Piperine, quercetin, and curcumin identified as promising natural products for topical treatment of cutaneous leishmaniasis.

Leishmania braziliensis (L. braziliensis) causes cutaneous leishmaniasis (CL) in the New World. The costs and the side effects of current treatments render imperative the development of new therapies that are affordable and easy to administer. Topical treatment would be the ideal option for the treatment of CL. This underscores the urgent need for affordable and effective treatments, with natural compounds being explored as potential solutions. The alkaloid piperine (PIP), the polyphenol curcumin (CUR), and the flavonoid quercetin (QUE), known for their diverse biological properties, are promising candidates to address these parasitic diseases. Initially, the in vitro cytotoxicity activity of the compounds was evaluated using U-937 cells, followed by the assessment of the leishmanicidal activity of these compounds against amastigotes of L. braziliensis. Subsequently, a golden hamster model with stationary-phase L. braziliensis promastigote infections was employed. Once the ulcer appeared, hamsters were treated with QUE, PIP, or CUR formulations and compared to the control group treated with meglumine antimoniate administered intralesionally. We observed that the three organic compounds showed high in vitro leishmanicidal activity with effective concentrations of less than 50 mM, with PIP having the highest activity at a concentration of 8 mM. None of the compounds showed cytotoxic activity for U937 macrophages with values between 500 and 700 mM. In vivo, topical treatment with QUE daily for 15 days produced cured in 100% of hamsters while the effectiveness of CUR and PIP was 83% and 67%, respectively. No failures were observed with QUE. Collectively, our data suggest that topical formulations mainly for QUE but also for CUR and PIP could be a promising topical treatment for CL. Not only the ease of obtaining or synthesizing the organic compounds evaluated in this work but also their commercial availability eliminates one of the most important barriers or bottlenecks in drug development, thus facilitating the roadmap for the development of a topical drug for the management of CL caused by L. braziliensis.

Evaluation of the effectiveness of cytisine for the treatment of smoking cessation: A systematic review and meta-analysis.

BACKGROUND AND AIMS: Smoking is considered the main cause of preventable death world-wide. This study aimed to review the efficacy and safety of cytisine for smoking cessation. METHODS: This review included an exhaustive search of databases to identify randomized controlled trials (RCTs) in health centers of any level with smokers of any age or gender investigating the effects of cytisine at standard dosage versus placebo, varenicline or nicotine replacement therapy (NRT). RESULTS: We identified 12 RCTs. Eight RCTs compared cytisine with placebo at the standard dose covering 5922 patients, 2996 of whom took cytisine, delivering a risk ratio (RR) of 2.25 [95% confidence interval (CI) = 1.42-3.56; I2  = 88%; moderate-quality evidence]. The greater intensity of behavioral therapy was associated directly with the efficacy findings (moderate-quality evidence). The confirmed efficacy of cytisine was not evidenced in trials conducted in low- and middle-income countries. We estimate a number needed to treat (NNT) of 11. Two trials compared the efficacy of cytisine versus NRT, and the combination of both studies yields modest results in favor of cytisine. Three trials compared cytisine with varenicline, without a clear benefit for cytisine. Meta-analyses of all non-serious adverse events in the cytisine group versus placebo groups yielded a RR of 1.24 (95% CI = 1.11-1.39; participants = 5895; studies = 8; I2 = 0%; high-quality evidence). CONCLUSIONS: Cytisine increases the chances of successful smoking cessation by more than twofold compared with placebo and has a benign safety profile, with no evidence of serious safety concerns. Limited evidence suggests that cytisine may be more effective than nicotine replacement therapy, with modest cessation rates.

Potential of piperine for neuroprotection in sepsis-associated encephalopathy.

AIMS: Sepsis-associated encephalopathy (SAE) is a common complication that increases mortality and leads to long-term cognitive impairment in sepsis survivors. However, no specific or effective therapy has been identified for this complication. Piperine is an alkaloid known for its anti-inflammatory, antioxidant, and neuroprotective properties, which are important characteristics for treatment of SAE. The objective of this study was to evaluate the neuroprotective effect of piperine on SAE in C57BL/6 mice that underwent cecum ligation and perforation surgery (CLP). MAIN METHODS: C57BL/6 male mice were randomly assigned to groups that underwent SHAM surgery or CLP. Mice in the CLP group were treated with piperine at doses of 20 or 40 mg/kg for short- (5 days) or long-term (10 days) periods after CLP. KEY FINDINGS: Our results revealed that untreated septic animals exhibited increased concentrations of IL-6, TNF, VEGF, MMP-9, TBARS, and NLRP3, and decreased levels of BDNF, sulfhydryl groups, and catalase in the short term. Additionally, the levels of carbonylated proteins and degenerated neuronal cells were increased at both time points. Furthermore, short-term and visuospatial memories were impaired. Piperine treatment reduced MMP-9 activity in the short term and decreased the levels of carbonylated proteins and degenerated neuronal cells in the long term. It also lowered IL-6 and TBARS levels at both time points evaluated. Moreover, piperine increased short-term catalase and long-term BDNF factor levels and improved memory at both time points. SIGNIFICANCE: In conclusion, our data demonstrate that piperine exerts a neuroprotective effect on SAE in animals that have undergone CLP.

Palmatine, a natural alkaloid, attenuates memory deficits and neuroinflammation in mice submitted to permanent focal cerebral ischemia.

Ischemic stroke is one of the major causes of human morbidity and mortality. The pathophysiology of ischemic stroke involves complex events, including oxidative stress and inflammation, that lead to neuronal loss and cognitive deficits. Palmatine (PAL) is a naturally occurring (Coptidis rhizome) isoquinoline alkaloid that belongs to the class of protoberberines and has a wide spectrum of pharmacological and biological effects. In the present study, we evaluated the impact of Palmatine on neuronal damage, memory deficits, and inflammatory response in mice submitted to permanent focal cerebral ischemia induced by middle cerebral artery (pMCAO) occlusion. The animals were treated with Palmatine (0.2, 2 and 20 mg/kg/day, orally) or vehicle (3% Tween + saline solution) 2 h after pMCAO once daily for 3 days. Cerebral ischemia was confirmed by evaluating the infarct area (TTC staining) and neurological deficit score 24 h after pMCAO. Treatment with palmatine (2 and 20 mg/kg) reduced infarct size and neurological deficits and prevented working and aversive memory deficits in ischemic mice. Palmatine, at a dose of 2 mg/kg, had a similar effect of reducing neuroinflammation 24 h after cerebral ischemia, decreasing TNF-, iNOS, COX-2, and NF- κB immunoreactivities and preventing the activation of microglia and astrocytes. Moreover, palmatine (2 mg/kg) reduced COX-2, iNOS, and IL-1ß immunoreactivity 96 h after pMCAO. The neuroprotective properties of palmatine make it an excellent adjuvant treatment for strokes due to its inhibition of neuroinflammation.

Ginkgolides and Huperzine A for complementary treatment of Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by gradual deterioration of cognitive function, memory, and inability to perform daily, social, or occupational activities. Its etiology is associated with the accumulation of ß-amyloid peptides, phosphorylated tau protein, and neuroinflammatory and oxidative processes in the brain. Currently, there is no successful pharmacological treatment for AD. The few approved drugs are mainly aimed at treating the symptoms; however, due to the increasing discovery of etiopathological factors, there are great efforts to find new multifunctional molecules to slow down the course of this neurodegenerative disease. The commercial Ginkgo biloba formulation EGb 761® and Huperzine A, an alkaloid present in the plant Huperzia serrata, have shown in clinical trials to possess cholinergic and neuroprotective activities, including improvement in cognition, activities of daily living, and neuropsychiatric symptoms in AD patients. The purpose of this review is to expose the positive results of intervention with EGb 761® and Huperzine in patients with mild to moderate AD in the last 10 years, highlighting the pharmacological functions that justify their use in AD therapy.

Anti-Trypanosoma cruzi activity of alkaloids isolated from Habranthus brachyandrus (Amaryllidaceae) from Argentina.

BACKGROUND: Chagas disease, caused by the parasite Trypanosoma cruzi, affects over six million people worldwide, mainly in Latin American countries. Currently available drugs have variable efficacy in the chronic phase and significant side effects, so there is an urgent need for safer chemotherapeutic treatments. Natural products provide privileged structures that could serve as templates for the synthesis of new drugs. Among them, Amaryllidaceae plants have proved to be a potential natural source of therapeutical agents due to their rich diversity in alkaloids. PURPOSE: To identify alkaloids with anti-T. cruzi activity from Habranthus brachyandrus (Baker) Sealy (Amaryllidaceae, subfamily Amaryllidoideae) collected in Argentina. METHODS: An H. brachyandrus alkaloid extract was tested against T. cruzi, and its cytotoxicity profile was evaluated against two mammalian cell lines to ascertain its selectivity against the parasite and potential liver toxicity. It was also assessed by a stage-specific anti-amastigote assay and analysed by GC/MS to determine its alkaloid profile. The isolated alkaloids were also tested using the aforementioned assays. RESULTS: The extract showed high and specific activity against T. cruzi. The alkaloids lycoramine, galanthindole, 8-O-demethylmaritidine, 8-O-demethylhomolycorine, nerinine, trisphaeridine, deoxytazettine, and tazettamide were identified by means of GC-MS. In addition, hippeastidine (also named aulicine), tazzetine, ismine, and 3-epimacronine were isolated. The alkaloid ismine was specifically active against the parasite and had low toxicity against HepG2 cells, but did not show anti-amastigote activity. CONCLUSION: The extract had specific anti-T. cruzi activity and the isolated alkaloid ismine was partially responsible of it. These results encourage further exploration of H. brachyandrus alkaloids in search of novel starting points for Chagas disease drug development.

The naturally-derived alkaloids as a potential treatment for COVID-19: A scoping review.

Coronavirus disease 2019 (COVID-19) is caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which has a high mortality rate and transmissibility. In this context, medicinal plants have attracted attention due to the wide availability and variety of therapeutic compounds, such as alkaloids, a vast class with several proven pharmacological effects, like the antiviral and anti-inflammatory activities. Therefore, this scoping review aimed to summarize the current knowledge of the potential applicability of alkaloids for treating COVID-19. A systematic search was performed on PubMed and Scopus, from database inception to August 2021. Among the 63 eligible studies, 65.07% were in silico model, 20.63% in vitro and 14.28% clinical trials and observational studies. According to the in silico assessments, the alkaloids 10-hydroxyusambarensine, cryptospirolepine, crambescidin 826, deoxynortryptoquivaline, ergotamine, michellamine B, nigellidine, norboldine and quinadoline B showed higher binding energy with more than two target proteins. The remaining studies showed potential use of berberine, cephaeline, emetine, homoharringtonine, lycorine, narciclasine, quinine, papaverine and colchicine. The possible ability of alkaloids to inhibit protein targets and to reduce inflammatory markers show the potential for development of new treatment strategies against COVID-19. However, more high quality analyses/reviews in this field are necessary to firmly establish the effectiveness/safety of the alkaloids here described.

Isoquinolines alkaloids and cancer metabolism: Pathways and targets to novel chemotherapy.

Cancer is one of the main causes of death in the world. This is a complex disease where the development of resistance to chemotherapy is frequent driving the search for new anticancer compounds. In this sense, isoquinolines have gained attention in the past few years. This review aims to highlight the new advances related to the use of isoquinolines compounds against cancer cells, and we point out targets for their anti-tumor action. Isoquinolines are compounds found in plants that are important for their protection. In cancer, many representatives of this class of compounds have demonstrated their efficacy against cancer by acting on cancer metabolism, such as triggering cell death, reducing pro-survival protein expression, inducing ROS production, inhibiting pro-survival cell signaling pathways, among other effects. The mechanisms triggered by isoquinolines in cancer cells represent robust anticancer strategies, which support that this class of compounds are strong candidates for cancer treatment.

Piperine for treating breast cancer: A review of molecular mechanisms, combination with anticancer drugs, and nanosystems.

Piperine (PIP) is an alkaloid found primarily in Piper longum, and this natural compound has been shown to exert effects on proliferation and survival against various types of cancer. In particular, PIP has potent inhibitory effects on breast cancer (BC), the most prevalent type of cancer in women worldwide. PIP targets numerous signaling pathways associated with the therapy of BC cells through the following mechanisms: (a) induction of arrest of the cell cycle and apoptosis; (b) alteration of the signaling protein expression; (c) reduction in transcription factors; and (d) inhibition of tumor growth. BC cells have the ability to resist conventional drugs, so one of the strategies is the combination of PIP with other phytochemicals such as paclitaxel, thymoquinone, hesperidin, bee venom, tamoxifen, mitoxantrone, piperlongumin, and curcumin. Nanotechnology-based drug encapsulation systems are currently used to enhance the release of PIP. This includes polymer nanoparticles, carbon nanotubes, and liposomes. In the present review, the chemistry and bioavailability of PIP, its molecular targets in BC, and nanotechnological strategies are discussed. Future research directions are also discussed to further understand this promising natural product.

Effects of ayahuasca and its alkaloids on substance use disorders: an updated (2016-2020) systematic review of preclinical and human studies.

Ayahuasca is a hallucinogenic/psychedelic traditionally used for ritual and therapeutic purposes. One such therapeutic use is related to Substance Use Disorders (SUDs). A previous systematic review of preclinical and human studies published until 2016 suggested that ayahuasca and its alkaloids have therapeutic effects in the treatment of SUDs. To conduct an update of this previous review. A systematic review of quantitative studies which analyzed the effects of ayahuasca and its alkaloids on drug use (primary outcome) and other measures (secondary outcomes) related to SUDs was conducted, including articles from 2016 to 2020. Nine studies (four preclinical, five observational) were included in the review. Preclinical studies in rodents reported reductions in amphetamine self-administration and anxiety, and in alcohol- and methylphenidate-induced conditioned place preference. Observational studies among healthy ritual ayahuasca users and patients with SUDs reported reductions in drug use, anxiety, and depression, and increases in quality of life and well-being. We replicated the findings of the previous review suggesting that ayahuasca and its alkaloids have therapeutic effects in the treatment of SUDs. However, translation of preclinical data to humans is limited, observational studies do not allow us to infer causality, and there is a lack of standardization on ayahuasca doses. Although promising, randomized, controlled trials are needed to better elucidate these results. The PROSPERO ID for this study is CRD42020192046.

Marine alkaloids as bioactive agents against protozoal neglected tropical diseases and malaria.

Covering: 2000 up to 2021Natural products are an important resource in drug discovery, directly or indirectly delivering numerous small molecules for potential development as human medicines. Among the many classes of natural products, alkaloids have a rich history of therapeutic applications. The extensive chemodiversity of alkaloids found in the marine environment has attracted considerable attention for such uses, while the scarcity of these natural materials has stimulated efforts towards their total synthesis. This review focuses on the biological activity of marine alkaloids (covering 2000 to up to 2021) towards Neglected Tropical Diseases (NTDs) caused by protozoan parasites, and malaria. Chemotherapy represents the only form of treatment for Chagas disease, human African trypanosomiasis, leishmaniasis and malaria, but there is currently a restricted arsenal of drugs, which often elicit severe adverse effects, show variable efficacy or resistance, or are costly. Natural product scaffolds have re-emerged as a focus of academic drug discovery programmes, offering a different resource to discover new chemical entities with new modes of action. In this review, the potential of a range of marine alkaloids is analyzed, accompanied by coverage of synthetic efforts that enable further studies of key antiprotozoal natural product scaffolds.

In vitro anthelmintic evaluation of three alkaloids against gastrointestinal nematodes of goats.

This study assessed the in vitro anthelmintic activity of the alkaloids berberine, harmaline and piperine on gastrointestinal nematodes (GIN) of goat and their possible cytotoxic effects in Vero cells. The anthelmintic evaluation was performed using the egg hatch (EHA) and larval motility (LMA) assays. Cytotoxicity was determined using the 3- (4,5-dimethylthiazol-2-yl) -2,5-diphenyl-tetrazolium bromide (MTT) assay. The alkaloids berberine and piperine inhibited the hatching of GIN eggs in more than 90 %. Piperine was the most active compound against goat GIN eggs with an EC50 (effective concentration 50 %) of 0.0074 mM (0.0021 mg/mL), while the EC50 of berberine was 1.32 mM (0.49 mg/mL). Harmaline (EC50 = 1.6 mM - 0.34 mg/mL) showed moderate ovicidal action (80.30 %). In LMA, piperine and harmaline reduced larval motility in 2.75 and 25.29 %, respectively. Larvicidal efficacy was evidenced only with the alkaloid berberine, which showed a percentage of inhibition of larval motility of 98.17 % (2.69 mM =1.0 mg/mL). In the MTT assay, all alkaloids showed low toxicity to Vero cells, with a percentage of cell viability greater than 50 % in all concentrations tested. These results suggest that berberine and piperine have anthelmintic potential on goat gastrointestinal nematodes with low toxicity to mammalian cells.

Pharmacological characterisation of anticonvulsant effects elicited by erythrartine.

OBJECTIVES: The erythrinan alkaloids erythravine and 11α-hydroxy-erythravine from Erythrina verna (Vell.) have been extensively investigated for their anxiolytic and anticonvulsant effects. Both are structurally similar to the erythrartine that also exhibit anxiolytic effects, but there is no report on its anticonvulsant potential. Since some anxiolytic drugs can be useful in the management of epileptic seizures, we investigated whether erythrartine could prevent seizures induced by different chemoconvulsants. METHODS: Experiments were performed using different concentrations of erythrartine injected via intracerebroventricular in rats submitted to pilocarpine, kainic acid, pentylenetetrazol or picrotoxin-induced seizures. Moreover, the rotarod test was performed to verify the effects of erythrartine on animal motor coordination. RESULTS: Our data showed for the first time that erythrartine prevented the occurrence of seizures induced by all of the chemoconvulsants tested and did not affect locomotor performance neither produced sedative effect on animals. CONCLUSION: Obtained results validate the ethnopharmacological significance of E. verna and provide new information on erythrartine, another erythrinian alkaloid of biotechnological and medicinal interest.

Effectiveness of the piperine-supplemented Curcuma longa L. in metabolic control of patients with type 2 diabetes: a randomised double-blind placebo-controlled clinical trial.

There is robust evidence of using Curcuma longa L. in reducing metabolic levels in people with diabetes. This study analysed the effectiveness of Curcuma longa L. in the metabolic control of patients with type 2 diabetes in Brazil. A randomised double-blind placebo-controlled clinical trial was conducted with 71 participants divided into a Curcuma longa L. group (500 mg/day with piperine 5 mg) and a placebo group, for 120 days. Anthropometric, clinical and biochemical variables were evaluated at baseline, 60 and 120 days after the beginning of the intervention. Paired and independent Student's t-test and chi-square test were used for statistical analysis. The curcuma group presented a significantly decreased glycaemia (p=.013), glycated haemoglobin (p=.015), HOMA index (p=.037) and triglycerides (TGs) (p=.002). The use of piperine-added Curcuma longa L. was effective in the glycaemic and TG control of patients with type 2 diabetes.

The combination of coffee compounds attenuates early fibrosis-associated hepatocarcinogenesis in mice: involvement of miRNA profile modulation.

Aberrant microRNA expression implicates on hepatocellular carcinoma (HCC) development. Conversely, coffee consumption reduces by ~40% the risk for fibrosis/cirrhosis and HCC, while decaffeinated coffee does not. It is currently unknown whether these protective effects are related to caffeine (CAF), or to its combination with other common and/or highly bioavailable coffee compounds, such as trigonelline (TRI) and chlorogenic acid (CGA). We evaluated whether CAF individually or combined with TRI and/or CGA alleviates fibrosis-associated hepatocarcinogenesis, examining the involvement of miRNA profile modulation. Then, male C3H/HeJ mice were submitted to a diethylnitrosamine/carbon tetrachloride-induced model. Animals received CAF (50 mg/kg), CAF+TRI (50 and 25 mg/kg), CAF+CGA (50 and 25 mg/kg) or CAF+TRI+CGA (50, 25 and 25 mg/kg), intragastrically, 5×/week, for 10 weeks. Only CAF+TRI+CGA combination reduced the incidence, number and proliferation (Ki-67) of hepatocellular preneoplastic foci while enhanced apoptosis (cleaved caspase-3) in adjacent parenchyma. CAF+TRI+CGA treatment also decreased hepatic oxidative stress and enhanced the antioxidant Nrf2 axis. CAF+TRI+CGA had the most pronounced effects on decreasing hepatic pro-inflammatory IL-17 and NFκB, contributing to reduce CD68-positive macrophage number, stellate cell activation, and collagen deposition. In agreement, CAF+TRI+CGA upregulated tumor suppressors miR-144-3p, miR-376a-3p and antifibrotic miR-15b-5p, frequently deregulated in human HCC. CAF+TRI+CGA reduced the hepatic protein levels of pro-proliferative EGFR (miR-144-3p target), antiapoptotic Bcl-2 family members (miR-15b-5p targets), and the number of PCNA (miR-376a-3p target) positive hepatocytes in preneoplastic foci. Our results suggest that the combination of most common and highly bioavailable coffee compounds, rather than CAF individually, attenuates fibrosis-associated hepatocarcinogenesis by modulating miRNA expression profile.

Annonaceae Family Alkaloids as Agents Against Leishmaniasis: A Review and Molecular Docking Evaluation.

Leishmaniasis is a neglected disease that affects 15 million people worldwide. Existing treatments are associated with limitations, including high costs and toxicity. Several classes of natural substances have been reported to display leishmanicidal activity in the literature. Isoquinoline alkaloids, which are commonly found in the Annonaceae family, represent an important skeleton for the development of anti-leishmaniasis products. This study presents an overview of the potential use of Annonaceae alkaloids to treat leishmaniasis and describes a molecular docking study examining 215 isoquinoline alkaloids. All selected compounds contain a bisbenzyltetrahydroisoquinoline, suggesting the affinity of this skeleton for the target.

Warifteine and methylwarifteine inhibited the type 2 immune response on combined allergic rhinitis and asthma syndrome (CARAS) experimental model through NF-кB pathway.

CARAS is an airway inflammation of allergic individuals, with a type 2 immune response. The pharmacotherapy is based on drugs with relevant side effects. Thus, the goal of this study evaluated the alkaloids warifteine (War) and methylwarifteine (Mwar) from Cissampelos sympodialis in CARAS experimental model. Therefore, BALB/c mice were ovalbumin (OVA) sensitized and challenged and treated with both alkaloids. Treated animals showed a decrease (p < 0.05) of allergic signs as sneezing and nasal rubbings, histamine nasal hyperreactivity, and inflammatory cell migration into the nasal (NALF) and the bronchoalveolar (BALF) fluids, main eosinophils. In the systemic context, only Mwar reduced eosinophilia, however, both alkaloids reduced the serum levels of OVA-specific IgE. Histological analysis revealed that the alkaloids decreased the inflammatory cells into the subepithelial and perivascular regions of nasal tissue and the peribronchiolar and perivascular regions of lung tissue. Hyperplasia/hypertrophy of nasal and lung goblet cells were reduced in alkaloid treated animals; however, the treatment did not change the number of mast cells. The lung hyperactivity was attenuated by reducing hyperplasia of fibroblast and collagen fiber deposition and hypertrophy of the lung smooth muscle layer. The immunomodulatory effect was by decreasing of type 2 and 3 cytokines (IL-4/IL-13/IL-5 and IL-17A) dependent by the increasing of type 1 cytokine (IFN-γ) into the BALF of treated sick animals. Indeed, both alkaloids reduced the NF-кB (p65) activation on granulocytes and lymphocytes, indicating that the alkaloids shut down the intracellular transduction signals underlie the transcription of TH2 cytokine gens.

Neuroprotective effects and improvement of learning and memory elicited by erythravine and 11α-hydroxy-erythravine against the pilocarpine model of epilepsy.

Deficits in cognitive functions are often observed in epileptic patients, particularly in temporal lobe epilepsy (TLE). Evidence suggests that this cognitive decline can be associated with the occurrence of focal brain lesions, especially on hippocampus and cortex regions. We previously demonstrated that the erythrinian alkaloids, (+)-erythravine and (+)-11α-hydroxy-erythravine, inhibit seizures evoked in rats by different chemoconvulsants. AIMS: The current study evaluated if these alkaloids would be acting in a neuroprotective way, reducing hippocampal sclerosis, and consequently, improving learning/memory performance. MAIN METHODS: Here we confirmed the anticonvulsant effect of both alkaloids by means of the pilocarpine seizure-induced model and also showed that they enhanced spatial learning of rats submitted to the Morris Water Maze test reverting the cognition deficit. Additionally, immunohistochemistry assays showed that neuronal death and glial activation were prevented by the alkaloids in the hippocampus CA1, CA3 and dentate gyrus regions at both hemispheres indistinctly 15 days after status epilepticus induction. KEY FINDINGS: Our results show, for the first-time, the improvement on memory/learning elicited by these erythrinian alkaloids. Furthermore, data presented herein explain, at least partially, the cellular mechanism of action of these alkaloids. Together, (+)-erythravine and (+)-11α-hydroxy-erythravine seem to be a promising protective strategy against TLE, comprising three main aspects: neuroprotection, control of epileptic seizures and cognitive improvement. SIGNIFICANCE: Moreover, our findings on neuroprotection corroborate the view that seizure frequency and severity, hippocampal lesions and memory deficits are interconnected events.

CDK2 and Bcl-xL inhibitory mechanisms by docking simulations and anti-tumor activity from piperine enriched supercritical extract.

Supercritical fluid technologies offer an innovative method for food industry and drug discovery from natural sources. The aim of the study is to investigate the anti-tumor activity of piperine rich extract by supercritical fluid (SFE) from black pepper (Piper nigrum). In silico docking simulations predicted anti-tumor molecular mechanism and protein-piperine hydrophobic interactions, showing hydrogen bonds between piperine and residue Ser5 inside the ATP binding site in CDK2. Moreover, piperine interacts with peptide substrate residue Lys8 inside its binding site in Cyclin A molecule. Other predicted interaction showed piperine inside the hydrophobic groove of Bcl-xL. Confirming the docking simulation, in vitro assays with SFE (40 °C/30 MPa) showed cytotoxicity to MCF-7 cells (IC50 = 27.8 ±â€¯6.8 µg/ml) correlated to increased apoptosis. Balb/c mice-bearing Ehrlich Ascites Carcinoma (EAC) group that received the SFE (100 mg/kg/day) showed tumor growth inhibition (60%) and increased mice survival (50%), probably related to cell cycle arrest (G2/M) and increased apoptosis. In vivo treatments with SFE increased the expression of pro-apoptotic proteins (p53 and Bax), inhibited cell cycle proteins (CDK2, Cyclin A) and anti-apoptotic protein (Bcl-xL). Thus, confirming in silico predicted inhibitory interactions. These results clearly showed promising performance of the piperine-rich fraction recovered from black pepper, drawing attention to its use as complementary therapy for cancer.

Antinociceptive and antioxidant effects of extract enriched with active indole alkaloids from leaves of Tabernaemontana catharinensis A. DC.

ETHNOPHARMACOLOGICAL RELEVANCE: Ethnopharmacological knowledge is important for the identification of active compounds from natural products. Pain may have different aetiologies with complex mechanisms. Tabernaemontana catharinensis A. DC. is well known for indole alkaloids, being used empirically in folk medicine, with antimicrobial and anti-inflammatory as well as antiofidic actions among others. AIM OF THE STUDY: This work aims to evaluate the antinociceptive and antioxidant effect in mice of the alkaloids extract from leaves of Tabernaemontana catharinensis A. DC. (AITc). MATERIALS AND METHODS: The AITc was produced by ultrasound and acid-base extraction, and the chemical composition was evaluated by high resolution mass spectrometry. Male mice (Mus musculus), Swiss, were used for in vivo tests. The AITc was administrated at doses of 1.0, 5.0, and 10.0 mg/kg in acetic acid model, formalin, tail-immersion, hot plate, and open field tests, and compared to saline, morphine, or diazepam controls, depending on the test. The toxicological, biochemical, haemogram and antioxidant effect were evaluated in mouse organs such as liver, brain, kidneys, spleen and stomach. RESULTS: In total, 10 compounds were identified in the AITc, being from the indole alkaloids from the ibogan and corynanthean classes. The extract in doses ranging from 5.0 to 10.0 mg/kg showed an antinociceptive effect for acetic acid, inhibiting by 47.7% and 61.6%. In the same line, reductions of 47.1% (first phase) and 43.6% (second phase) were observed for the 5.0 mg/kg dose in the formalin test. However, tail-immersion and hot plate tests did not show considerable modifications in the latency period, while in the open field test there was an inhibition of only 5.1%. It was observed no differences in NO levels and total antioxidant status of the mice in any of the studie tissues. CONCLUSIONS: The results justify the use of this plant in traditional medicine. in vivo tests indicate that these compounds possess central and peripheral mechanisms of action. This is study that reports the nociceptive action of these alkaloids, also including toxicity tests, which are intended to guarantee the safety of use of extracts of this plant.