Yes, it can. <a href=”http://technet.microsoft.com/en-us/library/aa998614%28EXCHG.140%29.aspx”>http://technet.microsoft.com/en-us/library/aa998614%28EXCHG.140%29.aspx</a>:
One of the big new feature areas in Exchange 2010 is our integration with Active Directory Rights Management Services (AD RMS). This integration allows administrators to protect sensitive information automatically using transport rules. This protection ensures that your information is kept secure and confidential (using persistent encryption on the e-mail and attachments) while also allowing you to control how users actually interact with content. For example, you can send RMS e-mail that is “Do Not Forward” preventing users from forwarding the e-mail within or outside of the organization.