Piperine can actually help with the absorption of curcumin, the active anti-inflammatory ingredient of tumeric. It is therefor important to include black pepper in with curries to maximize its health benefits.
It likely also helps with the absorption of other hydrophobic compounds in other spices as well.
some chemical compounds that make spices very special, sometimes with each other can neutralize.
why is black pepper important in the curry? maybe not all chefs know that, because the recipe is gained from generation to generation without scientific study.
thanks for your comment.