Abstract
Black rice is a functional food that is high in anthocyanin content, primarily C3G and P3G. It possesses nutraceutical properties that exhibit a range of beneficial effects on human health. Currently, the spike glycoprotein S1 subunit of SARS-CoV-2 (SP) has been reported for its contribution to pathological inflammatory responses in targeting lung tissue and innate immune cells during COVID-19 infection and in the long-COVID phenomenon. Our objectives focused on the health benefits of the C3G and P3G-rich fraction of black rice germ and bran (BR extract) on the inhibition of inflammatory responses induced by SP, as well as the inhibition of NF-kB activation and the NLRP3 inflammasome pathway in an in vitro model. In this study, BR extract was identified for its active anthocyanins, C3G and P3G, using the HPLC technique. A549-lung cells and differentiated THP-1 macrophages were treated with BR extract, C3G, or P3G prior to exposure to 100 ng/mL of SP. Their anti-inflammatory properties were then determined. BR extract at concentrations of 12.5-100 μg/mL exhibited anti-inflammation activity for both A549 and THP-1 cells through the significant suppression of NLRP3 , IL-1β , and IL-18 inflammatory gene expressions and IL-6, IL-1β, and IL-18 cytokine secretions in a dose-dependent manner ( p < 0.05). It was determined that both cell lines, C3G and P3G (at 1.25-10 μg/mL), were compatibly responsible for the significant inhibition of SP-induced inflammatory responses for both gene and protein levels ( p < 0.05). With regard to the anti-inflammation mechanism, BR extract, C3G, and P3G could attenuate SP-induced inflammation via counteraction with NF-kB activation and downregulation of the inflammasome-dependent inflammatory pathway proteins (NLRP3, ASC, and capase-1). Overall, the protective effects of anthocyanins obtained from black rice germ and bran can be employed in potentially preventive strategies that use pigmented rice against the long-term sequelae of COVID-19 infection.
Keywords: C3G; COVID-19; NLRP3 inflammasome; P3G; anthocyanins; anti-inflammation; black rice; post-acute COVID; spike glycoprotein S1.
【저자키워드】 COVID-19, Anti-inflammation, NLRP3 inflammasome, anthocyanins, C3G, P3G, black rice, post-acute COVID, spike glycoprotein S1., 【초록키워드】 SARS-CoV-2, Inflammation, Macrophage, Gene Expression, macrophages, Inflammatory responses, IL-6, spike glycoprotein, Anti-inflammation, NLRP3 inflammasome, NF-kB, Protein, Protective effects, Health, COVID-19 infection, pathway, immune cells, long-COVID, Innate immune cells, Inflammasome, HPLC, mechanism, protective effect, A549, NLRP3, IL-1β, Inflammatory response, Concentration, S1 subunit, Inflammatory, cell lines, black rice, exposure to, health benefits, functional food, black, Activation, dose-dependent manner, lung tissue, fraction, downregulation, protein level, protein levels, IL-18, in vitro model, cytokine secretion, Effect, benefit, Cell, THP-1, anthocyanin, bran, counteraction, responsible, reported, exhibited, treated, functional, was determined, attenuate, anti-inflammatory property, ASC, innate immune cell, 【제목키워드】 SARS-CoV-2, spike, inhibition, response, black, THP-1, Rice, Germ,