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

Abstract

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.

Bioactive components, antioxidative and anti‐inflammatory properties (on RAW 264.7 macrophage cells) of soaked and germinated purple rice extracts

“…Also, Petroni et al . () observed no growth effects on the macrophage cells with red and black rice extracts (125 μ m ). There is almost no information on the effects of soaked and germinated pigmented rice extracts on the viability and NO inhibition of the 264.7 RAW macrophage cells.…”

“…The TPC, TFC and TCC observed in this study (1.46 ± 0.11, 2.23 ± 0.07 and 2.08 ± 0.09 mg BE/100 g) were higher than those reported by Petroni et al . () who compared bioactive components of black/purple, red and white rice varieties. In their study, they observed that the black rice exhibited higher values for bioactive components with TPC 678 mg GAE/100 g compared with red rice (372.7 mg GAE/100 g) and brown rice (30.5–101.3 mg GAE/100 g); TFC 300 mg QE/100 g compared to red rice (200 mg QE/100 g) and brown rice (<100 mg QE/100 g); TCC 232.8 μg/100 g compared to red rice (20.59 μg/100 g) with no carotenoid detected in brown rice.…”

“…Limtrakul et al (2016Limtrakul et al ( , 2015 reported that red and black rice extracts even at a higher concentration of 200 lg mL À1 had no significant effect on the cell viability of the macrophage cell. Also, Petroni et al (2017) observed no growth effects on the macrophage cells with red and black rice extracts (125 lM). There is almost no information on the effects of soaked and germinated pigmented rice extracts on the viability and NO inhibition of the 264.7 RAW macrophage cells.…”

“…dark purple, red and black rice). This is because these coloured varieties contain polyphenols in their bran layers (Petroni et al, 2017). The black and purple varieties have been studied to contain mainly anthocyanins (Gamel et al, 2018), while the red rice mainly contain pro-anthocyanidins (Samaranayake et al, 2017).…”

The Genetic Basis and Nutritional Benefits of Pigmented Rice Grain

“…Analysis of extracts made from pigmented rice grain has shown that the phenolic compounds tocopherol and anthocyanin are efficient neutralizers of reactive oxygen species (Zhang et al, 2015;Ghasemzadeh et al, 2018), while animal tests have proven that these compounds are bioavailable (Tantipaiboonwong et al, 2017). Several studies have shown that the elevated anti-oxidation activity exhibited by pigmented rice grains (most markedly by black rice) can be used to mitigate the inflammatory response (Chakuton et al, 2012;Petroni et al, 2017).…”