This is most definitely an XY problem. Sounds like you want to do something like the following, but you haven't really said what you are trying to do.

# Tokenise
my @tokens = $doc =~ /<[^>]*>|./sg;

# Extract text
my @text_tokens = grep /^<|<[0-9]+>/, @tokens;

# Do stuff with @text_tokens
# ...

# Print resulting text
print join('', @text_tokens);
[download]

or maybe

# Tokenise
my @tokens = $doc =~ /<[^>]*>|./sg;

# Extract text
my $text = '';
for (@tokens) {
   if    (/^<([0-9]+)>/) { $text .= chr($1); }
   elsif (/^[^<]/)       { $text .= $1;      }
}

# Do stuff with $text
# ...

# Print resulting text
print join('', $text);
[download]

Or do you need to output back in the original format (e.g. with bold tags in)?

Update: Added second snippet.