Hello,
regrettably, there is no such macro or eval(). It is possible to use them only if they are document type properties (which you fill in on the Form tab). You can consider specifying 'title' on the Form tab.
In your current scenario, you can use the mentioned API method in:
a. a custom macro:
Macros - the 'Custom macro' section. Then you can enter the macro to the web part properties.
b. a custom form control for a new web part property which you will use instead of Content before:
Developing form controlsBest regards,
Helena Grulichova