This research can be true for curry in Thailand. Unless curcumin is included in Japanese-tasted curry, we can't expect the effectiveness of curry served in most restaurants in Japan.
As far as I know, 3 types of curry are available around my university. A students' cafeteria, a chain of curry restaurants called 'Karee CoCo Ichibanya' ,and 'UPHAR INDO KITCHEN' run by Indian chefs are major 3 restaurants.
So, around my university, UPHAR INDO KITCHEN is most likely to serve curry containing curcumin on the assumption that Indian food should similar to Thai food.
