有没有一种解码html实体的方法，同时使用PHP单独留下 等？

I am using tinyMCE as my text editor on my site and i want to reformat the text before saving it to my database (changing the &rsquo; tags into ' then in to &#39;). I cannot find a simple way of doing this using tinyMCe and using htmlentities() changes everything including <>. Any ideas?I am using tinyMCE as my text editor on my site