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R-CMD-check CRAN status DEV version

extractox is a comprehensive R package designed to simplify querying various chemical, toxicological, and biological databases:

  • the Integrated Chemical Environment (ICE) of the National Toxicology Program (NTP).
  • the Integrated Risk Information System (IRIS) of the Environmental Protection Agency (EPA).
  • the Provisional Peer-Reviewed Toxicity Values (PPRTVs) of EPA.
  • the Computational Toxicology Chemicals Dashboard Resource Hub (CompTox) of EPA,
  • the monographs of International Agency for Research on Cancer of the World Health Organization (WHO).
  • PubChem of the National Center for Biotechnology Information/National Institutes Of Health (NCBI, NIH).
  • the Comparative Toxicogenomics Database (CTP) of the MDI Biological Laboratory and NC State University.

The package facilitates interaction with APIs, providing curated and user-friendly outputs. To communicate with Pubchem, extractox relies on the packagewebchem.

Installation

Install the package extractox from CRAN.

# From CRAN
install.packages("extractox")

Development Version

To get a bug fix or to use a feature from the development version, you can install the development version of extractox from GitHub.

# Install pak if not already installed
if (!requireNamespace("pak", quietly = TRUE)) {
  install.packages("pak")
}

# Install the package from GitHub
pak::pkg_install("c1au6i0/extractox")

Features

NTP’s ICE

The ICE database provides access to a variety of data related to chemical toxicity, exposure, and risk assessment. It includes data from high-throughput screening assays, in vivo studies, and computational models.

extr_ice provides access to NTP’s ICE database for toxicological and exposure-related data.

library(extractox)
# assays is null so all assays are retrieved
ice_data <- extr_ice(casrn = c("50-00-0"), assays = NULL, verbose = FALSE)
names(ice_data)
#>  [1] "assay"                 "endpoint"              "substance_type"       
#>  [4] "casrn"                 "qsar_ready_id"         "value"                
#>  [7] "unit"                  "species"               "receptor_species"     
#> [10] "route"                 "sex"                   "strain"               
#> [13] "life_stage"            "tissue"                "lesion"               
#> [16] "location"              "assay_source"          "in_vitro_assay_format"
#> [19] "reference"             "reference_url"         "dtxsid"               
#> [22] "substance_name"        "pubmed_id"             "query"

There are more than 2000 possible assays in ICE. The extr_ice_assay_names() function allows to search for assay names that match a pattern you’re interested in. Please note that searches are case sensitive and accept regexp.

extr_ice_assay_names("Rat Acute", verbose = FALSE) # keep empty to retrieve all
#> [1] "Rat Acute Oral Toxicity"         "Rat Acute Inhalation Toxicity"  
#> [3] "Rat Acute Dermal Toxicity"       "CATMoS, Rat Acute Oral Toxicity"

EPA’s IRIS

The IRIS database contains information on the health effects of exposure to various substances found in the environment. It provides qualitative and quantitative health risk information.

extr_iris provides access to EPA’s IRIS database and accepts queries CASRN or IUPAC names of chemicals.

iris_info <- extr_iris(c("glyphosate", "50-00-0"), verbose = FALSE)
names(iris_info)
#> [1] "chemical_name"                 "casrn"                        
#> [3] "exposure_route"                "assessment_type"              
#> [5] "critical_effect_or_tumor_type" "woe_characterization"         
#> [7] "toxicity_value_type"           "toxicity_value"               
#> [9] "query"

EPA’s PPRTVs

The extr_pprtv function allows you to extract data for specified identifiers (CASRN or chemical names) from the EPA’s PPRTVs database. This function retrieves the file containing all the chemicals and processes it, but if has an argument (force) to allow users to use a cached file or force a fresh download.

# Example usage to extract data for a specific CASRN
dat_pprtv_1 <- extr_pprtv(ids = "107-02-8", search_type = "casrn", verbose = FALSE)

# Example usage to extract data for a chemical name
dat_pprtv_2 <- extr_pprtv(ids = "Acrolein", search_type = "name", verbose = FALSE)

EPA’s CompTox

The CompTox Chemistry Dashboard provides access to data on chemical structures, properties, and associated bioactivity data. It integratesdata from various sources to support chemical safety assessments.

extr_comptox extracts data from CompTox using either CASRN or IUPAC names of chemicals and returns a list of dataframes.

info_comptox <- extr_comptox(ids = c("Aspirin", "50-00-0"), verbose = FALSE)
names(info_comptox)
#> [1] "comptox_cover_sheet"           "comptox_main_data"            
#> [3] "comptox_abstract_sifter"       "comptox_synonym_identifier"   
#> [5] "comptox_related_relationships" "comptox_toxcast_assays_ac50"  
#> [7] "comptox_toxval_details"        "comptox_chemical_properties"

WHO’s IARC

The IARC Monographs database contains evaluations of the carcinogenic risks of various substances to humans. It provides detailed information about Monographs, including publication volumes and years, evaluation years, and additional relevant details.

The function extr_monograph provides access to the WHO IARC Monographs database and accepts queries using CASRN or the names of chemicals.

dat <- extr_monograph(
  search_type = "casrn",
  ids = c("105-74-8", "120-58-1"),
  verbose = FALSE
)
str(dat)
#> 'data.frame':    2 obs. of  8 variables:
#>  $ casrn                  : chr  "105-74-8" "120-58-1"
#>  $ agent                  : chr  "Lauroyl peroxide" "Isosafrole"
#>  $ group                  : chr  "3" "3"
#>  $ volume                 : chr  "36, Sup 7, 71" "10, Sup 7"
#>  $ volume_publication_year: chr  "1999" "1987"
#>  $ evaluation_year        : int  1998 1987
#>  $ additional_information : chr  "" ""
#>  $ query                  : chr  "105-74-8" "120-58-1"

# Example usage for name search
dat2 <- extr_monograph(
  search_type = "name",
  ids = c("Aloe", "Schistosoma", "Styrene")
)
#> ℹ Extracting WHO IARC monographs...
#> Last updated: 2024-11-29 5:08pm (CET)

NIH’s PubChem

PubChem provides information on chemical structures, identifiers, chemical and physical properties, biological activities, safety and toxicity information, patents, literature citations, and more.

A series of functions that rely on the webchem package are used to extract chemical information, Globally Harmonized System (GHS) classification data, or flavor classification (FEMA) from PubChem.

The function extr_chem_info retrieves chemical information of IUPAC-named chemicals. A warning is displayed if the chemical is not found.

chem_info <- extr_chem_info(
  iupac_names = c("Formaldehyde", "Aflatoxin B1"),
  verbose = FALSE
)
names(chem_info)
#>  [1] "cid"                         "iupac_name"                 
#>  [3] "casrn"                       "cid_all"                    
#>  [5] "casrn_all"                   "molecular_formula"          
#>  [7] "molecular_weight"            "canonical_smiles"           
#>  [9] "isomeric_smiles"             "inchi"                      
#> [11] "inchi_key"                   "iupac_name"                 
#> [13] "x_log_p"                     "exact_mass"                 
#> [15] "monoisotopic_mass"           "tpsa"                       
#> [17] "complexity"                  "charge"                     
#> [19] "h_bond_donor_count"          "h_bond_acceptor_count"      
#> [21] "rotatable_bond_count"        "heavy_atom_count"           
#> [23] "isotope_atom_count"          "atom_stereo_count"          
#> [25] "defined_atom_stereo_count"   "undefined_atom_stereo_count"
#> [27] "bond_stereo_count"           "defined_bond_stereo_count"  
#> [29] "undefined_bond_stereo_count" "covalent_unit_count"        
#> [31] "volume3d"                    "x_steric_quadrupole3d"      
#> [33] "y_steric_quadrupole3d"       "z_steric_quadrupole3d"      
#> [35] "feature_count3d"             "feature_acceptor_count3d"   
#> [37] "feature_donor_count3d"       "feature_anion_count3d"      
#> [39] "feature_cation_count3d"      "feature_ring_count3d"       
#> [41] "feature_hydrophobe_count3d"  "conformer_model_rmsd3d"     
#> [43] "effective_rotor_count3d"     "conformer_count3d"          
#> [45] "fingerprint2d"               "query"

Two functions are used to extract specific sections of PubChem chemical information using CASRN:

  • extr_pubchem_ghs extracts GHS codes.
  • extr_pubchem_fema extracts FEMA data.
ghs_info <- extr_pubchem_ghs(casrn = c("50-00-0", "64-17-5"), verbose = FALSE)
fema_info <- extr_pubchem_fema(casrn = c("50-00-0", "123-68-2"), verbose = FALSE)

Tox Info

The function extr_tox is a wrapper used to call all the above-mentioned functions and retrieve a list of dataframes.

info_tox <- extr_tox(casrn = c("Aspirin", "50-00-0"), verbose = FALSE)

MDI’s CTD

The CTP provides information about the interactions between chemicals, genes, and diseases. It helps in understanding the effects of environmental exposures on human health.

A series of functions interact with the CTP database.

extr_ctd extracts information related to chemical-gene or pathway associations.

input_terms <- c("50-00-0", "64-17-5", "methanal", "ethanol")
ctd_association <- extr_ctd(
  input_terms = input_terms,
  category = "chem",
  report_type = "genes_curated",
  input_term_search_type = "directAssociations",
  action_types = "ANY",
  ontology = c("go_bp", "go_cc"),
  verbose = FALSE
)

names(ctd_association)
#> [1] "chemical_name" "chemical_id"   "casrn"         "gene_symbol"  
#> [5] "gene_id"       "organism"      "organism_id"   "pubmed_ids"   
#> [9] "query"

# Get expresssion data
ctd_expression <- extr_ctd(
  input_terms = input_terms,
  report_type = "cgixns",
  category = "chem",
  action_types = "expression",
  verbose = FALSE
)

names(ctd_expression)
#>  [1] "chemical_name" "chemical_id"   "casrn"         "gene_symbol"  
#>  [5] "gene_id"       "organism"      "organism_id"   "pubmed_ids"   
#>  [9] "query"         NA              NA

Tetramers are computationally generated information units that interrelate four data types from the CTP: a chemical, gene product, phenotype, and disease. They help in understanding the complex relationships between these entities and their combined impact on human health.

extr_tetramer extracts info related to tetramers from CTD.

tetramer_data <- extr_tetramer(
  chem = c("50-00-0", "ethanol"),
  disease = "",
  gene = "",
  go = "",
  input_term_search_type = "directAssociations",
  qt_match_type = "equals",
  verbose = FALSE
)

names(tetramer_data)
#> [1] "chemical"     "chemical_id"  "gene"         "gene_id"      "phenotype"   
#> [6] "phenotype_id" "disease"      "disease_id"   "query"

Important Note for Linux Users

Please note that functions that pull data from EPA servers may encounter issues on some Linux systems. This is because these servers do not accept secure legacy renegotiation. On Linux system, those functions depend on curl and OpenSSL, which have known problems with unsafe legacy renegotiation in newer versions. One workaround is to downgrade to curl v7.78.0 and OpenSSL v1.1.1. However, please be aware that using these older versions might introduce potential security vulnerabilities. Refer to this gist for instructions on how to downgrade curl and OpenSSL on Ubuntu.