I'm confused as to what you are searching for.
Especially since you are using multiple instances of "*"
--- Which with regex are rarely necessary, and frequently will mangle your search results.

[[:alnum:];.] ---> means match *ANYTHING*

You haven't escaped the period. and it will match any char.
Possibly you meant:
[[:alnum:];\.]

But then, this: ([[:alnum:];\.])*
Means match any alphanumeric plus semi-colon plus a dot any number of times, or not at all. Meaning it will also match empty lines - that only have a carriage return.

Possibly, what you meant as your regex:
Quote: