Red rice bran extract (RRBE) is rich in phytonutrients and has been shown to have anti-diabetic, anti-inflammatory, and antioxidant properties. However, its anti-hepatic steatosis and anti-dyslipidemic properties have not been thoroughly investigated. This study examined the aforementioned properties of RRBE, the underlying mechanism by which it alleviated non-alcoholic fatty liver disease in high-fat diet (HFD)-fed mice, and its major bioactive constituents. The mice were divided into four groups based on their diet: (1) low-fat diet (LFD), (2) LFD with high-dose RRBE (1 g/kg/day), (3) HFD, and (4) HFD with three different doses of RRBE (0.25, 0.5, and 1 g/kg/day). The administration of RRBE, especially at medium and high doses, significantly mitigated HFD-induced hepatosteatosis and concomitantly improved the serum lipid profile. Further, RRBE modified the level of expression of lipid metabolism-related genes (adipose triglyceride lipase (ATGL), cluster of differentiation 36 (CD36), lipoprotein lipase (LPL), liver X receptor alpha (LXRα), sterol regulatory element-binding protein-1c (SREBP-1c), SREBP-2, 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), and carnitine palmitoyltransferase 1A (CPT1A)) in hepatic or adipose tissues and improved the expression of hepatic high-density lipoprotein cholesterol (HDL-C) cmetabolism-related genes (hepatic lipase (HL) and apolipoprotein A-ǀ (ApoA-ǀ)). RRBE also attenuated markers of liver injury, inflammation, and oxidative stress, accompanied by a modulated expression of inflammatory (nuclear factor-kappa B (NF-κB) and inducible nitric oxide synthase (iNOS)), pro-oxidant (p47^phox), and apoptotic (B-cell lymphoma protein 2 (Bcl-2)-associated X and Bcl-2) genes in the liver. High-performance liquid chromatography analyses indicated the presence of protocatechuic acid, γ-oryzanol, vitamin E, and coenzyme Q10 in RRBE. Our data indicate that RRBE alleviates HFD-induced hepatosteatosis, dyslipidemia, and their pathologic complications in part by regulating the expression of key genes involved in lipid metabolism, inflammation, oxidative stress, and apoptosis.

Red rice bran extract (RRBE) has been reported to have the potential for in vitro metabolic modulation and anti-inflammatory properties. However, little is known about the molecular mechanisms of these potentials in adipose tissue. This study aimed to evaluate the in vivo anti-adipogenic, anti-hypertrophic, and anti-inflammatory activities of RRBE and its major bioactive compounds in mice. After six weeks of consuming either a low-fat diet or a high-fat diet (HFD), 32 mice with initial body weights of 20.76 ± 0.24 g were randomly divided into four groups; the four groups were fed a low-fat diet, a HFD, a HFD plus 0.5 g/kg of RRBE, or a HFD plus 1 g/kg of RRBE, respectively. The 6-week treatment using RRBE reduced HFD-induced adipocyte hypertrophy, lipid accumulation, and inflammation in intra-abdominal epididymal white adipose tissue (p < 0.05) without causing significant changes in body and adipose tissue weight, which reductions were accompanied by the down-regulated expression of adipogenic and lipid metabolism genes, including CCAAT/enhancer-binding protein-alpha, sterol regulatory element-binding protein-1c, and hormone-sensitive lipase (p < 0.05), as well as inflammatory genes, including macrophage marker F4/80, nuclear factor-kappa B p65, monocyte chemoattractant protein-1, tumor necrosis factor-alpha, and inducible nitric oxide synthase (p < 0.05), in adipose tissue. Furthermore, RRBE significantly decreased serum tumor necrosis factor-alpha levels (p < 0.05). Bioactive compound analyses revealed the presence of phenolics, flavonoids, anthocyanins, and proanthocyanidins in these extracts. Collectively, this study demonstrates that RRBE effectively attenuates HFD-induced pathological adipose tissue remodeling by suppressing adipogenesis, lipid dysmetabolism, and inflammation. Therefore, RRBE may emerge as one of the alternative food products to be used against obesity-associated adipose tissue dysfunction.

Narongsuk Munkong, Arthid Thim-Uam, Sirinat Pengnet, Pintusorn Hansakul, Nuntiya Somparn, Jarinyaporn Naowaboot, Jiraporn Tocharus, and Chainarong Tocharus. Prev Nutr Food Sci 2022;27:180-7. https://doi.org/10.3746/pnf.2022.27.2.180

Type I interferons (IFNs-I) are inflammatory cytokines that play an essential role in the pathogenesis of inflammation and autoimmune diseases. Signaling through nucleic acid sensors causes the production of IFNs-I. A stimulator of interferon genes (STING) is a DNA sensor that signals transduction, leading to the production of IFNs-I after their activation. This study aims to determine the anti-inflammatory effects of red rice bran extract (RRBE) on macrophages through the activation of STING signaling. RAW264.7 macrophage cells were stimulated with STING agonist (DMXAA) with and without RRBE. Cells and supernatant were collected. The level of mRNA expression was determined by qPCR, and inflammatory cytokine production was investigated by ELISA. The results indicate that RRBE significantly lowers the transcription of STING and interferon-stimulated genes (ISGs). Moreover, RRBE suppresses the phosphorylation of STING, leading to a decrease in the expression of Irf3, a transcription factor that initiates IFN-I signaling. Our results provide evidence that red rice bran extract may be a protective compound for inflammatory diseases by targeting STING signaling.

Background/Objectives: Mulberries exhibit antioxidant properties that may attenuate metabolic abnormalities. Kamphaeng Saen mulberry (KPS-MB-42-1) contains anthocyanins, polyphenols, and nutrients, but few studies have explored its benefits for human health. This study investigated the effects of a concentrated mulberry drink (CMD) from the KPS-MB-42-1 cultivar on metabolic and cardiovascular risk factors in obese individuals. Methods: A single-blind, randomized crossover clinical pilot trial was performed on individuals with obesity. Participants consumed 100 g of CMD daily, alternating with placebo for 6 weeks. Body composition, blood pressure, and blood samples were assessed at baseline and post-intervention. Results: This study was completed with 12 participants (7 men, 5 women, aged 30–55 years, BMI 32.1 ± 5.98 kg/m²) consuming CMD with 1041.90 mg total phenolic compounds and 35.34 mg total anthocyanins. No significant changes in body composition were observed. CMD consumption significantly reduced systolic and diastolic blood pressure, and mean arterial pressure, compared to baseline and placebo periods (p < 0.05). While total cholesterol, LDL-C, and HDL-C remained unchanged, triglycerides were significantly lower during CMD consumption compared to placebo periods (p < 0.05). Fasting plasma glucose (FPG) levels were stable during CMD consumption but increased significantly with the placebo period (p < 0.05). C-reactive protein levels were also significantly lower during CMD consumption compared to placebo periods (p < 0.05). No changes in blood coagulation indicators (prothrombin time, activated partial thromboplastin time, and the international normalized ratio) were found. Conclusions: CMD improved metabolic markers, particularly regarding its antihypertensive effects. These findings highlight CMD’s potential as a health drink for managing metabolic syndrome and preventing chronic diseases.

Thongboontho R, et al. Nutr Res Pract. 2023 Oct;17(5):827-843. https://doi.org/10.4162/nrp.2023.17.5.827