姜黄素（Curcumin）是得自姜科植物姜黄（C.longa L.）根茎的一种黄色成份，具有降血脂、利胆及抑菌等作用。市售品种较多，姜黄素含量报导不一，而测定方法多采用在420nm波长测定黄色素的方法。420nm为末端吸收，测定结果不稳定，且受其他黄色素干扰。 Curcumin is a yellow component derived from the rhizome of C. longa L., which has the effects of reducing blood fat, gallbladder and bacteriostasis. There are many varieties available on the market, and the contents of curcumin are reported in different ways. The method of determination of yellow pigment at the wavelength of 420 nm is often used for the determination method. Absorption at the end of 420 nm results in an unstable measurement and is disturbed by other yellow pigments.