β-Cyclodextrin facilitates simultaneous analysis of six bioactive components in Rhizoma Smilacis Glabrae by capillary zone electrophoresis

Evaluation of cyclodextrin- and cyclofructan-based chiral selectors for the enantioseparation of psychoactive substances in capillary electrophoresis

During this study, a simple and easy-to-prepare electrophoretic method was developed for the enantioseparation of amphetamine and cathinone derivatives. Different types of β-cyclodextrin and cyclofructan-based chiral selectors (CSs), both native and derivatized, were utilized, and the most effective ones, in terms of resolution and analysis time, were identified. In addition, several electrophoretic parameters, such as background electrolyte concentration and pH, and CS concentration, were examined to optimize the separation conditions. Under the optimal electrophoretic conditions, 10 psychoactive substances were enantiomerically separated using 1 mM sulfated cyclofructan-6 (SCF-6) for the amphetamine derivatives and 1 mM sulfated cyclofructan-7 (SCF-7) for the cathinone derivatives dissolved in an aqueous solution of 20-mM monobasic sodium phosphate at pH 2.5, a temperature of 25°C, and an applied voltage of 25 kV. In addition, the method was validated by estimating the intra- and interday precision.

Production of Taxifolin from Astilbin by Fungal Biotransformation

Taxifolin is known to have multiple biological functions. It has been widely used as a multifunctional food additive, and consequently, the global demand for taxifolin is increasing. The main method for taxifolin production is an extraction from larch wood, but the global resources of larch are limited. Astilbin, taxifolin-3-o-rhamnoside, is abundant in many plants and much more readily available, meaning taxifolin can be obtained by deglycosylation of astilbin. In this study, a fungal strain, Aspergillus fumigatus SQH4, was isolated from an enrichment culture of Smilax glabra rhizome to achieve the deglycosylation reaction. A culture of SQH4, adjusted to pH 6.5, with 5 g/L astilbin achieved a yield of taxifolin of 91.3% after biotransformation for 14 h at 35 °C. These findings offer an alternative method for the production of taxifolin.

Metabolism, tissue distribution and excretion of taxifolin in rat

The metabolism, tissue distribution and excretion of taxifolin in rat after oral administration of taxifolin encapsulated zein-caseinate Nanoparticles (TZP) were studied. The isomerization of taxifolin in rat small intestine and colon was found. Besides isomers, 16 metabolites of taxifolin were identified in rat feces, plasma and urine by UPLC-QTOF-MS. In colon, taxifolin underwent the metabolism of hydration, dehydration and ring-fission through the gut microflora. The main metabolites of taxifolin found in plasma and urine were its sulfated, glucuronidated, and/or methylated products. The dynamic variation of taxifolin and its metabolites in tissues and urine were quantified by UPLC-QqQ-MS/MS. Taxifolin and its metabolites could be quickly absorbed and distributed in the tissues, and relatively low concentrations were found in the heart and brain. The feces excretion of taxifolin was determined by HPLC. The total excretion during 24 h was 2.83 ± 0.80% to its given does, and the maximum excretion was found during 8-10 h post administration. Compared with feces, the excretion of taxifolin and its metabolites in urine was much faster, and the total excretion was 1.96 ± 0.23% during 12 h.

The natural source, physicochemical properties, biological activities and metabolism of astilbin

Astilbin is a dihydroflavanol found in many plants and processed foods. Astilbin possesses multiple health-beneficial bioactivities and has received great attention. Hence, the natural source, physicochemical properties, biological activities and metabolism of astilbin are summarized in the present article. Engelhardia roxburghiana Wall. and Smilax glabra Roxb. are the main resource for astilbin purification because of high content. Because of chemical instability, astilbin amount in foods is dependent on the processing and storage conditions. The degradation of astilbin includes isomerization and decomposition. The interconversion of astilbin and its isomers occurs through a chalcone intermediates, which significantly affects the taste of wine during storage. Many factors such as temperature, pH, metal ions and food additives could affect the chemical stability of astilbin. Astilbin exhibits very novel selective immunosuppressive activity, which is not found in other compounds. The rhamnose moiety of astilbin is essential for this bioactivity. After digestion, astilbin was mainly absorbed and transported in circulatory blood in its intact form, and only one metabolite, 3'-O-methylastilbin, was found. Although having many bioactivities, astilbin faces the challenge of poor bioavailability. Some promising strategies were developed for improving its bioavailability, particularly through fabrication the zein nanoparticles.

Combined use of β-cyclodextrin and ionic liquid as electrolyte additives in EKC for separation and determination of carob's phenolics-A study of the synergistic effect

In this work, a simple, reliable, and fast capillary electrophoretic method was developed and validated for the simultaneous determination of 12 polyphenolic compounds, the most frequently found in carob's pulp and seeds. The present work deals with the development of a novel dual electrophoretic system based on the combined use of β-CD and ionic liquid (IL) as buffer additives. A baseline separation of the target analytes was achieved in less than 10 min by using a BGE consisting of 35 mM borate along with 15 mM β-CD and 3 mM l-alanine tert butyl ester lactate (l-AlaC₄ Lac) IL as buffer additives at pH 9.5, a temperature of 25°C, and an applied voltage of 30 kV. The application of the developed electrophoretic method to real samples enabled the identification and quantification of the main phenolic constituents of both ripe and unripe carob pulp extracts. The results revealed the predominance of gallic acid in both ripe (183.92 μg/g carob pulp) and unripe (205.10 μg/g carob pulp) carob pulp and highlighted the great influence of the ripening stage on carobs polyphenolic composition, with unripe pods being more enriched in polyphenols (total phenolics detected: 912.58 and 283.13 μg/g unripe and ripe carob pulp).

Acidic hydrolysis of astilbin and its application for the preparation of taxifolin from Rhizoma Smilacis Glabrae

The acidic hydrolysis of astilbin to produce its aglycone, taxifolin, was investigated in this study. The effects of aq. HCl concentration and temperature on the reaction were studied, and the kinetic parameters were calculated. The results showed that with higher aq. HCl concentration and temperature, the hydrolysis of astilbin became faster. The activation energy of the hydrolysis reaction under 1 mol L−1 aq. HCl was calculated with a value of 148.6 kJ mol−1. The reaction was successfully applied to produce taxifolin from a sample of Rhizoma Smilacis Glabrae. A simple method for the purification of taxifolin from Rhizoma Smilacis Glabrae was developed with purity of 97.5%.

Molybdenum sulfide-based electrochemical platform for high sensitive detection of taxifolin in Chinese medicine

MoS₂ and nitrogen doped active carbon composite (MoS₂/ANC) is fabricated to detect taxifolin and exhibits superior redox current response and decreased redox potential difference. Further investigation reveals that the kinetic process of the redox reaction of taxifolin on MoS₂/ANC electrode is controlled by both adsorption and diffusion process. Under the optimum conditions, the redox peak currents linearly relate with the concentration of taxifolin in the range of 1 × 10^-9-1 × 10^-6 mol L^-1, accompanied by the low detection limit (3 × 10^-10 mol L^-1). Meanwhile, outstanding selectivity, stability and repeatability are also obtained at MoS₂/ANC electrode. At last, the proposed method is applied to quantitatively detect taxifolin in fructus polygoni orientalis and satisfactory results have been achieved.

Purification of total flavonoids from Rhizoma Smilacis Glabrae through cyclodextrin-assisted extraction and resin adsorption

Flavonoids are the main bioactive components responded for the health promoting effects of Rhizoma Smilacis Glabrae (RSG), an herbal material used in many functional food of China. An eco-friendly method with β-cyclodextrin (β-CD)-assisted extraction and resin adsorption/desorption was developed for total flavonoids purification from RSG. Because of complexes formation between flavonoids and β-CD, aqueous solution was used for extraction instead of ethanol. The CD-assisted extraction was optimized through defining optimal CD species, concentration, extraction temperature, and time. The adsorption property of eight macroporous resins on astilbin was compared by adsorption kinetics and capacity. All resins could reach the adsorption equilibrium within 2 hr. Further analyzed by Langmuir and Freundlich models, H103 resin with the best adsorption capacity was selected. The desorption property of different ethanol-water solution was compared. Results showed that by using 75% ethanol, astilbin could be well desorbed from the resin with the recovery of 96.3%. Because of complexes formation, the presence of β-CD would slightly decrease the adsorption rate and capacity of H103 with concentration dependent. In dynamic adsorption, decreasing the flow rate could minish the effects of β-CD. The developed method was successfully used for total flavonoids purified from RSG. The yield of purified product was 8.78%, with astilbin and total flavonoids content of 363.8 and 505.7 mg/g, respectively. The purity was 1.74 times increased with the recovery of 94.38% compared with the extract obtained directly through 50% ethanol extraction.

Smilax aristolochiifolia Root Extract and Its Compounds Chlorogenic Acid and Astilbin Inhibit the Activity of α-Amylase and α-Glucosidase Enzymes

Regulating activities of α-amylase and α-glucosidase through the use of specific inhibitors is a main strategy for controlling type 2 diabetes. Smilax aristolochiifolia root decoctions are traditionally used in Mexico as hypoglycemic and for weight loss, but the active principles and mechanisms underlying such putative metabolic effects are yet unknown. Here, we isolated the major bioactive compounds from a hydroethanolic extract of S. aristolochiifolia root by fast centrifugal partition chromatography and evaluated their effects against pancreatic α-amylase and yeast α-glucosidase. A chlorogenic acid-rich fraction (CAF) inhibited α-amylase activity with an IC₅₀ value of 59.28 μg/mL in an uncompetitive manner and α-glucosidase activity with an IC₅₀ value of 9.27 μg/mL in a noncompetitive mode. Also, an astilbin-rich fraction (ABF) inhibited α-glucosidase activity with an IC₅₀ value of 12.30 μg/mL, in a noncompetitive manner. CAF inhibition α-amylase was as active as acarbose while both CAF and ABF were 50-fold more potent inhibitors of α-glucosidase than acarbose. The molecular docking results of chlorogenic acid and astilbin with α-amylase and α-glucosidase enzymes correlated with the inhibition mechanisms suggested by enzymatic assays. Our results prove that S. aristolochiifolia roots contain chlorogenic acid and astilbin, which inhibit carbohydrates-hydrolyzing enzymes, suggesting a new mechanism for the hypoglycemic effect reported for this plant.

Rapid discrimination of raw and sulfur-fumigated Smilax glabra based on chemical profiles by UHPLC-QTOF-MS/MS coupled with multivariate statistical analysis

Smilax glabra (SG) is commonly used as a traditional edible herb in eastern Asia. Recently, sulfur-fumigation has been frequently used in order to obtain better color and a longer storage lifetime. However, the chemical alterations caused by this process remain unknown. The aim of this research was to explore potential chemical differences between non-fumigated and sulfur-fumigated SG samples. A novel approach was developed by using ultra-high-performance liquid chromatography-quadrupole/time-of-flight mass spectrometry (UHPLC-QTOF-MS/MS) with principal component analysis (PCA) and orthogonal partial squared discriminant analysis (OPLS-DA). Fifty-eight compounds were unambiguously characterized or tentatively identified in the chemical profiles for the first time. Six newly generated sulfur-containing compounds, namely glucosyringic acid sulfate, 5-O-caffeoylshikimic acid sulfite, 3-O-caffeoylshikimic acid sulfite, 5-O-caffeoylshikimic acid sulfate, 3-O-caffeoylshikimic acid sulfate and astilbin sulfate, were screened out to be the most characteristic markers for distinguishing non-fumigated and sulfur-fumigated SG. This newly proposed approach can not only be applied for exploring chemical markers but can also be used to investigate the chemical transformation mechanism associated with sulfur for other edible herbs.

Simultaneous determination of phenylethanoid glycosides and aglycones by capillary zone electrophoresis with running buffer modifier

Although the separation efficiency of capillary electrophoresis (CE) is much higher than that of other chromatographic methods, it is sometimes difficult to adequately separate the complex ingredients in biological samples. This article describes how one effective and simple way to develop the separation efficiency in CE is to add some modifiers to the running buffer. The suitable running buffer modifier β-cyclodextrin (β-CD) was explored to fast and completely separate four phenylethanoid glycosides and aglycones (homovanillyl alcohol, hydroxytyrosol, 3,4-dimethoxycinnamic acid, and caffeic acid) in Lamiophlomis rotata (Lr) and Cistanche by capillary zone electrophoresis with ultraviolet (UV) detection. It was found that when β-CD was used as running buffer modifier, a baseline separation of the four analytes could be accomplished in less than 20 min and the detection limits were as low as 10(-3) mg L(-1). Other factors affecting the CE separation, such as working potential, pH value and ionic strength of running buffer, separation voltage, and sample injection time, were investigated extensively. Under the optimal conditions, a successful practical application on the determination of Lr and Cistanche samples confirmed the validity and practicability of this method.

Aqueous solubility and stability enhancement of astilbin through complexation with cyclodextrins

The complexation of astilbin with α-, β-, and γ-cyclodextrin (CD) was studied by phase solubility test and UV-vis spectral titration. Complexation with CDs gradually decreased the absorbance of astilbin at 291 nm and obviously increased its water solubility. The formation constant (K(a)) between astilbin and the three CDs was calculated. The stability of astilbin complexes increased in the order α-CD < γ-CD < β-CD, attributed to the CDs' cavity size. Temperature studies showed that the K(a) value decreased along with the rise of temperature. The negative values of enthalpy and entropy during complexation indicated that the complexation process was enthalpy-controlled. In alkaline medium isomerization and decomposition of astilbin were found; however, the addition of CDs significantly improved its stability through complexation. The solubility of astilbin in β-CD microcapsules prepared by the freeze-drying method was enhanced by 122.1-fold, and its dissolution profile was improved.

Chemical constituents comparison between Rhizoma Smilacis Glabrae and Rhizoma Smilacis Chinae by HPLC-DAD-MS/MS

Rhizoma Smilacis Glabrae (RSG) and Rhizoma Smilacis Chinae (RSC) are two herbal materials that belong to the same genera and are both listed in the Chinese Pharmacopoeia. Chemical constituents in the two species were compared by HPLC-DAD-MS/MS. Many common constituents were found in both species, including shikimic acid, 5-O-caffeoylshikimic acid, trans-resveratrol, taxifolin, astilbin and its three stereoisomers, engeletin and isoengeletin. However, syringic acid was found only in RSG, while chlorogenic acid was found only in RSC.

Development of HPLC fingerprint for species differentiation and quality assessment of Rhizoma Smilacis Glabrae

Rhizoma Smilacis Glabrae (RSG) is a commonly used herbal material in functional food and Traditional Chinese Medicine. A HPLC chromatographic fingerprint was developed for its quality control and species differentiation. Nine peaks were found in the chromatogram of RSG and all these peaks were identified by diode array detection and electrospray ionization-MS/MS: 5-O-caffeoylshikimic acid, taxifolin, engeletin, isoengeletin, trans-resveratrol, astilbin and its three stereoisomers. Six of these constituents were consistently found in 18 batches of samples. The standard fingerprint of RSG was generated by mean simulation of all tested samples. Using the standard fingerprint, RSG could be easily differentiated from Rhizoma Smilacis Chinae and Rhizoma Heterosmilacis, the two species that can be confused with RSG.

Development of capillary electrophoresis fingerprint for quality control of rhizoma Smilacis Glabrae

INTRODUCTION

Rhizoma Smilacis Glabrae (RSG) is a Chinese herbal medicine used for detoxication and as a diuretic. However, in some regions of China, RSG is used confusedly with some other herbs.

OBJECTIVE

To develop a capillary electrophoresis (CE)-DAD fingerprint method for quality evaluation, species differentiation and product identification of RSG.

METHODOLOGY

The CE separation conditions and extraction procedure were optimised. Eighteen batches of RSG samples were analysed and the standard fingerprint used for authentication was simulated by the average of all tested samples.

RESULTS

The optimal CE separation conditions were developed with running buffer of 20  mm borax containing 3  mm β-cyclodextrin at pH 9.4, voltage of 25  kV and temperature of 25°C. The separation could be completed within 8  min. Nine peaks were found in the electropherogram of RSG and five peaks were identified as astilbin, taxifolin, 5-O-caffeoylshikimic acid, shikimic acid and trans-resveratrol, respectively. Methanol and sonication were recommended for the sample preparation. All RSG samples showed similar chromatographic profile and six 'held in common' peaks were found. By the standard fingerprint, RSG could be well distinguished from its two confusable species, rhizoma Smilacis Chinae and rhizoma Heterosmilacis.

CONCLUSION

A CE-DAD fingerprint analysis method was developed for the quality control of RSG. The standard fingerprint could represent the chemical profile of RSG and be used for its authentication.

Advanced separation methods of food anthocyanins, isoflavones and flavanols

In recent years, increasing knowledge of the positive health effects of food polyphenols has prompted the need to develop new separation techniques for their extraction, fractionation and analysis. This article provides an updated and exhaustive review of the application of counter-current chromatography, high performance liquid chromatography, capillary electrophoresis, and their hyphenation with mass spectrometry to the study of food polyphenols. Flavonoids constitute the largest class of polyphenols, widely spread in the plant kingdom and common in human diet which has been the most widely studied with respect to their antioxidant and biological activities. The main subgroups are anthocyanins, catechins, isoflavones, flavonols and flavones. They are reported to exhibit antioxidant, anti-carcinogenic, anti-inflammatory, anti-atherogenic, anti-thrombotic, and immune modulating functions, among others. Since red fruit anthocyanins, soy isoflavones and flavanols from grapes and teas are currently the most used phenolic compounds for producing new nutraceuticals and functional foods, this review is focused on these three flavonoid groups.