L-tyrosine is one of the 20 amino acids that make up proteins and is an essential amino acid for mammals, often used as a nutritional supplement. The conventional methods for synthesizing L-tyrosine have some problems such as the production of many by-products, high requirements for production conditions, and environmental pollution. In this study, we designed and constructed a multi-enzyme cascade for the synthesis of L-tyrosine with alanine, glutamate, ammonium chloride, and phenol as substrates. Initially, the sources of glutamate oxidase, alanine aminotransferase, and tyrosine phenol lyase were screened and analyzed, which was followed by the identification of the rate-limiting enzyme in the reaction process. A colorimetric screening method was established, and the rate-limiting enzyme DbAlaA was engineered to enhance its activity by 40.0%. Subsequently, the reaction conditions, including temperature, pH, cell concentration, and surfactant and coenzyme dosages, were optimized. After optimization, the yield of L-tyrosine reached 9.93 g/L, with a alanine conversion rate of 54.90%. Finally, a feed-batch fermentation strategy was adopted, and the yield of L-tyrosine reached 56.07 g/L after 24 h, with a alanine conversion rate of 65.22%. This study provides a reference for the whole-cell catalytic synthesis of L-tyrosine and its industrialization.
Tyrosine/biosynthesis* ; Escherichia coli/metabolism* ; Tyrosine Phenol-Lyase/genetics* ; Multienzyme Complexes/metabolism* ; Fermentation

Neuroinflammation is an important process underlying a wide variety of neurodegenerative diseases. Carvacrol (CAR) is a phenolic monoterpene commonly used as a food additive due to its antibacterial properties, but it has also been shown to exhibit strong antioxidative, anti-inflammatory, and neuroprotective effects. Here, we sought to investigate the effects of CAR on inflammation in the hippocampus and prefrontal cortex, as well as the molecular mechanisms underlying these effects. In our study, lipopolysaccharide was injected into the lateral ventricle of rats to induce memory impairment and neuroinflammation. Daily administration of CAR (25, 50, and 100 mg/kg) for 21 days improved recognition, discrimination, and memory impairments relative to untreated controls. CAR administration significantly attenuated expression of several inflammatory factors in the brain, including interleukin-1β, tumor necrosis factor-α, and cyclooxygenase-2. In addition, CAR significantly increased expression of brain-derived neurotrophic factor (BDNF) mRNA, and decreased expression of Toll-like receptor 4 (TLR4) mRNA. Taken together, these results show that CAR can improve memory impairment caused by neuroinflammation. This cognitive enhancement is due to the anti-inflammatory effects of CAR medicated by its regulation of BDNF and TLR4. Thus, CAR has significant potential as an inhibitor of memory degeneration in neurodegenerative diseases.
Animals ; Brain ; Brain-Derived Neurotrophic Factor ; Cyclooxygenase 2 ; Cytokines ; Discrimination (Psychology) ; Food Additives ; Hippocampus ; Inflammation ; Lateral Ventricles ; Lipopolysaccharides ; Memory ; Necrosis ; Neurodegenerative Diseases ; Neuroprotective Agents ; Phenol ; Prefrontal Cortex ; Rats ; RNA, Messenger ; Toll-Like Receptor 4

Objective: To verify the health advisory for short-term exposure to phenol. Methods: The method of this validation experiment was the same as the US Environmental Protection Agency (EPA) methodology for toxicology experiments used to determine phenol drinking water equivalent level (DWEL). Pregnant female Sprague-Dawley rats were administered phenol in distilled water by gavage at daily doses of 15, 30, 60, 120, and 240 mg/kg body weight (b.w.) from implantation (the 6th day post-mating) to the day prior to the scheduled caesarean section (the 20th day of pregnancy). The following information was recorded: general behavior; body weight; number of corpus luteum, live birth, fetus, stillbirth, and implantation; fetal gender; body weight; body length; tail length; and abnormalities and pathomorphological changes in the dams. Results: In the 60 mg/kg b.w. dose group, the mortality of pregnant rats increased with increasing doses, suggesting maternal toxicity. Fetal and placental weights decreased as phenol dose increased from 30 mg/kg b.w., and were significantly different compared those in the vehicle control group, which suggested developmental toxicity in the fetuses. However, the phenol-exposed groups showed no significant change in other parameters compared with the vehicle control group ( > 0.05). Conclusion Despite using the same method as the US EPA, a different NOEAL of 15 mg/(kg·d) was obtained in this study.
Animals ; Dose-Response Relationship, Drug ; Environmental Pollutants ; toxicity ; Female ; Fetal Development ; drug effects ; Phenol ; toxicity ; Pregnancy ; Rats ; Rats, Sprague-Dawley ; Toxicity Tests, Acute

BACKGROUND: We aimed to find the exposure level of environmental harmful substances related to the secondhand smoke (SHS) using a nationally representative data of the general population in Korea. METHODS: Total 3,533 people were included in this study. We compared the proportion exceeding 95 percentile of the concentrations of harmful substances by sex according to SHS exposure. 16 kinds of substances related to tobacco smoke were analyzed including heavy metals, polycyclic aromatic hydrocarbons, volatile organic compounds, and environmental phenol. For 16 kinds of substances, the odds ratios (ORs) for exceeding 95 percentile of each harmful substance were calculated by multiple logistic regression according to SHS exposure. Age, education level, marital status, body mass index, drinking, and exercise were adjusted as covariates. Cotinine level was additionally adjusted to increase reliability of our results. RESULTS: SHS was associated with high exposure of mercury, methylhippuric acid, fluorene, and cotinine. In women, SHS was associated with mercury, methylhippuric acid, fluorene, and cotinine, while in men, it was associated with cotinine. After adjusting covariates, ORs of blood mercury, methylhippuric acid and hydroxyfluorene in the exposed gruop were greater than that in the non-exposed group. Especially in female, methylhippuric acid and hydroxyfluorene showed consistent result. CONCLUSIONS: Our finding demonstrates that SHS is related to several harmful substances. Therefore, to reduce the health effects of SHS, it is necessary to educate and publicize the risk of SHS. Future studies are necessary to more accurately analyze factors such as exposure frequency, time, and pathway of SHS.
Adult ; Body Mass Index ; Cotinine ; Cross-Sectional Studies ; Drinking ; Education ; Environmental Health ; Female ; Humans ; Korea ; Logistic Models ; Male ; Marital Status ; Metals, Heavy ; Odds Ratio ; Phenol ; Polycyclic Hydrocarbons, Aromatic ; Smoke ; Tobacco ; Tobacco Smoke Pollution ; Volatile Organic Compounds

Purpurogallin, a natural phenol obtained from oak nutgalls, has been shown to possess antioxidant, anticancer, and anti-inflammatory effects. Recently, in addition to ultraviolet B (UVB) radiation that induces cell apoptosis via oxidative stress, particulate matter 2.5 (PM(2.5)) was shown to trigger excessive production of reactive oxygen species. In this study, we observed that UVB radiation and PM(2.5) severely damaged human HaCaT keratinocytes, disrupting cellular DNA, lipids, and proteins and causing mitochondrial depolarization. Purpurogallin protected HaCaT cells from apoptosis induced by UVB radiation and/or PM(2.5). Furthermore, purpurogallin effectively modulates the pro-apoptotic and anti-apoptotic proteins under UVB irradiation via caspase signaling pathways. Additionally, purpurogallin reduced apoptosis via MAPK signaling pathways, as demonstrated using MAPK-p38, ERK, and JNK inhibitors. These results indicate that purpurogallin possesses antioxidant effects and protects cells from damage and apoptosis induced by UVB radiation and PM(2.5).
Antioxidants ; Apoptosis Regulatory Proteins ; Apoptosis ; DNA ; Humans ; Keratinocytes ; Oxidative Stress ; Particulate Matter ; Phenol ; Reactive Oxygen Species

PURPOSE: Aster glehnii (AG) and Aster yomena (AY) are medicinal plants that belong to the family Compositea and grow widely in Korea. Plants in the genus Aster have been used to treat snakebite wounds or bruises in oriental medicine. This study compared the effects of anti-oxidants and anti-adipocyte differentiation according to the species (the aerial parts of AG and AY). METHODS: AG and AY were extracted using 70% ethanol (−E) and water (−W) at room temperature. The anti-oxidant activities were measured by total phenol contents (TPC), total flavonoid contents (TFC), DPPH and ABTS+ assay. In addition, correlation analysis was performed for the anti-oxidant compounds and effect. The level of anti-adipocyte differentiation was assessed using an oil red O assay on pre-adipocytes. RESULTS: AG-W showed higher TPC (6.92 µg/mL) and AG-E presented higher TFC (8.22 µg/mL) than the other extracts. Furthermore, AG-E exhibited higher radical scavenging activity in the DPPH and ABTS+ assay (IC50: 104.88 and 30.06 µg/mL). In the cytotoxicity assay, AG and AY extracts at concentrations less than 100µg/mL were non toxic. AG-W reduced the lipid accumulation of 3T3-L1 cells significantly after differentiation (70.49%) compared to the other extracts. CONCLUSION: These results show that the water extract of AG has anti-oxidant effects and reduces the differentiation of 3T3-L1 cells. Therefore, AG has utility as a functional food material for its anti-oxidant activities and ability to prevent lipid accumulation.
3T3-L1 Cells ; Adipocytes ; Antioxidants ; Contusions ; Ethanol ; Functional Food ; Humans ; Korea ; Medicine, East Asian Traditional ; Phenol ; Plants, Medicinal ; Snake Bites ; Water ; Wounds and Injuries

PURPOSE: This study was conducted to evaluate the physicochemical properties of different batches of Saururus chinensis using different roasting temperature that were dried at different using different roasting temperatures and their were determined the antioxidative activities of water and 70% ethanol extracts. METHODS: Extracts were examined for the total phenolic acid content, the and flavonoids contents and the antioxidant properties, including DPPH radical scavenging activity, ABTs scavenging activity and, the reducing power. RESULTS: Moisture content was significantly higher in the LSC and the crude ash content was significantly higher in the HSC. The crude protein content was higher in the LSC (although not significantly), and the crude fat and carbohydrate contents were higher in the HSC (although not significantly). The total phenolic content was lower in the samples extracted with water, but there was no significant difference. However, the extracts extracted with 70% ethanol at a high drying temperature were significantly higher. The low temperature and high drying temperature batches of Saururus chinensis were significantly higher in the samples extracted with 70% ethanol than those extracted with 70% ethanol. The total phenolic acid content, the total flavonoid content and the electron donating ability were highest in the ethanol extract of Saururuschinensis treated at a high temperature. However, the ABTs radical activity was highest in the water extracted, high-temperature treated Saururuschinensis. The 70% ethanol extract of high temperature roasted Saururuschinensis had the highest antioxidative activities of all the Saururuschinensis batches. CONCLUSION: The total phenolic acid contents, total flavonoid contents, electron donating activity and reducing power activity were highest in all the 70% ethanol extraction batches of the high-temperature treated samples.
Ethanol ; Flavonoids ; Phenol ; Saururaceae ; Water

PURPOSE: Astragalus membranaceus (AM) is an important traditional medicinal herb. Pharmacological research has indicated that AM has various physiological activities such as antioxidant, anti-inflammatory, immunoregulatory, anticancer, hypolipidemic, antihyperglycemic, and hepatoprotective activities. The bioactive substances responsible for the physiological activities in AM, including many antioxidant substances, change during the roasting process. This study investigated and compared the changes in the antioxidant constituents of AM caused by roasting. METHODS: DPPH (1,1-diphenyl-2-picryl hydrazyl) and ABTS⁺ (2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) radical scavenging activities and their total phenolic content (TPC) were measured. High-performance liquid chromatography (HPLC) analysis was performed to confirm any changes in the isoflavonoids of roasted AM (R-AM),. The cell viability of UVB-induced HDF (Human dermal fibroblast) cells treated with AM and R-AM extracts was investigated. The comet assay was used to examine the inhibitory effects of R-AM extracts on DNA damage caused by oxidative stress. RESULTS: The DPPH and ABTS⁺ radical scavenging activities were 564.6±20.9 and 108.2±3.1 (IC₅₀ value) respectively, from the 2R-AM. The total phenol content was 47.80±1.40 mg GAE/g from the 1R-AM. The values of calycosin and formononetin, which are the known isoflavonoid constituents of AM, were 778.58±2.72 and 726.80±3.45 µg/g respectively, from the 2R-AM. Treatment of the HDF cells with R-AM (50 ~ 200 µg/mL) did not affect the cell viability. Furthermore, the R-AM extracts effectively protected against UVB-induced DNA damage. CONCLUSION: The findings of this study indicate that R-AM increases its isoflavonoid constituents and protects against UVB-induced DNA damage in HDF cells.
Astragalus membranaceus ; Cell Survival ; Chromatography, Liquid ; Comet Assay ; DNA Damage ; Oxidative Stress ; Phenol ; Plants, Medicinal

Soluble epoxide hydrolases (sEH) are enzymes present in all living organisms, metabolize epoxy fatty acids to 1,2-diols. sEH in the metabolism of polyunsaturated fatty acids plays a key role in inflammation. In addition, the endogenous lipid mediators in cardiovascular disease are also broken down to diols by the action of sEH that enhanced cardiovascular protection. In this study, sEH inhibitory guided fractionation led to the isolation of five phenolic compounds trans-resveratrol (1), trans-piceatannol (2), sulfuretin (3), (+)-balanophonin (4), and cassigarol E (5) from the ethanol extract of the seeds of Passiflora edulis Sims cultivated in Vietnam. The chemical structures of isolated compounds were determined by the interpretation of NMR spectral data, mass spectra, and comparison with data from the literature. The soluble epoxide hydrolase (sEH) inhibitory activity of isolated compounds was evaluated. Among them, trans-piceatannol (2) showed the most potent inhibitory activity on sEH with an IC₅₀ value of 3.4 µM. This study marks the first time that sulfuretin (3) was isolated from Passiflora edulis as well as (+)-balanophonin (4), and cassigarol E (5) were isolated from Passiflora genus.
Cardiovascular Diseases ; Epoxide Hydrolases ; Ethanol ; Fatty Acids ; Fatty Acids, Unsaturated ; Inflammation ; Metabolism ; Passiflora ; Passifloraceae ; Phenol ; Vietnam

Nelumbo nucifera Gaertn. (Nymphaeaceae) is commonly called lotus and its leaves are widely been used as functional ingredients due to its antioxidant activity. For maximum efficacy, optimized extraction condition was established using response surface methodology. The high F-values, low p-values and insignificant p-value for lack-of-fit supported the fitness of the model and yielded the second-order polynomial regression for the antioxidant activity. The optimized extract was obtained by the extraction of 1 g of lotus leaves with 40 mL of 50% MeOH at 10.0℃, which exerted 70.1% antioxidant activity. Close correlation between phenolic content and antioxidant activity suggested phenolic compounds as active constituents of lotus leaves. In addition, comparison of different parts of lotus demonstrated the most potent antioxidant activity of flowers, followed by leaves and roots. Taken together, these results provide useful information about lotus leaves for the development as antioxidant ingredients. In addition, flowers and roots as well as leaves are suggested as good sources for antioxidant activity.
Flowers ; Lotus ; Nelumbo ; Phenol