Sun-Il Choi

Comparative Analysis of γ-Oryzanol, β-Glucan, Total Phenolic Content and Antioxidant Activity in Fermented Rice Bran of Different Varieties

Rice bran, a by-product derived from processing rice, is a rich source of bioactive compounds. Recent studies have suggested that the fermentation can improve their biological activities. This study aimed to determined the level of γ-oryzanol, β-glucan and total phenol contents of fermented rice bran from 21 Korean varieties, as well as to evaluate their antioxidant activities. We also assessed the validation of the analytical method for determining γ-oryzanol content in fermented rice brans. Among the fermented rice brans, the Haedam rice bran contained the highest level of total phenol content (156.08 mg gallic acid equivalents/g), DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity (71.30%) and ORAC (Oxygen radical absorbance capacity) value (1101.31 μM trolox equivalents/g). Furthermore, the fermented Migwang rice bran showed the highest level of γ-oryzanol content (294.77 ± 6.74 mg/100 g).

Changes in the Anti-Allergic Activities of Sesame by Bioconversion

Sesame is an important oilseed crop, which has been used as a traditional health food to ameliorate the prevention of various diseases. We evaluated the changes in the anti-allergic activities of sesame by bioconversion. SDS-PAGE of non-fermented sesame proteins showed major allergen bands, while that of fermented sesame showed only a few protein bands. Additionally, we investigated the effectiveness of fermented sesame by bioconversion in tumor necrosis factor-α (TNF-α)- and interferon-γ (IFN-γ)-induced HaCaT cells. In HaCaT cells, fermented sesame inhibited the mRNA expression of interleukin-6 (IL-6) and interleukin-1β (IL-1β), thymus and macrophage-derived chemokine (MDC/CCL22), activation-regulated chemokine (TARC/CCL17), and intercellular adhesion molecule-1 (ICAM-1). Moreover, fermented sesame inhibited the activation of nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 1 (STAT1). Fermented sesame exerts anti-allergic effects by suppressing the expression of chemokines and cytokines via blockade of NF-κB and STAT1 activation.

Identifying method validation and measurement uncertainty of brominated vegetable oil in soft drinks and carbonated waters commonly consumed in South Korea

This study investigated a method for validating and determining the measurement uncertainty for the composition of brominated vegetable oil (BVO) in soft drinks and carbonated waters commonly consumed in South Korea. First, we studied a simple and precise qualitative colorimetric method at the maximum residues level 15 ppm. And an analytical method using ion chromatography (IC) was validated and identified with brominated fatty acids by gas chromatography electron ionization mass spectrometry (GC/EI-MS). The measurement uncertainty was evaluated based on the precisional study and confirmed by the preliminary inter-laboratory study. For IC analysis, the recovery range of BVO was from 97.8% to 107.2% with relative standard deviations between 0.18% and 0.69%. In addition, the expanded uncertainty of the BVO was 1.59. These results indicate that the validated method is appropriate for identifying of BVO and can be used to verify the safety of soft drinks or carbonated waters containing BVO residues.

Method Validation for Determination of Lignan Content in Fermented Sesame by Bioconversion

The aim of this study was to investigate method validation for determination of sesamol, sesamin, and sesamolin in non-fermented sesame and fermented sesame by bioconversion. For validation, the specificity, linearity, precision, accuracy, limits of detection (LOD), and quantification (LOQ) of sesamol, sesamin, and sesamolin were measured by HPLC. Linearity tests showed that the coefficients of calibration correlation (R) for sesamol, sesamin, and sesamolin were 0.9999. Recovery rates of lignan contents in non-fermented and fermented sesame were high in the ranges of 100.27∼115.10% and 98.43∼114.90%, respectively. The inter-day and intra-day precisions of sesamin and sesamolin analyses for non-fermented and fermented sesame were 0.27∼1.94% and 0.25∼0.69%, respectively. The LOD and LOQ were 0.23∼0.34 μg/g and 0.70∼1.03 μg/g, respectively. These results indicate that the validated method is appropriate for the determination of sesamol, sesamin, and sesamolin.

Anti-Photoaging Effect of Jeju Putgyul (Unripe Citrus) Extracts on Human Dermal Fibroblasts and Ultraviolet B-induced Hairless Mouse Skin

Ultraviolet (UV) radiation stimulates the expression of matrix metalloproteinases (MMPs) and inflammatory cytokines. These signaling pathways participate in the degradation of the extracellular matrix and induce inflammatory responses that lead to photoaging. This study evaluated the antioxidant activity and the effect on MMPs and procollagen of putgyul extract in vitro. The anti-photoaging activity of putgyul extracts was estimated in vivo using hairless mice (HR-1). The putgyul extracts reduced MMP-1 production and increased the content of procollagen type I carboxy-terminal peptide in human dermal fibroblasts. Ultravilot-B (UVB)-induced expression of inflammatory cytokines and MMPs was detected in mice, and putgyul extracts suppressed the expression. These results suggest that putgyul extract inhibits photoaging by inhibiting the expression of MMPs that degrade collagen and inhibiting cytokines that induce inflammatory responses. The mouse model also demonstrated that oral administration of putgyul extracts decreased wrinkle depth, epidermal thickness, collagen degradation, and trans-epidermal water loss, and increased β-glucosidase activity on UVB exposed skin. Putgyul extract protects against UVB-induced damage of skin and could be valuable in the prevention of photoaging.

Radical scavenging-linked anti-adipogenic activity of Alnus firma extracts

The purpose of the present study was to investigate the antioxidant activity and anti-adipogenic effect of extracts from Alnus firma (A. firma), which is an edible plant that grows in mountainous areas. The total phenolic, flavonoid and anthocyanin content as well as the antioxidant activity of a 70% ethanolic extract of A. firma (AFE) was assessed. Furthermore, the effects of AFE on lipid accumulation and reactive oxygen species (ROS) production during adipogenesis of 3T3-L1 cells were investigated. The results revealed that the total phenolic, flavonoid and pro-anthocyanidin content of AFE as 436.26±3.30 mg gallic acid equivalents/g, 73.82±0.54 mg quercetin equivalents/g and 149.25±6.06 mg catechin equivalents/g, respectively. In addition, AFE exerted significant antioxidant effects in terms of 1,1-diphenyl-2-picryl hydrazyl radical scavenging activity, 2,2′-azino-bis(3-ethylbenzothia-zoline-6-sulfonic acid) radical scavenging activity, reducing power, oxygen radical absorbance capacity and nitric oxide radical scavenging activity. As for its anti-adipogenic activity, AFE significantly inhibited ROS production and lipid accumulation during adipogenesis of 3T3-L1 cells compared with those in control cells. In addition, AFE regulated adipogenic transcription factors including peroxisome proliferator-activated receptor-γ, CCAAT/enhance-binding protein α and adipocyte protein 2. These results indicated that A. firma is a potential candidate for a functional food supplement.