curcumin

This term refers specifically to the primary bioactive compound extracted from the rhizome of Curcuma longa. In scientific and medical literature, it is distinguished from turmeric, which is the whole spice containing various compounds including curcuminoids.

As a chemical substance and a specific molecular entity, it is treated as an uncountable noun. It does not have a plural form in standard usage, as it refers to the substance itself rather than individual units.