memory that affect language, personality or cognitive control. For the AD diagnosis, neuropsychological tests are performed in different spheres of cognitive functions but since not all cognitive functions may be affected, cerebrospinal fluid biomarkers are used along with these tests. To date, cholinesterase inhibitors are used as treatment, they are the only drugs that have shown significant improvements in the cognitive functions of AD patients. Despite the proven effectiveness of cholinesterase inhibitors, an AD carrier, even while being treated, is continually subjected to progressive degeneration of the neuronal tissue. For this reason, other biochemical pathways associated with the pathophysiology of AD have been explored as alternatives to the treatment of this condition such as inhibition of ß-secretase and glycogen synthase kinase-3ß. The present study aims to conduct a review of the epidemiology, pathophysiology, symptoms, diagnosis and treatment of Alzheimer's disease, emphasizing the research and development of new therapeutic approaches.

Anti-inflammatory and antialgic actions of a nanoemulsion of Rosmarinus officinalis L. essential oil and a molecular docking study of its major chemical constituents.

We evaluate the anti-inflammatory and antialgic potency of a nanoemulsion (NEORO) containing the essential oil of Rosmarinus officinalis L. (EORO), which is composed primarily of limonene, camphor and 1,8-cineole. The EORO and NEORO were administered orally 30 min prior to starting the experiments. In a test of rat paw oedema induced by carrageenan, NEORO was effective in doses of 498 µg/kg, and it inhibited 46% of the maximum peak of the oedema; in a dose of 300 mg/kg, EORO inhibited 50% of the maximum peak of the oedema. In an acetic acid-induced writhing test, NEORO yielded a dose-dependent effect, and a dose of 830 µg/kg inhibited 84% of the algesic process; a dose of 100 mg/kg of EORO inhibited 55%. In an assay for H2S production in rat stomachs, a dose of 498 µg/kg of NEORO inhibited H2S production in all of the measurement phases, and a dose of 100 mg/kg EORO inhibited 60% and influenced the effect of the ethanol significantly, reducing the production of H2S. We suggest that NEORO potentiated the effect of EORO, demonstrating effectiveness in doses 600 times lower than those applied with EORO. Among the major compounds of EORO, the camphor molecule exhibited the largest number of interactions with the therapeutic targets related to the inflammatory process, suggesting that it is responsible for EORO's anti-inflammatory and antialgic effects. This work paves the way for future investigations related to the therapeutic role of NEORO in the inflammation process.