Collision-induced dissociation was performed with 30 ± 10 V collision offset-voltage. Targeted MS/MS analyses were performed when necessary for better spectral quality of metabolites which were not triggered by IDA method. TOF-MS spectra were acquired (with 250 ms accumulation time), followed by MS/MS in information-dependent acquisition (IDA) mode on the 5 most intense ions using dynamic background subtraction (175 ms each). Ion source parameters included ionization voltage of 5000 V, curtain gas of 35 psi, drying and nebulizer gases at 50 psi, source temperature of 450 ☌, and declustering potential of 60 V. However, the formation of reactive metabolites of tea catechins and synthetic gallate esters via the detection of glutathione conjugates has not been extensively studied. The sulfation of catechins via sulfotransferases has also been reported. They identified four major glucuronide conjugates of EGCG and EGC by tandem mass spectrometry (MS/MS) and NMR spectroscopy. investigated the glucuronidation of some catechins by hepatic and intestinal microsomes. The occurrence of methylated metabolites of tea catechins has been reported. Methylation is the primary metabolic route for these molecules performed by the enzyme catechol- O-methyltransferase (COMT). The major biotransformation reactions described in literature for tea catechins include methylation, glucuronidation, and sulfation. The data available on the biotransformation of tea catechins and synthetic gallate esters is limited and studies have concentrated mainly on EGCG or several of its analogs. The relative effectiveness of different catechins is related to their structure (for example, the number of hydroxyl groups and their positions, and the accessibility of active groups), concentration, and stability. These tea polyphenols have gained special attention due to their numerous beneficial effects (antioxidant, antimicrobial, antiviral, and antifungal effects, in addition to protective effects against different cancers ). Flavonoids consist of a flavan-3-ol unit, including catechin (C), epicatechin (EC), gallocatechin (GC), and epigallocatechin (EGC), in addition to galloylated catechins, in the case of catechin gallate (CG), epicatechin gallate (ECG), gallocatechin gallate (GCG), and epigallocatechin gallate (EGCG).
Green tea extracts have the highest total phenolic content, 94% of which are flavonoids (catechins) and phenolic acids (e.g., gallic acid (GA)). Plant extracts such as green and black teas have been widely studied for their antioxidant activities. They are often considered a healthier alternative to synthetic antioxidants. They are used as preservatives and bioactive molecules for prevention against diseases such as cancer, obesity, neurological disorders, aging, and cardiovascular diseases. These antioxidants include vitamins (C and E), herbs and spices, and natural products from plants.
However, as a result of the global movement toward using natural ingredients in food products, medications, and personal care products, natural antioxidants are gaining interest. Synthetic antioxidants present many advantages, including low cost, ease of synthesis, and high efficiency.
#HYDROGEN PEROXIDE NEBULIZER SIDE EFFECTS FREE#
These compounds can inhibit free radical formation and thus interrupt autoxidation. The addition of antioxidants is commonly used to inhibit or slow this process, to increase shelf life, and to maintain freshness and texture of consumer products. Lipid peroxidation is the primary cause of the formation of undesired byproducts in food, cosmetics, pharmaceuticals, and petrochemicals. These results serve to inform about the wide variety of possible metabolites formed upon exposure to these compounds. The developed method was applied to 14 different parent compounds with a wide range of polarities, for the structural elucidation of many known and novel metabolites. Liquid chromatography coupled with high-resolution tandem mass spectrometry (LC-HRMS/MS) was used to elucidate oxidative and methylated metabolites, in addition to glutathione conjugates, formed in vitro using human liver microsomal incubations. The objective of this study was to establish metabolic pathways involved in the biotransformation of green tea catechins and synthetic gallate esters. Green tea catechins are natural antioxidants, known for their health-promoting properties, and are also employed as food additives or in personal care products. Despite their widespread use, little is known about their human exposure, health effects, and metabolism. Synthetic gallic acid derivatives are employed as additives in food, personal care products, and pharmaceutical formulations.
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