You can use forEach loop :

const commentArray = [];

array.forEach(function(object) {

    var comment = object.Comments;

    commentArray.push(comment);

});

//You can store all comments in another array and use it...

console.log("This is comment array...", commentArray);

Or use map but it will work in new browsers possibly ones following ES6:

const commentArray = array.map(function(object) {

    return object.Comments;

});

console.log("This is comment array... ", commentArray);