The MathExt library was made to parse and calculate formulas of any complexity. It can easily be integrated into web applications. As developer you can set all kind of settings. You can even specify what commands should be available to the user.
Danaides stores meta-data from biological banks in a graph databases as well as OBO formatted ontologies.
It also provides a web query interface to parse ontologies or extract nodes based on ontology requirements.
Example: Get all known elements that are in family of Fish (species ontology) AND a RNA (sequence ontology).