my @target_words = qw/list of words/;  # or read from a file, or whatever
my $joined_targets = join "|", @target_words;
my $match_regex = qr/\b($joined_targets)\b/;

for my $file ( @file_list ) {
    open( F, "<", $file );
    while (<F>) {
        if ( /$match_regex/ ) {
            my $mathed_word = $1;
            store_to_db( $file, $matched_word );
            last;
        }
    }
    close F;
}