assertion  retraction  graph  subject          predicate        object           datatype    annotation
1          0           graph  obo:CHEBI_26401  rdfs:label       purines          xsd:string  
1          0           graph  obo:CHEBI_26401  oio:id           CHEBI:26401      xsd:string  
1          0           graph  obo:CHEBI_26401  rdfs:subClassOf  obo:CHEBI_35875  _IRI        
1          0           graph  obo:CHEBI_26401  rdf:type         owl:Class        _IRI