Polymeric Procyanidins Research Articles

Functional and sensory properties of pistachio nuts as affected by cultivar.

Modern agriculture allows farmers to choose among different cultivars of the same fruit to fulfill their agronomic needs and consumers' demands; however, there are only a few studies that describe and compare key functional and sensory properties of different pistachio cultivars. The main objective of this study was to compare eight pistachio cultivars by analyzing key functional properties (phenolic compounds, polymeric procyanidins, antioxidant activity, and inhibition of α-amylase and β-glucosidase), aromatic compounds with gas chromatography-mass spectrometry (GC-MS), and by examining their sensory properties with a trained panel. A combination of LC-PDA-MS-QTof (liquid chromatography photodiode array quadrupole time-off flight mass spectrometry) and electrospray ionization was used to determine two phenolic acids, nine flavonols, one anthocyanin, and three flavan-3-ols in pistachio cultivars, with a total concentration ranging from 500 to 6065 mg 100 g-1 dry weight (dw). The total polymeric procyanidins concentrations oscillated between 348 and 5919 mg 100 g-1 dw, (-)-epicatechin being the major monomer contributor. Pinene was the most abundant volatile compound (∼200 mg kg-1 dw), and, in the sensory analysis of samples, 23 sensory attributes were found to differ significantly among the cultivars. The cultivar 'Larnaka' stood out as having the best functional profile (high polyphenolic content, high antioxidant activity, and high values of α-amylase and β-glucosidase inhibition), and the cultivars 'Kastel' and 'Kerman' showed the most attractive sensory properties, mainly the most intense flavor. © 2019 Society of Chemical Industry.

Anti-Hyperglycemic and Anticholinergic Effects of Natural Antioxidant Contents in Edible Flowers.

In this study, 16 selected edible flowers were evaluated for their content of bioactive compounds (polyphenols, carotenoids, triterpenoids) and for their anti-diabetic (ability to inhibit α-amylase and α-glucosidases) and anti-aging (ability to inhibit acetylcholinesterase and butyrylcholinesterase) activities. Most of the flowers analyzed in this study have not been examined in this respect until now. Contents of the analyzed bioactive compounds differed significantly among the flowers. In particular, the highest contents of carotenoids and triterpenoids were determined in marigold, arnica, lavender, and daisy; in turn, the highest contents of phenolic acids, procyanidin polymers, and total polyphenols were assayed in hawthorn, primrose, and linden blossom. There was a positive correlation between the content of isoprenoids in edible flowers and their anti-aging activity, and between the content of polymeric procyanidins and flowers’ ability to inhibit α-glucosidase. In conclusion, edible flowers may be used to produce functional foods as well as for medical purposes.

Aqueous enzymatic pretreatment ionic liquid–lithium salt based microwave–assisted extraction of essential oil and procyanidins from pinecones of Pinus koraiensis

Abstract In this study, in order to simultaneously extract procyanidins and essential oil from pinecones of Pinus koraiensis, aqueous enzymatic pretreatment ionic liquid–lithium salt based microwave–assisted extraction (AEILLME) with a modified hydrodistillation concatenated Soxhlet extraction apparatus was proposed. 1-Butyl-3-methylimidazolium bromide solution was selected as extraction solvent, while LiCl and mixture of cellulase and pectinase (1:1, w/w) as additives by single factor experiment. Other parameters that affect the yield of target components were investigated and optimized by Plackett–Burman design and Box–Behnken design. The obtained optimal conditions were: microwave irradiation power 581.49 W, microwave irradiation time 15.95 min and liquid–solid ratio 11.91 mL/g. Under the optimized conditions, the predicted yields of oligomeric procyanidins, polymeric procyanidins and essential oil were 13.02, 32.19 and 7.76 mg/g, respectively. Analysis of chemical constituents in the essential oil was performed on gas chromatography–mass spectrometry and there was no significant difference on the components of essential oil obtained by proposed method and traditional methods. Ionic liquids were successfully recycled and reused, which could lower the process cost and being beneficial to industrial production. This study provides an approach with good prospects for the application in extracting active components from natural plant material.

Crown Procyanidin Tetramer: A Procyanidin with an Unusual Cyclic Skeleton with a Potent Protective Effect against Amyloid-β-Induced Toxicity.

The structure of a new procyanidin tetramer, which we call a crown procyanidin tetramer, with an unprecedented macrocyclic structure has been characterized for the first time. Its comprehensive spectroscopic analysis revealed that it is a symmetric procyanidin tetramer composed of four (−)-epicatechin sub-units linked alternatively via 4β→8 or 4β→6 B-type interflavanyl linkages to form the macrocyclic structure. This NMR-characterized carbon skeleton has never been reported before for procyanidins in grape or in wine, neither in the plant kingdom. Surprisingly, the crown procyanidin tetramer appeared to be specifically localized in grape skin, contrasting with the oligomeric and polymeric procyanidins present in seed, skin, and bunch stem. Moreover, this crown procyanidin tetramer showed promising protective effects against amyloid-β induced toxicity.

Comparison of the effect of four drying methods on polyphenols in saskatoon berry

The aim of the study was to evaluate the influence of different drying methods on physicochemical parameters of 3 saskatoon berry cultivars: ‘Honeywood’, ‘Smoky’ and ‘Martin’. Convective drying (CD), microwave-vacuum drying (MVD) and combined drying (CD/MVD) significantly affected moisture content, water activity and colour. Among polyphenolic compounds, 10 flavan-3-ols, 7 anthocyanins, 8 phenolic acids and 11 flavonols were identified by the UPLC-PDA-Q/TOF-MS system in dried saskatoon berries. The total content of identified polyphenolic compounds present in dried saskatoon berries ranged from 21.4 to 66.3 g/kg dry matter, for respectively ‘Martin’ and ‘Smoky’. The strongest ability of extracts to scavenge ABTS radical cations was noted for ‘Honeywood’, followed by both ‘Smoky’ and ‘Martin’. Antioxidant capacity of products was connected with the content of polyphenolic compounds. ‘Honeywood’ and ‘Smoky’ can be best recommended for the production of dried merchandise. The microwave vacuum drying at 480 W with reduction to 120 W give product with the quality similar to this obtained by freeze drying, especially when it comes to the retention of polymeric procyanidins and flavonols present in the fruit. In conclusion, quality of dried saskatoon berry can be successfully moderated by appropriate selection of drying techniques and parameters.

Profile of Bioactive Compounds in the Morphological Parts of Wild Fallopia japonica (Houtt) and Fallopia sachalinensis (F. Schmidt) and Their Antioxidative Activity.

The aim of this study was to determine the content of triterpenoids and polyphenols, and antioxidative activity in leaves, stalks, and roots of plants from the species Fallopia as well as to present the main relationship between them. Polyphenolic compounds and triterpenoids were identified with liquid chromatography-photodiode detector-mass spectrometry/quadrupole time of flight (LC-MS-Q/TOF; qualitatively) and quantified with an ultra-performance liquid chromatography-photodiode detector (UPLC-PDA (quantitatively), and their antioxidative activity was determined with radical scavenging capacity (ABTS) and oxygen radical absorbance capacity (ORAC) assays. Generally, the wild Fallopia japonica Houtt. species had 1.2 times higher content of bioactive compounds and antioxidative activity than Fallopia sachalinensis. Contents of polyphenolic compounds determined in leaves, stalks, and roots were on average 17.81, 10.60, and 9.02 g/100 g of dry weight (DW), whereas the average contents of triterpenoids reached 0.78, 0.70, and 0.50 g/100 g DW, respectively. The leaves were a better source of polymeric procyanidins, phenolic acids, flavones, and flavonols, as well as oleanolic and ursolic acids than the other morphological parts of the tested plants. However, the roots were an excellent source of flavan-3-ols (monomeric and oligomer) and stilbenes, such as resveratrol, and their derivatives. The results obtained showed significant differences between plants of the wild Fallopia species and their morphological parts, and enabled selecting the most valuable morphological part of the tested plants to be used for food enrichment and nutraceuticals production. Therefore, the leaves seem to be the best as potential food additives for health, due to the above-average content of polyphenolic compounds and triterpenoids. In turn, roots, with their high contents of stilbenes and polyphenolic compounds, represent a good material for the medical, pharmaceutical, and cosmetic industries. The principal component analysis of the plants of wild Fallopia species and their morphological parts confirmed significant differences in their chemical composition.

Changes of peach juices during the shelf‐life and their in vitro effect on glycolipid digestion and neurotransmitter metabolism

SummaryIn this study, the polyphenols content, α‐amylase, α‐glucosidase and cholinesterase‐inhibiting activities of cloudy peach (Prunus persica) juices, were measured immediately after thermal treatment and after storage (6 months at 4 and 30 °C). The study showed that some cultivars were more useable for industry than others. Due to the high content of polyphenols and a high ability to inhibit enzymes linked to type 2 diabetes and Alzheimer's disease, noteworthy are the juices obtained from ‘Redheaven early’ and ‘Redheaven’ cultivars. The content of total phenolics ranged from 1109.7 to 390.7 mg/L of juice, and the dominant fraction was polymeric procyanidins. Following 6 months of storage a significant change was observed in the content of polyphenols, especially flavonols and anthocyanins. The data compiled from the conducted study indicate that peach juice could be useful for the juice industry as a promising source of bioactive compounds.

Content of bioactive compounds in the peach kernels and their antioxidant, anti-hyperglycemic, anti-aging properties

In this study, the content of bioactive compounds (polyphenols and tetraterpenoids), antioxidative activity, and inhibitory activities toward α-amylase, α-glucosidase, cholinesterase of different cultivars of peach kernels were measured. Such results have not been published so far. It has been shown that peach kernels were characterized by a similar profile of bioactive compounds as the peach fruit, however, the content of some of these compounds was completely different. The total content of polyphenols ranged from 12.7 to 3.8 g/100 g dm, the carotenoids contains were from 101.7 to 0.0 mg/100 g dm and the amount of cyanogenic glycoside ranged from 245.7 to 17.4 mg/100 g dm. The peach kernels were also characterized by high antioxidative potential and the ability to inhibit enzymes linked to obesity, type 2 diabetes and Alzheimer’s disease. The study showed that the health-promoting properties of peach kernels are stimulated by polymeric procyanidins, hydroxycinnamic acids, carotenoids and cyanogenic glycosides. Generally, it was confirmed that peach kernels could be a valuable source of polyphenols used by the pharmaceutical industry for the production of dietary supplements to support the prevention of chronic non-communicable diseases.

A semisynthetic approach for the simultaneous reaction of grape seed polymeric procyanidins with catechin and epicatechin to obtain oligomeric procyanidins in large scale.

Polymeric procyanidins (PPCs) were the major constituents of procyanidins, while they have poor bioactivity. To better utilize PPCs, a semisynthetic approach for converting PPCs to oligomeric procyanidins (OPCs) was proposed. Grape seed PPCs were simultaneously reacted with catechin (C) and epicatechin (EC) under acid condition. Combining response surface methodology (RSM) and single-factor experiments, an optimized semisynthetic condition was confirmed with the ratio of PPCs with C and EC of 1:1:1, temperature of 40 °C, reaction time of 20 min and 0.1 M methanolic HCl. High-speed counter-current chromatography (HSCCC) was adopted to obtain three fractions from semisynthetic products and preparative-HPLC was used to isolate individual procyanidins. Thirteen B-type procyanidins including monomers, dimers and trimers were got with high yield of 0.8-17.8 mg from 200 mg semisynthetic products and high purity over 91%. The developed semisynthesis combined with separation method was efficient to obtain individual OPCs in preparative scale.

Self-aggregation of oxidized procyanidins contributes to the formation of heat-reversible haze in apple-based liqueur wine.

The ability of tannins to self-associate or form complexes with other macromolecules has important nutritional implications but can also result in defects in beverages. In addition, oxidation may be involved in the aggregation properties of tannins. In order to assess the impact of tannin oxidation on their self-association, oligomeric procyanidins were oxidized in a model solution and their aggregation kinetics were studied using light scattering. Under the conditions tested, only oxidized procyanidins were involved in haze formation. An increase in the level of oxidation and the degree of polymerization of procyanidins enhanced aggregation. Procyanidin oxidation products were depolymerized and the evolution of their markers was monitored throughout the aggregation process using liquid chromatography coupled with mass spectrometry. This revealed the involvement of intramolecular coupling in reversible haze formation. The haze formed in a model solution was partially reversible at high temperature. This property was similar in pommeau, an apple-based beverage. This work highlighted the involvement of oxidized tannins in reversible haze.

Effects of high intensity ultrasound on disaggregation of a macromolecular procyanidin-rich fraction from Vitis vinifera L. seed extract and evaluation of its antioxidant activity

The impact of high intensity ultrasound (US, 45 and 20 kHz) on a purified macromolecular fraction (more than 85% of polymeric procyanidins) from grape seed extract was investigated. Matrix-Assisted Laser Desorption/Ionisation (MALDI-TOF), Reverse Phase High Performance Liquid Chromatography (RP-HPLC) and Fourier-transform infrared spectroscopy (FTIR) revealed a modification in the chemical structure of these macromolecules treated by US and, particularly, bath US produced a considerable increase of up to 49, 41 and 35%, respectively, of catechins and oligomeric and polymeric procyanidin contents of the treated purified fraction. Bath US also produced an important increase in the number of procyanidins with higher molecular mass (up to decamers) and an overall increase in the mass signal intensities in most of the detected B-type procyanidin series, as well as an important increase of the antioxidant activity of the macromolecular fraction of procyanidins. These results could be ascribed to a certain disaggregation of procyanidins linked to other biopolymers, such as proteins and/or polysaccharides, indicating that US is an efficient technology to modify the chemical structure and hence the bioactivity of tannins.

Inhibitory effect of black chokeberry fruit polyphenols on pancreatic lipase – Searching for most active inhibitors

In this study, the effects of a chokeberry fruit crude extract (CE), its ethyl acetate fractions (EAF7 & EAF2) and a polyphenol-rich fraction (PRF) on esterase and lipolytic activities of pancreatic lipase (PL) were investigated. Ethyl acetate fractions, rich in flavonols, phenolic acids and low molecular procyanidins, showed a week inhibitory activity against PL while the CE and PRF, which contained the highly polymerized procyanidins exhibited the highest anti-lipase activity. The kinetic study showed that the inhibitory mode of CE was noncompetitive while PRF behaved like the mixed type inhibitor. Cumulative effects were observed when orlistat was used with either CE or PRF. These results indicate that black chokeberry fruits are a source of PL inhibitors with proanthocyanidins as the most active compounds.

Integrated Utilization of Red Radish for the Efficient Production of High-Purity Procyanidin Dimers.

Red radish was extracted by methanol to obtain crude radish procyanidin extracts. The purity of procyanidin (PP) and procyanidin dimers (PD) of crude radish procyanidin extracts under different ratios of methanol to radish was optimized to achieve the best extraction performance. Then the crude radish procyanidin extracts was, respectively, processed six macroporous resins separation to separate radish procyanidin oligomers (RPO) and polymers (RPP). Depolymerization of radish procyanidin polymers (RPP) into oligomers was then conducted. N-Acetylneuraminate lyase (NAL) was first used as the enzyme to depolymerize RPP. The depolymerization yield (DY) under different depolymerized conditions was also investigated. Results showed the DY of RPP would achieve 53.24 ± 0.35% at the best conditions. Then the high-purity procyanidin dimers was prepared by depolymerized procyanidin oligomers and PRO. Additionally, the chemical structure of the preparative radish procyanidin dimers was elucidated by high-resolution mass spectrometry and one- and two-dimensional NMR.

Formulation and storage effects on pomegranate smoothie phenolic composition, antioxidant capacity and color

Smoothies are an increasingly popular way of consuming fruits and the industry is focusing on the increment of shelf life and the maintenance original color and the content of bioactive compounds. The aim of the present study was to evaluate how formulation and storage conditions (6 months at 4 or 20 °C) of different pomegranate smoothies affected on functional compounds. Phenolic compounds, antioxidant capacity (ABTS, FRAP) and color of 12 different smoothies were studied. The study was completed evaluating the effect of ratio purée:juice (60:40 or 40:60), pomegranate cultivar (Mollar de Elche or Wonderful) and fruit purée (quince, jujube, or fig) on studied smoothies. The smoothies before storage presented high values of total polyphenolic content (TPC): 247–314 mg/100 g fresh weight (fw), 2939–3920 mg/100 g fw, and 3809–5324 mg/100 g fw, in fig, jujube and quinces pomegranate smoothies, respectively. A positive effect of the 40:60 ratio purée:juice, the Wonderful pomegranate juice storing at 4 °C was found on total polyphenolic content [sum of anthocyanins, flavanols, flavan-3-ols (as monomeric and dimeric), polymeric procyanidins and phenolic acids] and quality of smoothies (a* coordinate) being only a reduction of 30.1%, 13.1% and 9.5% in fig, jujube and quinces smoothies, respectively.

Phenolic and triterpenoid composition and inhibition of α-amylase of pistachio kernels (Pistacia vera L.) as affected by rootstock and irrigation treatment

The current water scarcity forces farmers to adopt new irrigation strategies to save water without jeopardizing the fruit yield and quality. In this study, the influence of 3 regulated deficit irrigation (RDI) treatments and 3 rootstocks on the functional quality of pistachios were studied. The functional parameters studied included, polyphenols, triterpenoids, and inhibition of α-amylase. The results showed that P. terebinthus and P. atlantica rootstocks led to pistachio kernels with higher contents of polyphenols and triterpenoids (mainly betulinic acid with 111 and 102 µg g−1, respectively) than pistachios obtained using P. integerrima rootstock (81 µg g−1). On the other hand, the use of moderate RDI (T1 treatment) increased the total content of polyphenols (∼10%), quercetin-O-galloyl-hexoside (∼15%), keampferol-3-O-glucoside (∼19%), and polymeric procyanidins (∼20%), as compared to the control trees, resulting in pistachios with a better functional profile, lower economic cost and with a lesser environmental impact.

Antisolvent precipitation for the preparation of high polymeric procyanidin nanoparticles under ultrasonication and evaluation of their antioxidant activity in vitro

An improved method of ultrasonic antisolvent precipitation was used to prepare micronized high polymeric procyanidins (HPC). Response surface methodology (Plackett–Burman and Box–Behnken design) was employed to predict the optimal preparation conditions and satisfactory mean particle size. Among seven parameters, three parameters (i.e., ultrasonic irradiation power, ultrasonic-stirring time, and stirring speed) were identified as the most significant variables using Plackett–Burman design; thus, these three parameters were further optimized using Box–Behnken design. The optimal preparation conditions for micronized HPC were obtained as follows: dropping speed of 4 mL/min, HPC solution concentration of 0.3 mg/mL, ratio of antisolvent and solvent of 5 mL/mL, precipitation temperature of 10 °C, ultrasonic-stirring time of 14 min, ultrasonic irradiation power of 620 W, and stirring speed of 760 r/min. A minimum mean particle size of 96 ± 2 nm was achieved under the aforementioned conditions. The obtained micronized HPC was analysed by scanning electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric and X-ray powder diffraction patterns. Micronized HPC enjoyed the higher quantity dissolved and exhibited stronger antioxidant activity in compared to the unprocessed HPC. These results demonstrated that the improved method has great potential for the production of micronized particles.

Effect of Proanthocyanidin-rich Extracts from Pinus radiata Bark on Termite Feeding Deterrence

Antioxidants are known to affect the feeding habits of termites and a good source is pine bark which contains high levels of antioxidants which can be extracted with neutral solvents. In this study procyanidins (PCs)-rich MeOH-extract and a hot-water extract (HWE) were prepared from Pinus radiata bark. HWE was further separated into crude PCs (CPCs), polymeric PCs (PPCs), and low-molecular-weight PCs (LMWPCs) fractions. The MeOH extract and these fractions were examined for termite (Reticulitermes flavipes Kollar) antifeedant activities using a no-choice test. Catechin was used as a positive control. The LMWPCs was found to be the most effective deterrent to termite feeding. The comparative efficiency of the compounds tested were LMWPCs > PPCs > CPCs > MeOH extract, with the latter being more dependent on molecular weight than on its antioxidant activity.

Procyanidins: a comprehensive review encompassing structure elucidation via mass spectrometry.

Procyanidins are polyphenols abundant in dietary fruits, vegetables, nuts, legumes, and grains with a variety of chemopreventive biological effects. Rapid structure determination of these compounds is needed, notably for the more complex polymeric procyanidins. We review the recent developments in the structure elucidation of procyanidins with a focus on mass spectrometric approaches, especially liquid chromatography-tandem mass spectrometry (LC-MS/MS) and matrix-assisted laser desorption ionization (MALDI) MS/MS.

Monomeric cocoa procyanidins enhances β‐cell function by increasing mitochondrial respiration

A hallmark of type 2 diabetes (T2D) is β‐cell dysfunction and the eventual loss of functional β‐cell mass. Therefore, mechanisms that can improve β‐cell function could be used as a treatment for the millions of individuals with T2D. Recent studies have shown that monomeric, oligomeric and polymeric cocoa derived procyanidins have vastly different effects on obesity, insulin resistance and glucose tolerance during high fat feeding. Based on these previously published data, we hypothesized that cocoa derived procyanidins may have beneficial effects on improving β‐cell function. 832/13 INS‐1 derived β‐cells and primary rat islets cultured with monomeric cocoa procyanidins demonstrated enhanced glucose stimulated insulin secretion (GSIS), while cells cultured with total cocoa extract, oligomeric procyanidins or polymeric procyanidins demonstrated no improvement. The increased GSIS observed with culture in the presence of monomeric procyanidin fractions corresponded with enhanced mitochondrial respiration, suggesting improvements in β‐cell fuel utilization. We demonstrated upregulation of electron transport chain components Complex III, IV and V after culture with monomeric procyanidins. Monomeric procyanidins also resulted in an increased cellular redox state and increased glutathione concentration, which corresponds with Nrf2 nuclear localization. We propose a model by which cocoa derived monomeric procyanidins enhance the cellular redox state, allowing Nrf2 to migrate to the nucleus and enhance expression of key mitochondrial genes that results in enhanced GSIS and improved β‐cell function. These results suggest that cocoa derived monomeric procyanidins could be leveraged as a treatment modality for patients with T2D.Support or Funding InformationBYU MEG Grant to JST, Diabetes Action Research and Education Grant to JST, BYU ORCA Grant to JDR and BFB

Trimeric and Tetrameric A-Type Procyanidins from Peanut Skins.

Peanut skins are a rich source of oligomeric and polymeric procyanidins. The oligomeric fractions are dominated by dimers, trimers, and tetramers. A multistep chromatographic fractionation led to the isolation of four new A-type procyanidins of tri- and tetrameric structures. The structures of the new trimers were defined by NMR, electronic circular dichroism, and MS data as epicatechin-(4β→8,2β→O→7)-epicatechin-(4β→8,2β→O→7)-catechin, peanut procyanidin B (3), and epicatechin-(4β→8,2β→O→7)-epicatechin-(4β→6)-catechin, peanut procyanidin C (4). The new tetramers were defined as epicatechin-(4β→8,2β→O→7)-epicatechin-(4β→6)-epicatechin-(4β→8,2β→O→7)-catechin, peanut procyanidin E (1), and epicatechin-(4β→8,2β→O→7)-epicatechin-(4β→6)-epicatechin-(4β→8,2β→O→7)-epicatechin, peanut procyanidin F (2). In addition, both A-type dimers A1, epicatechin-(4β→8,2β→O→7)-catechin, and A2, epicatechin-(4β→8,2β→O→7)-epicatechin, as well as two known peanut trimers, ent-epicatechin-(4β→6)-epicatechin-(4β→8,2β→O→7)-catechin, peanut procyanidin A (5), and epicatechin-(4β→8)-epicatechin-(4β→8,2β→O→7)-catechin, peanut procyanidin D (6), were also isolated. Dimer A1, the four trimers, and two tetramers were evaluated for anti-inflammatory activity in an in vitro assay, in which LPS-stimulated macrophages were responding with secretion of TNF-α, a pro-inflammatory cytokine. Tetramer F (2) was the most potent, suppressing TNF-α secretion to 82% at 8.7 μM (10 μg/mL), while tetramer E (1) at the same concentrations caused a 4% suppression. The results of the TNF-α secretion inhibition indicate that small structural differences, as in peanut procyanidin tetramers E and F, can be strongly differentiated in biological systems.