HPLC/MS-MS Identification of Oak Quercus aegilops Root Tannins

Tannins are natural polyphenolic compounds widely distributed in the plant kingdom in the leaves, bark, fruits, and other parts. They have various biological functions in humans and animals and are used mainly in the pharmaceutical and cosmetic industries. The aim of this work was to isolate, extract, purify, and identify the tannins from the root bark of a common oak tree (Quercus aegilops L.) in Jordan and around the Mediterranean. The results showed that at least one form of ellagitannin (ellagic acid ester), quercitrin, afzelechin, valoneic acid, trigalloyl glucose, and catechin was identified in addition to two unidentified compounds. Results of this work can help in developing an ESI MS/MS search library for the constituents of the tannins of oak (Quercus aegilops L.) root bark.

Predicting the absence of an unknown compound in a mass spectral database

Only a small subset of known organic compounds (amenable for gas chromatography/mass spectrometry) is present in the largest mass spectral databases (such as NIST or Wiley). Nevertheless, library search algorithms available in the market are not able to predict the absence of a compound in the database. In the present work, we have tried to implement such prediction by means of supervised classification. Training and validation set contained 1500 and 750 compounds, respectively. Two prediction sets (containing 750 and about 3000 mass spectra) were considered. The easiest-to-use models were built with only one input variable: match factor of the best candidate or InLib factor (both parameters were calculated within MS Search (NIST) software). Multivariate classification models were built by partial least squares discriminant analysis (PLS-DA); match factors of top n candidates were used as input variables. PLS-DA was found to be the most effective approach. The prediction efficiency strongly depended on the ‘uniqueness’ of mass spectra presented in the test set. PLS-DA model was able to correctly predict the absence of a compound in the database in 29.9% for prediction set #1 and in 74.4% for prediction set #2 (only 1.3% and 2.5% of compounds actually presented in the database were wrongly classified).

Comparative analysis of post-translational modifications in plasma proteome of patients with cerebral ischemia based on HPLC-MS/MS method

The relative differences between post-translational modifications (PTM) of proteins in blood plasma samples of patients with cerebral ischemia (CI) and healthy people were investigated using of the method of label-free comparative proteomic analysis based on the technology of tandem HPLC-MS/MS. For PTM detection we used multiple MS/MS search in the database Mascot for variable PTM and Progenesis LS-MS software. In the CI plasma samples, we observed an increase in the proportion of peptides with such PTM as phosphorylation of serine, threonine, and tyrosine, acetylation of lysine and protein N-term, ubiquitination of lysine and deamidation of glutamine related to clinically significant processes were revealed.

Mechanisms of arterial hypertension in metabolic syndrome

Arterial hypertension in patients with metabolic cardiovascular syndrome (MS) has a number of features which are of great theoretical and practical significance. It has been shown that hypertension is the most frequent component of MS and chronologically follows abdominal obesity while clinical manifestations of atherosclerosis and carbohydrate metabolism disturbances develop much later. In addition, the disorders of hypothalamic-pituitary-adrenal axis contribute to the development of arterial hypertension in patients with abdominal obesity. Besides the abnormalities of central regulatory mechanisms, increased sympathetic tone, insulin resistance and hyperinsulinemia, functional state of adipose tissue is an established important factor for the development of systemic hypertension in patients with abdominal obesity, and in some cases the dysfunction of adipocytes, which can be genetically determined or acquired, may cause the whole cascade of MS. Search for the causes and mechanisms of arterial hypertension in patients with MS can help to find the possible targeted treatment and prevention of the disease.