Progress in catechins oxidation products and their formation mechanism / 中国中药杂志

Catechins are the key components of tea and have a great impact on its quality. Catechins can be oxidized to form a new black tea polyphenols, some of which have better pharmacological effect. However, the formation mechanism of these new polyphenols is still unclear. In this paper, oxidation products coming from catechins and the formation mechanism of the new compounds are reviewed.It is the base of further study on theaflavins, thearubigins and theabrownines.

Estudos dos produtos da oxidação não enzimática do ácido docosahexaenoico como possíveis biomarcadores para doenças neurodegenerativas / Study of Docosahexaenoic acid non-enzymatic oxidation products as biomarkers for neurodegenerative diseases

Os n-3 e n-6 são duas famílias de ácidos graxos poli-insaturados. Os ácidos graxos de cadeia longa como o ácido araquidônico (AA) e docosahexaenoico (DHA) apresentam importantes funções no desenvolvimento e funcionamento do cérebro. Os produtos de oxidação dos ácidos graxos poli-insaturados estão presentes ou aumentados ao longo do desenvolvimento de doenças neurodegenerativas. A caracterização de tais produtos é crítica para o estudo que busca entender o seu papel fisiopatológico no desenvolvimento de tais doenças. No presente trabalho, buscou-se o desenvolvimento de uma ferramenta analítica sensível e específica para a detecção e quantificação dos hidroperóxidos e hidróxidos do AA (HpETE e HETE), do seu precursor, o ácido linoleico (HpODE e HODE) e do DHA (HpDoHE e HDoHE). Estes hidroperóxidos foram sintetizados por fotooxidação e os hidróxidos correspondentes foram obtidos através da redução com o NaBH4. Os isômeros isolados foram caracterizados por LC-MS/MS. Os íons produto específicos de cada isômero foram escolhidos para a construção do método de monitoramento de reação selecionada (selected reaction monitoring - SRM) para a realização da análise quantitativa dos analitos de interesse. Cabe salientar que os dados obtidos poderão ser utilizados em bibliotecas de análise lipidômica e oxi-lipidômica pois serão essenciais para a identificação e quantificação dos analítos de interesse do presente estudo em diversas doenças. Utilizando o método padronizado, buscamos investigar o papel dos hidroperóxidos e hidróxidos do DHA, LA e AA em um modelo animal para a esclerose lateral amiotrófica (ELA), uma doença neurodegenerativa que acomete neurônios motores. Foi observado um aumento nos níveis de 13-HpODE, 9-HpODE e 12-HETE no córtex motor dos animais avaliados. Adicionalmente, foram observadas alterações nas taxas lipólica e lipogênica no tecido adiposo para os animais ELA em relação aos respectivos controles. Em conjunto, os dados apresentados no presente trabalho corroboram com os trabalhos da literatura que associam alteração dos níveis dos produtos de oxidação dos ácidos graxos poli-insaturados em doenças neurodegenerativas e o metabolismo energético alterado em ELA. Futuramente é necessária uma investigação mais ampla dos níveis dos hidroperóxidos e hidróxidos lipídicos em diferentes tecidos e do metabolismo lipídico, e os conhecimentos gerados poderão ser uma importante fonte de novas opções terapêuticas para os pacientes portadores de ELA

The n-3 and n-6 are two olyunsaturated fatty acids families. The long chain fatty acids such as arachidonic (AA) and docosahexaenoic acid (DHA) have important roles in the development and function of the brain. Polyunsaturated fatty acids (PUFAs) oxidation products are present or increased during the progression of neurodegenerative diseases. The characterization of DHA oxidation products is critical to understand their roles in the development of such diseases. In the present study, we sought to develop a sensitive and specific analytical tool for the detection and quantification of AA hydroperoxides and hydroxides (HPETE and HETE), its precursor linoleic acid (HPODE and HODE) and DHA (HpDoHE and HDoHE). These hydroperoxides were synthesized by photooxidation and the corresponding hydroxides were obtained by reduction with NaBH4. The isolated isomers were characterized by LC-MS/MS, and unique and specific fragment ions were chosen to construct a selected reaction monitoring (SRM) method for the targeted quantitative analysis. It should be emphasized that the data obtained - in the form of lipidomics and oxy-lipidomics libraries - may be used to assist in several diseases. Using the standardized method, we investigated the role of hydroperoxides and hydroxides of DHA, LA and AA in an animal model of amyotrophic lateral sclerosis (ALS), a neurodegenerative disease that affects motor neurons. Increased levels of 13-HPODE, 9-HPODE and 12-HETE were observed in the animals motor cortex. Additionally, results show changes in lipogenic and lipolytic rates in adipose tissue for ALS animals when compared to their respective controls. Altogether, the data presented herein corroborate with the literature by linking altered levels of PUFAs oxidation products in neurodegenerative diseases with altered energetic metabolism in ALS. In the future, a more extensive investigation of the hydroperoxide and hydroxide level in different tissues as well as the lipid metabolism must be done, which could lead to new therapeutic options for ALS patients

The mechanism and significance of advanced oxidation protein products in acute coronary syndrome / 中国综合临床

Objective To examine the advanced oxidation protein products (AOPP) in patients with acute coronary syndrome(ACS) and discuss the relationship between oxidative stress with the development of atherosclero-sis(AS). Methods Plasma were collected in 59 acute myocardial infarction (AMI) patients including 35 patients underwent selective PCI,24 patients underwent emergency PCI,43 unstable angina pectoris(UA) patients and 10 non-coronary artery disease (non-CAD) patients. All cases underwent coronary angiography (CAG). Plasma was collected immediately,post-24 hours and post-48 hours after admission. AOPP was determined by measurements of absorbance (A) at 340 nm under acidic conditions via spectrophotometry. Results AOPP was (236.42±30.41) ( n = 35 ), ( 207.84±29.50 ) mmol/L ( n = 35 ), ( 227.79 ± 35.18 ) mmol/L ( n = 31 ) respectively immediately, post-24 hours and post-48 hours after admission in AMI ( selective PCI ), ( 239.95 ±39.94 ) mmol/L ( n = 43 ), (175.92 ±29.46) mmol/L(n =38) ,and (156.54 ±28.29) mmol/L(n =35) in UA group and (57.41 ± 13.60) mmol/L( n = 9 ), (56.11 + 11.90) mmol/L ( n = 10 ) and ( 61.75 ± 12.28 ) mmol/L ( n = 8 ) in non-CAD group. Compared with normal group ( without CAD ) , significantly higher plasma AOPP was detected in AMI ( selective PCI) and UA patients ( P < 0.05 ). AOPP level was significantly increased in AMI selective PCI patients as compared with that of emergency PCI group immediately and post-24 hours after admission( P <0.01 ) ,and post-48 hours after admission( P < 0.05 ), but there was no statistical significance between emergency PCI and UA group( P > 0.05 ). Conclusions Oxidative stress is an important step in the development of atherosclerosis, and the higher levels of AOPP in ACS patients show that AOPP may be as good markers in these patients.