Well, to just get the message and email address in a naive way you could do (untested)

my ($message,$email)=m{^-S\s* "([^"]*)" \s* (.*)}x;
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BUT this way you don't allow any escaped " in your message string. i.e. something like "hi, that \" char is difficult". If you change [^"]* to .* then it would allow escaped ", but then you would get into trouble if the email address had any " char in it, for example "John Doe" <doe@wo.com>.

Also note there is no real checking if the email address comforms to any email address standard. If you only expect doe@wo.com style addresses, that could be parsed with something like [^@]+@[^@]+, but to parse any valid email address you should use a module like Mail::Address.

If you get this line from unknown sources, there are more things to consider, depending on what you want to do