Hi Sumit,

Thanks for your question. I don't think there is a single tool that can address converting unstructured text into ontologies. Natural language is not annotated and requires a lot of work to extract concepts and their relationship - ideally being solved with an objective function.

So building ontologies is an active field of research (one step at a time). This is only my perspective, and love to hear your thoughts on this. To answer your question, maybe this paper proves to be a good starting point.

https://datascience.codata.org/articles/10.5334/dsj-2018-023