Quality and antioxidant activity detection of Crataegus leaves using on-line high-performance liquid chromatography with diode array detector coupled to chemiluminescence detection

Colorimetric sensor array based on Au2Pt nanozymes for antioxidant nutrition quality evaluation in food

Total antioxidant capacity (TAC) has become an important index to evaluate the food quality. Effective antioxidant detection has been the research hotspot of scientists. In this work, a novel three-channel colorimetric sensor array founded on Au₂Pt bimetallic nanozymes for the discrimination of antioxidants in food was constructed. Benefiting from the unique bimetallic doping structure, Au₂Pt nanospheres exhibited the excellent peroxidase-like activity with K_m of 0.044 mM and V_max of 19.37 × 10^-8 M s^-1 toward TMB. The density functional theory (DFT) calculation revealed that Pt atom in the doping system was active sites and there was no energy barrier in catalytic reaction which made Au₂Pt nanospheres had excellent catalytic activity. Accordingly, a multifunctional colorimetric sensor array was constructed based on Au₂Pt bimetallic nanozymes for rapid and sensitive detection of five antioxidants. Based on the different reduction ability of antioxidants, oxidized TMB could be reduced in different degrees. In the presence of H₂O₂, the colorimetric sensor array could generate differential colorimetric signals (fingerprints) by using TMB as the chromogenic substrate, which could be accurately discriminated through linear discriminant analysis (LDA) with a detection limit of <0.2 μM. The sensor array was able to the evaluate TAC in three actual samples (milk, green tea and orange juice). Furthermore, we prepared a rapid detection strip to meet the needs of practical application, making a positive contribution to food quality evaluation.

Application of multi-dimensional and multi-informational (MD-MI) integrated xanthine oxidase and superoxide anion fingerprint in quality evaluation of Scutellariae Radix

A multi-hyphenated analytical method that was successfully established in previous research was applied to quality evaluation of traditional Chinese medicine (TCM) to verify its feasibility in complex systems. Scutellariae Radix (SR), which significantly protects against oxidative damage from ischemia and reperfusion, was selected as the TCM for this study. A dual-activity detection system based on xanthine oxidase (XOD) inhibition and superoxide anion (O₂^-) scavenging activity was used to generate a multi-dimensional-multi-informational (MD-MI) integrated fingerprint of SR. Combined with HPLC-ESI-Q-TOF-MS analysis, 17 active compounds in SR were tentatively identified by comparison with reference substances or literature data. The quality of SR from different habitats was comprehensively and systematically evaluated in respect of chemical composition, XOD inhibition and O₂^- scavenging activity. It was confirmed that SR contains many antioxidants and XOD inhibitory substances with diverse functions. Among them, baicalin, norwogonin-7-O-glucuronide and baicalein are the main contributors to direct antioxidant activity. Acteoside, 5,7,2',5'-tetrahydroxy-8,6'-dimethoxy flavone, baicalin and baicalein are the main XOD inhibitory components of SR. Comprehensive analysis found that the antioxidant activity of SR from Gansu Province was superior to that from other provinces in terms of both XOD inhibition and O₂^- scavenging activity. It has been demonstrated that the method is capable of analyzing complex TCM matrices, and can provide a useful reference for establishing quality control of TCM from the perspective of MD-MI.

"Quantity-effect" research strategy for comparison of antioxidant activity and quality of Rehmanniae Radix and Rehmannia Radix Praeparata by on-line HPLC-UV-ABTS assay

Background

Quantitation analysis and chromatographic fingerprint of multi-components are frequently used to evaluate quality of herbal medicines but fail to reveal activity of the components. It is necessary to develop a rational approach of chromatography coupled with activity detection for quality assessment of herbal medicines.

Methods

An on-line HPLC-ultraviolet detection-2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radical scavenging (HPLC-UV-ABTS) method was developed to obtain the chromatographic fingerprints and ABTS^+• inhibition profiles (active fingerprints) of Rehmanniae Radix (Dihuang) and Rehmannia Radix Praeparata (Shu Dihuang). Eighteen compounds showing ABTS^+• inhibition activity were identified by HPLC-fourier-transform mass spectrometry (HPLC-FTMS). Verbascoside was used as a positive control to evaluate the total activities of the samples and the contribution rate of each compound. The similarities of the chromatographic and active fingerprints were estimated by the vectorial angle cosine method.

Results

The results showed that the HPLC-UV-ABTS method could efficiently detect antioxidant activity of the herbal medicine samples. The antioxidants were different between the two herbs and several new antioxidants were identified in Shu Dihuang. A function equation was generated in terms of the negative peak area (x) and the concentrations of verbascoside (y, μg/mL), y = 2E-07 × ⁴ - 8E-05 × ³ + 0.0079 × ² + 0.5755x + 1.4754, R² = 1. Iridoid glycosides were identified as main antioxidants and showed their higher contributions to the total activity of the samples. The total contributions of the three main active components in the Dihuang and Shu Dihuang samples to the total activity, such as echinacoside, verbascoside and an unknown compound, were 39.2–58.1% and 55.9–69.4%, respectively. The potencies of the main active components in the Shu Dihuang samples were two to ten times those in the Dihuang samples. Similarity values for S12 in the chromatographic fingerprints and S03, S12 and P03 in the active fingerprints were less than 0.9. The three batches of samples might show their different quality with the other samples.

Conclusions

The results suggested that the combination of “quantity-effect” research strategy and the HPLC-UV-ABTS analysis method could comprehensively evaluate the active components and quality of Dihuang and Shu Dhuang.

Optimizing Water-Based Extraction of Bioactive Principles of Hawthorn: From Experimental Laboratory Research to Homemade Preparations

Hawthorn (Crataegus) is used for its cardiotonic, hypotensive, vasodilative, sedative, antiatherosclerotic, and antihyperlipidemic properties. One of the main goals of this work was to find a well-defined optimized extraction protocol usable by each of us that would lead to repeatable, controlled, and quantified daily uptake of active components from hawthorn at a drinkable temperature (below 60 °C). A thorough investigation of the extraction mode in water (infusion, maceration, percolation, ultrasounds, microwaves) on the yield of extraction and the amount of phenolic compounds, flavonoids, and proanthocyanidin oligomers as well as on the Ultra High Performance Liquid Chromatography (UHPLC) profiles of the extracted compounds was carried out. High-resolution Fourier transform ion cyclotron resonance mass spectrometry was also implemented to discriminate the different samples and conditions of extraction. The quantitative and qualitative aspects of the extraction as well as the kinetics of extraction were studied, not only according to the part (flowers or leaves), the state (fresh or dried), and the granulometry of the dry plant, but also the stirring speed, the temperature, the extraction time, the volume of the container (cup, mug or bowl) and the use of infusion bags.

A novel multi-hyphenated analytical method to simultaneously determine xanthine oxidase inhibitors and superoxide anion scavengers in natural products

Natural products, such as rosmarinic acid and apigenin, can act as xanthine oxidase inhibitors (XOIs) as well as superoxide anion scavengers, and have potential for treatment of diseases associated with high uric acid levels and oxidative stress. However, efficient simultaneous screening of these two bioactivities in natural products has been challenging. We have developed a novel method by assembling a multi-hyphenated high performance liquid chromatography (HPLC) system that combines a photo-diode array, chemiluminescence detector and a HPLC system with a variable wavelength detector, to simultaneously detect components that act as both XOIs and superoxide anion scavengers in natural products. Superoxide anion scavenging activity in the analyte was measured by on-line chemiluminescence chromatography based on pyrogallol-luminol oxidation, while xanthine oxidase inhibitory activity was determined by semi-on-line HPLC analysis. After optimizing multiple elements, including chromatographic conditions (e.g., organic solvent concentration and mobile phase pH), concentrations of xanthine/xanthine oxidase and reaction temperature, our validated analytical method was capable of mixed sample analysis. The final results from our method are presented in an easily understood visual format including comprehensive bioactivity data of natural products.

An integrated antioxidant activity fingerprint for commercial teas based on their capacities to scavenge reactive oxygen species

An integrated antioxidant activity fingerprint, based on on-line screening methods for three reactive oxygen species (ROS: superoxide anion radical, hydrogen peroxide, and hydroxyl radical) was developed to comprehensively evaluate the quality of 12 batches of commercial tea. High-performance liquid chromatography (HPLC) coupled with a chemiluminescent detector was used to determine the antioxidant characteristics of a selection of teas as bioactivity fingerprints. An HPLC-electrospray ionization-mass spectrometry analysis was used to determine the chemical profiles of the teas in the chromatographic fingerprints. All of the green teas (S01-S08) were better scavengers of the three ROS compared to the oolong teas (S09-S12). The main scavengers of the three ROS in green tea were 5-galloylquinic acid, (-)-epigallocatechin-3-O-gallate, and (-)-epicatechin-3-O-gallate, whereas in oolong tea, they were (-)-epigallocatechin-3-O-gallate and (-)-epigallocatechin. This study demonstrates that comprehensive fingerprinting is a potentially meaningful method for evaluating the quality of food products.

Antioxidant Properties of Phenolic Compounds in Renewable Parts of Crataegus pinnatifida inferred from Seasonal Variations

In this study, the effect of seasonal variations on Crataegus pinnatifida, changes in antioxidant activity and active components in C. pinnatifida leaves, roots, twigs, and fruits from May to October were investigated. Through correlation analysis of climatic factors and 7 phenolic compounds yield, the phenolic compounds content was positively correlated with temperatures and daytime. The correlation coefficient of temperatures and daytime were 0.912 and 0.829, respectively. 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, 2,2'-azino-bis 3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging and reducing power tests were employed to evaluate the antioxidant activity of the C. pinnatifida. C. pinnatifida leaves exhibited significant advantages in terms of higher phenolic contents and excellent antioxidant activities. Principal component analysis (PCA) revealed that 2 main PC characterize the C. pinnatifida phenolic composition (82.1% of all variance). C. pinnatifida leaves in September possessed remarkable antioxidant activity. The results elucidate that C. pinnatifida leaves, as renewable parts, are suitable for application as antioxidant ingredients.

Optimization of ultrasound-assisted extraction (UAE) of phenolic compounds from Crataegus pinnatifida leaves and evaluation of antioxidant activities of extracts

In this study, a highly efficient BBD–RSM optimized ultrasound-assisted extraction combined with HPLC method has been established for the simultaneous extraction and determination of CA, VG, VR, ORT, RT, VIT and HYP from Crataegus pinnatifida leaves.

The Spectrum-Effect integrated fingerprint of Polygonum cuspidatum based on HPLC-diode array detection-flow injection-chemiluminescence

AIM

To establish the Spectrum-Effect integrated fingerprint of Polygonum cuspidatum to evaluate the quality of P. cuspidatum.

METHODS

An on-line HPLC-DAD-flow injection chemiluminescence (FICL) method was developed to investigate the quality of P. cuspidatum from different habitats based on the established Spectrum-Effect integrated fingerprint.

RESULTS

Nineteen batches of samples of P. cuspidatum were evaluated for the similarity of their chromatographic and free radical scavenging fingerprints, and the results compared. Main antioxidants were estimated by regression analysis between peak areas of thirteen compounds and their activities. Some active compounds were identified by HPLC-ESI-MS.

CONSULSIONS

The results indicated that main antioxidants in P. cuspidatum could be rapidly screened by the established Spectrum-Effect integrated fingerprint based on on-line HPLC-DAD-FICL, and would be more efficient and objective method to evaluate the quality of P. cuspidatum.

Effects of vitexin-2"-O-rhamnoside and vitexin-4"-O-glucoside on growth and oxidative stress-induced cell apoptosis of human adipose-derived stem cells

OBJECTIVES

Vitexin-2"-O-rhamnoside (VOR) and vitexin-4"-O-glucoside (VOG) are the two main flavonoid glycosides of the leaves of Cratagus pinnatifida Bge. var. major N. E. Br. that has been widely used for the treatment of cardiovascular system diseases. In this study, we simultaneously investigated the influence of VOR and VOG on human adipose-derived stem cells (hADSCs) injury induced by hydrogen peroxide (H2 O2 ) to further characterize their anti-oxidative and anti-apoptotic activity.

METHODS

hADSCs were isolated, cultured in vitro and pretreated with 62.5 μm VOR or 120 μm VOG for 24 h and then exposed to 500 μm H2 O2 for an additional 4 h.

KEY FINDINGS

Pretreatment of hADSCs with VOR and VOG was demonstrated to significantly ameliorate the toxicity and apoptosis effects, such as morphological distortion, nuclear condensation, decreased intracellular caspase-3 activity and percentage of cells in apoptosis/necrosis by using morphological assay, immunocytochemistry and flow cytometric evaluation. In addition, VOR and VOG caused no cytotoxic effect on hADSCs at concentrations up to 250 and 480 μm, respectively.

CONCLUSIONS

Our results indicated that both VOR and VOG contribute to the protection against H2 O2 -mediated oxidative stress damage and could be safely used for a wide range of concentrations.

Hepatic and gastrointestinal first-pass effects of vitexin-4″-O-glucoside in rats

Objectives

This paper was to clarify the reasons of low bioavailability of vitexin-4″-O-glucoside (VOG) in rats via hepatic combined with gastrointestinal first-pass effect.

Methods

Observed the hepatic first-pass effect through the comparison of area under the plasma concentration-time curve from zero to infinity (AUC0→∞) of VOG in arterial plasma after femoral and portal vein administration (10 mg/kg), similarly, evaluated the gastrointestinal first-pass effect after portal vein (10 mg/kg) and gastrointestinal administration (20 mg/kg). For the study on regulatory mechanisms of cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp) on the bioavailability of VOG, the solution of verapamil hydrochloride (60 mg/kg) was instilled into intestine at 10 min before the infusion of VOG.

Key findings

The bioavailability of VOG after intraportal, intestinal as well as gastric administration was 45.1%, 8.1% and 9.8%, respectively. The value of AUC0→∞ for verapamil group was approximately 1.4-fold higher than that for normal saline group, meaning that perhaps CYP3A participated in the metabolism of VOG or P-gp transported VOG outside.

Conclusions

The hepatic and intestinal first-pass effect were considered to mostly contribute to the low bioavailability of VOG in rats, and the gastric first-pass effect should be neglected. Also, the contribution of CYP3A to metabolism and P-gp mediated efflux have played a significant role in low bioavailability of VOG.

Activity of hawthorn leaf and bark extracts in relation to biological membrane

The aim of the study was to identify and determine the percent content of polyphenols in extracts from leaves and hawthorn bark, to examine the effect of the extracts on the properties of the biological membrane as well as to determine their antioxidant activity toward membrane lipids. In particular, a biophysical investigation was conducted on the effect of hawthorn extracts on the osmotic resistance and morphology of erythrocyte cells and on the packing of the heads of membrane lipids. Analysis of the polyphenol content of extracts used the HPLC method. Analysis of the polyphenol composition has shown a dominant share of procyanidins and epicatechin in both extracts. The research showed that the polyphenolic compounds contained in hawthorn extracts are incorporated mainly into the hydrophilic part of the erythrocyte membrane, inducing echinocyte shapes. They also diminish the packing order of the lipid polar heads of the membrane, as evidenced by the lowered generalized polarization values of Laurdan. The substances used induced increased osmotic pressure of erythrocytes, making them less sensitive to changes in osmotic pressure. The presence of the extract compounds in the outer hydrophilic part of the erythrocyte membrane, evidenced by examination of the shapes and packing in the hydrophilic part of membrane, indicates that the substances constitute a kind of barrier that protects the erythrocyte membrane against free radicals, while the membrane-bound extracts do not disturb the membrane structure and, thus, do not cause any side effects.