Hyun Ju You

Transformation of Rutin to Antiproliferative Quercetin-3-glucoside by Aspergillus niger

The flavonol quercetin in plants and foods occurs predominantly in the form of glycoside whose sugar moiety affects the bioavailability and the mechanism of its biological activities. The antiproliferative activities of quercetin derivatives such as quercetin aglycone, quercetin-3-β-D-glucoside (Q3G), and rutin were compared using six different cancer cell lines including colon, breast, hepatocellular, and lung cancer. The IC50 value of Q3G ranged between 15 and 25 μM in HT-29, HCT 116, MCF-7, HepG2, and A549 cells. In these five cell lines, Q3G showed the most potent growth inhibition, whereas rutin showed the least potency. Transformation of rutin to Q3G was conducted by controlling α-L-rhamnosidase and β-D-glucosidase activities from crude enzyme extract of Aspergillus niger. Carbon sources during culture and transformation conditions such as pH, temperature, and heat-stability were optimized. After 4 h biotransformation, 99% of rutin was transformed to Q3G and no quercetin was detected. This study presented an efficient biotransformation for the conversion of rutin to Q3G which was newly shown to have more potent antiproliferative effect than quercetin and rutin.

The effect of heritability and host genetics on the gut microbiota and metabolic syndrome

Objective Metabolic syndrome (MetS) arises from complex interactions between host genetic and environmental factors. Although it is now widely accepted that the gut microbiota plays a crucial role in host metabolism, current knowledge on the effect of host genetics on specific gut microbes related to MetS status remains limited. Here, we investigated the links among host genetic factors, gut microbiota and MetS in humans. Design We characterised the gut microbial community composition of 655 monozygotic (n=306) and dizygotic (n=74) twins and their families (n=275), of which approximately 18% (121 individuals) had MetS. We evaluated the association of MetS status with the gut microbiota and estimated the heritability of each taxon. For the MetS-related and heritable taxa, we further investigated their associations with the apolipoprotein A-V gene (APOA5) single nucleotide polymorphism (SNP) rs651821, which is known to be associated with triglyceride levels and MetS. Results Individuals with MetS had a lower gut microbiota diversity than healthy individuals. The abundances of several taxa were associated with MetS status; Sutterella, Methanobrevibacter and Lactobacillus were enriched in the MetS group, whereas Akkermansia, Odoribacter and Bifidobacterium were enriched in the healthy group. Among the taxa associated with MetS status, the phylum Actinobacteria, to which Bifidobacterium belongs, had the highest heritability (45.7%). Even after adjustment for MetS status, reduced abundances of Actinobacteria and Bifidobacterium were significantly linked to the minor allele at the APOA5 SNP rs651821. Conclusions Our results suggest that an altered microbiota composition mediated by a specific host genotype can contribute to the development of MetS.

Ginsenoside metabolite compound K differentially antagonizing tumor necrosis factor-α-induced monocyte–endothelial trafficking

Human leukocyte endothelial adhesion and transmigration occur in the early stage of the pathogenesis of atherosclerosis. Vascular endothelial cells are targeted by pro-inflammatory cytokines modulating many gene proteins responsible for cell adhesion, thrombosis and inflammatory responses. This study examined the potential of compound K to inhibit the pro-inflammatory cytokine TNF-α induction of monocyte adhesion onto TNF-α-activated human umbilical vein endothelial cells (HUVEC). HUVEC were cultured with 10ng/ml TNF-α with individual ginsenosides of Rb1, Rc, Re, Rh1 and compound K (CK). Ginsenosides at doses of ⩽50μM did not show any cytotoxicity. TNF-α induced THP-1 monocyte adhesion to HUVEC, and such induction was attenuated by Rh1 and CK. Consistently, CK suppressed TNF-α-induced expression of HUVEC adhesion molecules of VCAM-1, ICAM-1 and E-selectin, and also Rh1 showed a substantial inhibition. Rh1 and CK dampened induction of counter-receptors, α4/β1 integrin VLA-4 and αL/β2 integrin LFA-1 in TNF-α-treated THP-1 cells. Additionally, CK diminished THP-1 secretion of MMP-9 required during transmigration, inhibiting transendothelial migration of THP-1 cells. CK blunted TNF-α-promoted IL-8 secretion of HUVEC and CXCR1 expression of THP-1 monocytes. Furthermore, TNF-α-activated endothelial IκB phosphorylation and NF-κB nuclear translocation were disturbed by CK, and TNF-α induction of α4/β1 integrin was abrogated by the NF-κB inhibitor SN50. These results demonstrate that CK exerts anti-atherogenic activity with blocking leukocyte endothelial interaction and transmigration through negatively mediating NF-κB signaling.

Blockade of vascular angiogenesis by Aspergillus usamii var. shirousamii-transformed Angelicae Gigantis Radix and Zizyphus jujuba

The matrix metalloproteinases (MMP) play an important role in tumor invasion, angiogenesis and inflammatory tissue destruction. Increased expression of MMP was observed in benign tissue hyperplasia and in atherosclerotic lesions. Invasive cancer cells utilize MMP to degrade the extracellular matrix and vascular basement membrane during metastasis, where MMP-2 has been implicated in the development and dissemination of malignancies. The present study attempted to examine the antiangiogenic activity of the medicinal herbs of Aspergillus usamii var. shirousamii-transformed Angelicae Gigantis Radix and Zizyphus jujube (tAgR and tZj) with respect to MMP-2 production and endothelial motility in phorbol 12-myristate 13-acetate (PMA)- or VEGF-exposed human umbilical vein endothelial cells (HUVEC). Nontoxic tAgR and tZj substantially suppressed PMA-induced MMP-2 secretion. In addition, 25 µg/mL tAgR and tZj prevented vascular endothelial growth factor-stimulated endothelial cell transmigration and tube formation. The results reveal that tAgR and tZj dampened endothelial MMP-2 production leading to endothelial transmigration and tube formation. tAgR and tZj-mediated inhibition of endothelial MMP may boost a therapeutic efficacy during vascular angiogenesis.

Inactivation of norovirus and surrogates by natural phytochemicals and bioactive substances

Human norovirus is the leading cause of sporadic gastroenteritis, which is responsible for more than 90% of all nonbacterial gastroenteritis outbreaks. While norovirus infections typically cause mild and self-limiting symptoms lasting 24-48 h, chronic persistent infections can cause severe symptoms. Although recent advances have been made in understanding the molecular characteristics of norovirus infection, no norovirus-specific antiviral drugs, or vaccines are available. Conventional intervention methods used to inactivate norovirus, such as treatment with disinfecting agents (e.g. ethanol, hypochlorite, and quaternary ammonium formulations), have shown a lack of efficacy against human norovirus when they are applied to foods and in food preparation processes. Therefore, alternative antiviral or inactivating agents such as phytochemicals have received attention as potential norovirus inhibitors due to their relatively low toxicity and lack of side effects, which allows them to be prepared as food-safe formulations. Evidence from studies using viral surrogates suggests that numerous phytochemicals and foods containing flavonoids and polyphenols have anti-norovirus activity, and future studies will be necessary to confirm the effectiveness of such compounds against human norovirus and the molecular mechanisms through which they produce antiviral effects.

Prevotella as a Hub for Vaginal Microbiota under the Influence of Host Genetics and Their Association with Obesity

While the vaginal ecosystem is maintained through mutualistic relationships between the host and the vaginal bacteria, the effect of host genetics on the vaginal microbiota has not been well characterized. We examined the heritability of vaginal microbiota and its association with obesity in 542 Korean females, including 222 monozygotic and 56 dizygotic twins. The vaginal microbiota significantly varied depending on host menopausal status and bacterial vaginosis. Lactobacillus and Prevotella, whose relative abundances are strongly associated with bacterial vaginosis, were the most heritable bacteria among the beneficial and potentially pathogenic vaginal microbiota, respectively. Candidate gene analysis revealed an association between genetic variants of interleukin-5 and the abundance of Prevotella sp. Furthermore, host obesity significantly increased the diversity of the vaginal microbiota in association with Prevotella. Our results provide insight into the effect of host genetics on the vaginal microbiota and their association with both vaginal and non-vaginal health.

Whole-Cell Biocatalysis for Producing Ginsenoside Rd from Rb1 Using Lactobacillus rhamnosus GG.

Ginsenosides are the major active ingredients in ginseng used for human therapeutic plant medicines. One of the most well-known probiotic bacteria among the various strains on the functional food market is Lactobacillus rhamnosus GG. Biocatalytic methods using probiotic enzymes for producing deglycosylated ginsenosides such as Rd have a growing significance in the functional food industry. The addition of 2% cellobiose (w/v) to glucose-free de Man-Rogosa-Sharpe broths notably induced β-glucosidase production from L. rhamnosus GG. Enzyme production and activity were optimized at a pH, temperature, and cellobiose concentration of 6.0, 40°C, and 2% (w/v), respectively. Under these controlled conditions, β-glucosidase production in L. rhamnosus GG was enhanced by 25-fold. Additionally, whole-cell homogenates showed the highest β-glucosidase activity when compared with disrupted cell suspensions; the cell disruption step significantly decreased the β-glucosidase activity. Based on the optimized enzyme conditions, whole-cell L. rhamnosus GG was successfully used to convert ginsenoside Rb1 into Rd.

Review on Bifidobacterium bifidum BGN4: Functionality and Nutraceutical Applications as a Probiotic Microorganism

Bifidobacterium bifidum BGN4 is a probiotic strain that has been used as a major ingredient to produce nutraceutical products and as a dairy starter since 2000. The various bio-functional effects and potential for industrial application of B. bifidum BGN4 has been characterized and proven by in vitro (i.e., phytochemical bio-catalysis, cell adhesion and anti-carcinogenic effects on cell lines, and immunomodulatory effects on immune cells), in vivo (i.e., suppressed allergic responses in mouse model and anti-inflammatory bowel disease), and clinical studies (eczema in infants and adults with irritable bowel syndrome). Recently, the investigation of the genome sequencing was finished and this data potentially clarifies the biochemical characteristics of B. bifidum BGN4 that possibly illustrate its nutraceutical functionality. However, further systematic research should be continued to gain insight for academic and industrial applications so that the use of B. bifidum BGN4 could be expanded to result in greater benefit. This review deals with multiple studies on B. bifidum BGN4 to offer a greater understanding as a probiotic microorganism available in functional food ingredients. In particular, this work considers the potential for commercial application, physiological characterization and exploitation of B. bifidum BGN4 as a whole.

Changes in growth and survival of Bifidobacterium by coculture with Propionibacterium in soy milk, cow's milk, and modified MRS medium.

Bifidobacterium adolescentis Int57 (Int57) and Propionibacterium freudenreichii subsp. shermanii ATCC 13673 (ATCC 13673) were grown either in coculture or as pure cultures in different media, such as cows milk, soybean milk, and modified MRS medium. The viable cell counts of bacteria, changes in pH, concentrations of organic acids, and contents of various sugars were analyzed during incubation up to 7days. In soy milk, the survival of cocultured Int57 was six times higher than the monocultured cells, and ATCC 13673 cocultured with Int57 consumed 69.4% of lactic acid produced by Int57 at the end of fermentation. In cows milk, coculture with ATCC 13673 increased the growth of Int57 from 24h until 120h by approximately tenfold and did not affect the survival of Int57 cells. After 96h of fermentation of modified MRS, the survival of ATCC 13673 cells cocultured with Int57 increased by 3.2- to 7.4-folds as compared with ATCC 13673 monoculture, whereas the growth of Int57 cells was unaffected. The growth and metabolic patterns of two strains during coculture showed noticeable differences between food grade media and laboratory media. The consumption of stachyose in soy milk during coculture of Int57 with ATCC 13673 was increased by more than twice compared with Int57 monoculture, and completed within 24h. The combinational use of Bifidobacterium and Propionibacterium could be applied to the development of fermented milk or soy milk products.

Factor XII-mediated contact activation related to poor prognosis in disseminated intravascular coagulation

BACKGROUND The contact system that initiates the intrinsic coagulation pathway plays a role in thrombus formation. Since neutrophil extracellular traps (NET), which are mainly composed of histone and DNA, are actively formed in disseminated intravascular coagulation (DIC) and the NET can activate factor XII, it is plausible that a NET component strongly activates the contact system in patients with DIC. METHODS In 146 patients suspected of having DIC, the plasma levels of contact system factors including factor XII, activated factor XII (XIIa), prekallikrein, high-molecular-weight kininogen (HMWK), bradykinin, extrinsic factor VII and histone–DNA complex were measured. In an in vitro plasma clotting assay, factor XII–deficient plasma was stimulated with silica or histone. RESULTS The levels of not only extrinsic coagulation factor VII but also intrinsic coagulation factors including factors XI and XII were significantly decreased in patients with overt DIC in comparison with those with no overt DIC. Factor XIIa and histone-DNA complex were also significantly increased in patients with overt DIC. However,HMWK, prekallikrein and bradykin inw ere not significantly different between patients with and without overt DIC. Interestingly, factors XII and XIIa were revealed as significantly independent potential prognostic markers for DIC. The histone-DNA complex level significantly contributed to the factor XIIa level (20.6%). In an in vitro clotting assay, histone, a major component of NET, activated coagulation that was dependent, in part, on the presence of factor XII. CONCLUSION These findings suggest that active NET formation can induce factor XII-mediated coagulation activation in patients with DIC with poor prognosis. The resulting factor XIIa release can be used as an independent potential prognostic marker for DIC. Activation of factor XII-mediated coagulation may be a potential therapeutic target in DIC,