Centos 6
wget http://download.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
rpm -ivh epel-release-6-8.noarch.rpm
yum install php-pecl-mailparse
Centos 7
wget http://dl.fedoraproject.org/pub/epel/beta/7/x86_64/epel-release-7-0.2.noarch.rpm
wget http://dl.fedoraproject.org/pub/epel/7/x86_64/e/epel-release-7-5.noarch.rpm
rpm -ivh epel-release-7-0.2.noarch.rpm
yum install php-pecl-mailparse
Other examples:
yum --enablerepo=epel install php-pecl-mailparse
yum --enablerepo=remi install php-mailparse -y
yum --enablerepo=remi install php-imap -y