One of my colleagues found out a solution for this.
First we have to create a Site workflow for this.Not a list workflow for site feed.
In the site workflow we have to create a loop.
In the workflow first we have to create an infinite loop and wait for a item adding event for Microfeed list.
Then in the email action we can add lookups for the attributes in the item.
In the add look up window we can use following settings to get the values in the item.
Save and publish the workflow. Now it will send an email to the users mentioned in the workflow once a new post is added to the site feed/news feed/micro feed.