So I contacted a potential supervisor yesterday on phone to discuss possible graduate supervision. He told me to send an email with my profile so that we can discuss. He hasn't replied my email since. When do you guys think I should send him a gentle reminder or call him. P.S. I have notices he's very busy and doesn't check his mails regularly. Need your advice guys!

I'd give it at least a week before contacting him, as you say he's busy and also needs time to read and think through your email.