Shankar,
I would not consider may recommendation as an answer. However, until MathWorks adds all text elements to 'tex' and 'latex' interpreters for App Designer labels, I have been stacking labels to create the appearance of subscript and/or superscript text in my labels.
My primary label with spacing included:
My stacked labels. I reduced the font size for the labels displaying "min" and "max", then placed them over my primarly labels.
Hopefully this techinique or something similar will suffice until the interpreters can handle sub- and superscripts.
