Rapid, simultaneous and non-destructive determination of multiple adulterants in Panax notoginseng powder by front-face total synchronous fluorescence spectroscopy.

The authentication of traditional herbal medicines in powder form is of great significance, as they are always of high values but vulnerable to adulteration. Based on the distinct fluorescence of protein tryptophan, phenolic acids and flavonoids, front-face synchronous fluorescence spectroscopy (FFSFS) was applied for the fast and non-invasive authentication of Panax notoginseng powder (PP) adulterated with the powder of rhizoma curcumae (CP), maize flour (MF) and whole wheat flour (WF). For either single or multiple adulterants in the range of 5-40% w/w, prediction models were built based on the combination of unfolded total synchronous fluorescence spectra and partial least square (PLS) regression, and were validated by both five-fold cross-validation and external validation. The constructed PLS2 models simultaneously predicted the contents of multiple adulterants in PP and gave suitable results, with most of the determination coefficients of prediction (Rp2) >0.9, the root mean square error of prediction (RMSEP) no >4% and residual predictive deviation (RPD) >2. The limits of detections (LODs) were 12.0, 9.1 and 7.6% for CP, MF and WF, respectively. All the relative prediction errors for simulated blind samples were between -22% and + 23%. FFSFS offers a novel alternative to the authentication of powdered herbal plants.

Enhanced preservation effects of clove (Syzygium aromaticum) essential oil on the processing of Chinese bacon (preserved meat products) by beta cyclodextrin metal organic frameworks (ß-CD-MOFs).

The applications of clove (Syzygium aromaticum) essential oil (CEO) are limited by instability, low solubility and high volatility. The present study aimed to improve the properties of CEO by microencapsulation with cyclodextrin metal organic frameworks (ß-CD-MOFs) to enhance the preservation effects on Chinese bacon (preserved meat products). The microencapsulated CEO by ß-CD-MOFs (CEO/ß-CD-MOFs) not only did not inhibit the antioxidant activities of CEO, but also showed significant improvements on their ROS scavenging abilities and thermo-/pH-stabilities. The increases of superoxide anion and hydroxyl radical scavenging activities were 20.74% and 12.84%, respectively. In addition, less lipid oxidation, including malondialdehyde (MDA) contents and peroxide values (POV), of Chinese bacon was found after the CEO/ß-CD-MOFs treatment than CEO and synthetic antioxidant (BHT) treatments. These results suggested the enhanced preservation effects of microencapsulated CEO on the processing of Chinese bacon and the great potential of ß-CD-MOFs as carriers for essential oils in food industry applications.

Comparative Analysis of Intracellular and in vitro Antioxidant Activities of Essential Oil From White and Black Pepper (Piper nigrum L.).

Ethnopharmacological Relevance: Pepper essential oils have potential immunomodulatory, anti-tumor, and anti-cancer activities. Pepper exhibits the potential to prevent or attenuate carcinogenesis as therapeutic tools. However, the related mechanism remains unelucidated. Aim of the Study: The present study aims to provide reasonable information for the explanation of the dissimilarity of the essential oils from white (WPEO) and black pepper (BPEO). Materials and Methods: WPEO, BPEO, and their single active component, as well as synthetic antioxidants, were compared by the cell model methods and chemical methods, including intracellular antioxidant activity (CAA), total antioxidant activities (TAA), superoxide radical (SR), hydroxyl radical (HR), DPPH radical (DR) scavenging activities and inhibition ability of lipoprotein lipid peroxidation (ILLP). Results: The median effective concentration (EC50) values (mg/mL) of the WPEO and BPEO of SR, HR, DR, and ILLP were 0.437 and 0.327, 0.486 and 0.204, 7.332 and 6.348, 0.688, and 0.624 mg/mL, respectively. The CAA units of WPEO and BPEO were 50.644 and 54.806, respectively. CAA, DR, and TAA of BPEO were significantly higher than those of WPEO (p < 0.05). The BPEO and WPEO can be differentiated as the former have higher correlations with 3-carene, α-pinene, ß-pinene, and limonene while the latter has a higher caryophyllene correlation. The WPEO and BPEO show a good intracellular scavenging ability of reactive oxygen species in HeLa cells. Conclusion: Generally, pepper oil has stronger activities than single components, indicating that pepper is a broad-spectrum natural antioxidant.

Improvement of the stabilities and antioxidant activities of polyphenols from the leaves of Chinese star anise (Illicium verum Hook. f.) using ß-cyclodextrin-based metal-organic frameworks.

BACKGROUND: Polyphenols extracted from plants are usually highly unstable and rapidly transformed into various reaction products during food and drug processing, thus limiting their applications. To improve the stability and solubility of polyphenols from the leaves of Chinese star anise (Illicium verum Hook. f.), and hence to expand their application to food and medicine, the extracted anise leaf polyphenols (ALPs) were microencapsulated using ß-cyclodextrin (ß-CD) and cyclodextrin-based metal-organic frameworks (ß-CD-MOFs). RESULTS: The optimum inclusion rate of ALP/ß-CD-MOFs was 97.80% at a core-wall ratio of 1:10. Meanwhile, the stabilities, solubilities and antioxidant activities of the polyphenols before and after inclusion were compared. The results showed both the stabilities and solubilities of ALP/ß-CD-MOFs were significantly improved compared with those of ALPs and ALP/ß-CD, suggesting the potential of ß-CD-MOFs as newer and better carriers than ß-CD for polyphenols in food industry applications. The free radical (including superoxide, hydroxyl and DPPH radicals) scavenging activities were also improved by microencapsulation. Superoxide radical scavenging reaction also showed slow-release property of ALP/ß-CD-MOFs. The formation of the inclusion complex was further confirmed using Fourier transform infrared spectral characterization. CONCLUSIONS: Microencapsulation with ß-CD-MOFs could expand the application scope of ALPs, and it is more effective than encapsulation with ß-CD. This is important for a better understanding and application of this useful traditional Chinese plant. As a new material with high efficiency and edibility, ß-CD-MOFs are not limited to the chemical field, but also have potential in new areas of food, medicine and healthcare products. © 2020 Society of Chemical Industry.

One pot synthesis of water-soluble quercetin derived multifunctional nanoparticles with photothermal and antioxidation capabilities.

As a member of flavonoids, the application of quercetin has been mainly focused on antioxidation study. Fabrication of multifunctional nanoplatforms with quercetin is limited. In the present study, water-soluble quercetin derived nanoparticles (QFNPs) were fabricated through the one pot synthesis strategy with Fe3+, quercetin and poly (vinyl pyrrolidone) (PVP). The raw materials were dissolved in absolute ethanol and the mixed together. After stirring at room temperature for 6 h, the QFNPs could be simply harvested by centrifugation without the need of time-consuming dialysis procedure. Due to the protective effect of PVP, the synthesized nanoparticles could be well dispersed in water with the hydrodynamic size about 23 nm. DPPH free radical scavenging capacity assay showed QFNPs could act as efficient antioxidant. Besides antioxidation activity, the QFNPs also exhibited good photothermal capacity. Temperature stability result suggested the good stability of QFNPs between 35 and 95 °C. MTT and hemolysis assay showed the good biocompatibility of QFNPs. What's more, the QFNPs showed good cellular antioxidation activity and efficient photothermal killing effect to cancer cells (4T1 cells). The QFNPs could be promising nanoplatform for biomedical application.

Antioxidant activity evaluation of rosemary ethanol extract and their cellular antioxidant activity toward HeLa cells.

Rosemary ethanol extract (REE) from Rosmarinus officinalis was identified by LC-ESI-MS/MS and 12 compounds were found. Among them, rosmarinic acid (389.78 µg/mg in REE), luteolin-3'-O-glucuronide (325.58 µg/mg), luteolin-5-O-glucuronide (120.92 µg/mg), and geniposide (120.83 µg/mg) are the major components. The antioxidant activity evaluation of REE by off-line HPLC methods indicated that among the 12 compounds, rosmarinic acid had the strongest scavenging activities in both DPPH· and ·OH. The cytotoxicity experiment showed that REE with the concentration ranges from 1 to 100 µg/ml did not significantly affect the cell viability of HeLa, while inhibitory rate reduced to 62.3% when the concentration was increased to 1,000 µg/ml. The results of intracellular antioxidation assay showed that the ability of REE in reducing the reactive oxygen species (ROS) in HeLa cells was higher than rosmanol, and lower than rosmarinic acid without cell toxicity. PRACTICAL APPLICATIONS: Plant polyphenols are essential components of functional foods, due to their antioxidant and enzyme inhibition activities. This paper is the first study about the quantification of antioxidant compounds, antioxidant activity evaluation, and their cellular antioxidant activity of polyphenols extract from R. officinalis toward HeLa cells. We aimed to elucidate the chemical composition and recognition of antioxidant components with DPPH and OH free radicals scavenging activity. In addition, the polyphenols dose-response correlations with cellular antioxidant activity were also determined. These results indicated that off-line HPLC method with DPPH and OH free radicals as markers is available for screening antioxidant activity of polyphenols from the mixture.

Screening and evaluation of active compounds in polyphenol mixtures by HPLC coupled with chemical methodology and its application.

An off-line high performance liquid chromatography (HPLC) coupled with chemical methods has been developed to evaluate antioxidant activity of 11 standard polyphenol compounds (SPCs) and vitamin C (Vc) in terms of radical scavenging abilities. The structure-activity relationships of each SPC were also discussed. SPCs showed different abilities in scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azinobis-3-ethyl-benzthiazoline-6-sulphonate (ABTS+) and hydroxyl (OH) free radicals. Among SPCs, quercetin and kaempferol, as typical flavonoids, displayed the greatest radical-scavenging activities and even exhibited higher activity in OH radical removal ability than that of Vc. Furthermore, the proposed method was also applied to screening polyphenolic antioxidant components from Cichorium endivia L. (C. endivia) seed extract. The results indicated that cynarin in the extract was a more active compound to scavenge DPPH and ABTS+ radicals than chlorogenic acid, while chlorogenic acid had stronger capacity in scavenging OH free radicals.

Synchronous front-face fluorescence spectroscopy for authentication of the adulteration of edible vegetable oil with refined used frying oil.

Synchronous front-face fluorescence spectroscopy has been developed for the discrimination of used frying oil (UFO) from edible vegetable oil (EVO), the estimation of the using time of UFO, and the determination of the adulteration of EVO with UFO. Both the heating time of laboratory prepared UFO and the adulteration of EVO with UFO could be determined by partial least squares regression (PLSR). To simulate the EVO adulteration with UFO, for each kind of oil, fifty adulterated samples at the adulterant amounts range of 1-50% were prepared. PLSR was then adopted to build the model and both full (leave-one-out) cross-validation and external validation were performed to evaluate the predictive ability. Under the optimum condition, the plots of observed versus predicted values exhibited high linearity (R(2)>0.96). The root mean square error of cross-validation (RMSECV) and root mean square error of prediction (RMSEP) were both lower than 3%.

Flavonoids in Juglans regia L. leaves and evaluation of in vitro antioxidant activity via intracellular and chemical methods.

Flavonoids are rich in Juglans regia L. leaves. They have potent antioxidant properties, which have been related to regulating immune function and enhancing anticancer activity. Herein, qualitative and quantitative determination of flavonoids from J. regia leaves was carried out using high performance liquid chromatography coupled with tandem mass spectrometry with electrospray ionization and negative ion detection (HPLC-ESI-MS/MS) by comparison of the retention times and mass spectral fragments with standard substances or related literatures. Seventeen compounds were identified and major components are quercetin-3-O-rhamnoside (453.11 µg/g, dry weight), quercetin-3-O-arabinoside (73.91 µg/g), quercetin-3-O-xyloside (70.04 µg/g), kaempferol-O-pentoside derivative (49.04 µg/g), quercetin-3-O-galactoside (48.61 µg/g), and kaempferol-O-pentoside (48.46 µg/g). The in vitro intracellular antioxidation indicated that flavonoids from J. regia leaves could reduce the reactive oxygen species (ROS) level in RAW264.7 cells and showed good radical scavenging activities. These results proved to be more related to the flavonoids that could be considered in the design of new formulations of dietary supplements or functional foods.

Polyphenolics composition of the leaves of Zanthoxylum bungeanum Maxim. grown in Hebei, China, and their radical scavenging activities.

High performance liquid chromatography coupled with tandem mass spectrometry with electrospray ionization and negative ion detection (HPLC-ESI-MS/MS) was used to identify the polyphenols from the leaves of a traditional vegetable and spice, Zanthoxylum bungeanum Maxim., in China by comparison of the retention times and mass spectral fragment with standard substances or related literature. A phenolic acid glucoside, two acids, and eight flavonoids were determined including vanillic acid-4-glucoside (22.75 µg/g, dry weight of leaves), quinic acid (58.58 µg/g), chlorogenic acid (2515.96 µg/g), epicatechin (77.80 µg/g), 5-feruloyquinic acid (16.63 µg/g), syringetin-3-glucoside (103.23 µg/g), rutin (89.41 µg/g), hyperoside (886.36 µg/g), quercetin-3-arabinoside (118.75 µg/g), quercitrin (645.82 µg/g), and isorhamnetin-3-glucoside (104.27 µg/g). The obtained polyphenols show good radical scavenging activities in DPPH and superoxide anion. Through the intracellular antioxidation assay, the result shows that the polyphenols could reduce the ROS in HT-29 cells without cell toxicity.