What do you want to do with them in a different part of the program? The primes just indicate that the collection of letters are a single string rather than 5 independent chars 'H', 'o', 'r', 's', 'e', but even as single chars you get the primes too to indicate a char rather than a variable or function name.
By the way, you should be using a cell array to have separate strings there as e.g.
C={'Horse' 'Apple' 'House' 'Van'}.
Your version will concatenate all those into a single string.
