Differential toxicity and teratogenic effects of the hot water and cold water extracts of Lignosusrhinocerus (Cooke) Ryvarden sclerotium on zebrafish (Danio rerio) embryos.

ETHNOPHARMACOLOGICAL RELEVANCE: The sclerotium of Lignosusrhinocerus (Cooke) Ryvarden is highly valued for its purported medicinal properties. The decoction and macerated materials prepared from the sclerotium are used for treating cancer and other ailments based on extensive traditional knowledge. Scientific evidence from in vitro cytototoxicity, anti-inflammatory and immunomodulatory analyses showed the effectiveness of sclerotial water extracts but toxicity assessment of such preparations has not been reported. AIM OF THE STUDY: This study aimed to compare the differential toxicity and teratogenicity (if any) of the hot water (HW) and cold water (CW) extracts of both wild and cultivated sclerotium on zebrafish (Danio rerio) embryos. MATERIALS AND METHODS: Zebrafish embryos were treated with varying concentrations of the sclerotial HW and CW extracts (0.3-500 µg/mL) for 72 h until hatching. The hatching, mortality and heartbeat rate of the embryos as well as the potential teratogenic effect of the extracts were assessed in embryos post-treatment with the extracts. RESULTS: While the sclerotial HW extracts were nontoxic (LC50 > 500 µg/mL), the sclerotial CW extracts delayed the hatching of the embryos up to 48 h and showed slight toxicity with LC50 values of 398.4 µg/mL and 428.3 µg/mL for the cultivated and wild sclerotium, respectively. The sclerotial CW extracts also induced minor tachycardia in zebrafish larvae. Phenotypic assessment revealed that, while yolk sac edema was observed at high concentrations (300 and 500 µg/mL) of all extracts, curved trunk and bent tail were only observed in the embryos treated with CW extracts of wild sclerotium (300 and 500 µg/mL) but not for CW extracts of cultivated sclerotium at similar concentrations. CONCLUSION: The sclerotial water extracts of L.rhinocerus prepared using different methods have varying degree of toxicity and teratogenicity in zebrafish embryos with the sclerotial CW extracts showed higher toxicity than the HW extracts.

Virtual screening and in vitro validation of natural compound inhibitors against SARS-CoV-2 spike protein.

The COVID-19 pandemic caused by the SARS-CoV-2 virus has led to a major public health burden and has resulted in millions of deaths worldwide. As effective treatments are limited, there is a significant requirement for high-throughput, low resource methods for the discovery of novel antivirals. The SARS-CoV-2 spike protein plays a key role in viral entry and has been identified as a therapeutic target. Using the available spike crystal structure, we performed a virtual screen with a library of 527 209 natural compounds against the receptor binding domain of this protein. Top hits from this screen were subjected to a second, more comprehensive molecular docking experiment and filtered for favourable ADMET properties. The in vitro activity of 10 highly ranked compounds was assessed using a virus neutralisation assay designed to facilitate viral entry in a physiologically relevant manner via the plasma membrane route. Subsequently, four compounds ZINC02111387, ZINC02122196, SN00074072 and ZINC04090608 were identified to possess antiviral activity in the µM range. These findings validate the virtual screening method as a tool for identifying novel antivirals and provide a basis for future drug development against SARS-CoV-2.

Safety assessment of natural products in Malaysia: current practices, challenges, and new strategies.

The belief that natural products are inherently safe is a primary reason for consumers to choose traditional medicines and herbal supplements for health maintenance and disease prevention. Unfortunately, some natural products on the market have been found to contain toxic compounds, such as heavy metals and microbes, as well as banned ingredients such as aristolochic acids. It shows that the existing regulatory system is inadequate and highlights the importance of thorough safety evaluations. In Malaysia, the National Pharmaceutical Regulatory Agency is responsible for the regulatory control of medicinal products and cosmetics, including natural products. For registration purpose, the safety of natural products is primarily determined through the review of documents, including monographs, research articles and scientific reports. One of the main factors hampering safety evaluations of natural products is the lack of toxicological data from animal studies. However, international regulatory agencies such as the European Food Safety Authority and the United States Food and Drug Administration are beginning to accept data obtained using alternative strategies such as non-animal predictive toxicological tools. Our paper discusses the use of state-of-the-art techniques, including chemometrics, in silico modelling and omics technologies and their applications to the safety assessments of natural products.

Pharmacological Approaches to Attenuate Inflammation and Obesity with Natural Products Formulations by Regulating the Associated Promoting Molecular Signaling Pathways.

Obesity is a public health problem characterized by increased body weight due to abnormal adipose tissue expansion. Bioactive compound consumption from the diet or intake of dietary supplements is one of the possible ways to control obesity. Natural products with adipogenesis-regulating potential act as obesity treatments. We evaluated the synergistic antiangiogenesis, antiadipogenic and antilipogenic efficacy of standardized rebaudioside A, sativoside, and theasaponin E1 formulations (RASE1) in vitro in human umbilical vein endothelial cells (HUVECs), 3T3-L1 preadipocytes respectively, and in vivo using a high-fat and carbohydrate diet-induced obesity mouse model. Orlistat was used as a positive control, while untreated cells and animals were normal controls (NCs). Adipose tissue, liver, and blood were analyzed after dissection. Extracted stevia compounds and green tea seed saponin E1 exhibited pronounced antiobesity effects when combined. RASE1 inhibited HUVEC proliferation and tube formation by suppressing VEGFR2, NF-κB, PIK3, and-catenin beta-1 expression levels. RASE1 inhibited 3T3-L1 adipocyte differentiation and lipid accumulation by downregulating adipogenesis- and lipogenesis-promoting genes. RASE1 oral administration reduced mouse body and body fat pad weight and blood cholesterol, TG, ALT, AST, glucose, insulin, and adipokine levels. RASE1 suppressed adipogenic and lipid metabolism gene expression in mouse adipose and liver tissues and enhanced AMP-activated protein kinase levels in liver and adipose tissues and in serum adiponectin. RASE1 suppressed the NF-κB pathway and proinflammatory cytokines IL-10, IL-6, and TNF-α levels in mice which involve inflammation and progression of obesity. The overall results indicate RASE1 is a potential therapeutic formulation and functional food for treating or preventing obesity and inflammation.

Spike protein recognizer receptor ACE2 targeted identification of potential natural antiviral drug candidates against SARS-CoV-2.

Angiotensin-converting enzyme 2 (ACE2), also known as peptidyl-dipeptidase A, belongs to the dipeptidyl carboxydipeptidases family has emerged as a potential antiviral drug target against SARS-CoV-2. Most of the ACE2 inhibitors discovered till now are chemical synthesis; suffer from many limitations related to stability and adverse side effects. However, natural, and selective ACE2 inhibitors that possess strong stability and low side effects can be replaced instead of those chemicals' inhibitors. To envisage structurally diverse natural entities as an ACE2 inhibitor with better efficacy, a 3D structure-based-pharmacophore model (SBPM) has been developed and validated by 20 known selective inhibitors with their correspondence 1166 decoy compounds. The validated SBPM has excellent goodness of hit score and good predictive ability, which has been appointed as a query model for further screening of 11,295 natural compounds. The resultant 23 hits compounds with pharmacophore fit score 75.31 to 78.81 were optimized using in-silico ADMET and molecular docking analysis. Four potential natural inhibitory molecules namely D-DOPA (Amb17613565), L-Saccharopine (Amb6600091), D-Phenylalanine (Amb3940754), and L-Mimosine (Amb21855906) have been selected based on their binding affinity (-7.5, -7.1, -7.1, and -7.0 kcal/mol), respectively. Moreover, 250 ns molecular dynamics (MD) simulations confirmed the structural stability of the ligands within the protein. Additionally, MM/GBSA approach also used to support the stability of molecules to the binding site of the protein that also confirm the stability of the selected four natural compounds. The virtual screening strategy used in this study demonstrated four natural compounds that can be utilized for designing a future class of potential natural ACE2 inhibitor that will block the spike (S) protein dependent entry of SARS-CoV-2 into the host cell.

Species selection for nonclinical safety assessment of drug candidates: Examples of current industry practice.

In drug development, nonclinical safety assessment is pivotal for human risk assessment and support of clinical development. Selecting the relevant/appropriate animal species for toxicity testing increases the likelihood of detecting potential effects in humans, and although recent regulatory guidelines state the need to justify or dis-qualify animal species for toxicity testing, individual companies have developed decision-processes most appropriate for their molecules, experience and 3Rs policies. These generally revolve around similarity of metabolic profiles between toxicology species/humans and relevant pharmacological activity in at least one species for New Chemical Entities (NCEs), whilst for large molecules (biologics) the key aspect is similarity/presence of the intended human target epitope. To explore current industry practice, a questionnaire was developed to capture relevant information around process, documentation and tools/factors used for species selection. Collated results from 14 companies (Contract Research Organisations and pharmaceutical companies) are presented, along with some case-examples or over-riding principles from individual companies. As the process and justification of species selection is expected to be a topic for continued emphasis, this information could be adapted towards a harmonized approach or best practice for industry consideration.

Computational study on new natural compound agonists of dopamine receptor.

Dopamine receptor, a polypeptide chain composed of 7 hydrophobic transmembrane regions, is a new and vital drug target, especially Dopamine receptor 2(D2). Targeting dopamine receptors, Dopamine receptor agonists are a class of drugs similar in function and structure to dopamine and can directly act on dopamine receptors and activate it. Clinically, Dopamine receptor agonist drugs have achieved significant therapeutic effects on prolactinoma and Parkinson's Disease. In the study, we virtually screened a series of potential effective agonists of Dopamine receptor by computer techniques. Firstly, we used the Molecular Docking (LibDock) step to screen out some molecules that can dock well with the protein. Then, analysis of toxicity prediction and ADME (adsorption, distribution, metabolism and excretion) were carried out. More precise molecular docking (CDOCKER) and 3-Dimensional Quantitative Structure-Activity Relationship Modeling Study(3D-QSAR) pharmacophore generation were implemented to research and explore these compounds' binding mechanism with Dopamine receptor. Last but not least, to assess compound's binding stabilities, we carried out a molecular dynamic analysis. As the results show, two compounds (ZINC000008860530 and ZINC000004096987) from the small molecule database (ZINC database) were potential effective agonists of Dopamine receptor. These two compounds can combine with Dopamine receptor with higher affinity and proved to be no toxic. The cell experiment showed that two compounds could inhibit the proliferation and PRL secretion of MMQ cells (pituitary tumor cells). Thus, this study provided valuable information about Dopamine receptor agonist-based drug discovery. So, this study will benefit patients with prolactinoma and Parkinson's disease a lot.

Perspectives on natural compounds in chemoprevention and treatment of cancer: an update with new promising compounds.

Cancer is the second deadliest disease worldwide. Although recent advances applying precision treatments with targeted (molecular and immune) agents are promising, the histological and molecular heterogeneity of cancer cells and huge mutational burdens (intrinsic or acquired after therapy) leading to drug resistance and treatment failure are posing continuous challenges. These recent advances do not negate the need for alternative approaches such as chemoprevention, the pharmacological approach to reverse, suppress or prevent the initial phases of carcinogenesis or the progression of premalignant cells to invasive disease by using non-toxic agents. Although data are limited, the success of several clinical trials in preventing cancer in high-risk populations suggests that chemoprevention is a rational, appealing and viable strategy to prevent carcinogenesis. Particularly among higher-risk groups, the use of safe, non-toxic agents is the utmost consideration because these individuals have not yet developed invasive disease. Natural dietary compounds present in fruits, vegetables and spices are especially attractive for chemoprevention and treatment because of their easy availability, high margin of safety, relatively low cost and widespread human consumption. Hundreds of such compounds have been widely investigated for chemoprevention and treatment in the last few decades. Previously, we reviewed the most widely studied natural compounds and their molecular mechanisms, which were highly exploited by the cancer research community. In the time since our initial review, many promising new compounds have been identified. In this review, we critically review these promising new natural compounds, their molecular targets and mechanisms of anticancer activity that may create novel opportunities for further design and conduct of preclinical and clinical studies.

Prediction of oral hepatotoxic dose of natural products derived from traditional Chinese medicines based on SVM classifier and PBPK modeling.

The risk of drug-induced liver injury (DILI) poses a major challenge for development of natural products derived from traditional Chinese medicines (NP-TCMs). It is urgent to find a new method for the safety assessment of the NP-TCMs. Recent study has reported an in vitro/in silico method to estimate the acceptable daily intake of hepatotoxic compounds using support vector machine (SVM) classifier and physiologically based pharmacokinetic (PBPK) modeling. However, this method is not suitable for estimating the dosing schedule of compounds which are administered in multiple daily doses. Thus, in this study, the method mentioned above was in particular optimized, and used to estimate the hepatotoxic plasma concentrations of 17 NP-TCMs. Additionally, the oral dosing schedules of the triptolide, emodin, matrine and oxymatrine were also predicted by the SVM classifier and PBPK modeling. The optimization included that: (1) in vitro cytotoxicity data of 28 training set compounds was optimized using benchmark concentrations (BMC) modeling; (2) AUC of the training set compound was used as the in vivo metric instead of Cmax to better reflect the total daily exposure of compounds which are administered in multiple daily doses; (3) using the mean AUC in plasma as in vivo metric and BMC value as in vitro metric could achieve the better toxicity separation index (0.962 vs. 0.938); (4) The TSI for Cmax and BMC values was 0.985 calculated in this study, and the results indicated that BMC modeling improved the separation performance. This optimized in vitro-in vivo extrapolation (IVIVE) workflow could extrapolate in vitro BMC to blood concentrations and the oral dosing schedule which are corresponding to certain risk of hepatotoxicity. The estimated safe dosing schedule of oxymatrine by this optimized method was close to the clinical recommended dosing regimen. The results indicate that the optimized method could be used to predict the dosing schedule of compounds administered in multiple daily doses, and our optimized workflow could be helpful for the safety assessment as well as the research and development on NP-TCMs.

A Phosphonate Natural Product Made by Pantoea ananatis is Necessary and Sufficient for the Hallmark Lesions of Onion Center Rot.

Pantoea ananatis is the primary cause of onion center rot. Genetic data suggest that a phosphonic acid natural product is required for pathogenesis; however, the nature of the molecule is unknown. Here, we show that P. ananatis produces at least three phosphonates, two of which were purified and structurally characterized. The first, designated pantaphos, was shown to be 2-(hydroxy[phosphono]methyl)maleate; the second, a probable biosynthetic precursor, was shown to be 2-(phosphonomethyl)maleate. Purified pantaphos is both necessary and sufficient for the hallmark lesions of onion center rot. Moreover, when tested against mustard seedlings, the phytotoxic activity of pantaphos was comparable to the widely used herbicides glyphosate and phosphinothricin. Pantaphos was also active against a variety of human cell lines but was significantly more toxic to glioblastoma cells. Pantaphos showed little activity when tested against a variety of bacteria and fungi.IMPORTANCEPantoea ananatis is a significant plant pathogen that targets a number of important crops, a problem that is compounded by the absence of effective treatments to prevent its spread. Our identification of pantaphos as the key virulence factor in onion center rot suggests a variety of approaches that could be employed to address this significant plant disease. Moreover, the general phytotoxicity of the molecule suggests that it could be developed into an effective herbicide to counter the alarming rise in herbicide-resistant weeds.

In silico evaluation of multispecies toxicity of natural compounds.

Natural compounds are widely explored in industries, as a lead compound. Evaluating their toxicity is of utmost importance, as they may cause other side effects. The major hassles in evaluating the toxicity of compounds through in vivo and in vitro methods such as time, money, workforce, and use of animal models can be overcome by computational methods. Quantitative structure-activity relationship (QSAR) models predict the toxicity from the structure of a compound. In the present study, the methanolic extracts of three plants, namely, Carissa carandas, Canthium angustifolium, and Epiphyllum oxypetalum, were subjected to Gas Chromatography-Mass Spectrometry (GC-MS), in which 27 different compounds were identified. The compounds were evaluated for their toxicity through QSAR-Toxicity Estimation Software Tool (TEST) against multispecies - Daphnia magna, Pimephales promelas, Tetrahymena pyriformis, and rat (Oral). The study revealed that the order of toxicity of the natural compounds was D. magna > T. pyriformis > P. promelas > Rat (Oral). All the compounds were non-bioaccummulative, while most of them were developmental toxicants. Only one compound (Dasycarpidan-1-methanol, acetate (ester)) was a mutagen. Further studies of the compounds on in vivo models are recommended after in silico analysis, for exploration in different industries.

Industry experiences with immune-mediated findings in biotherapeutic nonclinical toxicology studies.

With the growth of monoclonal antibodies and other proteins as major modalities in the pharmaceutical industry, there has been an increase in pharmacology and toxicity testing of biotherapeutics in animals. Animals frequently mount an immune response to human therapeutic proteins. This can result in asymptomatic anti-drug antibody formation, immune complexes that affect drug disposition and/or organ function such as kidney, cytokine release responses, fatal hypersensitivity, or a range of reactions in between. In addition, an increasing number of oncology therapeutics are being developed that enhance or directly stimulate immune responses by a variety of mechanisms, which could increase the risk of autoreactivity and an autoimmune-like syndrome in animals and humans. When evaluating the risk of biotherapeutics prior to entering the clinic, the nonclinical safety data may include any of these responses and it is critical to understand whether they represent a safety liability for humans. The DruSafe Leadership group of the IQ Consortium conducted a survey of industry to understand sponsors' experiences with these immune reactions in nonclinical studies related to both immunogenicity and pharmacologically-mediated immune perturbations. The survey covered what pathways were affected, how the immune responses were presented, how the company and health authorities interpreted the data and whether the immune responses were observed in the clinic. Additionally, the survey gathered information on association of these findings with anti-drug antibodies as well as sponsor's use of immunogenicity predictive tools. The data suggests that the ability of a biotherapeutic to activate the immune system, intended or not, plays a significant role on characteristics of the response and whether theys are translatable.

Toxicological safety evaluation of the cultivated Chinese cordyceps.

ETHNOPHARMACOLOGICAL RELEVANCE: The Chinese cordyceps, a parasitic Thitarodes insect-Ophiocordyceps sinensis fungus complex in the Qinghai-Tibet Plateau, is one of the most valuable traditional Chinese medicines and health food for ameliorating conditions associated with aging and for treating fatigue, night sweats, hyperglycemia, hyperlipidemia, respiratory, renal and liver diseases, and hyposexuality. The natural Chinese cordyceps resource is rare due to its harsh growing environment, limited geographical distribution and global climate warming. Artificial cultivation of Chinese cordyceps has been successfully established to meet its high demand in market. AIMS OF THE STUDY: The present study aims to evaluate the toxicological safety of the cultivated Chinese cordyceps and provide scientific data for subsequent development and utilization of this valuable biological resource. MATERIALS AND METHODS: The Chinese cordyceps was cultivated by mimicking the habitat environment in low-altitude areas and identified by morphological and microscopic characteristics. Its phytochemical profile was determined by the HPLC. Toxicological studies based on the cultivated Chinese cordyceps were conducted, including chromosomal aberration test of Chinese hamster lung (CHL) cells, Ames test, acute toxicity test and micronucleus (MN) test of bone marrow cells. RESULTS: The Chinese cordyceps successfully cultivated in low-altitude areas exhibited the same morphological and microscopic characteristics as natural Chinese cordyceps. The adenosine content was in accordance with the Chinese Pharmacopoeia (2015 Edition). The HPLC fingerprint was determined and five main chromatographic peaks representing uracil, uridine, inosine, guanosine and adenosine were identified. No dose-dependent increase in the rates of chromosomal aberration was detected in the presence or absence of metabolic activation system. Ames test also demonstrated no dose-dependent increase in the number of reversion mutation for five bacterial strains, with or without rat liver microsomal enzyme mixture (S9) metabolic activation, at a quantity range of 128-5000 µg cultivated Chinese cordyceps per plate. The acute toxicity test with mice showed that after 20 g/kg oral administration of cultivated Chinese cordyceps, neither animal death nor any abnormal change in general dissection of various tissues and organs of the animals were found within 14 days. The median lethal dose (LD50) was greater than 5 g/kg, which is regarded as a non-toxic level, and maximum tolerable dose (MTD) of cultivated Chinese cordyceps in ICR mice was more than 20 g/kg. MN test of mouse bone marrow cells indicated no significant differences among each sample dose and the negative control. CONCLUSION: Based on the results from four toxicological tests, it was concluded that the cultivated Chinese cordyceps was classified as non-toxic in one single administration at high doses by intragastric route in mice. This study provides scientific experimental basis for its safety.

Gamma irradiation for enhancing active chemical compounds in leaf extracts of Libidibia ferrea (Leguminosae).

This research was designed to evaluate the influence of the irradiation process of the leaf extracts of Libidibia ferrea (Leguminosae) on the production of secondary chemical compounds, including their biological activity. Leaves were collected and prepared to obtain the crude extract, which was then aliquoted and separately exposed to a Co-60 source with different doses, namely: 5, 7, 10, 12, 15, 20, 25, and 30 kGy. From irradiated and control samples, tests of toxicity were carried out with the microcrustacea Artemia salina Leach at three moments: 24 h, 60 and 180 days after the irradiation of the samples. Bioassays showed an increase in the toxicity of the irradiated extracts, correlated with the dose. The toxicity level did not change with the storage time, indicating the excellent stability of the samples. To assess the phytochemical profile of the crude and irradiated extracts, three techniques were employed: thin-layer chromatography (TLC), liquid chromatography coupled to mass spectrometry (LC-MS), and gas chromatography coupled to mass spectrometry (GC-MS). The phytochemical results emphasized the presence of phenols, tannins, and triterpenes. The analytical tests confirmed the role of ionizing radiation in breaking down macromolecules into simpler chemical species responsible for increasing chemical activity of the extract. This report presents and discusses ionizing radiation as an outstanding tool for enhancing active chemical compounds in leaf extracts of Libidibia ferrea, which reflects on their biochemical properties.

The strategies and techniques of drug discovery from natural products.

Natural products have been the main sources of new drugs. The different strategies have been developed to find the new drugs based on natural products. The traditional and ethic medicines have provided information on the therapeutic effects and resulted in some notable drug discovery of natural products. The special activities of the medicine plants such as the side effects have inspired scientists to develop the novel small molecular. The microorganisms and the endogenous active substances from human or animal also become the important approaches to the drug discovery. The tremendous progress in technology led to the new strategies in drug discovery from natural products. The bioinformation and artificial intelligence have facilitated the research and development of natural products. We will provide a scene of strategies and technologies for drug discovery from natural products in this review.

Stem cells in natural product and medicinal plant drug discovery-An overview of new screening approaches.

Natural products remain a rich source of new drugs, and the search for bioactive molecules from nature continues to play an important role in the development of new medicines. Also, there is increasing use of herbal medicines for the treatment of a plethora of diseases, and demands for more scientific evidence for their efficacy and safety remains a huge challenge. The propensity of stem cells to differentiate into almost every cell type not only holds promise for the delivery of cell-based therapies for currently incurable diseases or a useful tool in studying cell physiology and pathophysiology. Increasingly, stem cells are becoming an important tool in preclinical drug screening and toxicity testing. In this review, we examine the scientific advances made towards the use of pluripotent stem cells as a model for the screening of plant-based medicines. The combination of well-established in vitro electrophysiological and a plethora of toxicogenomic technologies, together with the optimisation of culture methods of herbal plants and pluripotent stem cells can be explored to establish the basis for efficacy, and tissue/organ-based toxicities of many currently used medicinal plants whose efficacies and toxicities remain unknown.

A 26-week toxicological study of Xuezhikang (XZK), red yeast rice extract, in Beagle dogs with a 4-week recovery period.

Xuezhikang (XZK) is an extract derived from red yeast rice that is commonly used to treat cardiovascular conditions as a traditional Chinese medicine, both within China and globally. Genotoxicity, acute toxicity, and a 26-week toxicity study in rat have been reported in our previous publication. The present study was designed to assess the long-term safety of XZK when administered orally to dogs. Dogs were treated with encapsulated XZK at a maximum dose of 2000 mg/kg followed by 1000 mg/kg and 500 mg/kg (n = 6/sex/group) for this 26-week oral toxicity study. Control animals were given an empty capsule. Treated animals were then monitored through measurements of body weight, body temperature, food intake, ophthalmic and electrocardiogram examinations, general clinical observations, mortality rates, and clinical and anatomic pathological findings. Additionally, blood samples were collected and used to conduct hematological and biochemical analysis. Several abnormalities were found in all groups including: fecal abnormalities (including mucoid, poorly formed, or liquid feces). Moreover, reduced CHOL and TRIG values were seen in all XZK groups (p < 0.05), increased WBC and NEUT levels in 500 mg/kg group (males only, p < 0.05), and elevated AST, ALT, and ALP activities in 2000 mg/kg group (p < 0.05). These changes were resolved in the recovery period. The results indicated that XZK may temporarily impact the liver enzyme levels, but were not considered adverse effects. These findings yielded a NOAEL for XZK in dogs of 2000 mg/kg.

Naphthylisoquinoline alkaloids, validated as hit multistage antiplasmodial natural products.

The discovery and development of multistage antimalarial drugs targeting intra-erythrocytic asexual and sexual Plasmodium falciparum parasites is of utmost importance to achieve the ambitious goal of malaria elimination. Here, we report the validation of naphthylisoquinoline (NIQ) alkaloids and their synthetic analogues as multistage active antimalarial drug candidates. A total of 30 compounds were tested, of which 17 exhibited IC50 values <1 µM against drug-sensitive P. falciparum parasites (NF54 strain); 15 of these retained activity against a panel of drug-resistant strains. These compounds showed low in vitro cytotoxicity against HepG2 cells, with selectivity indices of >10. The tested compounds showed activity in vitro against both early- and late-stage P. falciparum gametocytes while blocking male gamete formation (>70% inhibition of exflagellation at 2 µM). Additionally, five selected compounds were found to have good solubility (≥170 µM in PBS at pH 6.5), while metabolic stability towards human, mouse, and rat microsomes ranged from >90% to >7% after 30 min. Dioncophylline C (2a) emerged as a front runner from the study, displaying activity against both asexual parasites and gametocytes, a lack of cross-resistance to chloroquine, good solubility, and microsomal stability. Overall, this is the first report on the multistage activity of NIQs and their synthetic analogues including gametocytocidal and gametocidal effects induced by this class of compounds.

A scientometric visualization analysis for global toxicology and pharmacology research of natural products from 1962 to 2018.

BACKGROUND: A growing number of studies have been focused on the medicinal potential of natural products since 1962, while few scholars have analyzed the existing documents comprehensively. PURPOSE: Aiming to visualize the researches on toxicology and pharmacology of natural products (TPNP) published between 1962 and 2018, as well as to reveal their spatiotemporal patterns, a scientometric analysis with 3210 relevant documents collected from Web of Science was conducted in this study. RESULTS: The most prominent contributors of TPNP research are mainly from the USA, China, Brazil, India and Germany. The knowledge domains of TPNP research focus mainly on the topics of (1) traditional Chinese medicine, (2) richardia grandiflora, (3) chemical conversion, (4) new generation, (5) modern medicine, (6) intelligent mixture, (7) hplc-based activity. Most countries have recognized the pharmaceutical potential of natural products, and have paid more attention to the pharmacological and toxicological characteristics of natural products in the past decade. Future TPNP research tends to focus more on complex analysis of mechanisms for diseases treatment, such as toxicology and pharmacology. CONCLUSION: This research has firstly demonstrated a comprehensive knowledge map for the existing toxicological and pharmacological researches of natural products, which offered essential instructions on medical application of natural products to future research.