Structural elucidation of the ellagitannin with a molecular weight of 2038 isolated from strawberry fruit (Fragaria ananassa Duch.) and named fragariin A

Biotransformation of camu-camu galloylated ellagitannins by Lactiplantibacillus plantarum with extracellular tannase activity

Some strains of Lactiplantibacillus plantarum produce specific tannases that could enable the metabolism of ellagitannins into more bioavailable phenolic metabolites, thereby promoting the health effects of these polyphenols. However, the metabolic ability of these strains remains poorly understood. In this study, we analyzed the ability of broad esterase-producing (Est_1092+) and extracellular tannase-producing (TanA+) strains to convert a wide assortment of ellagitannins from camu-camu (Myrciaria dubia) fruit. To this end, forty-three strains were screened to identify and sequence (WGS) those producing Est_1092. In addition, six previously reported TanA+ strains were included in the study. Each strain (Est_1092+ or TanA+) was inoculated into a minimal culture medium supplemented with an aqueous camu-camu extract. After fermentation, supernatants were collected for semi-quantification of ellagitannins and their metabolites by mass spectrometry. For analysis, the strains were grouped according to their enzyme type and compared with an Est_1092 and TanA-lacking strain. Out of the forty-three isolates, three showed Est_1092 activity. Of the Est_1092+ and TanA+ strains, only the latter hydrolyzed the tri-galloyl-HHDP-glucose and various isomers of HHDP-galloyl-glucose, releasing HHDP-glucose and gallic acid. TanA+ strains also transformed three isomers of di-HHDP-galloyl-glucose, liberating di-HHDP-glucose and gallic acid. Overall, TanA+ strains released 3.6-4.9 times more gallic acid than the lacking strain. In addition, those exhibiting gallate decarboxylase activity pursued gallic acid metabolism to release pyrogallol. Neither Est_1092+ nor TanA+ strains transformed ellagitannin-core structures. In summary, TanA+ L. plantarum strains have the unique ability to hydrolyze a wide range of galloylated ellagitannins, releasing phenolic metabolites with additional health benefits.

Stability of ellagitannins in processing products of selected Fragaria fruit during 12 months of storage

The aim of the study was to determine the stability of ellagitannins (ETs), ellagic acid, and conjugates (EAC) in unclarified juices and purees produced from two selected berries of the Rosaceae family, genus Fragaria. A total of 16 ellagitannins have been identified in the products. Stability studies were carried out for 1 year in three temperature variants: -20, 4, and 20°C (±2°C). The quantitative and qualitative determinations of ETs + EAC were performed every 3 months using the HPLC-DAD and LC-MS techniques. An important element of the research was also the determination of ETs transformations that occur in juices and purees during storage. The stability of ETs + EAC is primarily determined by the temperature and storage time as well as the matrix. After 1 year of storage at -20°C, the sum of ETs and EAC did not decrease in strawberry juice. On the other hand, the decrease was shown at the level of 30 and 20% at temperatures of 4 and 20°C, respectively. In strawberry purees, a decrease in ETs + EAC of 15-28% was recorded during storage in all three temperature variants. After 1 year, in wild strawberry juice, 20-50% of ellagitannin decreased, in puree the decrease in ETs + EAC concentration was 40-54%. With increasing temperature, the percentage of compounds with lower molecular weight increased-from 10 to 14% at temperatures of 4 and 20°C, respectively. At the temperature of -20°C, the proportion of low- and high-molecular-weight compounds remained stable in each case.

Nutritional and Polyphenolic Composition of Agrimonia procera Wallr. from Experimental Cultivation with Different Levels of Nitrogen Fertilization

Plants of the genus Agrimonia, including fragrant agrimony Agrimonia procera Wallr., mainly used as pharmaceutical raw material, perfectly fit into the current trends in nutrition and food technology that are searching for organic raw materials with high contents of bioactive compounds, such as dietary polyphenols and fiber. The aim of the research was to determine the nutritional and polyphenolic composition of fragrant agrimony Agrimonia procera Wallr. from experimental cultivation with varying levels of nitrogen fertilization in the nitrate, ammonium, or amide forms. In the experimental cultivation of fragrant agrimony in a seeding medium with a moderately high level of mineral content, the aerial parts, especially the leaves, were characterized by contents protein, dietary fiber, fat, and polyphenols at levels of 11.5, 58.0, 3.0, and 10.5% of dry matter, respectively, and an energy value of about 260 kcal/100 g of dry matter. The effect of additional nitrogen fertilization, in the form of ammonium nitrate and urea, on the content and yield of nutrients and polyphenol in fragrant agrimony depends both on the dose and the form of nitrogen, as well as the morphological part, of the plant.

Fragaria × ananassa cv. Senga Sengana Leaf: An Agricultural Waste with Antiglycation Potential and High Content of Ellagitannins, Flavonols, and 2-Pyrone-4,6-dicarboxylic Acid

Strawberry leaves are considered a valuable waste material; so far, mainly due to their antioxidant properties. Since the annual production of this crop is high, our study aimed to thoroughly examine the chemical composition and antidiabetes-related bioactivity of Fragaria × ananassa leaf of its popular and productive cultivar Senga Sengana. Leaves from three different seasons, collected after fruiting, were extensively analyzed (UHPLC-qTOF-MS/MS, HPLC-DAD). Some individual components were isolated and quantified, including specific flavonol diglycosides (e.g., 3-O-[β-xylosyl(1‴→2″)]-β-glucuronosides). The separated quercetin glycosides were tested in an antiglycation assay, and their methylglyoxal uptake capacity was measured. In addition, the biodegradable polyester precursor 2-pyrone-4,6-dicarboxylic acid (PDC) was confirmed at relatively high levels, providing further opportunity for strawberry leaf utilization. We want to bring to the attention of the food, pharmaceutical, and cosmetic industries the Senga Sengana strawberry leaf as a new botanical raw material. It is rich in PDC, ellagitannins, and flavonols—potent glycation inhibitors.

The Aerial Parts of Agrimonia procera Wallr. and Agrimonia eupatoria L. as a Source of Polyphenols, and Especially Agrimoniin and Flavonoids

Plants of the genus Agrimonia L. perfectly fit the current trends in nutrition and food technology, namely, the need for raw materials with a high content of bioactive natural compounds, including polyphenols, which could be added to food. The composition of polyphenolics, including agrimoniin and flavonoids, in the aerial parts of Agrimonia procera Wallr. (A. procera) and Agrimonia eupatoria L. (A. eupatoria) (Rosaceae) was determined using HPLC-DAD-MS. The polyphenolic content of A. procera was found to be 3.9%, 3.2%, 2.9%, 1.8% and 1.1%, and that of A. eupatoria was determined to be 1.3%, 0.3%, 0.9%, 0.6% and 0.5% in the dry matter of leaves, stems, fruits, seeds and hypanthia, respectively. Except for A. procera hypanthia, agrimoniin was the main polyphenolic compound in the aerial parts of the studied Agrimonia species. Both plants are also a valuable source of flavonoid glycosides, especially apigenin, luteolin and quercetin. The obtained data indicate that both A. procera and A. eupatoria are potentially good sources of polyphenols (albeit significantly different in terms of their qualitative and quantitative composition), and may not only be a medicinal raw material, but also a valuable material for food use such as nutraceuticals or functional food ingredients.

Strawberry phenolic extracts effectively mitigated metabolic disturbances associated with high-fat ingestion in rats depending on the ellagitannin polymerization degree

In the present experiment it was hypothesised that dietary strawberry ellagitannin-rich extracts would mitigate negative consequences associated with consumption. Therefore, two extracts rich in dimeric (D-ET) or monomeric (M-ET) ellagitannins (ETs) were added to a standard or high-fat diet fed to rats for four weeks. The D-ET-rich extract contained 82.3% polyphenols, and the M-ET/D-ET ratio was 40 : 60, while the M-ET-rich extract contained 88.0% and 96 : 4, respectively. The experimental feeding with high-fat diets containing extracts resulted in beneficial mitigating effects in the lipid profile, redox status of the rat's liver and blood plasma. According to the accepted hypothesis, the obtained results pointed at increased desired hepatic and plasma modifications when the extract was rich in M-ET, as indicated by favourable changes in the hepatic fat content, GSH and GSSG concentrations and GSH/GSSG ratio as well as blood plasma FRAP, ACL, HDL-cholesterol, and atherogenic coefficient values. These changes were partly connected to the fact that M-ET was more prone vs. D-ET to intestinal microbial conversion into respective metabolites. The urinary daily excretion of ET metabolites and their blood plasma concentrations were higher in rats fed with M-ET vs. D-ET-rich diets. To conclude, the metabolic action of the M-ET-rich extract in the normalization of high-fat-induced disturbances was more pronounced.

Transfer of ellagitannins to unclarified juices and purees in the processing of selected fruits of the Rosaceae family

The present study investigated the transfer of ellagitannins (ETs) from selected berry fruits of the Rosaceae family to the products of their processing - unclarified juices and purees, as well as ET retention in pomace. Percentage distribution was calculated not only for total ETs, but also separately for each ET identified by HPLC-MS. In the case of all fruits tested, ET transfer to purees was two to six times greater as compared to juices. The content of oligomeric ETs in juices was five times lower than that of low molecular weight compounds, while the transfer of high molecular weight compounds (>1569 Da) to purees ranged from 56% to 87%. An increase in molecular weight from 1569 Da to 3740 Da resulted in a fivefold decrease in ET transfer for raspberry juice, a twofold decrease for blackberry and wild strawberry juices, and a fourfold decrease for strawberry juice.

Fragaria viridis Fruit Metabolites: Variation of LC-MS Profile and Antioxidant Potential during Ripening and Storage

Fragaria viridis Weston or creamy strawberry is one of the less-known species of the Fragaria genus (Rosaceae family) with a wide distribution in Eurasia and is still in the shadow of more popular relatives F. ananassa (garden strawberry) or F. vesca (wild strawberry). Importantly, there is a lack of scientific knowledge on F. viridis compounds, their stability in the postharvest period, and bioactivity. In this study, metabolites of F. viridis fruits in three ripening stages were characterized with high-performance liquid chromatography with photodiode array and electrospray ionization triple quadrupole mass spectrometric detection (HPLC-PAD-ESI-tQ-MS). In total, 95 compounds of various groups including carbohydrates, organic acids, phenolics, and triterpenes, were identified for the first time. The quantitative content of the compounds varied differently during the ripening progress; some of them increased (anthocyanins, organic acids, and carbohydrates), while others demonstrated a decrease (ellagitannins, flavonols, etc.). The most abundant secondary metabolites of F. viridis fruits were ellagitannins (5.97–7.54 mg/g of fresh weight), with agrimoniin (1.41–2.63 mg/g) and lambertianin C (1.20–1.86 mg/g) as major components. Antioxidant properties estimated by in vitro assays (2,2-diphenyl-1-picrylhydrazyl radical (DPPH), 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) cation radical (ABTS), ferric reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC)) showed good antioxidant potential in all ripening stages of F. viridis fruits. The pilot human experiment on the effect of F. viridis fruit consumption on the serum total antioxidant capacity confirmed the effectiveness of this kind of strawberry. Postharvest storage of ripe fruits at 4 °C and 20 °C lead to declining content in the majority of compounds particularly ascorbic acid, ellagitannins, and flavonols, with the most significant loss at room temperature storage. These results suggest that F. viridis fruits are a prospective source of numerous metabolites that have potential health benefits.

Transformation of Oligomeric Ellagitannins, Typical for Rubus and Fragaria Genus, during Strong Acid Hydrolysis

The strong acid hydrolysis analysis of galloyl-O-digalloyl-type ellagitannins (ETs), lambertianin C (LC) and sanguiin H-6, and dehydrodigalloyl-type ET, agrimoniin (AM), was performed. A quantitative and qualitative analysis of the degradation products of individual ETs was conducted using high-performance liquid chromatography-diode array detecto-electrospray ionization interface-mass spectrometry (HPLC-DAD-ESI-MS). The data indicate that ETs undergo multidirectional changes in a strongly acidic environment, where the process of successive hydrolysis of ester bonds to form ellagic acid (EA) is the dominant phenomenon in the initial phase of the reaction, followed by the depolymerization process and the formation of low-molecular ETs. Characteristic products of ET hydrolysis were distinguished: for LC: dimeric ET plus one galloyl moiety without one EA moiety (M = 1736 Da), for all analyzed ETs: sanguisorbic acid dilactone (M = 470 Da), and for AM: dehydrodigallic acid (M = 338 Da). The research carried out has allowed to create a database of possible products and routes of transformation of individual ETs, which should facilitate future research on the transformation of ETs, including potential prohealth properties of its breakdown products, under conditions occurring during food processing or digestion.

Fragaria Genus: Chemical Composition and Biological Activities

The strawberries represent in our days one of the main fresh fruits consumed globally, inevitably leading to large amounts of by-products and wastes. Usually appreciated because of their specific flavor, the strawberries also possess biological properties, including antioxidant, antimicrobial, or anti-inflammatory effects. In spite of the wide spread of the Fragaria genus, few species represent the subject of the last decade scientific research. The main components identified in the Fragaria species are presented, as well as several biological properties, as emerging from the scientific papers published in the last decade.