Yeah, I've tried pretty high doses of curcumin. Usually 500mg a cap, twice a day, and either mixed with bioperine (black pepper extract for supposedly better absorption--this is added to other supplements also) or phosphatidylcholine (an oil base complex for supposedly better absorption). I believe it is hard to absorb, or make the curcurmin biologically available, unless taken with fatty/oily food.
Not so sure what effect this has had; I just felt I should take some kind of anti-inflammatory. Curcumin seems to keep mounting praise for a variety of health effects (brain/cardio/inflam...).
As for the blueberry extracts, I haven't researched or tried them. I know most proanthocyanin (probably spelled wrong) containing, purple/blue fruits, are supposed to help generally with colon health. Things like aronia berry and black raspberries are supposed to be really good in that dept. For any marked effect, these things probably need to be eated 3x a day.
Some ?perhaps shoddy? wikipedia info on bioperine states that it slows metabolism of some supplements/drugs to allow longer bioactivity:
"Notably, piperine may enhance bioavailability of curcumin by 2000% in humans.[12]"Shoba G, Joy D, Joseph T, Majeed M, Rajendran R, Srinivas PS (May 1998). "Influence of piperine on the pharmacokinetics of curcumin in animals and human volunteers". Planta Med. 64 (4): 353–6. doi:10.1055/s-2006-957450. PMID 9619120.