The Protective Effects of L-Theanine against Epigallocatechin Gallate-Induced Acute Liver Injury in Mice.

Epigallocatechin-3-gallate (EGCG) is a main bioactive constituent in green tea. Being a redox-active polyphenol, high-dose EGCG exhibits pro-oxidative activity and could cause liver injury. L-theanine is a unique non-protein amino acid in green tea and could provide liver-protective effects. The purpose of this study was to investigate the hepatoprotective effects of L-theanine on EGCG-induced liver injury and the underlying mechanisms. A total of 300 mg/kg L-theanine was administrated to ICR mice for 7 days. Then, the acute liver injury model was established through intragastric administration of 1000 mg/kg EGCG. Pretreatment with L-theanine significantly alleviated the oxidative stress and inflammatory response caused by high-dose EGCG through modulation of Nrf2 signaling and glutathione homeostasis. Furthermore, metabolomic results revealed that L-theanine protects mice from EGCG-induced liver injury mainly through the regulation of amino acid metabolism, especially tryptophan metabolism. These findings could provide valuable insights into the potential therapeutic applications of L-theanine and highlight the importance of the interactions between dietary components.

Influence of ultrasound and microwave treatments on the structural and thermal properties of normal maize starch and potato starch: A comparative study.

The effects of ultrasound and microwave on the physicochemical properties of normal maize and potato starches were compared. The cavitation effect of ultrasound loosened the internal space and destroyed the structure of starch granules, increased the damaged starch content, which was consistent with the decrease in relative crystallinity and the number and brightness of Maltese crosses, and the increase in D(0.5) and D(4,3) values. Microwave vibrated the molecules inside the granules and generated heat to destroy the structure of starch. The content of damaged starch was significantly lower in microwave-treated starch compared with ultrasound-treated starch. Microwave treatment promoted the formation of amylose-lipid complex, with the larger peak area at 20°(2θ) than that of the ultrasound-treated starch. The type of starch and the treatment sequence showed a significant effect. The results might help understand the mechanism of ultrasound and microwave treatments influencing the structural properties of starches.

3'-Oxo-tabernaelegantine A (OTNA) selectively relaxes pulmonary arteries by inhibiting AhR.

BACKGROUND: Pulmonary arterial hypertension (PAH), characterized by pulmonary artery constriction and vascular remodeling, has a high mortality rate. New drugs for the treatment of PAH urgently need to be developed. PURPOSE: This study was designed to investigate the vasorelaxant activity of OTNA in isolated pulmonary arteries, and explore its molecular mechanism. METHODS: Pulmonary arteries and thoracic aortas were isolated from mice, and vascular tone was tested with a Wire Myograph System. Nitric oxide levels were determined with DAF-FM DA and DAX-J2™ Red. Cellular thermal shift assays, microscale thermophoresis, and molecular docking were used to identify the interaction between OTNA and aryl hydrocarbon receptor (AhR). The levels of PI3K, p-PI3K, Akt, p-Akt, eNOS, p-eNOS, and AhR were analyzed by Western blotting. RESULTS: OTNA selectively relaxed the isolated pulmonary artery rings in an endothelium-dependent manner. Mechanistic study showed that OTNA induced NO production through activation of the PI3K/Akt/eNOS pathway in endothelial cells. Furthermore, we also found that OTNA directly bound to AhR and activated the PI3K/Akt/eNOS pathway to dilate pulmonary arteries by inhibiting AhR. CONCLUSIONS: OTNA relaxes pulmonary arteries by antagonizing AhR. This study provides a new natural antagonist of AhR as a promising lead compound for PAH treatment.

Survey of mineral oil hydrocarbons in Chinese commercial complementary foods for infants and young children.

Recently, mineral oil hydrocarbons (MOH) in various foods have raised significant concern, especially for infants and young children due to their potential adverse health effects. Two fractions can be distinguished by certain analytical techniques, mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). The toxicological profile of MOSH and MOAH differs greatly. The toxicity of MOSH is linked with long-term accumulation of some hydrocarbons. MOAH with three to seven, non- or simple-alkylated, aromatic rings may be mutagenic and carcinogenic. However, data on the occurrence of mineral oils in commercial complementary foods for infants and young children are lacking in China. In the present study, 100 commercial food samples were collected, including 26 pureed or paste canned foods, 21 high-protein ground cereal foods (rice flour), 25 raw cereal foods (noodles), and 28 cereal-based molar sticks and biscuits. The content of MOSH and MOAH in those samples was determined by optimised sample preparation methods combined with on-line high-performance liquid chromatography coupled with gas chromatography and flame ionisation detector (HPLC-GC-FID), with a limit of quantification of 0.5 mg/kg. The results indicated that there were no MOAH detected in any of the foods, but MOSH and polyolefin oligomeric saturated hydrocarbons (POSH) existed in most of the food samples, at <0.5-23.68 mg/kg. Moreover, the data and chromatograms of the MOSH and POSH also indicated that these contaminants were closely correlated to their ingredients and manufacturers. The current study provides basic data to understand MOH exposure and consequent health impact.

Research progress of black tea thearubigins: a review.

As the most abundant component in black tea, thearubigins (TRs) contribute a lot to black tea's characteristic color, mouthfeel, and potential health benefits. But compared to lower molecular weight black tea polyphenols, there are fewer researches that focus on TRs because of their heterogeneity. This review summarized recent research progress on (1) isolation method of TRs; (2) structure analysis and formation mechanism of TRs; (3) biofunctions of TRs, including antioxidation, antimutagenic and anticancer effects, effects on mitochondrial activation, gastrointestinal motility and skeletal health, to show some future research aspects and prospects of TRs.

Inhibitory effect of chestnut (Castanea mollissima Blume) inner skin extract on the activity of α-amylase, α-glucosidase, dipeptidyl peptidase IV and in vitro digestibility of starches.

This study aimed to investigate the inhibitory effect of chestnut inner skin extract (CISE) on the activity of postprandial blood sugar-related enzymes. In total, 12 flavonoids were identified by HPLC-TOF-MS. CISE showed strong and weak inhibition on α-amylase and α-glucosidase, with the IC50 of 27.2 and 2.3 µg/mL, respectively. The inhibition modes of CISE against α-amylase and α-glucosidase were mixed-type and non-competitive type, respectively. Epicatechin gallate noncompetitively inhibited α-amylase, α-glucosidase and dipeptidyl peptidase IV (DPP-IV). Analysis by ultraviolet-visible spectroscopy, fluorescence spectroscopy and circular dichroism suggested that flavonoids altered the hydrophobicity and microenvironment of these enzymes. CISE decreased the starch bioavailability by reducing the enzymatic hydrolysis rate and increasing the fraction of undigested starch. The extract reduced the rapidly digestible starch and increased the resistant starch after incorporation into A-, B- or C- crystallinity starch. Thus, the chestnut inner skin is a useful resource for regulating postprandial blood sugar level.

Offline Solid-phase Extraction Large-volume Injection-Gas chromatography for the Analysis of Mineral Oil-saturated Hydrocarbons in Commercial Vegetable Oils.

An offline solid-phase extraction (SPE) approach combined with a large-volume injection (LVI)-gas chromatography-flame ionization detector (LVI-GC-FID) is improved for routine analysis of mineral oil saturated hydrocarbons (MOSH) in vegetable oils. The key procedure of the method consists in using offline SPE columns for MOSH purification. The SPE column packed with 1% Ag-activated silica gel was used to separate MOSH from triglycerides and olefins in variety of vegetable oils. The eluent of MOSH fraction was only 3 mL and the concentration step was quick with little evaporation loss. The limit of quantification (LOQ) of the method was 2.5 mg/kg and the linearity ranged from 2 to 300 mg/kg. The accuracy was assessed by measuring the recoveries from spiked oil samples and was higher than 90%. Twenty-seven commercial vegetable oils were analyzed, and different levels of MOSH contamination were detected with the highest being 259.4 mg/kg. The results suggested that it is necessary to routinely detect mineral oil contamination in vegetable oils for food safety.

Flash Extraction and Physicochemical Characterization of Oil from Elaeagnus mollis Diels Seeds.

A flash extraction method was used to isolate Elaeagnus mollis oil (EMO). The optimal extraction parameters, sample/solvent ratio and extraction temperature, were determined to be 1:10 (g/mL) and 40°C, respectively. Especially, the extraction yield reached 49.30% when the extraction time was as short as 2 min. No obvious difference was observed in fatty acid composition, iodine value, saponification number, total phenolic content and tocopherol content between flash-extracted EMO and Soxhlet-extracted EMO, but their physicochemical values were lower than those of cold-pressed EMO. Cold-pressed EMO had higher oxidation stability, DPPH (1-diphenyl-2-picrylhydrazyl) and hydroxyl radical-scavenging activities than flash-extracted EMO and Soxlet extracted EMO. The flash extraction is demonstrated to be an alternative, efficient method for the vegetable oil production.

Rapid detection of authenticity and adulteration of walnut oil by FTIR and fluorescence spectroscopy: a comparative study.

Fourier transform infrared (FTIR) and fluorescence spectroscopy combined with soft independent modeling of class analogies (SIMCA) and partial least square (PLS) were used to detect the authenticity of walnut oil and adulteration amount of soybean oil in walnut oil. A SIMCA model of FTIR spectra could differentiate walnut oil and other oils into separate categories; the classification limit of soybean oil in walnut oil was 10%. Fluorescence spectroscopy could differentiate oil composition by the peak position and intensity of emission spectrum without multivariate analysis. The classification limit of soybean oil adulterated in walnut oil by fluorescence spectroscopy was below 5%. The deviation of the prediction model for fluorescence spectra was lower than that for FTIR spectra. Fluorescence spectroscopy was more applicable than FTIR in the adulteration detection of walnut oil, both from the determination limit and prediction deviation.

Purification and structural characterization of an α-glucosidase inhibitory polysaccharide from apricot (Armeniaca sibirica L. Lam.) pulp.

In this study, the crude polysaccharide (APPS) from the fruiting bodies of apricot (Armeniaca sibirica L. Lam.) was isolated and fractionated by ultrafiltration and Sephadex G-75 gel chromatography. The hypoglycemic activities of all fractions were determined by α-glucosidase inhibitory activity in vitro. The fraction APPS1-2 showed the best activity with an IC50 of 6.06 mg/mL. The properties and chemical compositions of this fraction were analyzed with high-performance liquid chromatography, gel permeation chromatography-eighteen angle laser light scattering instrument, UV spectroscopy, infrared spectroscopy, and NMR spectroscopy ((1)H). The results demonstrated that APPS1-2 was a neutral glycoconjugate with a molecular weight of 25.93 kDa. It comprised rhamnose, glucose, mannose, and galactose, with a relative molar ratio of 1.34:2.01:0.48:0.35. The backbone of APPS1-2 may consist of rhamnose and glucose, but its branches may consist of mannose and galactose. The IR and UV spectrum of APPS1-2 revealed the typical characteristics of heteropolysaccharide. (1)H NMR spectrum showed that APPS1-2 contained α-configurations.

[Authentication and adulteration analysis of sesame oil by FTIR spectroscopy].

It's common in edible oil market that adulterating low price oils in high price oils. Sesame oil was often adulterated because of its high quality and price, so the authentication and adulteration of sesame oil were qualitatively and quantitatively analyzed by Fourier transform infrared (FTIR) spectroscopy combined with chemometrics. Firstly, FTIR spectra of sesame oil, soybean oil, and sunflower seed oil in 4,000-650 cm(-1) were analyzed. It was very difficult to detect the difference among the spectra of above edible oils, because they are all mixtures of triglyceride fatty acids and have similar spectra. However, the FTIR data of edible oils in the fingerprint region of 1,800-650 cm(-1) differed slightly because their fatty acid compositions are different, so the data could be classified and recognized by chemometric methods. The authenticity model of sesame oil was built by principal component analysis (PCA) and soft independent modeling of class analogy (SIMCA). The recognition rate was 100%, and the built model was satisfactory. The classification limits of both soybean oil and sunflower seed oil adulterated in sesame oil were 10%, with the chemometric treatments of standard normal variation (SNV), partial least square (PLS) and PCA. In addition, the FTIR data processed by PCA and PLS were used to establish an analysis model of binary system of sesame oil mixed with soybean oil or sunflower oil, the prediction values had good corresponding relationship with true values, and the relative errors of prediction were between -6.87% and 8.07%, which means the quantitative model was practical. This method is very convenient and rapid after the models have been built, and can be used for rapid detection of authenticity and adulteration of sesame oil. The method is also practical and suitable for the daily analysis of large amount of samples.

Adsorption properties and preparative separation of phenylethanoid glycosides from Cistanche deserticola by use of macroporous resins.

A simple and efficient chromatographic method for large-scale preparative separation of phenylethanoid glycosides (mainly contain echinacoside and acteoside) from Cistanche deserticola was developed. The adsorption properties of eight macroporous resins were evaluated. Three selected resins were further screened depending on the adsorption kinetics curves, in which HPD300 resin showed the best separation efficiency. The adsorption isotherm data on HPD300 resin were fitted to the Freundlich equation in certain concentration range. The dynamic adsorption and desorption experiments were carried out on columns packed with HPD300 resin to optimize the separation process. The breakthrough curves showed that acteoside had a higher affinity to the resin than echinacoside. The contents of echinacoside and acteoside in the product increased from 1.79% and 1.43% in the crude extracts to 16.66% and 15.17%, with recovery yields of 80.41% and 90.17%, respectively. The purity of total phenylethanoid glycosides in the product was 76.58%.

[Study on the processing of leech by FTIR and 2D-IR correlation spectroscopy].

The chemical differences of traditional Chinese medicine leech before and after processing were analyzed by FTIR and two-dimensional correlation infrared (2D-IR) spectroscopy. The result showed that the leech was high in protein, with characteristic peaks of amide I, II bands. Comparing the IR spectra of samples, the primary difference was that the characteristic peak of fresh leech was at 1 543 cm(-1), while that of crude and processed leech was at 1 535 cm(-1). A 2D-IR spectrum with heating perturbation was used to track the processing dynamics of leech In the 2D-IR correlation spectra, fresh leech exhibited stronger automatic peaks of the amide I and II bands than that of processed leech, which indicates that the protein components of the fresh leech were more sensitive to heat perturbation than the processed one. Moreover, the result of FTIR and 2D-IR correlation spectra validated that the 3-dimensional structure of protein was damaged and hydrogen bonds were broken after processing, which resulted in the inactivation of protein. The fatty acids and cholesterol components of leech were also oxidized in this process.