• Fisheries and Aquatic Sciences
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• v.26 no.3
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• pp.204-215
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• 2023

The thermolabile haemolysin (tlh) of Vibrio parahaemolyticus (Vptlh) from V. parahaemolyticus is a multiple-function enzyme, initially describes as a haemolytic factor activated by lecithin and phospholipase A2 enzymatic activity (Shinoda, 1991; Vazquez-Morado, 2021; Yanagase et al., 1970). Until now, the tlh structure has hypothesized including N-terminal and C-terminal domain, but what domain of the Vptlh structure does the haemolytic activity has not been refined yet. In this study, a 450-bp VpTLH nucleotide sequence of the entire Vptlh gene encoded the C-terminal domain cloned firstly to examine its responsibility in the activity of the Vptlh. The C-terminal domain fused with a 6-His-tag named the His-tag-VpC-terminal domain was expressed successfully in soluble form in the BL21 (DE3) PlysS cell. Remarkably, both expression and purification results confirmed a high agreement in the molecular weight of the His-tag-VpC-terminal domain was 47 kDa. This work showed the His-tag-VpC-terminal domain lysed the erythrocyte membranes in the blood agar and the phosphate buffered saline (0.9%) media without adding the lecithin substrate of the phospholipase enzyme. Haemolysis occurred at all tested diluted concentrations of His-tag-VpC-terminal domain (p < 0.05), providing evidence for the independent haemolytic activity of the His-tag-VpC-terminal domain. The content of 100 ㎍ of the His-tag-VpC-terminal domain brought the highest haemolytic activity of 80% compared to that in the three remaining contents. Significantly, the His-tag-VpC-terminal domain demonstrated not to involve the phospholipase activity in Luria-Bertani agar supplemented with 1% (vol/vol) egg yolk emulsion. All results proved the vital responsibility of the His-tag-VpC-terminal domain in causing the haemolytic activity without the required activation by the phospholipase enzyme. Raw extracts of Phellinus igniarus and Phellinus pipi at 10^-1 mg/mL inhibited the haemolytic activity of the His-tag-VpC-terminal domain from 67.7% to 87.42%, respectively. Hence applying the His-tag-VpC-terminal domain as a simple biological material to evaluate quickly potential derivatives against the Vptlh in vivo conditions will accessible and more advantageous than using the whole of the Vptlh.

• Journal of Ginseng Research
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• v.38 no.2
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• pp.154-159
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• 2014

Background: This study was carried out to investigate the effect of the steaming process on chemical constituents, free radical scavenging activity, and antiproliferative effect of Vietnamese ginseng. Methods: Samples of powdered Vietnamese ginseng were steamed at $120^{\circ}C$ for various times and thei extracts were subjected to chemical and biological studies. Results: Upon steaming, contents of polar ginsenosides, such as Rb1, Rc, Rd, Re, and Rg1, were rapidly decreased, whereas less polar ginsenosides such as Rg3, Rg5, Rk1, Rk3, and Rh4 were increased as reported previously. However, ocotillol type saponins, which have no glycosyl moiety at the C-20 position, were relatively stable on steaming. The radical scavenging activity was increased continuously up to 20 h of steaming. Similarly, the antiproliferative activity against A549 lung cancer cells was also increased. Conclusion: It seems that the antiproliferative activity is closely related to the contents of ginsenoside Rg3, Rg5, and Rk1.

• ALGAE
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• v.30 no.2
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• pp.147-161
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• 2015

Brown algal extracts have long been used as feed supplements to promote health of farm animals. Here, we show new molecular insights in to the mechanism of action of a fucose containing polymer (FCP) rich fraction from the brown seaweed Ascophyllum nodosum using the Caenorhabditis elegans-Pseudomonas aeruginosa PA14 infection model. FCP enhanced survival of C. elegans against pathogen stress, correlated with up-regulation of key immune response genes such as: lipases, lysozyme (lys-1), saponin-like protein (spp-1), thaumatin-like protein (tlp-1), matridin SK domain protein (msk-1), antibacterial protein (abf-1), and lectin family protein (lfp). Further, FCP caused down regulation of P. aeruginosa quorum sensing genes: (lasI, lasR, rhlI, and rhlR), secreted virulence factors (lipase, proteases, and elastases) and toxic metabolites (pyocyanin, hydrogen cyanide, and siderophore). Biofilm formation and motility of pathogenic bacteria were also greatly attenuated when the culture media were treated with FCP. Interestingly, FCP failed to mitigate the pathogen stress in skn-1, daf-2, and pmk-1 mutants of C. elegans. This indicated that, FCP treatment acted on the regulation of fundamental innate immune pathways, which are conserved across the majority of organisms including humans. This study suggests the possible use of FCP, a seaweed component, as a functional food source for healthy living.

• Journal of Ginseng Research
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• v.34 no.4
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• pp.288-295
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• 2010

Ginsenosides are the principal components responsible for the pharmacological and biological activities of ginseng. Ginsenoside Rd was transformed into compound K using cell-free extracts of food microorganisms, with Lactobacillus pentosus DC101 isolated from kimchi (traditional Korean fermented food) used for this conversion. The optimum time for the conversion was about 72 h at a constant pH of 7.0 and an optimum temperature of about $30^{\circ}C$. The transformation products were identified by thin-layer chromatography and high-performance liquid chromatography, and their structures were assigned using nuclear magnetic resonance analysis. Generally, ginsenoside Rd was converted into ginsenoside F2 by 36 h post-reaction. Consequently, over 97% of ginsenoside Rd was decomposed and converted into compound K by 72 h post-reaction. The bioconversion pathway to produce compound K is as follows: ginsenoside Rd$\rightarrow$ginsenoside F2$\rightarrow$compound K.

• Natural Product Sciences
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• v.8 no.1
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• pp.1-15
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• 2002

An International Cooperative Biodiversity Group (ICBG) program based at the University of Illinois at Chicago initiated its activities in 1998, with the following specific objectives: (a) inventory and conservation of of plants of Cuc Phuong National Park in Vietnam and of medicinal plants of Laos; (b) drug discovery (and development) based on plants of Vietnam and Laos; and (c) economic development of communities participating in the ICBG project both in Vietnam and Laos. Member-institutions and an industrial partner of this ICBG are bound by a Memorandum of Agreement that recognizes property and intellectual property rights, prior informed consent for access to genetic resources and to indigenous knowledge, the sharing of benefits that may arise from the drug discovery effort, and the provision of short-term and long-term benefits to host country institutions and communities. The drug discovery effort is targeted to the search for agents for therapies against malaria (antimalarial assay of plant extracts, using Plasmodium falciparum clones), AIDS (anti-HIV-l activity using HOG.R5 reporter cell line (through transactivation of the green fluorescent protein/GFP gene), cancer (screening of plant extracts in 6 human tumor cell lines - KB, Col-2, LU-l, LNCaP, HUVEC, hTert-RPEl), tuberculosis (screening of extracts in the microplate Alamar Blue assay against Mycobacterium tuberculosis $H_{37}Ra\;and\;H_{37}Rv),$ all performed at UIC, and CNS-related diseases (with special focus on Alzheimer's disease, pain and rheumatoid arthritis, and asthma), peformed at Glaxo Smith Kline (UK). Source plants were selected based on two approaches: biodiversity-based (plants of Cuc Phuong National Park) and ethnobotany-based (medicinal plants of Cuc Phuong National Park in Vietnam and medicinal plants of Laos). At mc, as of July, 2001, active leads had been identified in the anti-HIV, anticancer, antimalarial, and anti- TB assay, after the screening of more than 800 extracts. At least 25 biologically active compounds have been isolated, 13 of which are new with anti-HIV activity, and 3 also new with antimalarial activity. At GSK of 21 plant samples with a history of use to treat CNS-related diseases tested to date, a number showed activity against one or more of the CNS assay targets used, but no new compounds have been isolated. The results of the drug discovery effort to date indicate that tropical plant diversity of Vietnam and Laos unquestionably harbors biologically active chemical entities, which, through further research, may eventually yield candidates for drug development. Although the substantial monetary benefit of the drug discovery process (royalties) is a long way off, the UIC ICBG program provides direct and real-term benefits to host country institutions and communities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.11
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• pp.1674-1680
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• 2014

The aim of this study was to investigate the protective effects of methanolic extracts of cooked mixed grain rice samples, including grain rice (sorghum, black bean, proso millet, and Job's tears) mixed with fermented brown rice (GR), GR added with 0.5% water extract of Sanghwang mushroom (GRS) or 0.1% curry (GRK), and traditional five grain mixed rice (TMR, Ohgokbap), on $H_2O_2$-induced oxidative injury in LLC-PK1 pig renal epithelial cells. White rice (WR) was used as a positive control. Cells were first exposed to $H_2O_2$ ($250{\mu}M$) for 4 hr, followed by treatment with $100{\mu}g/mL$ of different GR extracts for 24 hr. $H_2O_2$ significantly induced cell damage (P<0.05). Cellular levels of reactive oxygen species (ROS), lipid peroxidation, and antioxidant enzymes, including catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-px), were measured. In addition, mRNA levels of antioxidant enzymes were determined by RT-PCR assay. Mixed grain rice, particularly GRS and GRK, were able to reduce cellular levels of ROS, decrease lipid peroxidation, and also increase mRNA expression of antioxidant enzymes compared to other samples. These results suggest that mixed grain rice, specifically GRS and GRK, have strong protective effects against $H_2O_2$-induced oxidative injury in LLC-PK1 cells through inhibition of lipid peroxidation, reduction of ROS levels, and elevation of antioxidant enzyme activities.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.2
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• pp.161-167
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• 2013

The aim of this study was to investigate the protective effects of methanolic extract from perilla (Perilla frutescens Britt var. japonica) leaves (PLME) on oxidative injury from hydrogen peroxide ($H_2O_2$) in human HaCaT keratinoctyes. Cells were co-incubated with various concentrations (0~200 ${\mu}g/mL$) of PLME for 24 hr, and then exposed to $H_2O_2$ (500 ${\mu}M$) for 4 hr. $H_2O_2$ significantly decreased cell viability (p<0.05). However, PLME provided protection from $H_2O_2$-induced HaCaT cell oxidation in a dose-dependent manner. To further investigate the protective effects of PLME on $H_2O_2$-induced oxidative stress in HaCaT cells, the cellular levels of lipid peroxidation, and antioxidant enzymes (including superoxide dismutase (SOD), glutathione peroxidase (GSH-px) and catalase (CAT)) were measured. PLME decreased cellular levels of lipid peroxidation, and also increased the activities of antioxidant enzymes. In addition, the antioxidant activities of PLME were also determined by DPPH and hydroxyl (${\cdot}OH$) radical scavenging assay, and major antioxidant compounds of PLME were measured by colorimetric methods. DPPH and ${\cdot}OH$ radical scavenging activities of PLME increased in a dose dependent manner and was similar to the DPPH scavenging activity of ascorbic acid at 50 ${\mu}g/mL$; however PLME activities were stronger than ascorbic acid (50 ${\mu}g/mL$) in the ${\cdot}OH$ scavenging assay. The amounts of antioxidant compounds, including total polyphenolics, total flavonoids, and total ascorbic acid from PLME were $52.2{\pm}1.1$ mg gallic acid (GAE)/g, $33.7{\pm}4.7$ mg rutin (RUE)/g, and $17.0{\pm}0.5$ mg ascorbic acid (AA)/g, respectively. These results suggest that PLME has a strong free radical-scavenging activity and a protective effect against $H_2O_2$-induced oxidative stress in the keratinocytes.