• Journal of Applied Biological Chemistry
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• v.64 no.3
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• pp.309-316
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• 2021

Kaempferol 3-O-galactoside (Trifolin), a member of the flavonol group, has been reported to have anticancer effects against promyelocytic leukemia, histocytic lymphoma, skin melanoma and lung cancer. Trifolin has been extracted and used from several plants, but the extraction process is complicated and the final yield is low. Biotransformation is an alternative tool to produce high value-added chemicals from inexpensive compounds. To synthesis trifolin from naringenin, three genes (PeFLS and OsUGE-PhUGT) were introduced into Escherichia coli, respectively. In order to synthesis trifolin from naringenin, a co-culture fermentation system was established by optimizing the cell concentration, biotransformation temperature and medium, isopropyl-β-D-thiogalactoside (IPTG) concentration, substrate supply concentration, and recombinant protein induction time. The established optimal conditions for trifolin production were a 3:1 ratio of BL-UGTE to BL-FLS, induction of recombinant protein at 25 ℃ for 4 h after addition of 2.0 mM IPTG, biotransformation at 30 ℃, and supply of 300 μM naringenin. Through the optimized co-culture fermentation system, trifolin was biosynthesized up to 67.3 mg/L.

• Genes and Genomics
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• v.40 no.11
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• pp.1199-1211
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• 2018

Soil acidification is one of major problems limiting crop growth and especially becoming increasingly serious in China owing to excessive use of nitrogen fertilizer. Only the STOP1 of Arabidopsis was identified clearly sensitive to proton rhizotoxicity and the molecular mechanism for proton toxicity tolerance of plants is still poorly understood. The main objective of this study was to investigate the transcriptomic change in plants under the low pH stress. The low pH as a single factor was employed to induce the response of the wheat seedling roots. Wheat cDNA microarray was used to identify differentially expressed genes (DEGs). A total of 1057 DEGs were identified, of which 761 genes were up-regulated and 296 were down-regulated. The greater percentage of up-regulated genes involved in developmental processes, immune system processes, multi-organism processes, positive regulation of biological processes and metabolic processes of the biological processes. The more proportion of down-regulation genes belong to the molecular function category including transporter activity, antioxidant activity and molecular transducer activity and to the extracellular region of the cellular components category. Moreover, most genes among 41 genes involved in ion binding, 17 WAKY transcription factor genes and 17 genes related to transport activity were up-regulated. KEGG analysis showed that the jasmonate signal transduction and flavonoid biosynthesis might play important roles in response to the low pH stress in wheat seedling roots. Based on the data, it is can be deduced that WRKY transcription factors might play a critical role in the transcriptional regulation, and the alkalifying of the rhizosphere might be the earliest response process to low pH stress in wheat seedling roots. These results provide a basis to reveal the molecular mechanism of proton toxicity tolerance in plants.

• Journal of Plant Biotechnology
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• v.46 no.3
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• pp.236-245
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• 2019

Fruit ripening is a genetically programmed process involving a number of biochemical and physiological processes assisted by variations in gene expression and enzyme activities. This process generally affects the phytochemical profile and the bioactive principles in fruits and vegetables. To appraise the variation in bioactive principles of fruits from Rosa rugosa during its ripening process, we analyzed the changes in antioxidant and anti-elastase activities and polyphenolic compounds during the four ripening stages of fruits. Overall, an extract of unripe fruits contained the highest levels of total phenolic and flavonoid contents, radical scavenging activity, reducing power, oxygen radical antioxidant capacity, and elastase inhibitory activity, compared with the extracts of fruits at other stages of ripening. Additionally, we found that the reduction of flavonoid content occurs because of decreased transcriptional levels of genes involved in flavonoid biosynthesis pathway during the ripening process. Based on HPLC analysis, we found that the extract of unripe fruits contained the highest amount of myricetin, caffeic acid, chlorogenic acid, syringic acid, and p-coumaric acid and suggested that the antioxidant and anti-elastase activities of the extract obtained from stage 1, should be mediated by the presence of these compounds. Additionally, we analyzed the interaction sites and patterns between these compounds and elastase using the structure-based molecular docking approach, and suggested that chlorogenic acid strongly interacted with elastase. Together, these findings suggest that the maturity of fruits has profound effects on the pharmaceutical value of R. rugosa.

• Journal of Life Science
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• v.30 no.1
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• pp.96-105
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• 2020

Sirtuin inhibitors are pharmaceutically and therapeutically valuable compounds that inhibit sirtuin, a type III histone deacetylase. Synthetic sirtuin inhibitors were discovered and characterized using cell-based screens in yeast (Saccharomyces cerevisiae) and have been used in the study of aging, carcinogenesis, and diabetes, all of which are related to sirtuin function. For medical applications, synthetic inhibitors have been further developed for increased potency and specificity, including compounds containing nicotinamide, thioacetyl lysine, β-naphthol, and indole derivatives. Suramin, tenovin, and their analogues were developed as a result. Sirtuin inhibitors were found to affect organic development and have been used to genetically modify plants, although a sirtinol-resistant mutation in the biosynthesis of a molybdopterin cofactor for an aldehyde oxidase has been identified. Some natural flavonoids, and catechin and quercetin derivatives also act as sirtuin inhibitors have been studied to identify a more potent inhibitor for therapeutic purposes. In this review, sirtuin is introduced and the therapeutic inhibitors that have been developed are presented, particularly sirtinol which has been used for genetic modification in plants though it was not designed to be so. Sirtuin inhibitors with greater potency and selectivity are required and those developed in pharmaceutics should be used in plant research to identify more authentic sirtuins in plants.

• Journal of Life Science
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• v.28 no.2
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• pp.247-256
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• 2018

3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) are widely used drugs for lowering blood lipid levels and preventing cardiovascular diseases. HMG-CoA reductase is a key enzyme to control the biosynthesis of cholesterol. We have tested HMG-CoA reductase-inhibitory activity on the flavonoids of 98 species in vitro. The anti-hypercholesterolemic activities of flavonoids were studied using an HMG-CoA reductase assay equipped with a 96-well UV plate. This assay was based on the spectrophotometric measurement of the decrease in absorbance, which represents the oxidation of NADPH by the catalytic subunit of HMG-CoA reductase in the presence of the substrate HMG-CoA. Among the clinically available statins, pravastatin was used as a positive control. Among the tested compounds, kuraridin, morin and sophoraflavanone G showed strong inhibition activities. In particular, morin and sophoraflavanone G inhibited HMG-CoA reductase by 45.0% and 54.6% at a concentration of $10{\mu}g/ml$, and the $IC_{50}$ values were calculated to $13.31{\mu}g/ml$ and $7.26{\mu}g/ml$ respectively.

• Applied Biological Chemistry
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• v.44 no.2
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• pp.122-128
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• 2001

This review showed a discussion on the biofunctional activities of citrus flavonoids. The major flavonoids of citrus species, hesperidin, hesperetin, naringin, and naringenin, were selected to evaluate their biological effects on the lipid metabolism in rats and hamsters, the proliferation of human hepatocyte HepG2 cells, and the antioxidative effect in lipid peroxidation models. These flavonoids showed hypotriglyceridemic effect in hamsters and hypochloesterolemic effect in rats. They also significantly inhibited the activities of phosphatidate phophohydrolase and acyl-CoA: cholesterol acyltransferase, which are key enzymes for biosynthesis of triglyceride and cholesterol, repectively, in vivo and in vitro experiments. These biofunctional activities by citrus flavonoids were shown more potent in the aglycone flavonoids, hespreretin and naringenin, than their corresponding glycoside flavonoids, hesperidin and naringin. These aglycone flavonoids also have inhibitory effects on proliferation of human hepatocyte cancer HepG2 cells. Hesperidin showed lowering activities of cellular triglyceride and cholesterol concentrations in HepG2 cells. Citrus flavonoids have significant importance in functional food industry as biofunctional active ingredients.

• Journal of Life Science
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• v.18 no.2
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• pp.234-240
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• 2008

Anthocyanin synthesis in strawberry (Fragaria x ananassa cv Maehyang) begins approximately 26 days postflowering and continued throughout fruit ripening. A set of cDNA clones encoding the anthocyanin biosynthetic enzymes were isolated from strawberry. A pair of primers were designed for polymerase chain reaction (PCR) through the comparison of the nucleotide sequences of homologous genes from diverse plants. Reverse transcriptase-PCRs were performed using cDNA synthesized from ripe fruit total RNA and the primers corresponding to each gene. Eight genes of the anthocyanin pathway were cloned and confirmed by sequencing to code for phenylalanine ammonia lyase (PAL), 4-cummarate CoA ligase (4CL), chalcone synthase (CHS), chalcone isomerase (CHI), flavanone-3-hydroxylase (F3H), dihydroflavonol 4-reductase (DFR), anthocyanidine synthase (ANS), UDP-glucose:flavonoid-3-O-glucosyl-transferase (UFGT). Northern analyses showed that the corresponding genes were differentially expressed during the fruit development process. All genes except PAL were predominantly expressed in fruit. Expression of PAL, DFR and ANS was detected 10 days postflowering at the early stage of fruit development, declined for a while and sharply increased 22 days postflowering then showed a peak 34 days postflowering. The other genes, however, were not expressed up to 22 or 30 days postflowering when the initial fruit ripening events occur at the time of initiation of anthocyanin accumulation. The onset of anthocyanin synthesis in ripening strawberry coincides with a coordinated induction of the anthocyanin pathway genes, suggesting the involvement of regulatory genes. We propose that at least two different regulatory mechanisms playa role in the biosynthesis of anthocyanin during color development of strawberry.

• Food Science and Preservation
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• v.19 no.3
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• pp.393-399
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• 2012

In this study, the antioxidant and anti-wrinkling effects of extracts from Aruncus diocius var. kamtschaticus (ADV) were investigated. According to the results, the ethanol extract has better antioxidant and anti-wrinkling effects than the water extract. The amounts of total polyphenol and flavonoid compounds in the ethanol extract were 122 and 36 mg/g, respectively, while those in the water extract were 87 and 26 mg/g. The antioxidant activities of the ethanol and water extracts were 395 and 4,682 ${\mu}g/mL$ as the $RC_{50}$ values for the DPPH radical scavenging activity, and 227 and 366 ${\mu}g/mL$ for the $ABTS^+$ radical scavenging activity, respectively. The reducing power of the ethanol extract (1.58 at 2 mg/mL) was higher than that of the water extract (0.88 at 2 mg/mL). The astringent activities of the ethanol and water extracts were 91.27 and 16.35% at 10 mg/mL, respectively. Furthermore, the ADV ethanol extract treatment of the fibroblast cell after UV irradiation resulted in increased cell viability (10% at 100 ${\mu}g/mL$) and collagen biosynthesis (33% at 100 ${\mu}g/mL$), with a lowering in the MMP-1 expression level (16.8 % at 100 ${\mu}g/mL$). These results demonstrate that AVD provides a remarkable and significant tensor and anti-wrinkling effect on the skin, which could be of a great use in anti-aging skin care products.