Ji-Hye Song

Heat processing decreases Amadori products and increases total phenolic content and antioxidant activity of Korean red ginseng.

The functional properties of Korean red ginseng (KRG) are known to be dependent upon the extent of heat processing. We demonstrated that repeated heat processing in the preparation of KRG decreased its arginyl-fructosyl-glucose (AFG) content and metal chelating capacity. On the other hand, the total phenolic compound content, in vitro peroxyl radical scavenging ability, and cellular peroxyl and hydroxyl radical scavenging ability increased with repeated heat processing. The peroxyl radical scavenging ability of KRG may be due to the total phenolic compound content. The hydroxyl radical scavenging ability of KRG seems to result mainly from the chelating ability of Amadori compounds such as arginyl-fructose and AFG. The protective ability of KRG against Cu²(+)-induced oxidative stress in hepatoma HepG2 cells may be due to permeability into the cell membrane rather than antioxidant activity. These results can be used to predict the physiological functions of KRG in in vivo models.

Curcumin ameliorates AAPH-induced oxidative stress in HepG2 cells by activating Nrf2

In this study, 3 major curcuminoids were analyzed and the cellular anti-oxidant activities of E-TE(K) and E-TE(M) were assessed in HepG2 cells. The contributions and molecular targets of the 3 curcuminoids in the anti-oxidant activities of E-TE(K) and E-TE(M) were revealed. The curcuminoids including curcumin (CCM) was the most abundant curcuminoid [10.7% of ETE( K) and 17.5% of E-TE(M)] and the curcuminoid content, particularly CCM, was crucial for anti-oxidant activities of E-TE(K) and E-TE(M). The anti-oxidant activity of CCM involved the regulation of Nrf2, the central transcriptional factor for expression of phase II detoxifying enzymes such as heme oxygenase-1. The CCM-activated Nrf2 was shown to be regulated by the PI3K/Akt signaling pathway. Taken together, the results indicate that the activation of Nrf2 through PI3K/Akt signaling pathway is required for anti-oxidant activity of CCM. These findings provide the scientific evidence for the development of Nrf2 targeted dietary anti-oxidant.

Anti-Adipogenic Effects of Ethanol Extracts Prepared from Selected Medicinal Herbs in 3T3-L1 Cells

Obesity is a major risk factor for various metabolic diseases such as cardiovascular disease, hypertension, and type 2 diabetes mellitus. In this study, we prepared ethanol extracts from Agastache rugosa (ARE), Chrysanthemum zawadskii (CZE), Mentha arvensis (MAE), Perilla frutescens (PFE), Leonurus sibiricus (LSE), Gardenia jasminoides (GJE), and Lycopus coreanus (LCE). The anti-oxidant and anti-adipogenic effects were evaluated. The IC50 values for ascorbic acid and LCE against 2,2-diphenyl-1-picrylhydrazyl radicals were 246.2 μg/mL and 166.2 μg/mL, respectively, followed by ARE (186.6 μg/mL), CZE (198.6 μg/mL), MAE (337.1 μg/mL), PFE (415.3 μg/mL), LSE (548.2 μg/mL), and GJE (626.3 μg/mL). In non-toxic concentration ranges, CZE had a strong inhibitory effect against 3T3-L1 adipogenes (84.5%) than those of the other extracts. Furthermore, the anti-adipogenic effect of CZE is largely limited in the early stage of adipogenesis, and we revealed that the inhibitory role of CZE in adipogenesis is required for the activation of Wnt signaling. Our results provide scientific evidence that the anti-adipogenic effect of CZE can be applied as an ingredient for the development of functional foods and nutri-cosmetics for obesity prevention.

Ferulic Acid Released by Treatment with Aspergillus oryzae Contributes to the Cellular Antioxidant Capacity of Wheat Germ Extract

An extract of fermented wheat germ (EFWG) was prepared by treatment with Aspergillus oryzae and in vitro antioxidant and cellular antioxidant capacities were measured. The induction of phase II detoxifying and antioxidant enzymes in exerting a cellular antioxidant capacity was determined. Treatment of wheat germ with A. oryzae significantly (p<0.001) increased the ferulic acid content, compared to controls, among 4 phenolic acids analyzed. The peroxyl radical-scavenging and reducing capacities and the cellular antioxidant capacity of EFWG were more potent than for extracts of wheat grain (EWG). The cellular antioxidant capacity of EFWG against AAPH and H2O2-induced oxidative stress was stronger than for EWG due to enhanced induction of the phase II enzymes HO-1, GST, and NQO-1. Potent in vitro and cellular antioxidant capacities of EFWG may result from an increased ferulic acid content due to treatment with A. oryzae.

Anti-oxidant and anti-adipogenic effects of acorn (Quercus acutissima CARR.) shell extracts via regulation of wnt signaling in 3T3-L1 cells

Acorn (Quercus acutissima CARR.) is a nut from the Fagaceae family that has been used in traditional medicine for many years. However, shells from acorns are regarded as a by-product and are mostly discarded. Anti-adipogenic activities of acorn shells were investigated using 3T3-L1 cells and methanol shell extracts (AE-M). AE-M demonstrated Cu2+-chelation activities and anti-oxidant activities via reduction of oxidative stress levels induced using AAPH. Six days after adipocyte differentiation, 50 and 100 μg/mL AE-M completely suppressed 3T3-L1 adipogenesis and the anti-adipogenic effect was stronger than for the positive control 50 μM quercetin. Treatment with AE-M in 3T3-L1 cells reduced mRNA expression levels of adipogenic genes. AE-M-inhibition was found in pre-adipogenic, early, and intermediate stages of adipogenesis in 3T3-L1 cells. The Wnt/β-catenin signaling pathway is required for AE-M-inhibition of 3T3-L1 adipogenesis.