Yes, I think that no formalized arabic ontologies do exist, but there are many research works in the filed of Arabic knowledge extraction. My question is about the usage of NLP tools in knowledge extraction approaches.
Mohamed Mahdi Boudabous, Lamia Hadrich Belguith et Fatiha Sadat, Exploiting Arabic Wikipedia for automatic construction of a lexical ontology, International Journal of Metadata, Semantics and Ontologies (IJMSO), Vol. 8, No. 1, 2013.