Quantification Of Phenolic Compounds Research Articles

Optimization of microwave-assisted extraction using response surface methodology and HPLC-DAD phenolic compounds quantification from Hylocereus undatus peel and pulp cultivated in Tunisia

The present study aimed to optimize the microwave-assisted extraction process for both the peel and pulp of Hylocereus undatus (white dragon fruit) cultivated in Tunisia, using response surface methodology. Total phenolic content, total flavonoid content, FRAP (ferric reducing antioxidant power), and DPPH (1,1-diphenyl-2-picrylhydrazyl) antioxidant activities were optimized. A central composite design (CCD) was applied, considering three key variables: extraction time, extraction temperature, and liquid-to-solid ratio. The optimized extraction parameters for Hylocereus undatus peel and pulp were determined respectively (9.57 min, 42.20 °C and 27.79 mL/g) and (10.08 min, 40.84 °C and 31.52 mL/g). The main phenolic compounds identified in Hylocereus undatus peel and pulp extracts using HPLC-DAD were chlorogenic and caffeic acids and rutin, quercetin, luteolin-7-O-glucoside as flavonoids. Therefore, this research has revealed the potential of a sustainable and eco-friendly process hold promise a directional option and encouraging a circular economy approach for industrial production of antioxidant-rich Hylocereus undatus extracts.

Optimizing a Facile and Rapid Method for Extraction of Flavonoids from Matricaria Chamomilla Using TiO2 Nanoparticles

AbstractFlavonoids are known as valuable natural compounds and Chamomile is a rich source of flavonoids. The extraction efficiency of flavonoids is affected by various conditions. So it appears necessary to develop a practical method for the extraction of these compounds. In this study, we attempted to extract the phenolic compounds from chamomile using the surface capacity of titanium oxide nanoparticles (TiO2). UV and FT‐IR spectroscopy was used to determine the accuracy of the binding. The HPLC‐PDA technique was used for the quantification of phenolic compounds and the recovery test result was 84 %. Determining the antioxidant, phenolic, and flavonoid contents suggested that the developed method is successful for the extraction of phenolic compounds. The influential extraction parameters after optimization consisted of the pH of 7, extraction temperature of 25 °C, extraction time of 15 min, and TiO2 nanoparticle concentration of 4 mM. The method seems acceptable for industrial applications.

Extraction and Quantification of Phenolic Compounds in Maize.

Plants accumulate hundreds of thousands of specialized metabolites that participate in their interactions with the environment. Among these compounds, phenolics represent a large class, and they play important physiological roles, such as providing a first barrier against pathogens, cues to pollinators, and radiation protection. Maize is one of the most important crops worldwide for food, animal feed, and biofuels, and it has the potential to accumulate different phenolics in vegetative tissues as well as in seeds. Recent studies have identified a large number of phenolic compounds-with a diversity of chemical decorations-in different maize tissues, but these likely represent just a fraction of the metabolic diversity of maize. In this protocol, we describe a specific method for the extraction and quantification of maize phenolic compounds by ultra-high-pressure liquid chromatography-tandem multiple reaction monitoring mass spectrometry (UHPLC-MRM-MS/MS) analysis. We provide detailed instructions for the extraction of phenolics using acidic methanol, and for the quantification of 33 different compounds in maize stems, including flavonoids, phenolic acids, and lignin precursors.

Ultrasound-assisted extraction, optimisation using response surface methodology and HPLC-DAD phenolic compounds quantification from Passiflora edulis S. peels cultivated in Tunisia

A new ultrasound-assisted extraction method was developed for the determination of phenolic compounds extracted from Passiflora edulis Sims peels cultivated in Tunisia. Several extraction variables including: extraction time, temperature, liquid/solid ratio and pH have been studied using response surface methodology. The extraction efficiency was evaluated by measuring the total phenolics; flavonoids and antioxidants content. The highest values of the studied response were observed after 9.78 min at 49.64 °C in a liquid-to-solid ratio 22.07 ml/g and in pH (5.54). The individual phenolic compounds content of the optimum extract peels of the Passiflora edulis Sims have been analysed using HPLC-DAD. The results revealed the presence of gallic followed by caffeic acids, while the apigenin-7-glucoside and rutin have been quantified as the abundant flavonoid compounds (0.653 and 0.488 mg/ml, respectively). This green procedure should be a promising option to guide industrial design for the production of phenolic-rich plant extracts.

Microencapsulation of roasted mate tea extractives with lasiodiplodan (a (1 → 6)-β-D-glucan) and maltodextrin as combined coating materials: A strategic tool to stabilize and protect the bioactive components

Microencapsulation has emerged as a promising strategy to enhance the stability and protection of bioactive compounds. In this work, roasted mate tea was microencapsulated using 15 % maltodextrin and lasiodiplodan (0.5–1.25 %) as wall coating materials. The microcapsules were characterized for encapsulation efficiency, hygroscopicity, moisture, water activity, water solubility, dissolubility, scanning electron microscopy, FT-IR spectroscopy, thermal analysis, colorimetry, antioxidant activity, as well as quantification of phenolic compounds and caffeine. Microencapsulation yields ranged from 44.92 to 56.39 %, and encapsulation efficiency varied from 66.54 to 70.16 by increasing the lasiodiplodan concentration. FT-IR revealed phenolic acids, flavonoids, and polyphenolics. Minor color variations were observed among the samples. Thermal analysis demonstrated the microencapsulates exhibited good thermal stability with no degradation below 250 °C. Encapsulated samples showed high levels of bioactive compounds, suggesting that microencapsulation by spray-drying was a favorable process, where maltodextrin, a low-cost protective agent, when combined with the properties of lasiodiplodan, can be a good option for stabilizing mate extracts.

Phytochemical analysis of Robinia pseudoacacia flowers and leaf: quantitative analysis of natural compounds and molecular docking application

Phenolic compounds are widely found and well-known secondary metabolites in plants. Identification, and quantification of phenolic compounds, and determination of their biological activities reveal the unknown secrets of plants. Robinia pseudoacacia (RP) is known as the white-flowered false acacia and is distributed in Northern Anatolia in Turkey. Spectrophotometric and chromatographic techniques are used to identify the presence and amount of phenolics. In this study, RP flowers and leaves were extracted with methanol and analyzed by LC-MS/MS to determine their phytochemical content. Salicylic acid and syringic acid were found as major products in leaves and flowers. RP extracts have been reported to have antibacterial activity and BChE inhibitory properties. Therefore, the BChE and DD peptidase enzyme inhibitory properties of the main components salicylic acid and syringic acid were investigated by molecule docking (MolDock). According to MolDock results, syringic acid interacted with BChE and DD peptidase and was calculated as a MolDock score of -79.38, and -71.25, with binding energies -5.90, and -5.40 kcal/mol respectively. Salicylic acid interacted with BChE and DD peptidase and was calculated as a MolDock score of -63.54, and -66.18, with binding energies of -6.10, and -5.70 kcal/mol respectively. As a result, salicylic acid had higher binding energy in its interactions with BChE and DD peptidase enzymes. In theory, salicylic acid can be used as a good BChE and DD peptidase inhibitor.

Revealing the Phenolic Composition and the Antioxidant, Antimicrobial and Antiproliferative Activities of Two Euphrasia sp. Extracts.

The species of the genus Euphrasia present important medicinal potential according to their traditional uses. However, few studies aim to sustain this fact by scientific evidence. The present study aimed to explore the phytochemical profile and investigate the antioxidant, antimicrobial and antiproliferative potential of E. officinalis subsp. pratensis Fr. (EO) and E. stricta J.P.Wolff ex J.F.Lehm (ES). The tested samples consisted of ethanolic extracts. The identification and quantification of phenolic compounds were performed using spectrophotometric and LC-MS/MS methods. The antioxidant capacity was evaluated using the DPPH, FRAP and xanthine oxidase methods. Antimicrobial properties were screened using disk diffusion, broth microdilution and anti-biofilm assays, while antiproliferative potential was assessed on a colorectal adenocarcinoma human cancer cell line (DLD-1). The LC-MS/MS analysis showed chlorogenic acid and rutin as the dominant constituents in the tested extracts. The antioxidant activity assays showed important capacity for both samples; in vitro antimicrobial and anti-biofilm properties were exhibited, especially against Gram-positive bacteria, and an important inhibitory potential was observed on the proliferation of the DLD-1 cell line. The findings in the present study contribute to the recommendation of EO and ES for the prevention and treatment of oxidative stress-related pathologies, cancer and microbial infections.

Evaluation of the antiasthmatic properties of stems and leaves of Waltheria indica L. (Malvaceae): Focus on antioxidant and anti-inflammatory activity, and quantification of phenolic compounds

BackgroundWaltheria indica L. (Malvaceae) has a long history of use in traditional medicine for treating inflammation and asthma. This study aimed to evaluate the antiasthmatic properties of the hydroethanolic extract derived from the stems and leaves of W. indica. MethodPhytochemical analysis was conducted using thin-layer chromatography, and phytoconstituents were quantified using appropriate techniques. The antioxidant activity was determined through DPPH radical scavenging, ABTS+ radical cation decolorization, ferric ion reduction, and lipid peroxidation inhibition. The fractions' acute general toxicity was assessed following the guidelines of OECD 423. The in vitro anti-inflammatory activity was evaluated by inhibiting the 15-lipoxygenase and phospholipase A2 (PLA2), while the in vivo evaluation involved carrageenan-induced paw edema in mice at doses of 100, 200, and 400 mg/kg of body weight (b.w.). ResultsThe study revealed a total phenolic content of 116.03 ± 1.02 mg TAE/g in the residual fraction and 146.62 ± 2.02 mg TAE/g in the hydroethanolic extract. The extract and fractions also exhibited significant flavonoid content. The fractions' lethal dose was estimated to equal 5000 mg/kg b.w. Furthermore, the extract and fractions demonstrated substantial antioxidant and anti-inflammatory effects. ConclusionThe observed pharmacological activities provide scientific evidence for the traditional medicinal use of the leafy stems of W. indica in treating asthma.

Bioinspired amino acid-functionalized cobalt ferrite nanocomposite: A nanozyme-based colorimetric sensor for sensitive and selective quantification of phenolic compounds and ascorbic acid antioxidant capacity

The escalating oxidative stress has heightened the daily human demand for diverse antioxidants. Therefore, development of the novel approaches to assess the total antioxidant capacity (TAC) of various nutrients is essential. In this study, drawing inspiration from the active site of native peroxidase enzymes, a novel peroxidase (POD)-like nanozyme was developed based on the cobalt ferrite (CoFe2O4) nanoparticles functionalized with different catalytic amino acids. Based on the TMB/H2O2 colorimetric system, the most substantial enhancement in POD-like activity was obtained by the glutamic acid coating among different charged amino acids studied, with more than 74% increase in specific activity compared to the bare CoFe2O4. A signal-off colorimetric sensing platform based on the obtained nanobiocatalyst was developed for the accurate quantification of the antioxidant capacity of phenolic compounds and vitamin C. The sensitive and selective quantification of ascorbic acid, tannic acid, gallic acid, cyanidin-3-glucoside, and quercetin was obtained by this colorimetric method.

Quantification of phenolic compounds in dietary supplements and antioxidant activities

Dietary supplements (DS) are products that are recommended for the treatment of various health issues, especially during the global pandemic, and the accuracy of the labeling information of these supplements plays a significant role in human health. In this study, a novel high performance liquid chromatography-diode array detector (HPLC-DAD) method was developed and validated to determine the accuracy of the labeling information of commercial dietary supplements containing phenolic compounds (rutin, quercetin, and resveratrol). The mobile phase, flow rate, and column temperature were optimized. Validation studies were carried out to prove the validity of the developed method. The limit of detection (LOD) and limit of quantification (LOQ) values ​​of rutin, quercetin, and resveratrol were found in the range of 4.83-6.62 ng/mL and 16.09-22.07 ng/mL, respectively. Recoveries% were calculated in the range of 99.52-100.19% and 99.78-100.34% in the intra-day and inter-day analysis, respectively. The IC50 values of the dietary supplement extracts obtained by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method ranged from 0.08 to 0.76 mg/mL. Total Antioxidant Capacity (TAC) values of DS1, DS2, DS3, DS4, DS5, measured employing the Cupric Reducing Antioxidant Capacity (CUPRAC) method, were found to be 0.09, 0.03, 0.10, 0.10 and 0.40 mmol trolox per gram of extract, respectively. KEY WORDS: Dietary supplement, HPLC-DAD, Phenolic compound, Antioxidant activity Bull. Chem. Soc. Ethiop. 2024, 38(4), 853-862. DOI: https://dx.doi.org/10.4314/bcse.v38i4.3

Microbiological and Physicochemical Evaluation of Hydroxypropyl Methylcellulose (HPMC) and Propolis Film Coatings for Cheese Preservation.

Dairy products are highly susceptible to contamination from microorganisms. This study aimed to evaluate the efficacy of hydroxypropyl methylcellulose (HPMC) and propolis film as protective coatings for cheese. For this, microbiological analyses were carried out over the cheese' ripening period, focusing on total mesophilic bacteria, yeasts and moulds, lactic acid bacteria, total coliforms, Escherichia coli, and Enterobacteriaceae. Physicochemical parameters (pH, water activity, colour, phenolic compounds content) were also evaluated. The statistical analysis (conducted using ANOVA and PERMANOVA) showed a significant interaction term between the HPMC film and propolis (factor 1) and storage days (factor 2) with regard to the dependent variables: microbiological and physicochemical parameters. A high level of microbial contamination was identified at the baseline. However, the propolis films were able to reduce the microbial count. Physicochemical parameters also varied with storage time, with no significant differences found for propolis-containing films. Overall, the addition of propolis to the film influenced the cheeses' colour and the quantification of phenolic compounds. Regarding phenolic compounds, their loss was verified during storage, and was more pronounced in films with a higher percentage of propolis. The study also showed that, of the three groups of phenolic compounds (hydroxybenzoic acids, hydroxycinnamic acids, and flavonoids), hydroxycinnamic acids showed the most significant losses. Overall, this study reveals the potential of using HPMC/propolis films as a coating for cheese in terms of microbiological control and the preservation of physicochemical properties.

Phenolic profile and chronic gastric ulcer healing effects of Cameroonian propolis

BackgroundGastric ulcers continue to affect millions of people worldwide, with reported cases of fatalities and the diagnosis, prevention and treatment constitute a burden on the patients especially in case of chronic ulcers which are difficult to treat. Natural medicines such as propolis provide suitable therapeutic alternatives in the treatment and curation of ulcers. ObjectiveThis work focused on the evaluation of the phenolic profile and healing effect of Cameroonian propolis on gastric ulcers in rats. MethodsIdentification and quantification of phenolic compounds in the propolis extract was done using HPLC-DAD. Chronic gastric ulcers were induced using ethanol (70%; 1 mL/200 g p.o.)/indomethacin (1 mg/kg p.o.), and “unhealed” gastric ulcerations were induced using acetic acid (30%)/indomethacin (1 mg/kg p.o.). The animals were administered with the vehicle (Tween 20, 1 mL/100 g p.o.), propolis extract (200 mg/kg, 400 mg/kg and 600 mg/kg p.o.) or sucralfate (50 mg/kg p.o.), once daily for ten to fourteen days. At the end of each treatment period, the animals were sacrificed and ulcer indices, gastric mucus weight, histological and oxidative stress parameters were assessed. ResultsEight phenolic compounds were identified and quantified and most abundant were Caffeic acid (45.31 ± 0.25 µg/g), Chrysin (37.65 ± 0.17 µg/g) and p-Hydroxy benzoic acid (34.14 ± 0.21 µg/g). The treatment of ulcerated rats (chronic and unhealed gastric ulcer models) with propolis extract at 200 mg/kg, 400 mg/kg and 600 mg/kg resulted in reduction of ulcer index compared to negative controls in both models. Histological observation of stomach tissues showed that treatment with propolis extract led to a dose-dependent normalization of the mucosa. There was a significant increase (P < 0.05; P < 0.01 and P < 0.001) in mucus weight that accompanied the healing of the ulcers. Furthermore, doses of 200 mg/kg, 400 mg/kg and 600 mg/kg of the propolis extract induced an increase in the amounts of SOD, catalase, nitrite and GSH while MDA concentrations decreased in both models. ConclusionThe healing effect of propolis extract is due to the stimulation of mucus production followed by an improvement of in vivo antioxidant status. These results support the use of propolis in the development of new pharmacological strategies for the management of peptic ulcers disease.

Development and application of a high-performance liquid chromatography diode-array detection (HPLC–DAD) method for the simultaneous quantification of phenolic compounds in the aerial part of Glehnia littoralis

Glehnia littoralis, a medicinal herb employed in traditional practices for alleviating fatigue, cough, and a dry throat, is recognized for its beneficial properties due to a diverse array of active compounds found in its extracts. For example, the G. littoralis roots (Radix Glehniae) mainly contain coumarins and phenolic acids, serving as the primary focus of this study. Despite the widespread use of the tools in various industries and the development of multiple analytical methods for their examination, the edible aerial parts have industrial potential, and there is currently no analytical method available to identify their key components. In this study, a high-performance liquid chromatography method combined with diode array detection (HPLC–DAD) was developed to simultaneously detect 16 phenolic compounds previously reported to be present in the edible aerial parts of G. littoralis. The proposed approach included using gradient elution to change the solvent system from water/acetonitrile to water/methanol. Furthermore, the method validation was conducted, assessing its linearity, limit of detection, limit of quantification, precision, accuracy, and recovery, all of which demonstrated satisfactory results. Subsequently, the developed method was applied to quantify the phenolic compounds in various G. littoralis samples obtained from different organs, solvent extraction processes, and processing methods. Moreover, the online HPLC-ABTS (2,2ʹ-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) assay was used to evaluate the antioxidant capacities of individual constituents, identifying four important antioxidants and estimate the overall antioxidant capacity of the G. littoralis extract.

Analysis of the chemical constituents of Myrcia glomerata G.Burton &amp; E.Lucas leaves and assessment of their antimicrobial, antioxidant, and antibiofilm potential against pathogenic microorganisms

The Myrtaceae family plays a significant role in the Angiosperm landscape in Brazil, standing out as one of the most relevant. Within this context, the genus Myrcia ranks as the fourth largest, and its plant extracts and essential oils from these species are recognized as a valuable source of plant bioactives. In this context, Myrcia glomerata, popularly known as guamirim, stands out. Despite belonging to the Myrtaceae family, there is a lack of detailed research on its biological activities and chemical composition. The phytochemical investigation of the different plant extracts: ethanolic (EE), methanolic (ME), hexane (HE), acetone (AE), ethyl acetate (EAE) and dichloromethane (DE) revealed the presence of saponins, free steroids, alkaloids, anthocyanins, anthocyanidins, flavones, flavonols, xanthones, chalcones, aurones, flavononols and tannins, leading to the quantification of phenolic compounds (flavonoids, tannins, and alkaloids). The essential oil of the leaves, identified by gas chromatography coupled to mass spectrometry (GC-MS) identified 29 compounds, corresponding to 97.54% of the total area of the essential oil of M. glomerata. The main compounds found were sesquiterpenes, Elemicin (76.85%), Elixene (3.99%), E-caryophyllene (2.25%). EE showed the best antimicrobial potential, with concentrations ranging from 0.39 to 25 mg.mL-1, with Staphylococcus aureus and Proteus mirabilis strains being more susceptible in EE, ME and AE, showing 98.72%, 96.23% and 88.60% antioxidant activity, respectively. As for the antibiofilm potential, ME showed the greatest biomass reduction (90.53%) for Salmonella enterica Typhimurium, with cell viability of 9.02%. These results demonstrate the potential of EE and ME extracts from M. glomerata, representing a possible source of natural bioactives to be used in pharmaceuticals for the control of resistant microorganisms.

HPLC profiling for the simultaneous estimation of antidiabetic compounds from Tradescantia pallida

Diabetes is a long-term metabolic disease epitomized by postprandial hyperglycemia. The prolonged use of synthetic drugs renders distinct side effects, necessitating the development of safe and cost-effective substitutes. The aim of the current study is to isolate, evaluate the antidiabetic potential and HPLC method development for simultaneous estimation of antidiabetic compounds from the leaves of Tradescantia pallida. The leaves were extracted, fractionated and subjected to column chromatography. The isolated compounds' antidiabetic potential was evaluated using α-amylase and glycosylation of hemoglobin assays. The study employed molecular docking to scrutinize interactions between antidiabetic compounds and human α-amylase and hemoglobin protein. Prime MM-GBSA calculations determined binding energies of ligand–protein complexes. Further analysis of morin and catechin involved exploring dynamic and thermodynamic constraints through molecular dynamics simulations under specific biological conditions. A rapid HPLC method was developed and validated for the simultaneous estimation of isolated compounds. The column chromatography culminated in the isolation of four antidiabetic compounds (syringic acid, catechin, p-coumaric acid and morin). The in vitro analyses revealed that morin and catechin exhibited 72.67 % and 78 % α-amylase inhibition and 67 % and 71.66 % inhibition of hemoglobin glycosylation, respectively. In silico studies substantiated the in vitro assay, confirming the stability of catechin and morin complexes via root mean square deviation analysis. Interactions, encompassing hydrophilic, hydrophobic, water bridges, and ionic interactions, identified key residues involved in these processes. The validated HPLC method exhibited excellent correlation coefficients ranged from 0.9909 to 0.9997. The antidiabetic compounds were quantified from the extract in the range of 0.072 – 0.160 µg/mL. The study concluded that the isolated compounds from Tradescantia pallida have remarkable antidiabetic activity, and the developed method can be successfully used for the identification and quantification of phenolic compounds in Tradescantia pallida and other plant-derived matrix.

Chemical Characterization, Phenolic Compounds Quantification, and Assessment of Antioxidant and Anti-Acetylcholinesterase Activities of Byrsonima sericea DC fruits.

Byrsonima sericea is a species native to Brazil that is widely used in traditional medicine. The seed ethanol extract (SEE) had the highest content of total phenols (179.35 mg GAE g-1 extract) and flavonoids (10.42 mg QE g-1 extract) and was the most active in relation to antioxidant activity (DPPH: IC50 =4.25 μg mL-1 and ABTS: IC50 =4.82 μg mL-1 ). The peel/pulp ethanol extract (PEE) had the best anticholinesterase activity (IC50 =6.02 μg mL-1 ). Chromatographic investigation identified gallic acid, isoquercitrin, quercetin and amentoflavone in SEE, and gallic acid, isoquercitrin, quercetin and rutin in PEE. Six fatty acid methyl esters and seven triterpenes were identified, highlighting oleic acid in the seed hexane extract (61.85 %) and in the peel/pulp hexane extract (52.61 %), and betulin in the peel/pulp hexane extract (5.25 %). The substances and biological activities identified in B. sericea characterize this fruit as a functional food for future studies.

Chemical composition and biological properties of Thymus capitatus plants from Algerian high plains: A comparative and analytical study

Abstract The Lamiaceae family contains bioactive medicinal compounds mostly used as ornamental plants and traditional medicine, as well as in the food, cosmetics, and pharmaceutical sectors. Common uses include treating high cholesterol, diabetes, respiratory diseases, heart disease, and food poisoning. These medicinal uses were linked to their components and numerous biological properties, including antimicrobial and antioxidants. The goal of this study was to investigate the phytochemicals and biological activities of the petroleum ether extract of Thymus capitatus plant from two different regions of eastern Algeria (Souk ahras and Guelma), as well as to extract volatile oils using a Clevenger device and then analyze by using GC-MS. The results revealed that the total amount of phenolic compounds was better in the phenolic extract of Souk Ahras (3.41 mg GAE g−1), while the amount of flavonoid compounds was higher in the region of Guelma (26.31 mg QE g−1). Following the quantification of phenolic compounds by HPLC, we observed that the phenolic extracts contained most of the standard compounds in variable proportions. Furthermore, we tested the antioxidant activity of the phenolic compounds electrochemically with the cyclic voltammetry method. We concluded that the highest antioxidant content was recorded in the Guelma region extract (3.17 mg GAE g−1). We have also evaluated the antioxidant activity by a chemical method using 2,2-diphenyl-1-picrylhydrazyl, and the results showed that the Guelma extract exhibited a high effectiveness in terms of IC50% values. When extracting the volatile oils, it was found that the highest yield was in the Guelma region

Chlorophyll a fluorescence and phytochemical response in blackberry species (Rubus sp) cultivated in the high tropics

BACKGROUND: The evaluation of chlorophyll fluorescence activity is a useful tool for rapid and effective assessments of the effect of abiotic factors on the physiology of different crops. In Rubus, this type of measurements describes tolerance to high temperatures, sensitivity to heat and morphological alterations in flowering and chlorophyll content, as a result of plant stress. OBJECTIVE: The present research estimated chlorophyll fluorescence and the presence of some phenolic compounds in the leaves of three cultivars of blackberry ( Rubus sp.) established in the central region of Colombia, under conditions of open air between 2400 and 2800 masl. MATERIAL AND METHODS: This was done through the measurement of chlorophyll a (Junior-PAM II modulated fluorometer), the quantification of phenolic compounds (Folin Ciocalteu), the determination of antioxidant capacity (DPPH and ABTS) and the study of phenolic profiles (UHPLC) in leaves of three blackberry cultivars. RESULTS: Cultivars R. alutaceus (0.66), R. glaucus (0.73) and R. alpinus (0.76), presented values lower than the optimum (0.83), for the parameter F v/ F m. In addition, the direct relationships between the parameters that define the behavior of PSII and the accumulation of different polyphenols were described. Reference was also made to the content of phenolic compounds (ranging from 125 to 150 mg GA g–1 dw), which did not show significant statistical differences. The heat map and principal component analysis show the close relationship between the parameters that characterize the functioning of PSII and the accumulation of phenolic compounds, as a mechanism of adaptation to the adverse conditions of the blackberry cultivars studied. CONCLUSIONS: The results reveal that the leaves of the Rubus studied could be a source of functional ingredients for use in the cosmetic, nutraceutical and food industries and epigallocatechin was attributed the greatest responsibility for the antioxidant capacity.

Evaluation of phenolic and anthraquinone profiles of Polygonacaeae family from Turkey

The purpose of this research is to compare the content of phenolic compounds (catechin, esculetin, polydatin, rutin, resveratrol, quercetin) and anthraquinones (aloe-emodin, emodin, chrysophanol, physcion) in Polygonum cognatum Meissn. and Rumex crispus L. plant taxa from the flora of Turkey. Extraction parameters such as solvent, solvent ratio, and time for soxhlet method were optimized, and the most effective extraction was carried out for eight hours with methanol-water (3:1 v/v). The development and validation of an HPLC-DAD method allowed for the simultaneous quantification of phenolic compounds and anthraquinones in the plant extracts. The analytical method conditions were defined through an investigation of various parameters, including mobile phase composition, flow rate, and column temperature. The method was validated with good linearity, precision, sensitivity, and recovery. The LOD and LOQ values of the compounds were in the range of 0.032–0.457 µg/mL and 0.106–1.523 µg/mL, respectively. The findings of the study showed that this analytical method was successfully applied to identify and measure the phenolic and anthraquinone compounds in Polygonum cognatum Meissn. and Rumex crispus L. plants.

Development and validation of a LC–MS/MS method for the quantification of phenolic compounds in human saliva after intake of a procyanidin-rich pine bark extract

Plant-derived phenolic compounds are regularly ingested as food compounds or as food supplements. Concentrations of individual compounds and metabolites are typically measured in serum or urine samples. This, however, allows no conclusion on the distribution into organs and tissues. An easily accessible biofluid is saliva. At this point, it was not clear yet, whether polyphenols circulating in the blood would be secreted or diffuse into saliva. The purpose of the present study was to develop and validate a method using liquid chromatography coupled to electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) for analysis of phenolic compounds in human saliva. Method validation for the quantification of taxifolin, ferulic acid, caffeic acid, gallic acid, para-coumaric acid, and protocatechuic acid and the gut microbial catechin metabolite δ-(3,4-dihydroxyphenyl)-γ-valerolactone (M1) in human saliva was performed according to current guidelines for bioanalytical method validation. The lower limit of quantification ranged from 0.82 ng/ml for M1 to 8.20 ng/ml for protocatechuic acid. The method was successfully applied to an authentic saliva sample of a volunteer after swallowing of procyanidin-rich pine bark extract capsules (dietary supplement Pycnogenol®). All polyphenols except ferulic acid were quantified at concentrations ranging from 1.20 ng/ml (M1) to 10.34 ng/ml (gallic acid). Notably, in contrast to serum samples, all phenolic compounds were present without sulfate or glucuronic acid conjugation in saliva, suggesting an enzymatic deconjugation, e.g., by a β-glucuronidase activity, during compound transfer from serum to saliva. Since M1 is only produced in the gut, its presence in saliva ruled out the possibility of sample contamination by phenolic compounds residing in the oral cavity after food intake. To the best of our knowledge, this is the first time that the gut microbiota-derived metabolite M1 has been detected in saliva. To further investigate the role of phenolic compounds in saliva, the described analytical method can be applied in clinical studies investigating the biodistribution of polyphenols and their metabolites.