Kyeonghwan Hwang

Synthesis of oligosaccharide-containing orange juice using glucansucrase

Orange juice is a well-accepted fruit juice, and is a natural source of various vitamins, especially vitamin C, as well as sugar, potassium, thiamine, folate, flavonoids and antioxidants. The respective fructose, glucose, and sucrose concentrations were 9.3, 22.9, and 48.1 g/L in the original orange juice used in this study, and 183.4, 170.1, and 142.8 g/L after concentration. Over 97% of the sucrose in the juice was enzymatically converted to glucooligosaccharides upon addition of 3 U/mL dextransucrase, prepared from Leuconostoc mesenteroides 512FMCM, at 16°C. The synthesized oligosaccharides comprised 35.0% of the total saccharides in the concentrated juice and 31.7% in the original juice. The optimum conditions for oligosaccharide synthesis using the concentrated juice were 35.2 × 10−1 U/mL dextransucrase and 1% Ca(OH)2. The calories in the original and modified concentrated orange juices were 325.4 and 246.7 kcal/L, respectively. Compared to the original concentrated juice, the enzyme-modified concentrated juice prevented the formation of 62.7% of the insoluble glucan resulting from addition of mutansucrase, produced by Streptococcus mutans.

AKT-targeted anti-inflammatory activity of the methanol extract of Chrysanthemum indicum var. albescens

ETHNOPHARMACOLOGICAL RELEVANCE Wild chrysanthemum (Chrysanthemum indicum) is one of well-known medicinal plants traditionally used in Korea and China. As a variant of wild chrysanthemum, white wild chrysanthemum (Chrysanthemum indicum var. albescens) is also ethnopharmacologically applied to treat various symptoms such as inflammatory diseases. AIM OF STUDY Although the anti-inflammatory activity of Chrysanthemum indicum has been reported, the anti-inflammatory activity and underlying molecular mechanism of white wild chrysanthemum are poorly understood. MATERIALS AND METHODS The effects of Chrysanthemum indicum var. albescens methanol extract (Civ-ME) on the production of inflammatory mediators, expression of pro-inflammatory genes, cell viability, and the activities of intracellular signaling molecules and transcription factors were investigated in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. RESULTS Civ-ME suppressed the production of both nitric oxide (NO) and prostaglandin E2 (PGE2) without cytotoxicity in LPS-stimulated RAW264.7 cells. Civ-ME was found to reduce the mRNA levels of inflammatory genes such as inducible NO synthase (iNOS) and tumor necrosis factor (TNF)-α and reduced NF-κB-mediated transcriptional activation. Civ-ME inhibited the nuclear translocation of NF-κB (p65 and p50), and its upstream signaling composed of IκBα and IKKα/β. An NF-κB luciferase reporter gene assay and an in vitro kinase assay confirmed that AKT1 and AKT2 might be direct pharmacological targets of Civ-ME. In addition, luteolin was identified by HPLC analysis as the main active pharmacological components of Civ-ME. CONCLUSION Civ-ME exerts an anti-inflammatory effect by targeting AKT1 and AKT2 in the NF-κB signaling pathway in macrophage-mediated inflammatory responses.

Skin Protective Effect of Epigallocatechin Gallate

Epigallocatechin gallate (EGCG) is a catechin and an abundant polyphenol in green tea. Although several papers have evaluated EGCG as a cosmetic constituent, the skin hydration effect of EGCG is poorly understood. We aimed to investigate the mechanism by which EGCG promotes skin hydration by measuring hyaluronic acid synthase (HAS) and hyaluronidase (HYAL) gene expression and antioxidant and anti-pigmentation properties using cell proliferation assay, Western blotting analysis, luciferase assay, 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and reverse transcription polymerase chain reaction (RT-PCR) analysis. RT-PCR showed that EGCG increased the expression of natural moisturizing factor-related genes filaggrin (FLG), transglutaminase-1, HAS-1, and HAS-2. Under UVB irradiation conditions, the expression level of HYAL was decreased in HaCaT cells. Furthermore, we confirmed the antioxidant activity of EGCG and also showed a preventive effect against radical-evoked apoptosis by downregulation of caspase-8 and -3 in HaCaT cells. EGCG reduced melanin secretion and production in melanoma cells. Together, these results suggest that EGCG might be used as a cosmetic ingredient with positive effects on skin hydration, moisture retention, and wrinkle formation, in addition to radical scavenging activity and reduction of melanin generation.

Cytoprotective Effect of Epigallocatechin Gallate (EGCG)-5′-O-α-Glucopyranoside, a Novel EGCG Derivative

Epigallocatechin gallate (EGCG) is a well-studied polyphenol with antioxidant effects. Since EGCG has low solubility and stability, many researchers have modified EGCG residues to ameliorate these problems. A novel EGCG derivative, EGCG-5′-O-α-glucopyranoside (EGCG-5′Glu), was synthesized, and its characteristics were investigated. EGCG-5′Glu showed antioxidant effects in cell and cell-free systems. Under SNP-derived radical exposure, EGCG-5′Glu decreased nitric oxide (NO) production, and recovered ROS-mediated cell viability. Moreover, EGCG-5′Glu regulated apoptotic pathways (caspases) and cell survival molecules (phosphoinositide 3-kinase (PI3K) and phosphoinositide-dependent kinase 1 (PDK1)). In another radical-induced condition, ultraviolet B (UVB) irradiation, EGCG-5′Glu protected cells from UVB and regulated the PI3K/PDK1/AKT pathway. Next, the proliferative effect of EGCG-5′Glu was examined. EGCG-5′Glu increased cell proliferation by modulating nuclear factor (NF)-κB activity. EGCG-5′Glu protects and repairs cells from external damage via its antioxidant effects. These results suggest that EGCG-5′Glu could be used as a cosmetics ingredient or dietary supplement.

Enhanced Production of β-D-glycosidase and α-L-arabinofuranosidase in Recombinant Escherichia coli in Fed-batch Culture for the Biotransformation of Ginseng Leaf Extract to Ginsenoside Compound K

Ginsenoside compound K is an essential ingredient in nutritional supplements, cosmetics, and traditional medicines. However, cultivation for the production of enzymes involved in ginsenoside biotransformation has not been attempted in a fermenter. The host strain Escherichia coli ER2566 and the constitutive pHCE vector were selected for the efficient production of β-D-glycosidase, and expression medium composition to produce Sulfolobus solfataricus β-glycosidase expressed in E. coli was optimized in flask and batch cultures. The total activity of β-Dglycosidase in fed-batch culture using a fermenter increased 14-fold before optimization. S. solfataricus β-D-glycosidase and Thermotoga petrophila α-L-arabinofuranosidase were produced in a fed-batch culture. These two enzymes completely converted protopanaxadiol-type ginsenosides in ginseng leaf extract obtained from discarded ginseng leaves as a renewable substrate to compound K. The effective bioprocess for compound K production developed here will contribute to the industrial biological production of compound K.