Naringenin is a natural flavonoid compound with anti-inflammatory, anti-oxidation, anti-viral, anti-atherosclerosis and other pharmacological activities. It is also an important precursor of other flavonoid synthesis and with great value of application. At present, the production of flavonoids such as naringenin by microbial methods has a low yield due to imbalance of metabolic pathways, which greatly limits its industrial application. In this study, a naringenin-producing strain of Saccharomyces cerevisiae Y-01 was used in the research object. The expression levels of 4-coumaric acid: CoA ligase (4CL), chalcone synthase (CHS) and chalcone isomerase (CHI) were controlled by promoter and copy numbers to investigate the quantitative effect of key enzyme expression level on the accumulation level of target products. The results showed that the correlation between naringenin production and 4CL or CHI expression was not significant while there was a positive correlation with the expression level of CHS. Strain Y-04 with high yield of naringenin was obtained by regulating the expression level of chs gene, and the yield was increased by 4.1-folds compared with the original strain Y-01. This study indicated that CHS is a key regulatory target of naringenin synthesis. Rational regulation of CHS expression can significantly promote the accumulation of naringenin. The related results provide an important theoretical reference for the use of metabolic engineering to strengthen microbial synthesis of important flavonoids such as naringenin.
Flavanones ; metabolism ; Metabolic Engineering ; Saccharomyces cerevisiae

In this study,liquiritigenin sulfonation was characterized using recombinant human sulfotransferases( SULTs). The chemical structure of liquiritigenin sulfate was determined by ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry( UPLC-Q-TOF-MS/MS). Then model fitting and parameter estimation were performed using the Graphpad Prism V5 software. Various SULT enzymes( SULT1 A1,1 A2,1 A3,1 B1,1 C2,1 C4,1 E1 and 2 A1) were able to catalyze the formation of liquiritigenin-7-O-sulfate. Sulfonation of liquiritigenin-7-hydroxy( 7-OH) by these eight SULT enzymes consistently displayed the classical Michaelis-Menten profile. According to the intrinsic clearance( CLint) value,the sulfonation rates of liquiritigenin-7-OH by expressed SULT enzymes followed the following rank order: SULT1 C4 > SULT1 A3 > SULT1 E1 > SULT1 A1 > SULT1 A2 > SULT1 B1 >SULT1 C2>SULT2 A1. Further,liquiritigenin-7-O-sulfonation was significantly correlated with the SULT1 A3 protein levels( P<0. 05).Then,human embryonic kidney( HEK) 293 cells over expressing SULT1 A3( named as HEK-SULT1 A3 cells) were conducted. As a result,liquiritigenin-7-O-sulfate( L-7-S) was rapidly generated upon incubation of the cells with liquiritigenin. Consistent with SULT1 A3,sulfonation of liquiritigenin-7-OH in HEK-SULT1 A3 cells also followed the Michaelis-Menten kinetics. The derived Vmaxvalues was( 0. 315±0. 009) μmol·min-1·g-1,Kmwas( 7. 04±0. 680) μmol·L^-1,and CLintwas( 0. 045±0. 005) L·min^-1·g^-1. Moreover,the sulfonation characters of liquiritigenin( 7-OH) in SULT1 A3 were strongly correlated with that in HEK-SULT1 A3 cells( P<0. 001).The results indicated that HEK-SULT1 A3 cells have shown the catalytic function of SULT1 A3 enzymes. In conclusion,liquiritigenin was subjected to efficient sulfonation,and SULT1 A3 enzyme plays an important role in the sulfonation of liquiritigenin-7-OH. Significant sulfonation should be the main reason for the low bioavailability of liquiritigenin. In addition,HEK-SULT1 A3 cells were conducted and successfully used to evaluate liquiritigenin sulfonation,which will provide an appropriate tool to accurately depict the sulfonation disposition of liquiritigenin in vivo.
Arylsulfotransferase ; Flavanones/metabolism* ; Humans ; Tandem Mass Spectrometry

Flavonoids have a variety of biological activities and have important applications in food, medicine, cosmetics, and many other fields. Naringenin is a platform chemical for the biosynthesis of many important flavonoids. Ubiquitination plays a pivotal role in the post-translational modification of proteins and participates in the regulation of cellular activities. Ubiquitinated proteins can be degraded by the ubiquitin-protease system, which is important for maintaining the physiological activities of cells, and may also exert a significant impact on the expression of exogenous proteins. In this study, a real-time in-situ detection system for ubiquitination modification has been established in Saccharomyces cerevisiae by using a fluorescence bimolecular complementation approach. The ubiquitination level of protein was characterized by fluorescence intensity. By using the approach, the potential ubiquitination sites of proteins involved in the naringenin biosynthesis pathway have been obtained. The lysine residues of the relevant ubiquitination sites were mutated to arginine to reduce the ubiquitination level. The mutants of tyrosine ammonia-lyase (FjTAL) and chalcone synthase (SjCHS, SmCHS) showed decreased fluorescence, suggested that a decreased ubiquitination level. After fermentation verification, the S. cerevisiae expressing tyrosine ammonia-lyase FjTAL mutant FjTAL-K487R accumulated 74.2 mg/L p-coumaric acid at 72 h, which was 32.3% higher than that of the original FjTAL. The strains expressing chalcone synthase mutants showed no significant change in the titer of naringenin. The results showed that mutation of the potential ubiquitination sites of proteins involved in the naringenin biosynthesis pathway could increase the titer of p-coumaric acid and have positive effect on naringenin biosynthesis.
Biosynthetic Pathways ; Flavanones/metabolism* ; Saccharomyces cerevisiae/metabolism* ; Ubiquitination

OBJECTIVE: To explore the effects of Eriodictyol to the growth, apoptosis and oxidative stress of Burkitt lymphoma (BL) cells and phosphorylation of protein kinase B (AKT) in children. METHODS: The effects of Eriodictyol (0, 1.25, 2.5, 5, 10, 20, 40, 80, 160, 320 μmol/L) to viability of BL cell line DG-75 cells were detected by CCK-8. The effects of Eriodictyol (0, 10, 20, 40 μmol/L) to the proliferation activity of DG-75, apoptosis rate, levels of apoptosis-related proteins, oxidative stress indexes ［superoxide dismutase (SOD), malondialdehyde (MDA)］, mitochondrial membrane potential (MMP) and phosphorylation level of phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycinm (mTOR) were detected by clony formation assay and Wester blot. RESULTS: When the treatment concentration of Eriodictyol was 20 μmol/L, the proliferation activity of the cells was decreased (P<0.05). The concentrations at 10, 20, 40 μmol/L were selected for subsequent experiments. Compared with 0 μmol/L Eriodictyol, the proliferation activity of DG-75, SOD activity, MMP, phosphorylation levels of PI3K, AKT and mTOR in 20 and 40 μmol/L Eriodictyol treatment groups were significantly decreased (P<0.05), while cells apoptosis rate, Cleaved-Caspase-3/Caspase-3, Bax/Bcl-2 and MDA level were significantly increased (P<0.05). CONCLUSION Eriodictyol may promote the mitochondrial apoptosis pathway by inhibiting the abnormal activation of PI3K/AKT/mTOR to reduce the proliferation activity of DG-75, and inhibit oxidative stress response to increase the apoptosis rate and play anti-tumor roles.
Apoptosis ; Flavanones ; Phosphatidylinositol 3-Kinases/metabolism* ; Signal Transduction

This experiment aimed to explore and research the process of preparing baicalein and wogonin through liquid fermentation with Bacillus natto. Active enzymes of produced by B. natto was used for the biological transformation of baclin and wogonoside, in order to increase the content of the haicalein and wogonin in the scutellaria. With the content of the baicalein and wogonin as evaluating indexes, the effects of carbon source, nitrogen source, the types and suitable concentration of inorganic salt, medium pH, granularities of medical materials, liquid volume in flask, shaking speed, liquid-to-solid ratio, fermentation time on the fermentation process were studied. The optimal process conditions for liquid fermentation of scutellaria were 1.0% of peptone, 0.05% of NaCl, pH at 6, the granularities of medical materials of the scutellaria screened through 40-mesh sifter, 33% of liquid, shaker incubator speed at 200 r x min(-1), liquid-to-solid ratio of 5:1, temperature at 37 degrees C, fermentation for 6 days, baclin's conversion rate at 97.6% and wogonoside's conversion rate at 97% in the scutellaria. According to the verification test, the process was stable and feasible, and could provide data reference for the industrial production.
Bacillus subtilis ; metabolism ; Biotransformation ; Fermentation ; Flavanones ; metabolism ; Flavonoids ; metabolism ; Glucosides ; metabolism ; Soy Foods ; microbiology

Naringenin (1) was transformed to three metabolites (2-4) by Mucor sp. Based on LCMS(n)-IT-TOF and NMR spectroscopic data, 2-4 were identified as naringenin-7-O-sulphate, naringenin-4'-O-sulphate, and naringenin-5-O-sulphate, respectively. These results might provide hints to the mammalian/human metabolism of naringenin.
Biotransformation ; Drugs, Chinese Herbal ; chemistry ; metabolism ; Flavanones ; chemistry ; metabolism ; Magnetic Resonance Spectroscopy ; Molecular Structure ; Mucor ; metabolism ; Sulfates ; metabolism

OBJECTIVETo study the transdermal absorbability of gentiopicroside, naringin and protosappanin B contained in Xuanbi gel plaster.

METHODThe Franz diffusing cells method was adopted for the in vitro model of rat belly skins. Three indexes, gentiopicroside, naringin and protosappanin B, residued in the accept liquid, skins and plaster were determined by HPLC.

RESULTThe penetration rates of gentiopicroside, naringin and protosappanin B were respectively 3.47, 1.59, 2.13 microg x cm(-2) x h(-1). After 24 h, their penetration rates were 25.42%, 11.73%, 17.78%, respectively. The residual quantities of gentiopieroside, naringin and protosappanin B in skin were 0.231, 0.593, 0.568 microg x cm(-2), ith the retention rates of 0.027%, 0.227%, 0.475%, respectively. The amount of residue of gentiopicroside, naringin and protosappanin B in plaster were 2179, 674, 278 microg, with the retention rates of 81.36%, 81.92%, 73.83%, respectively.

CONCLUSIONThe in vitro transdermal behavior of Xuanbi gel plaster is close to a zero-order process. The residual quantity the retention rate in skins is much lower than the penetration rate and the residual rate in plaster.

Administration, Cutaneous ; Animals ; Flavanones ; metabolism ; Gels ; chemistry ; Iridoid Glucosides ; metabolism ; Male ; Phenols ; metabolism ; Rats ; Rats, Sprague-Dawley ; Skin Absorption

The objective of this study was to investigate the protection by naringenin against doxorubicin-induced oxidative damage in normal blood cells. Inhibiting effects of naringenin, doxorubicin and naringenin combined with doxorubicind on K562 cells and polymorphonuclear leukocytes were detected with MTT method, the level of reactive oxygen species (ROS) and lipid peroxidation (MDA), the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were examined with spectrophotometric method in the K562 cells and polymorphonuclear leukocytes. The results indicated that the proliferation of K562 cells was not inhibited by the cytotoxicity of doxorubicin in combination of naringenin with doxorubicin. As compared with the doxorubicin, the addition of naringenin after doxorubicin for 1 hour, the levels of reactive oxygen species (ROS) and lipid peroxidation (MDA) obviously decreased, the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) obviously increased in the polymorphonuclear leukocytes, but these were not changed obviously in K562 cells. It is concluded naringenin can protect against doxorubicin-induced oxidative damage in normal blood cells. The mechanism of naringenin may be elevating activities of antioxidant enzyme and degrading oxidative production level in normal blood cells, and meanswhile decreasing level of oxidative products.
Antioxidants ; pharmacology ; Doxorubicin ; adverse effects ; Erythrocytes ; drug effects ; Flavanones ; pharmacology ; Humans ; Oxidative Stress ; Reactive Oxygen Species ; metabolism ; Superoxide Dismutase ; metabolism

OBJECTIVETo compare the effects of 8-prenylnaringenin (PNG) and naringenin (NG) on the activity and apoptosis of osteoclasts cultured in vitro, in order to study physiological activity of 8-prenyl perssad.

METHODOsteoclasts were separated from long-limb bones of newly born rabbits, cultured in alpha-MEM containing 10% FBS, and then added with PNG and NG with the concentration of 1 x 10(-5) mol x L(-1). They were stained with TRAP and determined for enzymatic activity with TRAP after 4 d, and analyzed by toluidine blue staining after 7 d. The apoptotic osteoclasts were analyzed by Annexin V-FITC staining after 2, 4, 8, 12, 24, 36, and 48 hours, to observe their apoptosis. Their total RNAs were extracted, and analyzed for TRAP and Cathepsin K expressions by Real-time RT-PCR.

RESULTCompared with the control group, both of the PNG group and the NG group showed much less osteoclasts (TRAP positive cells), lower TRAP activity and TRAP and Cathepin K (CTSK) expression, and smaller number of bone resorption pits and areas. The PNG group show lower indexes than the NG group. Additionally, the PNG group reached the apoptotic peak of osteoclasts at 12 h after drug administration, whereas the NG group reached after 24 h. And the former had more apoptotic cells than the latter.

CONCLUSION8-PNG is much more active than NG in inhibiting the resorption of osteoclasts and inducing apoptosis of osteoclasts. Their only difference lies in 8-prenyl perssad, which is proved to be able to enhance the anti-bone resorption activity of 8-prenylnarigenin.

Acid Phosphatase ; metabolism ; Animals ; Bone Resorption ; prevention & control ; Cathepsin K ; metabolism ; Cells, Cultured ; Flavanones ; pharmacology ; Osteoclasts ; drug effects ; Rabbits

OBJECTIVETo evaluate colon targeting characteristic of Kuikang colon targeted pellets (KCP) with determination of residual baicalin and baicalein concentration in gastrointestinal tract (GIT).

METHODThe baicalin and baicalein were assayed by HPLC. The recovery differences of the drug between KCP and conventional pellets from GIT were investigated, three and six hours after administration.

RESULTThe baicalin recovery of KCP (70%) from rat GIT was higher than that of CP (about 20%). Most of KCP were intact at 3 h after oral administration, and distributed in lower ileum. It indicated that release site of KCP was in lower ileum and colon. Six hours later, a small amount of baicalin was recovered in intestime, which showed that the release of baicalin from KCP was complete.

CONCLUSIONThe determination of residual baicalin in rat GIT was feasibility for evaluating KCP. The result confirmed KCP of colon targeting property.

Animals ; Colon ; metabolism ; Drug Delivery Systems ; Drug Implants ; Drugs, Chinese Herbal ; administration & dosage ; metabolism ; Flavanones ; metabolism ; Flavonoids ; metabolism ; Ileum ; metabolism ; Logistic Models ; Rats ; Rats, Wistar