Detect end of email

Am writing a code in php. I get emails to parse in my app. I need to detect end of email, like if you reply any email on yahoo, email body and response both comes in inbox. In this response i only need to get the repl开发者_运维技巧y part .

Similarly there are long signatures at end of email like name, address and some notes. I don't need them . I just need the response part . How an this be achieved ???

The only way you are going to do this is by starting and ending the content of the email with the same "known" text ... ie something you have placed there and you can search for.