Bioactive Coumarins and Xanthones From Calophyllum Genus and Analysis of Their Druglikeness and Toxicological Properties

Calophyllum spp. (Calophyllaceae) is a genus of tropical trees valued in the chemopharmacological industry as an important source of biogenetically related coumarins and xanthones, which can lead to the development of new drugs due to their relevant pharmacological activities and diversity of molecular structural. These compounds have relevant pharmacological activities, such as: cytotoxicity against human tumor cell lines (especially leukemia), parasites (Plasmodium, Leshmania, and Trypanosoma), retroviruses (e.g., HIV), and Mycobacterium tuberculosis. Chemoinformatic and toxicoinformatic tools were used here to perform a computational analysis of 70 coumarins and 70 xanthones isolated from this genus in order to explore their potential as new drugs. Most coumarins from this genus possess similar patterns of druglikeness with differences in its physicochemical properties. Xanthones, on the other hand, show quite similar physicochemical properties and druglikeness. It is interesting to note that the vast majority of these compounds (57 coumarins and 59 xanthones) are in compliance with Lipinski´s Rule of Five. Remarkably, two xanthones (2-hydroxyxanthone and caledonixanthone-B) have leadlikeness potential that accordingly with chemoinformatic analysis may target MAO A and B, respectively, and therefore may exhibit antidepressant potential. These compounds also target tyrosine-phosphorilation-regulated kinase 1A (DYRK1A) which is over-expressed in a variety of hematological and brain cancers, therefore they could act as anticancer compounds. Several toxicological predictions were also depicted. Coumarins could be an irritant and may affect the reproductive system, while xanthones may have mutagenic results. To our knowledge, this is the first chemoinformatic report on the main active compounds of this genus and its potential for drug development.

Multi-parametric profiling network based on gene expression and phenotype data: a novel approach to developmental neurotoxicity testing

The establishment of more efficient approaches for developmental neurotoxicity testing (DNT) has been an emerging issue for children’s environmental health. Here we describe a systematic approach for DNT using the neuronal differentiation of mouse embryonic stem cells (mESCs) as a model of fetal programming. During embryoid body (EB) formation, mESCs were exposed to 12 chemicals for 24 h and then global gene expression profiling was performed using whole genome microarray analysis. Gene expression signatures for seven kinds of gene sets related to neuronal development and neuronal diseases were selected for further analysis. At the later stages of neuronal cell differentiation from EBs, neuronal phenotypic parameters were determined using a high-content image analyzer. Bayesian network analysis was then performed based on global gene expression and neuronal phenotypic data to generate comprehensive networks with a linkage between early events and later effects. Furthermore, the probability distribution values for the strength of the linkage between parameters in each network was calculated and then used in principal component analysis. The characterization of chemicals according to their neurotoxic potential reveals that the multi-parametric analysis based on phenotype and gene expression profiling during neuronal differentiation of mESCs can provide a useful tool to monitor fetal programming and to predict developmentally neurotoxic compounds.

Integrating mechanistic and polymorphism data to characterize human genetic susceptibility for environmental chemical risk assessment in the 21st century

Response to environmental chemicals can vary widely among individuals and between population groups. In human health risk assessment, data on susceptibility can be utilized by deriving risk levels based on a study of a susceptible population and/or an uncertainty factor may be applied to account for the lack of information about susceptibility. Defining genetic susceptibility in response to environmental chemicals across human populations is an area of interest in the NAS' new paradigm of toxicity pathway-based risk assessment. Data from high-throughput/high content (HT/HC), including -omics (e.g., genomics, transcriptomics, proteomics, metabolomics) technologies, have been integral to the identification and characterization of drug target and disease loci, and have been successfully utilized to inform the mechanism of action for numerous environmental chemicals. Large-scale population genotyping studies may help to characterize levels of variability across human populations at identified target loci implicated in response to environmental chemicals. By combining mechanistic data for a given environmental chemical with next generation sequencing data that provides human population variation information, one can begin to characterize differential susceptibility due to genetic variability to environmental chemicals within and across genetically heterogeneous human populations. The integration of such data sources will be informative to human health risk assessment.

The role of molecular biology in the biomonitoring of human exposure to chemicals

Exposure to different substances in an occupational environment is of utmost concern to global agencies such as the World Health Organization and the International Labour Organization. Interest in improving work health conditions, particularly of those employees exposed to noxious chemicals, has increased considerably and has stimulated the search for new, more specific and selective tests. Recently, the field of molecular biology has been indicated as an alternative technique for monitoring personnel while evaluating work-related pathologies. Originally, occupational exposure to environmental toxicants was assessed using biochemical techniques to determine the presence of higher concentrations of toxic compounds in blood, urine, or other fluids or tissues; results were used to evaluate potential health risk. However, this approach only estimates the presence of a noxious chemical and its effects, but does not prevent or diminish the risk. Molecular biology methods have become very useful in occupational medicine to provide more accurate and opportune diagnostics. In this review, we discuss the role of the following common techniques: (1) Use of cell cultures; (2) evaluation of gene expression; (3) the “omic” sciences (genomics, transcriptomics, proteomics and metabolomics) and (4) bioinformatics. We suggest that molecular biology has many applications in occupational health where the data can be applied to general environmental conditions.