Simultaneous identification of low-molecular weight phenolic and nitrogen compounds in craft beers by HPLC-ESI-MS/MS

Phenolic and nitrogenous compounds from different styles craft beers were identified by high performance liquid chromatography and mass spectrometry in order to stratify beer samples according to their style. For this, an exploratory assessment relying on Linear Discriminant Analysis was performed. Fifty-seven phenolic compounds were reported and twelve of them were found for the first time in beer: benzoic acids, 2,4-dihydroxybenzoic acid, 2,3-dihydroxybenzoic acid, dimethoxybenzoic acid; phenolic acid conjugates, 3-p-coumaroylquinic acid, 4-p-coumaroylquinic acid, 3-feruloylquinic acid, 4-feruloylquinic acid, 5-feruloylquinic acid; flavonoids, taxifolin hexoside, quercetin dihexoside, apigenin-6,8-dipentoside, and isofraxidin hexoside. Additionally, 11 nitrogenous compounds belonging to the phenolamide class were found. Two discriminant functions were generated and allowed a satisfactory separation among all beer styles. 3-Caffeoylquinic acid, 3-p-coumaroylquinic acid, 4-p-coumaroylquinic acid, 5-caffeoylquinic acid, coumaric acid, kaempferol-3-O-rutinoside, proanthocyanidin B dimer III and proanthocyanidin B dimer V were the compounds that showed the highest capacity of discriminate the beer styles (IPA, Lager and Weiss).

Countercurrent Separation of Natural Products: An Update

This work assesses the current instrumentation, method development, and applications in countercurrent chromatography (CCC) and centrifugal partition chromatography (CPC), collectively referred to as countercurrent separation (CCS). The article provides a critical review of the CCS literature from 2007 since our last review (J. Nat. Prod. 2008, 71, 1489-1508), with a special emphasis on the applications of CCS in natural products research. The current state of CCS is reviewed in regard to three continuing topics (instrumentation, solvent system development, theory) and three new topics (optimization of parameters, workflow, bioactivity applications). The goals of this review are to deliver the necessary background with references for an up-to-date perspective of CCS, to point out its potential for the natural product scientist, and thereby to induce new applications in natural product chemistry, metabolome, and drug discovery research involving organisms from terrestrial and marine sources.

Hydroxybenzoic acid isomers and the cardiovascular system

Today we are beginning to understand how phytochemicals can influence metabolism, cellular signaling and gene expression. The hydroxybenzoic acids are related to salicylic acid and salicin, the first compounds isolated that have a pharmacological activity. In this review we examine how a number of hydroxyphenolics have the potential to ameliorate cardiovascular problems related to aging such as hypertension, atherosclerosis and dyslipidemia. The compounds focused upon include 2,3-dihydroxybenzoic acid (Pyrocatechuic acid), 2,5-dihydroxybenzoic acid (Gentisic acid), 3,4-dihydroxybenzoic acid (Protocatechuic acid), 3,5-dihydroxybenzoic acid (α-Resorcylic acid) and 3-monohydroxybenzoic acid. The latter two compounds activate the hydroxycarboxylic acid receptors with a consequence there is a reduction in adipocyte lipolysis with potential improvements of blood lipid profiles. Several of the other compounds can activate the Nrf2 signaling pathway that increases the expression of antioxidant enzymes, thereby decreasing oxidative stress and associated problems such as endothelial dysfunction that leads to hypertension as well as decreasing generalized inflammation that can lead to problems such as atherosclerosis. It has been known for many years that increased consumption of fruits and vegetables promotes health. We are beginning to understand how specific phytochemicals are responsible for such therapeutic effects. Hippocrates’ dictum of ‘Let food be your medicine and medicine your food’ can now be experimentally tested and the results of such experiments will enhance the ability of nutritionists to devise specific health-promoting diets.

Developments of instruments and methods related with high-speed countercurrent chromatography and their applications in research of natural medicines

High-speed countercurrent chromatography (HSCCC) is a liquid-liquid separation chromatographic technique which uses no solid supporting medium. During its rapid development in the last 30 years, great progress has been made in the instrumentation, the basic study and application of HSCCC. It has significant advantages over other instrumental separation techniques, in its high efficiency and continuous processing capability. In recent years, HSCCC has been widely used in research and development of natural medicines and functional foods, including preparative separation, fingerprint analysis and screening of bioactive constituents. A review of the technique is presented in this paper.

Separation and purification of hydrolyzable tannin from Geranium wilfordii Maxim by reversed-phase and normal-phase high-speed counter-current chromatography

Three hydrolyzable tannins, geraniin, corilagin and gallic acid, main active components of Geranium wilfordii Maxim, have been separated and purified in one-step by both reversed-phase and normal-phase high-speed counter-current chromatography. Gallic acid, corilagin and geraniin were purified from 70% aqueous acetone extract of G. wilfordii Maxim with solvent system n-hexane-ethyl acetate-methanol-acetic acid-water (1:10:0.2:0.2:20) by reversed-phase high-speed counter-current chromatography at purities of 94.2, 91.0 and 91.3%, at yields of 89.3, 82.9 and 91.7%, respectively. Gallic acid, corilagin and geraniin were purified with solvent system n-hexane-ethyl acetate-methanol-acetic acid-water (0.2:10:2:1:5) by normal-phase high-speed counter-current chromatography at purities of 85.9, 92.2 and 87.6%, at yields of 87.4, 94.6 and 94.3%, respectively. It was successful for both reversed-phase and normal-phase high-speed counter-current chromatography to separate high-polarity of low-molecular-weight substances.