I think the confusion of whether curcumin passes the BBB or not ,lies in the health of the BBB you are testing. If you say 100 % represents the low permeability of a healthy person, and 60% represents a typical advanced PWP,then this difference may show curcumin doesn't pass the 100% membrane, but does pass the 60%. As far as I am aware, not one of the researchers who publish on pass or no pass, have measured the permeability of the BBB they are testing. I have managed 3 research centres in my time, in the USA and UK. This is the sort of fundemental error that is typical of your average researcher.

Ron