ABSTRACT
Hydroxytyrosol as one of natural anti-oxidants，extracted from the fruits and leaves of Olea europaea，is a natural polyphenol compound in the form of esters. Recently，considerable studies showed that hydroxytyrosol demonstrated intrinsic biological activity for metabolic syndromes， cardiovascular- and neurodegenerative-related diseases，and it was revealed to play the roles in the anti-activities of cancerous，inflammatory as well as depressing issues. In addition，hydroxytyrosol is an oleophilic and hydrophilic compound with high bioavailability and low cellular cytotoxicity. It could be absorbed by various tissues and could easily passe through blood brain barrier. Therefore，hydroxytyrosol was introduced as one of the key subjects targeted by innovative drug development. However，it has a short half-life in vivo and non-tissue specific，which lead to its limitation in clinical application， so further in-depth studies are still needed. The authors had a literature review of hydroxytyrosol，and summarized the basic properties of its pharmacokinetic，pharmacological effects and molecular mechanisms. This article mainly focused on it’s pharmacological activity and the mechanism involved in treating damages induced by the oxidative stress，in alleviating cardiovascular diseases and in inhibition of neurodegenerative diseases. In this article， its anti-inflammatory，anti-tumor，anti-depressant effects，other biological activities，and pharmacokinetics were also briefly reviewed. The authors put forward some personal thoughts on its future research direction，hoping to provide ideas and inspirations for the vast number of researchers，and provide references for its further development，research and application.
ABSTRACT
Hydroxytyrosol is an important fine chemical and is widely used in food and medicine as a natural antioxidant. Production of hydroxytyrosol through synthetic biology is of important significance. Here we cloned and functionally characterized a hydroxylase encoding gene HpaBC from Escherichia coli BL21, and both subunits of this enzyme can be successfully expressed to convert the tyrosol into hydroxytyrosol. A HpaBC gene integration expression cassette under the tac promoter was constructed, and integrated into the genome of a tyrosol hyper-producing E. coli YMG5A*R using CRISPR-Cas9 technology. Meanwhile, the pathway for production of acetic acid was deleted, resulting in a recombinant strain YMGRD1H1. Shake flask fermentation showed that strain YMGRD1H1 can directly use glucose to produce hydroxytyrosol, reaching a titer of 1.81 g/L, and nearly no by-products were detected. A titer of 2.95 g/L was achieved in a fed-batch fermentation conducted in a 5 L fermenter, which is the highest titer for the de novo synthesis of hydroxytyrosol from glucose reported to date. Production of hydroxytyrosol by engineered E. coli lays a foundation for further construction of hydroxytyrosol cell factories with industrial application potential, adding another example for microbial manufacturing of aromatic compounds.
Subject(s)
Escherichia coli/genetics , Fermentation , Glucose , Metabolic Engineering , Phenylethyl Alcohol/analogs & derivativesABSTRACT
Objective: To determine the apparent oil/water(O/W)partition coefficient of hydroxytyrosol butyrate(HT-Bu), and investigate the solubility, dissolution tendency and stability of HT-Bu in different buffers, so as to provide theoretical basis for the preparation research of HT-Bu. Methods: The appearance and solubility of HT-Bu were investigated, and a high performance liquid chromatography(HPLC)method was established for the quantitative determination of HT-Bu. The solubility and O/W partition coefficient of HT-Bu in different pH buffer solutions were determined by the shakeing flask method. Results: HT-Bu was slightly yellow-colored, viscous, odorless and tasteless oily liquid. The quantitative HPLC method for the HT-Bu determination showed a good linearity within the concentration range of 5-50 μg/ml(r=0.9998). The apparent O/W partition coefficient of HT-Bu was 1.0. In the acetonitrilewater(60:40, V/V) solution, HT-Bu was stable within 12 hours at room temperature. In the different pH buffer solutions(pH 2.0-9.0), the solubility of HT-Bu increased at first and then decreased with the increase of the solution pH. HT-Bu was unstable at pH 5.5, with a large amount decomposed after kept in the solution for 6 h. HT-Bu was stable at pH 8, 0 giving a little amount decomposed after 12 h in the solution, and stable at pH 7.4 showing no significant decomposition after 12 h keeping in the solution. Conclusion: HT-Bu showed a good water solubility, which is unstable in acidic and alkaline solutions.
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Long-term consumption of olive oil helps reduce the risks of developing a series of diseases including cardiovascular disease, nervous system disease, cancer, etc. The minor compounds of olive oil, especially the star molecule--hydroxytyrosol, play an important role in these beneficial effects on human health. As a polyphenolic compound, hydroxytyrosol not only act as antioxidant and scavenge oxidizing substances directly, but also inhibit oxidative stress by regulating the Nrf2 antioxidant system. Thus, hydroxytyrosol has great potential in the prevention and treatment of oxidative damage related diseases. This review focuses mainly on recent progresses in pharmacological effects of hydroxytyrosol on nervous system disease, angiocardiopathy, metabolic syndrome, inflammation and cancer.
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Objective To investigate the uptake mechanism of HepG2.2.15 cells to the nanoparticles co-loaded with syringopicroside and hydroxytyrosol (SH-NPs). Methods The nanoparticles were prepared by using a nanoprecipitation method with mPEG-PLGA as nano-carrier co-loaded with syringopicroside and hydroxytyrosol. The uptake mechanism of HepG2.2.15 cells to SH-NPs was studied by fluorescence microscopy and flow cytometry using fluoresceineisothiocyanate (FITC) as a fluorescent marker. Results With colchicine as the inhibitor, the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 1.9% to 56.4%; When the drug concentration was 125, 250 μg/mL and 500 μg/mL, the positive cell percentages were 4.9%, 3.4% and 3.9%. With chloroquine as the inhibitor; the incubation time ranged from 0.5 to 24 h, the percentage of positive cells increased from 7.4% to 55.4%; When the drug concentration was 125, 250 and 500 μg/mL, the percentage of positive cells was 19.5%, 22.5% and 27.6%. Conclusion Colchicine and chloroquine have an inhibitory effect on HepG2.2.15 cells uptake, and the uptake of SH-NPs in HepG2.2.15 cells was positively correlated with drug concentration and incubation time. It can be concluded that the uptake mechanism of HepG2.2.15 cells to SH-NPs was nonspecific adsorption endocytosis.
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Olive oil is one of the important byproducts in agriculture. It is rich in oleuropein, which can be hydrolyzed into several bioactive phenolic compounds, including hydroxytyrosol (HT).There are many literatures have been confirmed that HT has significant pharmacological effects in the anti-inflammatory, anti-virus, regulation of metabolic disorders and treatment of degenerative diseases. However, HT has severe instability in vivo and in vitro. It is a challenge how to improve its stability through structural transformation or utilization of pharmaceutical means to processing. This paper will focus on biological activity of HT and its stability improvement, and provid some new ideas for expanding the research and promoting the development of HT in the field of Medicine.
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Hydroxytyrosol ( 3 , 4-dihydroxyphenyle-thanol) presents in olive leaves and fruits with an ex-ceptional antioxidative activity. As a promising func-tional food ingredient, hydroxytyrosol shows many bio-logical activities, including preventing cardiovascular diseases, protecting retinal pigment epithelial cells, preventing osteoporosis, and improving the cognitive a-bility. According to the research progress in recent years,we have summarized the biological effect and the metabolism of hydroxytyrosol in this review.
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Objective To investigate the expression of glucose-regulated protein 78(GRP78)and cysteine aspartic acid protease 12(Caspase-12) and evaluate the endoplasmic reticulum stress (ERS) in rats with contrast-induced nephropathy (CIN),and observe the protective effects of hydroxytyrosol on CIN rats.Methods Eighty-four Wistar rats,(220±20) g,were randomly divided into control group,CIN group,hydroxytyrosol treated group (group C+H).At 12th,24th,48th,72th day after the rats model were established,BUN and Scr were detected.ELISA were used to detect the expression of methane dicarboxylic aldehyde (MDA),superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px).HE staining were used to evaluate the pathological change of kidney.TUNEL were used to detect the apoptosis of tubular ceils.Real-time PCR were used to detect the expression of GRP78 mRNA and Caspase-12 mRNA in tubular cells.Immunohistochemistry and Western blotting were used to detect the expression of GRP78 and Caspase-12 protein in tubular cells.Results BUN,Scr,the mRNA and protein expression of GRP78,Caspase-12 in hydroxytyrosol treated group were higher than that in control group(P ＜ 0.05),but were significantly lower than that in CIN group (P ＜ 0.05).Pathological changes and the apoptosis of tubular cells in CIN group were more serious than that in hydroxytyrosol treated group (P ＜ 0.05).Conclusions Endoplasmic reticulum stress may be associated with contrast-induced nephropathy.Hydroxytyrosol can protect kidney from contrast medium via reducing the endoplasmic reticulum stress.
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2-Hydroxytyrosol (2-HT), originally reported as a synthetic compound, was isolated for the first time as a fungal metabolite. 2-HT was found to inhibit mushroom tyrosinase with an IC50 value of 13.0 µmol/L. Furthermore, 2-HT dose-dependently inhibited tyrosinase activity (IC50, 32.5 µmol/L) in the cell-free extract of B16 melanoma cells and α-melanocyte stimulating hormone (α-MSH)-stimulated melanin formation in intact B16 melanoma cells.
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Objective: To prepare hydroxytyrosol (HT) by alkaline hydrolysis of oleuropein and to investigate its anti-oxidative property. Methods: According to single factor experiments, four variables: temperature, sodium hydroxide concentration, time, and the ratio of solid to liquid, were selected. On the basis of single factor experiments, orthogonal tests of L9(34) were carried out. HPLC-MS method was also further applied for the qualitative analysis on HT. Under the same conditions, contrast experiments on the acid and alkaline actions were made. Finally, anti-oxidative activity of HT was evaluated. Results: The results showed that the selected variables were all highly significant. Also, the descending influence orders on HT were temperature > sodium hydroxide concentration > time > the ratio of solid to liquid. Lastly, the optimal conditions on HT yield were obtained as follow: temperature 90°C, sodium hydroxide concentration 0.2 mol/L, time 45 min, and the ratio of solid to liquid 1:15. The HPLC retention time of HT was about 10.3 min, and its relative molecular weight of fragment ion by MS was 134.8. By comparison with the acid action, it was proved that the alkaline action was better in HT yield. In addition, the anti-oxidative activity of HT was carried out on scavenging DPPH radical. The results showed that DPPH scavenging capability of HT was 2.45 times of BHT. Conclusion: HT yield is well obtained under the alkaline condition and has a good anti-oxidation.
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Objective:To investigate whether hydroxytyrosol (HT) may ameliorate oxidative stress and nuclear factor kappa B (NF-?B) activation in the lipopolysaccharide (LPS)-stimulated THP-1 cell line.Methods:The intracellular formation of reactive oxygen species (ROS) was detected by 2,7-dichlorofluorescein diacetate (DCFH-DA) as a fluorescent probe.Intracellular glutathione (GSH) level was estimated by fluorometric methods;Nitric oxide (NO) production was measured as nitrite (a stable metabolite of NO) concentrations.Western blot analysis was used to detect the expressin level of NF-?B.Results:The results showed that treatment of THP-1 cells with HT significantly reduced LPS-stimulated NO production and ROS formation in a concentration-dependent manner.HT at 50 and 100 ?mol/L concentrations increased the GSH level.The specific DNA-binding activities of NF-?B in nuclear extracts from 50 and 100 ?mol/L HT treatments were significantly suppressed.The antioxidant N-acetylcysteine (NAC) also showed the same effects as HT on LPS-induced ROS and NO production,change of GSH level,and NF-?B activation.Conclusion:These findings suggest that HT has antioxidant activity by suppressing intracellular oxidative stress and NF-?B activation in THP-1 cells.