Ji-Eun Ra

Comparative analysis of physicochemicals and antioxidative properties of new giant embryo mutant, YR23517Acp79, in rice (Oryza sativa L.)

Nutritional and physicochemical properties of new giant embryo mutant rice (YR23517Acp79, YR) were analyzed. YR exhibited increased total protein (9.3±0.3%), lipid (3.7±1.1%), amino acid (663.28±1.9 mg/g), and mineral contents (Ca=284.0±6.2, Mg=1417.5±13.6 mg/kg). In YR brown rice four major physicochemicals, including gamma-aminobutyric acid (brown rice= 0.46±0.014 mg/g), γ-oryzanol (0.43±0.021 mg/g), vitamin B1 (6.42±0.3 mg/kg), and tocopherols (alpha= 2.68±0.1, beta=0.11±0.01, gamma=0.05±0.001 mg/100 g) increased in comparison to reported giant embryo (Keunnunbyeo, KB) and normal embryo rice (Ilmibyeo, IB). YR showed higher scavenging activities against 1,1-diphenyl-2-picrylhydrazyl (0.2 g/mL=57.1±2.25) and 2,2′-Azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (0.2 g/mL=50.2±1.45) radicals but also inhibited lipopolysaccharide-induced nitric oxide production without cytotoxicity. These results indicate YR is a high quality functional rice due to its high nutrition content and antioxidant effects of physicochemicals.

Relationship of radical scavenging activities and anthocyanin contents in the 12 colored rice varieties in Korea

Total polyphenolic, protein, lipid, and anthocyanin contents in grains of 12 Korean colored rice varieties were evaluated for their 2,2-di(4-tert-octylphenyl)-1-picrylhydrazyl) (DPPH) and 2,2- Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium (ABTS) radical- scavenging activities. Three anthocyanins, cyanidin-3-O-glucoside (Cy-3-G), petunidin-3-O-glucoside (Pt-3-G), and peonidin-3-O-glucoside (Pn-3-G), were also characterized by ultra performance liquid chromatography. Among the rice varieties, ‘Heugjinju’, ‘Heugseol’, and ‘Sintoheugmi’ contained high total phenolic contents compared to other varieties. Anthocyanin content was highest in ‘Heugjinju’; no anthocyanins were detected in ‘Hongjinju’ and ‘Jeogjinju’. Highest antioxidant activity was observed in ‘Heugjinju’ and ‘Jeogjinju’ exhibited the lowest activity. To determine the correlation of total polyphenolic and anthocyanin contents to antioxidant activity, linear regression analysis was carried out. The results showed total polyphenolic content was strongly correlated with antioxidant activity, suggesting total phenolic content as key factor in antioxidant activity of colored rice. ‘Heugjinju’, ‘Heugseol’, and ‘Sintoheugmi’ could have important nutritional value.

Comparative analysis of physicochemicals and antioxidative properties in new red rice (Oryza sativa L. cv. Gunganghongmi)

The main objectives of this study were to investigate physicochemicals and antioxidant activities of new red rice (Oryza sativa cv. Gunganghongmi (GH)) by comparing normal brown (Nampyeongbyeo, NB) and reported red rice (Jukjinjubyeo, JB) in Korea. The nutritional constituents, including protein, oil, sugar, fatty acid, GABA, and γ-oryzanol were not significantly different between normal brown and colored rice. However, the ethanol extract of GH showed the highest phenolic content (24.7 ± 1.3 mg g−1). The ethanol extracts of GH showed higher scavenging activities against DPPH (0.2 mg mL−1 = 62.1 ± 2.5%) and ABTS (0.2 mg mL−1 = 63.2 ± 3.5%) radicals. Moreover, GH more inhibited LPS-induced nitric oxide (NO) production (13.2 ± 1.4 μM) than JB (18.3 ± 2.3 μM) and NB (22.1 ± 1.4 μM) at the same concentration (0.2 mg mL−1) without cytotoxicity. These results suggest that new red rice (GH) would be considered to be new functional rice due to its anti-oxidative effect and high nutrition.

Comparative studies on major nutritional components of black waxy rice with giant embryos and its rice bran

The concentration of nutrients in brown rice is mainly associated with embryo size. Various beneficial components have been purified from rice bran. Recently developed black waxy rice with a giant embryo (‘Milyang 263’, BGE), which is the get mutant of the GE gene, was selected and analyzed to produce high quality nutritional components. γ-Aminobutyric acid (GABA) content in BGE rice bran, one of the most important nutritional compounds in rice, showed a 10.6-fold increase (2.66±0.48 mg/g) compared to that of BGE brown rice (0.25±0.01 mg/g). In addition, brown rice and BGE rice bran showed enriched amylopectin (94.5±0.5 and 97.0±0.0%) and bioactive anthocyanin [Cy-3-G: 75.15±4.18 (brown rice), 82.97±0.81 (rice bran) and Pn-3-G: 1.52±0.50 (brown rice), 4.33±0.20 (rice bran); mg/100 g] contents. These results suggest that BGE rice bran can be used as an excellent raw material to efficiently produce high quality essential amino acids, cyanidin-3 glycoside-enriched anthocyanins, and GABA.

Anti-pigmentation effect of serotonin alkaloid isolated from Korean barnyard millet ( Echinochola utilis )

Investigation of the melanogenesis inhibitory effect of barnyard millet grain extracts (BME) led to isolation of compounds against mushroom tyrosinase and B16 melanoma cells. Chromatography yielded five phenolic compounds, among which n-p-coumaroyl serotonin (1, CS) exhibited potent non-competitive inhibition (IC50 =8.8 μM) compared with that of kojic acid (IC50=14.6 μM) against mushroom tyrosinase. More importantly, CS decreased melanin content to eight times lower (IC50 =11.6 μM) in B16 melanocytes than that of feruloyl serotonin (2, FS, IC50 =86.5 μM) without cytotoxicity. CS significantly inhibited the protein expression of tyrosinase, tyrosinase-related protein-1 (TRP-1), TRP-2, and microphthalmia-associated transcription factor using immunoblotting. Furthermore, molecular docking simulations were also carried out to investigate the structure related to the inhibitory activities. Therefore, BME can be used as a natural source of depigmentation to prevent melanogenesis.

Antioxidative Effect and Neuraminidase Inhibitory Activity of Polyphenols Isolated from a New Korean Red Waxy Sorghum (Sorghum bicolor L. cv. Hwanggeumchalsusu)

To identify nutritional and therapeutic properties of the new Korean red waxy sorghum cultivar ‘Hwanggeumchalsusu (HGC)’, we assayed the antioxidative effects and neuraminidase inhibitory activity. A methanol and 70% ethanol extract of HGC exhibited strong antioxidative effects (IC 50 values of 83.2±2.7 for DPPH) and 85.6±2.4 μg/ml for ABTS) and neuraminidase (ND) inhibitory activity (IC 50 values of 1.8±0.1 from extracted with methanol and 3.4±0.1 μg/ml from extracted with 70% ethanol) compared with that of the control, noncolored sorghum cultivar ‘Huinchalsusu (HC)’ (IC 50 > 200μg/ml). We isolated nine polyphenols, Gallic acid (1), Protocatecuic acid (2), p-Hydroxy benzoic acid (3), Vanillic acid (4), Caffeic acid (5), Ferulic acid (6), Luteolinidin (7), Apigeninidin (8), Luteolin (9), from the HGC?methanol extract, to determine whether they were the active components Luteolinidin of one kind of polyphenols from the HGC, exhibited significant antioxidative effects (IC 50 values of 10.9±0.5 μM for DPPH and 8.6 0.6 μM for ABTS) and neuraminidase (ND) inhibitory activity (IC 50 values of 26.3±0.6) showed noncompetitive inhibition model. The binding affinity of the ND inhibitors in molecular docking experiments correlated with their ND inhibitory activities. These results suggest that HGC may be utilized to serve as a potential effective antioxidant and inhibitor of ND.

Studies of Physicochemical Properties of Baby Powder Developed from Rice-flour

Baby powder is an astringent powder used to prevent diaper rash. It also has other cosmetic uses. In general, it is composed of talc powder (talcum powder). Talc powder is harmful if inhaled because it can cause significant lung damage. With the aim of developing a new rice-based baby powder, three kinds of rice varieties were selected and pulverized. To determine the cost-effectiveness of the different states of rice powder, several milling processes were tried, and the powder characteristics of the resulting rice powder, such as particle size, biological activities, digitalized color value, and moisture content before and after coating treatment with essential oil and silicon oil, were examined. “Goami” showed good flour characteristics with respect to lightness (92.0, L*[D65] value) and particle size (8.9 μm). SEM analysis showed that the rice powder particles coated in the essential oil and silicon oil showed a smoother and rounder appearance than those of the talc powder. In addition, the average particle size was decreased by the essential oil and silicon oil coating. The silicon oil coating solved the problem of moisture absorption in rice flour. Rice flour properly coated with essential oil and silicon oil shows great potential as a new material source of powder.