Generating API documentation with JSDoc and markdown for node.js

I am new to node.js and trying to use grunt JSDoc plugin to generate API documentation. I am also trying to specify markdown comments; however, documentation HTML files are not correctly generated from markdown comment - they are generated as if they are written regularly. I can see that markdown plugin is definitely invoked (had put some logging statements there).

My JSDoc conf file looks like:

{
    "plugins"   : ["plugins/markdown"],
    "markdown"  : {
        "parser"   : "gfm",
        "hardwrap" : true
    },
    // Using docstrap for templating
}

My comment in the function looks like:

/**
this is sample function description
* list item1
* list item2
Also some code sample
    object.func(arg1)
@param arg1
@return
*/

Cannot find any other help anywhere. Looked for many node modules to find some example without any success.