Novel nonaqueous capillary electrophoresis separation and determination of bioactive flavone derivatives in Chinese herbs

Polyphenols of the Inuleae-Inulinae and Their Biological Activities: A Review

Polyphenols are ubiquitous plant metabolites that demonstrate biological activities essential to plant-environment interactions. They are of interest to plant food consumers, as well as to the food, pharmaceutical and cosmetic industry. The class of the plant metabolites comprises both widespread (chlorogenic acids, luteolin, quercetin) and unique compounds of diverse chemical structures but of the common biosynthetic origin. Polyphenols next to sesquiterpenoids are regarded as the major class of the Inuleae-Inulinae metabolites responsible for the pharmacological activity of medicinal plants from the subtribe (Blumea spp., Dittrichia spp., Inula spp., Pulicaria spp. and others). Recent decades have brought a rapid development of molecular and analytical techniques which resulted in better understanding of the taxonomic relationships within the Inuleae tribe and in a plethora of data concerning the chemical constituents of the Inuleae-Inulinae. The current taxonomical classification has introduced changes in the well-established botanical names and rearranged the genera based on molecular plant genetic studies. The newly created chemical data together with the earlier phytochemical studies may provide some complementary information on biochemical relationships within the subtribe. Moreover, they may at least partly explain pharmacological activities of the plant preparations traditionally used in therapy. The current review aimed to systematize the knowledge on the polyphenols of the Inulae-Inulinae.

Analysis of Natural Dyes from Historical Objects by High Performance Liquid Chromatography and Electromigration Techniques

Based on material published between 1989 and 2018 in this paper high performance liquid chromatography and electromigration techniques used in studies of natural dyes that can be found in historical objects are rewieved. Different aspects of analysis have been discussed: the stationary and mobile phase, the choice of sample solvent, methods of extraction and detection, including sensitivity parameters, such as LOD and/or LOQ. The discussed dyes have been divided into three categories (a) red antraquinone dyes along with dyes extracted from bark and tree juices, (b) yellow flavonoid dyes and saffron and (c) blue indigoid dyes. The main markers (chromophores or auxochromes) typical for each dye source were presented which allows to identify specific species of source plants and animals. The first part of the study involved the analysis of most critical findings when it comes to HPLC or represented an significant analytical approach. The second part of the study is focused on different aspects of electromigration techniques application in analysis of natural dyes with special attention paid on such parameters as the running buffer/mobile phase composition and sample solvent. Detection methods along with LOD and LOQ comparison in HPLC and electromigration techniques were also discussed. Methods of sample preparation, such as hydrolysis and extraction, used in HPLC and electromigration techniques were also briefly discussed.

Simultaneous determination of iridoid glycosides and flavanoids in Lamionphlomis rotate and its herbal preparation by a simple and rapid capillary zone electrophoresis method

Iridoid glycosides and flavanoids are two main effective components of Lamiophlomis rotata (Benth.) kudo. However, there is no method for simultaneous analysis of iridoid glycosides and flavanoids in L. rotata and its pharmaceutical preparations. A simple and rapid capillary zone electrophoresis (CZE) method was developed and validated for simultaneous determination of two iridoid glycosides (8-O-acetylshanzhiside methylester and 8-deoxyshanzhiside) and three flavanoids (apigenin, quercetin and luteolin) in L. rotata. Operational variables, such as the voltage, buffer concentration and pH were optimized, the final optimum separation condition was 10 mM sodium tetraborate-20 mM NaH(2) PO(4) (pH 8.5)-15% (v/v) methanol, 238 nm UV detection, 18 kV applied voltage. The linearity and the recovery of the proposed method were very satisfactory (correlation coefficients were 0.9994-0.9998 and the recoveries were 94.5-108.8% for the analytes) and the method allowed analytes in real samples to be determined within 9 min. The proposed CZE method can be used for quality control of iridoid glycosides and flavanoids in L. rotata and its herbal preparation.

Determination of total antioxidant capacity of commercial beverage samples by capillary electrophoresis via inline reaction with 2,6-dichlorophenolindophenol

This paper demonstrates proof-of-concept for the use of electrophoretically mediated microanalysis (EMMA) as a new approach to the determination of total antioxidant capacity (TAC). EMMA is a low-volume, high-efficiency capillary electrophoretic technique that has to date been underutilized for small molecule reactions. Here, nanoliter volumes of 2,6-dichlorophenolindophenol (DCIP) reagent solution are mixed with an antioxidant-containing sample within the confines of a narrow-bore capillary tube. The mixing is accomplished by exploiting differential migration rates of the reagents when a voltage field is applied across the length of the capillary tube. The ensuing electron transfer reaction between DCIP and the antioxidant(s) is then used as a quantitative measure of the TAC of the sample. Linear calibration using either redox form of DCIP is accomplished with standard solutions of ascorbic acid. Several commercial beverage samples are analyzed, and the TAC values obtained with the reported methodology are compared to results obtained with the widely used ferric reducing antioxidant power (FRAP) spectroscopic method. For the analysis of real samples of unknown ionic strength, the method of standard additions is shown to be superior to the use of external calibration. This easily automated EMMA method may represent a useful new approach to TAC determination.

Nonaqueous capillary electrophoresis in pharmaceutical analysis

This review presents different solvents and electrolytes commonly used as BGEs in NACE for the analysis of pharmaceutical compounds. Most NACE applications carried out since 1998 for the analysis of compounds of pharmaceutical interest are presented in four tables: (i) analysis of drugs and related substances, (ii) analysis of chiral substances, (iii) analysis of phytochemical extracts and (iv) analysis of drugs in biological fluids. These selected examples are used to illustrate the interest in NACE versus conventional aqueous CE.

Optimization of CZE for analysis of phytochemical bioactive compounds

Advantages of CZE such as high efficiency, low cost, short analysis time, and easy implementation result in its wide applications for analysis of phytochemical bioactive compounds (e.g. flavonoids, alkaloids, terpenoids, phenolic acid, saponins, anthraquinones and coumarins). However, several aspects, including sample preparation, separation, and detection have significant effects on CZE analysis. Therefore, optimization of these procedures is necessary for development of the method. In this review, sample preparation such as extraction method and preconcentration, separation factors including buffer type, concentration and pH, additives, voltage and temperature, as well as detection, e.g. direct and indirect UV detection, LIF and MS were discussed for optimization of CZE analysis on phytochemical bioactive compounds. The optimized strategies were also reviewed.