Quantification Of Phenolic Compounds Research Articles

Simultaneous optimization of the ultrasound-assisted extraction for phenolic compounds content and antioxidant activity of Lycium ruthenicum Murr. fruit using response surface methodology

Lycium ruthenicum Murr. (LR) is a functional food that plays an important role in anti-oxidation due to its high level of phenolic compounds. This study aims to optimize ultrasound-assisted extraction (UAE) of phenolic compounds and antioxidant activities of obtained extracts from LR using response surface methodology (RSM). A four-factor-three-level Box-Behnken design (BBD) was employed to discuss the following extracting parameters: extraction time (X1), ultrasonic power (X2), solvent to sample ratio (X3) and solvent concentration (X4). The analysis of variance (ANOVA) results revealed that the solvent to sample ratio had a significant influence on all responses, while the extraction time had no statistically significant effect on phenolic compounds. The optimum values of the combination of phenolic compounds and antioxidant activities were obtained for X1=30min, X2=100W, X3=40mL/g, and X4=33% (v/v). Five phenolic acids, including chlorogenic acid, caffeic acid, syringic acid, p-coumaric acid and ferulic acid, were analyzed by HPLC. Our results indicated that optimization extraction is vital for the quantification of phenolic compounds and antioxidant activity in LR, which may be contributed to large-scale industrial applications and future pharmacological activities research.

Chemometric compositional analysis of phenolic compounds in fermenting samples and wines using different infrared spectroscopy techniques

The wine industry requires reliable methods for the quantification of phenolic compounds during the winemaking process. Infrared spectroscopy appears as a suitable technique for process control and monitoring. The ability of Fourier transform near infrared (FT-NIR), attenuated total reflectance mid infrared (ATR-MIR) and Fourier transform infrared (FT-IR) spectroscopies to predict compositional phenolic levels during red wine fermentation and aging was investigated. Prediction models containing a large number of samples collected over two vintages from several industrial fermenting tanks as well as wine samples covering a varying number of vintages were validated. FT-NIR appeared as the most accurate technique to predict the phenolic content. Although slightly less accurate models were observed, ATR-MIR and FT-IR can also be used for the prediction of the majority of phenolic measurements. Additionally, the slope and intercept test indicated a systematic error for the three spectroscopies which seems to be slightly more pronounced for HPLC generated phenolics data than for the spectrophotometric parameters. However, the results also showed that the predictions made with the three instruments are statistically comparable. The robustness of the prediction models was also investigated and discussed.

Screening of bioactive components in grape and apple vinegars: Antioxidant and antimicrobial potential

Vinegars contain several bioactive compounds that are characterized according to the type of the raw material, such as grape vinegars and apple vinegars. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry was used for identification and quantification of phenolic compounds. Antioxidant properties of vinegars were determined by 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid assays. Antimicrobial activities of vinegars were examined with an agar disc diffusion method with Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. Gallic acid and chlorogenic acid were found to be the major phenolic acids accounting for the largest proportion of the total phenolic acid contents in grape vinegars and apple vinegars. Within the flavonols, quercetin-3-O-galactoside and quercetin were detected as the major compounds in grape vinegars. Apple vinegars were characterized by phloridzin, phloretin and high chlorogenic acid content. Antimicrobial activity results indicated that grape vinegars exhibited higher antimicrobial activity against tested bacterial strains correlated with their higher antioxidant capacity. Copyright © 2017 The Institute of Brewing & Distilling

Simultaneous determination of 13 phenolic bioactive compounds in guava (Psidium guajava L.) by HPLC-PAD with evaluation using PCA and Neural Network Analysis (NNA)

A reliable, simple and accurate method was developed to simultaneously determine 13 bioactive phenolic compounds in guava (Psidium guajava L.) by reversed-phase high-performance liquid chromatography with diode array detection (HPLC-DAD). The proposed methodology was fully validated and proven successful in the analysis of methanolic extracts of lyophilized whole guavas at two maturation stages: green and ripe. The quantification of phenolic compounds revealed that the highest concentrations (mg 100g−1 DW) in all samples were: gallic acid (2.43–7.28); chlorogenic acid (1.83–10.75); ellagic acid (5.72–30.60); catequin (1.09–13.09) and rutin (5.09–45.02). Total polyphenol content (55–516mg GAE 100g−1); total flavonoid content (35.26–75.19mg QE 100g−1); antioxidant capacity in DPPH and ABTS assays (5.22–5.62 and 17.63–18.74 TEAC·100g−1 DW, respectively) were also determined, and can be related to the diverse range of phenolics detected. The results (TPC and TFC) for most green samples were higher than for ripe samples. There were no significant differences for antioxidant activity between the samples analyzed. Applying Pearson correlation test, the results indicate a significant positive correlation between the variables. The exploratory evaluation of guava samples was performed through Principal Component Analysis (PCA). The bioactive phenolics that most contributed to the variability between green and ripe fruits were: rutin, catequin, and: elagic, syringic, cafeic, transcinamic and p-coumaric acids. Neural Network Analysis (NNA) was applied for more insights about cluster separation and the influence of each variable. The parameters evaluated for NNA indicated good separation in two clusters: green and ripe fruits.

Real Time Quantification of Phenolic Compounds in Oil and Gas Wells Produced Wastewater Using a QCM Sensor

Phenols (phenol, m-cresol, o-cresol and p-cresol) are contaminant compounds and due to its toxicity and persistence in the environment are listed in the Environmental Protection Agency as dangerous substances [1]; its presence in the environment is widely associated with wastewater effluents as is the produced water generated by oil and gas production. One of the systems that has been gaining importance to measure phenols in real time is the Quartz Crystal Microbalance (QCM). This technique comprises a thin quartz crystal sandwiched between two metal electrodes and senses the changes in frequency that suffers the quartz crystal when a certain amount of mass is deposited on its surface [3]. In order to improve the sensibility of compounds to measurement using a QCM have been used coatings on quartz crystal electrode surface, for example for phenols determination polymethylmethacrylate (PMMA) is used. The main objective of this research is to determine in real time and in continuous flow the concentration of phenolic compounds in produced water using the technique QCM with PMMA as coating on quartz crystal electrode surface. This work is conducted in three stages mainly: 1. Determination of a suitable layer of PMMA to use as coating, 2. Evaluation of the effect of the concentration of phenols, pH and flow rate in the measurements by QCM, 3. Comparison of sensitivity and time response obtained in the technique QCM with standard method by colorimetry.Results have shown that the PMMA films are more uniform when is used dichloroethane as solvent instead of chloroform and the stability and sensitivity in the measurements improve due to the vapor pressure of solvent that allows more dispersion of the polymer during spin coating, which is consistent with other authors [2]. Increase in the concentration of phenolic compounds, the flow rate and the pH increases the changes in frequency of the quartz crystal. Keywords : Quartz crystal microbalance, PMMA, phenols, produced water, real time. Mirmosheni, A., Oladegaragoze, A. Application of the quartz crystal microbalance for determination of phenol in solution. 2003. Sensors and Actuators, B: Chemical, Vol.98 (1), p. 28-36.Mohajerani, E. Morphological and thickness analysis for PMMA spin coated films. 2007. Journal of optoelectronics and advanced materials, Vol. 9 (12), p. 3901-3906.Reddy, S. Detection of phenol in aqueous solution using an AT-cut quartz thickness shear mode sensor. 2000. Materials Science and Engineering C, Vol. 12 (1), p. 23-28.

Uma abordagem sobre caracterização e avaliação do potencial antioxidante de extratos fenólicos de microalgas Spirulina sp. LEB-18 e Chlorella pyrenoidosa

The object of the study was to evaluate the proximate composition, amino acid profile, protein digestibility, quantification of individual and total phenols and antioxidant effect of phenolic extracts of Spirulina LEB-18 and Chlorella pyrenoidosa front of various methods. The Spirulina and Chlorella microalgae stand out on the nutrient profile and antioxidant activity through different mechanisms, the most important being the scavenging free radicals, which depends on the structure of the compound involved. Microalgae were evaluated for proximate composition, aminogram, protein digestibility in vitro, extraction and quantification of phenolic compounds by high-performance liquid chromatography, as well as, the antioxidant activity through the kidnapping of DPPH (2,2-diphenyl -1 -picrilhidrazil) and ABTS•+ (2,2'-azinobis (3-ethylbenzthiazoline sulfonic acid-6)), and s-carotene / linoleic acid system. It is concluded that both microalgae have complete amino acid profile, a good antioxidant activity against the methods used, especially spirulina, which showed higher values compared to Chlorella.

Isolation and Quantification of Phenolic Compounds in Acer tegmentosum by High Performance Liquid Chromatography

Determination of bioactive chemicals in Acer tegmentosum is essential for its industrial application. Twelve phenolic compounds were isolated from A. tegmentosum. Specific seven compounds in the plant were simultaneously analyzed by high performance liquid chromatography‐UV. The content of bioactive chemicals in the branch extract was determined to be 3.38 mg/g of (−)‐epigallocatechin, 66.95 mg/g of salidroside, 39.61 mg/g of tyrosol, 17.04 mg/g of catechin, 7.39 mg/g of 1,2,4‐tri‐O‐galloyl‐β‐d‐glucose, 8.88 mg/g of 6‐O‐galloylsalidroside, and 4.61 mg/g of scopoletin. The method was validated with linearity ( R 2 > 0.9947), as well as intra‐ and inter‐day precision (0.07–2.77%) and accuracy (>97.0%). This analytical method is expected to be applied for standardization of dietary food containing A. tegmentosum.

Phenolic acid composition of flaxseed cultivars by ultra-performance liquid chromatography (UPLC) and their antioxidant activities: Effect of sand roasting and microwave heating

Six flaxseed cultivars were studied for their antioxidant activity (AOA), total phenolic content (TPC), reducing power, and metal chelating activity after being subjected to sand roasting and microwave heating. Various phenolic compounds from methanol extracts were identified and quantified using ultra-performance liquid chromatography (UPLC). Both roasting and microwave heating significantly (p < .05) affected the antioxidant properties of flaxseed. A significant (p < .05) increase in AOA, metal chelating activity as well as reducing power of flaxseed was observed after heat processing. The results revealed that microwave heating resulted in significantly (p < .05) higher decrease and a higher increase in TPC and reducing power, respectively, as compared to sand roasting. UPLC data revealed the presence of 10 phenolic compounds namely: Ellagic acid, catechin, chlorogenic acid, gallic acid, Kaempferol, umbelliferone, Caffeic acid, coumaric acid, epicatechin, and rutin. The most abundant phenolic constituent was Ellagic acid whose concentration varied significantly among control and various heat processed flours. Practical applications The present study was undertaken to investigate separation and quantification of phenolic compounds in different flaxseed cultivars and their corresponding antioxidant activity after subjecting them to sand roasting and microwave heating. There are no published papers on quantification of phenolic compounds in flaxseed by UPLC as influenced by heat-processing methods. This work has shown that heat processing significantly influence the antioxidant properties of flaxseed. Microwave heating might be successfully employed as an innovation tool for flaxseed so as to develop minimally processed flaxseed to be used in different food and nonfood industries.

Antioxidant capacity and identification of the constituents of ethyl acetate fraction from Rhus verniciflua Stokes by HPLC-MS

Ethyl acetate fraction (EAF) from Rhus verniciflua Stokes is an important source of bioactive compounds. The aim of this study was the tentative identification and quantification of phenolic compounds, comparison of the phenolic structure–antioxidant activity relationships. Twelve compounds of EAF belonging to polyphenol types were detected by high performance liquid chromatography and analysed on line with negative ion electrospray ionisation tandem mass spectrometry, which were ethoxy 3-hydroxy benzoic acid, gallic acid (GA), 3,4-dihydroxy amygdalic acid, gallic acid cetyl ester, protocatechuic acid (PA), fustin, ethyl gallate (EG), garbanzol, fisetin, sulfuretin, butin and 3,7-dihydroxyflavanone-4′-rhamnoside. The antioxidant activity were evaluated based on the different types of radical scavenging capacities, i.e. DPPH·, ABTS·+ and OH. The antioxidant capacity of EAF mainly depended on the GA, EG, PA, fisetin, sulfuretin and butin. The phenolics exhibited a dose-dependent behaviour and high antioxidant ability.

Identification and Quantification of Phenolic Compounds and Bioactive Properties of Sorghum-cowpea-based Food Subjected to an In vitro Digestion Model

Identification and Quantification of Phenolic Compounds and Bioactive Properties of Sorghum-cowpea-based Food Subjected to an In vitro Digestion Model

Novel perspectives on two Digitalis species: Phenolic profile, bioactivity, enzyme inhibition, and toxicological evaluation

The present study outlines the phenolic composition of methanolic extracts of Digitalis ferruginea and Digitalis lamarckii aerial parts and evaluates their biological activities. The quantification of phenolic compounds was carried out by HPLC–DAD analysis. Antioxidant properties were assessed using different assays. Enzyme inhibition was tested on AChE, BChE, α-amylase, α-glucosidase, and tyrosinase. The antimicrobial properties of the extracts were determined using the microdilution method. Genotoxicity of the extracts was assessed on Drosophila melanogaster by comet assay. D. lamarcki extract was richer in phenolic compounds than D. ferruginea, with chlorogenic acid as dominant compound in both D. lamarckii and D. ferruginea extracts (2.99 and 1.30mg/g, respectively). Both extracts showed similar values in terms of antioxidant activity. The extracts showed enzyme inhibitory activity on above-mentioned enzymes and moderate antimicrobial activity (MIC range 0.625–10mg/mL). D. ferruginea extract (20mg/mL) indicated the absence of genotoxicity, while all concentrations of D. lamarckii extract showed significant DNA damage. Antigenotoxic effect was more evident in the group treated with D. lamarckii extract, 80mg/mL (%R=80.3). The results emphasized the biological potential of examined plants and encourage further studies for their potential use as phytopharmaceuticals.

Characterization and Quantification of Phenolic Compounds from Leaf of Agarista salicifolia

Agarista salicifolia is the wild tree and has been used as important medicinal plants in South Ethiopia since a long time ago. The aim of this work was to carry out a chemical analysis focusing on secondary metabolites, particularly phenolic compounds, which have several roles in the plant physiological processes and have demonstrated significant capacity in the prevention of human health diseases. Phenolic acids, flavonols, flavan-3-ols, and dihydrochalcones were characterized and quantified using ultra high-performance liquid chromatography coupled with diode array and electrospray ionization mass spectrometric detection (LC-MS), FTIR, and UV-Visible spectroscopy techniques. After extraction with ethanol, compounds were characterized and quantified based on retention time, molecular ions, and the comparison with reference compounds. Six flavan-3-ols, four phenolic acids, five flavonols, and two dihydrochalcones were identified and quantified in the extract. Chlorogenic (279.23 ± 28.75 µg/g of dried leaf) acid, Quercetin-3-O- rhaminoside (97.24 ± 4.07 µg/g of dried leaf), and epicatechin (304. 57 ± 20.88 µg/g of dried leaf), were the most abundant phenolic acid, flavonol, and flavanols, respectively. This is the first study on the phenolic composition of A. salicifolia, highlighting the importance of these natural products as a source of medicinal applications in pharmaceutical industries by herbal drug manufacturers.

Phenolic composition and antioxidant activity assessment of southeastern and south Brazilian propolis

Propolis is a resinous substance collected by honey bees Apis mellifera from several plant sources and used in the hive to seal the walls, to strengthen the ends of the honey comb or embalm dead invaders. The chemical specificity of propolis is directly determined by the variability of the plant origins and by geographical and climatic features of the collection site. The aim of this work was the quality assessment of 16 south and southeast Brazilian propolis samples through the identification and quantification of phenolic compounds using chromatographic and spectroscopic techniques such as HPLC and LC/DAD/ESI-MSn. Generally, the samples presented a phenolic profile related to Brazilian green propolis with origin in Baccharis spp. leaves, where the caffeoylquinic acid derivatives as well as dihydrokaempferide and artepillin C were the main compounds. Moreover, DPPH• free radical-scavenging activity, reducing power and differential pulse voltammetry were applied to evaluate the antioxidant activity. Differential pulse voltammetry proved to be a rapid and easy tool for the quantification of the total electroactive species present in the samples. The results revealed a richer phenolic composition and higher bioactivity in Minas Gerais samples rather than the southern ones.

Comparative Analysis of Phenolic Compound Characterization and Their Biosynthesis Genes between Two Diverse Bread Wheat (Triticum aestivum) Varieties Differing for Chapatti (Unleavened Flat Bread) Quality.

Phenolic compounds (PCs) affect the bread quality and can also affect the other types of end-use food products such as chapatti (unleavened flat bread), now globally recognized wheat-based food product. The detailed analysis of PCs and their biosynthesis genes in diverse bread wheat (Triticum aestivum) varieties differing for chapatti quality have not been studied. In this study, the identification and quantification of PCs using UPLC-QTOF-MS and/or MS/MS and functional genomics techniques such as microarrays and qRT-PCR of their biosynthesis genes have been studied in a good chapatti variety, “C 306” and a poor chapatti variety, “Sonalika.” About 80% (69/87) of plant phenolic compounds were tentatively identified in these varieties. Nine PCs (hinokinin, coutaric acid, fertaric acid, p-coumaroylqunic acid, kaempferide, isorhamnetin, epigallocatechin gallate, methyl isoorientin-2′-O-rhamnoside, and cyanidin-3-rutinoside) were identified only in the good chapatti variety and four PCs (tricin, apigenindin, quercetin-3-O-glucuronide, and myricetin-3-glucoside) in the poor chapatti variety. Therefore, about 20% of the identified PCs are unique to each other and may be “variety or genotype” specific PCs. Fourteen PCs used for quantification showed high variation between the varieties. The microarray data of 44 phenolic compound biosynthesis genes and 17 of them on qRT-PCR showed variation in expression level during seed development and majority of them showed low expression in the good chapatti variety. The expression pattern in the good chapatti variety was largely in agreement with that of phenolic compounds. The level of variation of 12 genes was high between the good and poor chapatti quality varieties and has potential in development of markers. The information generated in this study can be extended onto a larger germplasm set for development of molecular markers using QTL and/or association mapping approaches for their application in wheat breeding.

Quantification of phenolic compounds and antioxidant capacity of an underutilized Indian fruit: Rayan [Manilkara hexandra (Roxb.) Dubard

The fruit of Manilkara hexandra (Roxb.) Dubard is one of the most underutilized fruits of India and in Gujarat state. It is popularly known as ‘Rayan’. The fruit and seed of Rayan were analysed for their total phenolic and flavonoid content, phenolic compounds and total antioxidant capacity with six different assay methods. The results indicated that the methanolic extract of Rayan fruit being a good source of phenolic (811.3mg GAE/100g fw) and flavonoid (485.56mg RE/100g fw) content. Also, eleven known phenolic compounds were tentatively identified for the first time from the fruit and seed of Rayan. The LC–MS/MS analysis of fruit revealed the presence of major phenolic compounds such as gallic acid, quercetin and kaempferol, while quercetin, gallic acid and vanillic acid in seed. The presence of quercetin suggests health benefits. The fruit of Rayan was also proved to be a better source of antioxidants as measured by FRAP, RPA, DPPHRSA, ABTSRSA and HRSA except NORSA in comparison with that of seed. The current study explains that M. hexandra is a relatively good source of antioxidants such as phenols and flavonoids for diet.

Extraction and quantification of phenolic compounds from Prunus armeniaca seed and their role in biotransformation of xenobiotic compounds

The current research project has been devoted to isolating new low cost and eco-friendly phenolic compounds from fruit seeds, peels and vegetables to reduce the atmospheric pollution. Natural phenolic compounds were extracted from different fruit seeds and agriculture waste: P. armeniaca, P. persica, P. domestica and Triticum aesativum. The total phenolic content was quantified, and the maximum value (1 mL extract having 1,933 μg) was found in P. armeniaca seed extract. Phytochemical screening showed that P. armeniaca seeds contain higher amount of alkaloid, tannins, saponins and flavonoid. P. armeniaca seeds enhanced the biotransformation of reactive yellow dye up to 69.89% with maximum laccase (322.45 IU/mL) production. Biodegradation of reactive yellow was only 23.34% without natural redox mediator at sixth day of incubation. Use of P. armeniaca seed stimulators resulted in maximum laccase activity (894.4 IU/mL) with 99.5% rate of removal. UV-Vis, HPLC & FTIR analysis confirmed the transformation of parent dye into various new products. Phytotoxicity study indicated 0% germination index of Avena sativa seeds with reactive yellow, whereas 83% germination index having 100% seed germination while 83% root elongation with treated sample. Thus, the study revealed that the natural phenolic compounds could serve as high potential redox mediators for enhanced laccase-mediated decolorization of reactive yellow dye.

An Approach Based on HPLC-Fingerprint and Chemometrics to Quality Consistency Evaluation of Matricaria chamomilla L. Commercial Samples.

Chamomile has been used as an herbal medication since ancient times and is still popular because it contains various bioactive phytochemicals that could provide therapeutic effects. In this study, a simple and reliable HPLC method was developed to evaluate the quality consistency of nineteen chamomile samples through establishing a chromatographic fingerprint, quantification of phenolic compounds and determination of antioxidant activity. For fingerprint analysis, 12 peaks were selected as the common peaks to evaluate the similarities of commercial samples of chamomile obtained from different manufacturers. A similarity analysis was performed to assess the similarity/dissimilarity of chamomile samples where values varied from 0.868 to 0.990 what indicating that samples from different manufacturers were consistent. Additionally, simultaneous quantification of five phenolic acids (gallic, caffeic, syringic, p-coumaric, ferulic) and four flavonoids (rutin, myricetin, quercetin and keampferol) was performed to interpret the quality consistency. In quantitative analysis, the nine individual phenolic compounds showed good regression (r > 0.9975). Inter- and intra-day precisions for all analyzed compounds expressed as relative standard deviation (CV) ranged from 0.05% to 3.12%. Since flavonoids and other polyphenols are commonly recognized as natural antioxidants, the antioxidant activity of chamomile samples was evaluated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing/antioxidant power (FRAP) assay. Correlation analysis was used to assess the relationship between antioxidant activity and phenolic composition, and multivariate analysis (PCA and HCA) were applied to distinguish chamomile samples. Results shown in the study indicate high similarity of chamomile samples among them, widely spread in the market and commonly used by people as infusions or teas, as well as that there were no statistically significant differences among them, which in turn is a proof of high quality of commercially available samples of chamomile. The study indicated that the combination of chromatographic fingerprint and quantitative analysis can be readily utilized as a quality consistency method for chamomile and related medicinal preparations. Moreover, the applied strategy seems to be the most promising for the assessment of the investigated plant material.

Chemical characterization and protective effect of the Bactris setosa Mart. fruit against oxidative/nitrosative stress.

Bactris setosa Mart. is a Brazilian tree from the palm family (Arecaceae), whose fruits are scientifically underexploited. Here, we report, for the first time, the identification and quantification of phenolic compounds and carotenoids in the pulp, seed, and peel extracts of B. setosa fruits and their in vitro biological activity. The anthocyanins cyanidin deoxyhexose hexoside and cyanidin hexoside and other phenolic compounds were detected mainly in the peel but also in the pulp extracts. All-trans-lutein was the unique carotenoid identified and quantified, and only in the peel extract. All extracts were able to scavenge reactive oxygen and nitrogen species (ROS and RNS, respectively), to modulate human neutrophils' oxidative burst and to protect Caco-2 cells against oxidative damage, the peel extract being the most efficient. This study indicates that extracts from B. setosa fruits, especially the peel extract, are a source of bioactive compounds with promising antioxidant and anti-inflammatory properties.

A Phenolic Extract Obtained from Methyl Jasmonate-Treated Strawberries Enhances Apoptosis in a Human Cervical Cancer Cell Line

ABSTRACTIn the present study, we evaluated the effect of methyl jasmonate (MeJA) treatment on strawberry phenolic composition. Strawberry extracts contain a mixture of phenolic compounds possessing several biological properties. We demonstrated that these extracts were more effective in inducing apoptosis in HeLa cells compared to phenolic preparations derived from untreated strawberries. Treatment of strawberries with 0.5% MeJA resulted in increased polyphenols content (from 7.4 to 8.6 mM quercetin equivalents) and antioxidant properties (from 3.9 to 4.6 mM quercetin equivalents). The identification and quantification of phenolic compounds by liquid chromatography–mass spectrometry in the strawberry extracts showed that cyanidin glucoside, pelargonidin glucoside, and ellagic glucoside acid were significantly higher in strawberries treated with MeJA. Phenolic extracts from MeJA-treated strawberries significantly decreased the cell viability in HeLa cells, compared to extracts derived from untreated fruits. We hypothesized that the enhanced apoptotic activity of MeJA-treated strawberries was due to a synergistic or additive effect of different phenolic compounds present in the extract, rather than the activity of a single molecule.

Fractionation of Plant Bioactives from Black Carrots (Daucus carota subspecies sativus varietas atrorubens Alef.) by Adsorptive Membrane Chromatography and Analysis of Their Potential Anti-Diabetic Activity.

Black and purple carrots have attracted interest as colored extracts for coloring food due to their high content of anthocyanins. This study aimed to investigate the polyphenol composition of black carrots. Particularly, the identification and quantification of phenolic compounds of the variety Deep Purple carrot (DPC), which presents a very dark color, was performed by HPLC-PDA and HPLC-ESI-MS(n) analyses. The separation of polyphenols from a DPC XAD-7 extract into an anthocyanin fraction (AF) and co-pigment fraction (CF; primarily phenolic acids) was carried out by membrane chromatography. Furthermore, possible anti-diabetic effects of the DPC XAD-7 extract and its AF and CF were determined. DPC samples (XAD-7, CF, and AF) inhibited α-amylase and α-glucosidase in a dose-dependent manner. Moreover, DPC XAD-7 and chlorogenic acid, but not DPC CF and DPC AF, caused a moderate inhibition of intestinal glucose uptake in Caco-2 cells. However, DPC samples did not affect glucagon-like peptide-1 (GLP-1) secretion and dipeptidyl peptidase IV (DPP-4) activity. Overall, DPC exhibits an inhibitory effect on α-amylase and α-glucosidase activity and on cellular glucose uptake indicating potential anti-diabetic properties.