Antiobesity and Antioxidative Effect of Fermented Brown Rice Using In Vitro with In Vivo Caenorhabditis elegans Model

Abstract

Naturally occurring phytochemicals from plants or grains are crucial in reducing various metabolic disorders. Bioactive phytonutrients are abundant in the Asian dietary staple, brown rice. This research evaluated the impact of lactic acid bacteria (LABs) bioconversion and fermentation on antioxidant and antiobesity activities and ferulic acid content in brown rice. The combination of bioconversion with Pediococcus acidilactici MNL5 among all LABs used showed a synergistic impact with 24 h of solid-state brown rice fermentation. The 24-h MNL5 fermented brown rice (FBR) demonstrated the most potent pancreatic lipase inhibitory activity (85.5 ± 1.25%) compared to raw brown rice (RBR) (54.4 ± 0.86%). The antioxidant potential of MNL5-FBR was also found to be highest in the DPPH assay (124.40 ± 2.40 mg Trolox Equiv./100 g, DW), ABTS assay (130.52 ± 2.32 mg Trolox Equiv./100 g, DW), and FRAP assay (116.16 ± 2.42 mg Trolox Equiv./100 g, DW). Based on higher antioxidant and antiobesity activities, samples were quantified for ferulic acid content using the HPLC-MS/MS approach. Furthermore, C. elegans supplementation with FBR showed enhanced life span and lipid reduction in fluorescence microscope analysis compared to the control. Our results indicate that the expression study using the C. elegans model (N2 and Daf-2 models) fat gene was conducted, showing a lowering of obesity ability in FBR-fed worms. Our study indicates that FBR has improved antioxidant and antiobesity actions, especially in MNL5-FBR, and can be employed to develop functional foods that combat obesity.

Keywords: Pediococcus acidilactici MNL5; brown rice; ferulic acid; lipase inhibitory; lipid reduction.

Figure A1

Ferulic acid (FA) content was found to be higher in the MNL5 fermented brown rice sample. During fermentation, different period samples were analyzed by HPLC—(a) 6 h; (b) 12 h; (c) 18 h; (d) 20 h; (e) 22hr; and (f) 24 h.

Figure A2

Glucose-supplemented raw and fermented brown rice diet alteration of C. elegans body width and length. Worm size measurements were assessed by Olympus SZ 61 zoom stereomicroscope ToupViewTM 3.7 software.

Figure 1

In vitro pancreatic Lipase-inhibiting antiobesity efficacy of several strains of LAB fermented brown rice. All results are shown as the mean ± standard error mean.

Figure 2

The FA content of RBR and different LABs FBR samples. The data are shown as means SEM, with p < 0.05 indicating statistical significance.

Figure 3

Impact of C.elegans lifespan on glucose supplemented RBR and FBR diet. (a) N2; (b) Daf-2. The different treatments, such as OP50 (NC), OP50 + GLU (E. coli OP50 with glucose (positive control), Orlistat + GLU (DC), raw + GLU (raw), FBR + GLU (MNL5, LS21, LS-651, LS-65, LS-803 with glucose) in each test. One hundred worms were fed, repeated, and analyzed by OASIS II. The data are shown as means SEM, with p < 0.05 indicating statistical significance.

Figure 4

The impact of RBR and FBR diet reduction in C. elegans lipid droplets visualized by Nile-red staining method (a) N2 and Daf-2 model by fluorescence image (20× magnification); (b) mean of fluorescence intensity measured by ImageJ software; (c) the lipid and TG levels of worms are shown in a bar chart. The data are shown as means SEM, with p < 0.05 indicating statistical significance.

Figure 5

Analysis of gene expression for the RBR and FBR diets on C. elegans. (a) N2; (b) Daf-2; the bar chart shows the gene expression in C. elegans treated with RBR and FBR diets. The data are shown as means SEM, with p < 0.05 indicating statistical significance.