Proximate Composition, Polyphenol Content and Anti-inflammatory Properties of White and Pigmented Italian Rice Varieties

Rice (Oryza sativa L.) is a major staple food for the majority of the world population. Grown and harvested as paddy, it is present on our tables as white rice (milled), brown rice (dehusked) or, after being subjected to thermal processes, as parboiled rice. Recently, pigmented varieties are also appreciated (red and black rice). In this study, we evaluated proximate composition, polyphenol content and anti-inflammatory properties of Italian pigmented rice varieties and bran as well as white rice in different processed forms (milled, parboiled and integral), in order to assess the nutritional and antioxidant properties of Italian rice varieties and their capacity to reduce inflammation. Our results showed that pigmented rice varieties displayed high antioxidant capacity along with the highest flavonoid and polyphenol content. Anthocyanins were mainly present in black rice, whereas alkylresorcinols were found only in red rice. Rice bran proved to be particularly rich in carotenoids. The evaluation of the anti-inflammatory properties using lipopolysaccharide (LPS)-induced mouse RAW 264.7 macrophages pre-treated with extracts obtained from integral, black, red rice and bran showed that the expression of inducible Nitric Oxide Synthase (iNOS) was specifically reduced at both transcript and protein level by extracts, indicating the capacity of rice extracts to modulate the inflammatory response.