Search Results (82)

Oca (Oxalis tuberosa) skin is considered an agroindustrial waste byproduct, which currently holds no economic value. Nevertheless, this waste is a natural source of antioxidant compounds, which can be recovered through the use of sustainable technologies. Thus, this study aims to evaluate and compare the efficacy of 15% ethanol combined with two extraction techniques like solid–liquid extraction (SLE) and pressurized liquid extraction (PLE) for the recovery of antioxidant compounds from five oca skin cultivars. Regardless of the oca cultivar, the use of PLE was more efficient for obtaining extracts rich in polyphenol with high antioxidant capacity compared to the SLE process. Under PLE conditions, Pachatusan and Yawar cultivars presented the highest value of total polyphenols and antioxidant capacity. In comparison, the QuesWe and Pachatusan cultivars presented the lowest values. Polyphenol profile analysis showed that the PLE process effectively disrupted the cell wall matrix, resulting in a greater release of monomers (gallic acid, catechin, and epicatechin) and procyanidin B2 compared to the SLE process, while procyanidin A2 was more efficiently recovered under SLE, particularly in the Pachatusan cultivar. Principal component analysis (PCA) confirmed cultivar-dependent polyphenolic patterns, explaining 81.7% and 84.8% of total variance for SLE and PLE, respectively, with PLE generating more pronounced differentiation among cultivars driven by catechin, epicatechin, and gallic acid. The integration of PLE technology with the Oca skin framework facilitates the standardized production of extracts rich in antioxidants. Future research should concentrate on evaluating the stability of these specific dimers within food matrices, as well as their bioavailability in human clinical models. Full article

Polymeric procyanidins (PPCs) constitute the major fraction of procyanidins, but they have poor bioactivity. The purpose of this study is to clarify the composition and content of PPCs from Vitis amurensis Rupr. (Vitaceae) seeds before and after depolymerization, thereby providing a theoretical basis for activity evaluation and application of proanthocyanidins (PCs). PPCs extracted from V. amurensis seeds were depolymerized by catechin-assisted sulfitation. The compositions and contents of PCs before and after depolymerization were qualitatively and quantitatively analyzed by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS/MS), high-performance liquid chromatography (HPLC), and liquid chromatography–tandem mass spectrometry (LC-MS/MS). Results showed that twenty-eight components were identified (7 monomers, 13 dimers, 5 trimers, 1 tetramer and 2 unknowns). Before depolymerization, tetrameric and higher polymers dominated, accounting for 58.81% of the relative content. After depolymerization, these high-molecular-weight compounds declined to <1% or became undetectable, while monomers and dimers (with minor trimers) surged to 42.89%. Among them, the relative content of two monomers and three dimers, catechin, epicatechin gallate and procyanidin B1–B3, increased by 37.00, 3.75, 10.98, 3.72 and 9.74 times, respectively. In conclusion, the method utilizing catechin-assisted sulfitation effectively depolymerizes PPCs from V. amurensis seeds into oligomeric components such as monomers and dimers. Full article

Actinidia arguta is a valuable plant resource known for its diverse bioactive constituents. However, organ-dependent metabolic variation remains insufficiently explored. In this study, an integrated approach combining LC–QTOF–MS-based metabolomic profiling, multivariate analysis, and phytochemical isolation was employed to investigate metabolic differences among fruits, leaves, and roots of A. arguta. Comparative LC–QTOF–MS profiling and principal component analysis (PCA) revealed clear organ-specific metabolic differentiation. The root extract formed a distinct cluster, primarily characterized by flavan-3-ol oligomers, including procyanidin dimers and a trimer. Targeted isolation and spectroscopic analysis identified these compounds as major constituents of the root. Quantitative analysis showed that the root exhibited the highest antioxidant activity (60.8 ± 6.2%) and total phenolic content (10.8 ± 0.7 mg GAE/g dried weight), followed by leaves and fruits, indicating significant organ-dependent variation. The enhanced antioxidant activity observed in the root extract was consistent with the enrichment of oligomeric procyanidins, which are known for their strong radical-scavenging capacity. These findings demonstrate pronounced organ-specific metabolic specialization in A. arguta, with the root characterized by a condensed tannin–dominant chemical profile. This study highlights the potential of root-derived procyanidins as bioactive natural products and provides a basis for their utilization in functional and phytochemical applications, as well as insights into plant defense-related metabolism. Full article

Jatobá is a fruit-bearing plant whose pod husk accounts for approximately 70% of the fruit weight, becoming a residue after consumption or processing. Recent studies indicate that this byproduct is a promising source of phenolic compounds. However, extraction process variables, particularly solvent composition, can significantly impact recovery yields, although their effect remains poorly understood. In this context, a simplex-centroid mixture design was applied to optimize the solvent system to maximize the extraction of phenolic compounds and antioxidants from jatobá fruit husk. Different combinations of water, methanol, and acetone were evaluated using TPC, ABTS, and FRAP as response variables. Statistical analyses confirmed the significance of the models, with no lack of fit and high coefficients of determination. Multi-response optimization using the desirability function identified a nearly equivalent mixture of water and acetone (51.52%:48.48%, water/acetone) as the optimal condition, yielding predicted values of 41.51 mg GAE/g dw (TPC), 340.36 µmol TE/g dw (ABTS), and 485.74 µmol TE/g dw (FRAP), which did not differ statistically from the experimental values obtained in the validation assay (40.64 mg GAE/g dw for TPC, 334.31 µmol TE/g dw for ABTS, and 482.69 µmol TE/g dw for FRAP). HPLC-DAD analysis revealed that the fruit husk is predominantly composed of monomeric and dimeric procyanidins, especially epicatechin and procyanidin B2. Overall, these findings demonstrate the effectiveness of mixture design in optimizing extraction conditions and highlight jatobá fruit husk as a promising byproduct for the sustainable obtention of phenolic compounds and antioxidants with potential applications in products intended for human consumption after security validation. Full article

During this phytochemical study, 13 compounds from the bark of Salix cinerea L. were isolated and their structures elucidated. These included two salicylic alcohol derivatives, one flavonol, two phenylpropanoids, two flavan-3-ols, two dimeric procyanidins, two dimeric prodelphinidins, and a unique ester of catechin (3-O-(1-hydroxy-6-oxo-2-cyclohexen-1-carboxylic acid), HCH-catechin). Furthermore, seasonal variations in the composition of Salix cortex regarding proanthocyanidins (PA) and the degree of polymerization were examined using NMR spectroscopy, revealing an increase in polymerization throughout the growing season 2020 associated with a consistent hydroxylation pattern in the B-ring. The isolated HCH-catechin was tested in vitro for its inhibitory effect on TNF-α-induced ICAM-1 expression in human microvascular endothelial cells (HMEC-1). A 24 h treatment with a 25 µM solution of HCH-catechin significantly reduced ICAM-1 expression (83.7 ± 3.2%) compared to unsubstituted catechin (97.9 ± 4.4%). Additionally, during a mass-spectrometric screening, numerous HCH adducts within the PA fraction could be identified, allowing for the proposition of a characteristic fragmentation pattern. This study establishes a foundation for a comprehensive assessment of the phenolic, PA-rich fraction in willow bark, particularly the occurrence of HCH adducts, which may contribute to the medicinal properties of Salicis cortex. Findings on seasonal variations and mass spectrometric profiling offer new insights into the quality standards for Salicis cortex as a medicinal remedy. Full article

Plant materials rich in proanthocyanidins are fractionated to determine the structure of these compounds and relate it to bioactivity. The aim of this study was to fractionate a procyanidin-rich hawthorn bark extract using low-pressure liquid chromatography and to determine the compound profile and antioxidant activity of the obtained fractions. We identified and quantified the phenolics of four fractions (I–IV) separated on a Toyopearl HW-40S column with methanol as the mobile phase, using HPLC-DAD and LC-ESI-MS techniques. The antioxidant activity was determined to comprise ABTS^•+ and DPPH^• scavenging activity, ferric-reducing antioxidant power (FRAP), and inhibition of β-carotene-linoleic acid emulsion oxidation. Characteristic data were subjected to principal component analysis (PCA). Fraction I contained mainly (−)-epicatechin (741.3 mg/g) and a lower amount of flavones and quercetin derivatives (100.7 mg/g). Fraction II was almost pure procyanidin B2, which accounted for 88.8% of the total phenolics. The subsequent fractions were rich in B-type procyanidin dimers, trimers, and tetramers. FRAP and antiradical activity against ABTS^•+ and DPPH^• of the fraction containing low-molecular weight phenolics was lower than those of the fractions with procyanidin oligomers. The antioxidant activity of fractions II–IV ranged from 8.95 to 9.28 and from 6.45 to 6.71 mmol TE/g in the ABTS and DPPH assays, respectively. Their FRAP was in the range of 17.67–21.06 mmol Fe²⁺/g. According to PCA, the procyanidin dimers of fractions II and III were associated with antioxidant activity in these assays. In turn, the procyanidins with the highest degree of polymerization (trimers and tetramers) present in fraction IV were related to the antioxidant activity measured in the β-carotene-linoleic acid emulsion system. Overall, the separation of purified hawthorn bark extract using low-pressure Toyopearl HW-40S column chromatography resulted in a fraction rich in procyanidin B2, as well as fractions containing procyanidins with an increasing degree of polymerization, all with high levels of antioxidant activity under various conditions and the potential for future applications in food, pharmaceuticals, and cosmetics products. Full article

Procyanidins are oligomeric flavonoids with several bioactive properties. Their antidiabetic potential is related to their capacity to inhibit enzymes responsible for the absorption of dietary carbohydrates, such as pancreatic α-amylase. Procyanidins possess great structural diversity, including types of monomers and interflavanic bonds (A- or B-), and the degree of polymerization. However, there is a lack of evidence that systematically analyzes the effect of these structural features on their α-amylase inhibitory activity. In this paper, the activity of a mammalian pancreatic α-amylase was assessed using two different substrates, and the inhibitory activity of five commercially available procyanidins and three monomeric flavonoids was compared. The enzyme-binding sites of the eight compounds were predicted by in silico analysis to help explain the different enzyme-inhibitory activities. The inhibitory activity of procyanidins and monomeric flavonoids depended on the substrate used. A-type dimers presented the best activity against a polymeric substrate, while a B-type dimer was the best inhibitor for an oligomeric substrate. The predicted binding site for dimers and monomers was close to the active site. For the B-type trimer, the binding site was on the back side (approximately 180°) of the catalytic triad. In silico predictions suggested that dimeric procyanidins, especially A-type, could better enter the active site cavity, which could explain their superior inhibitory activity. We may conclude that inhibition of pancreatic α-amylase by procyanidins is mainly related to the type of interflavanic bond and the degree of polymerization. Dimers could be the most effective procyanidins to mildly inhibit this enzyme and present antidiabetic potential. Full article

Grape pomace (GP), a significant by-product of winemaking, is gaining increasing recognition for its potential as a source of bioactive compounds with antioxidant and cardioprotective properties. This study aimed to characterize the polyphenolic profile, fatty acid composition, and antioxidant activity of 17 GP samples from Transylvanian cultivars. Polyphenolic content was determined using the Folin–Ciocalteu method and high-performance liquid chromatography coupled with diode array detection and electrospray ionization mass spectrometry (HPLC–DAD–ESI MS) analysis. Fatty acid composition was analyzed using gas chromatography with flame ionization detection (GC–FID). Antioxidant capacity was assessed using five methods, which included the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, 2,2′-azino-bis (3-ethylbenzothialzoline-6-sulfonic acid) (ABTS) radical scavenging, ferric-reducing antioxidant power (FRAP), cupric ion reducing antioxidant capacity (CUPRAC), and reducing power (RP) assays. Additionally, all extracts were analyzed by Fourier transform infrared (FTIR) spectroscopy to identify the presence of functional groups and chemical bonds associated with bioactive compounds. The results showed that Neuburger (NE), Radames (RA), and Regent (RE) cultivars had the highest phenolic concentrations, particularly of catechin, epicatechin, and procyanidin dimers. NE and Feteascǎ Regalǎ (FR) exhibited the greatest radical scavenging and electron transfer activities across multiple antioxidant assays. Rose Blaj (RB) and Astra (AS) displayed the most favorable fatty acid profiles, with high unsaturated-to-saturated fatty acid (UFA/SFA) and hypocholesterolemic-to-hypercholesterolemic fatty acid (H/H) ratios, as well as low atherogenicity (AI) and thrombogenicity (TI) indices, suggesting cardioprotective potential. Additionally, RB and NE cultivars also demonstrated a strong chelation of Cu²⁺ and Fe²⁺ ions, enhancing their antioxidant efficacy by mitigating metal-catalyzed oxidative stress. These findings underscore the potential of GP, particularly from NE, RB, RA, and AS cultivars, the last three of which were homologated in Transylvania at SCDVV Blaj, as valuable sources of health-promoting compounds for use in food, nutraceuticals, and other health-related applications. Full article

Background/Objectives: Diabetes mellitus (DM) is one of the most common metabolic disorders, with a continually increasing population incidence. One of the main therapeutic approaches for this condition involves the inhibition of alpha-amylase and alpha-glucosidase—key enzymes involved in carbohydrate breakdown. Silver nanoparticles have exhibited inhibitory activity against both enzymes, suggesting their potential in regulating postprandial blood glucose levels. This study aimed to evaluate the antidiabetic potential of silver nanoparticles biosynthesized with Stenocereus queretaroensis flower extract. Methods: The flower extract was prepared and, following a qualitative and quantitative phytochemical analysis, was utilized in the reaction to biosynthesize S. queretaroensis flower extract nanoparticles (SAgNPs). The SAgNPs were characterized using UV–visible spectroscopy, dynamic light scattering (DLS), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), X-ray diffraction (XRD), and Fourier transform infrared spectrophotometry (FTIR). The antidiabetic potential of the biosynthesized SAgNPs was evaluated in vitro using alpha-amylase and alpha-glucosidase inhibitory assays, while an animal model was used for postprandial hypoglycemic activity in healthy mice. Results: The phytochemical analyses showed the presence of phenolic compounds and flavonoids like sinapic acid, p-coumaroyl tyrosine, procyanidin dimer β1, and dihydroquercetin in the flower extract. The SAgNPs were found to be rough and spherical in shape, with an average size of 99.5 nm. The inhibition of alpha-amylase and alpha-glucosidase by SAgNPs exhibited an IC₅₀ of 4.92 µg/mL and 0.68 µg/mL, respectively. The animal model results suggested that SAgNPs at 100 mg/kg caused a significant decrease in the postprandial glucose level; this effect is likely attributable to delayed carbohydrate digestion, as supported by the in vitro findings. Conclusions: S. queretaroensis-synthesized silver nanoparticles may constitute a promising option for antidiabetic therapy. Full article

Oxidative and inflammatory stresses contribute to the development of many intestinal pathologies. This study characterized the polyphenolic profile and biological activity of a hydroalcoholic extract obtained from the fruit pulp of Feijoa sellowiana on HT29 intestinal epithelial cells subjected to oxidative (H₂O₂) and inflammatory (cytokines) stress. HPLC-DAD-MS analysis revealed an interesting phenolic composition, rich in hydrolyzable tannins (HHDP-glucose, pedunculagin and other ellagic acid derivatives) and condensed tannins (procyanidin dimers), with a total polyphenol content of 8.07 mg/g GAE. The extract was non-cytotoxic up to 160 µg/mL and exerted a protective effect against the cytokine-induced reduction in cell viability. In vitro assays confirmed its strong antioxidant and scavenging capacity. The scratch assay suggested enhanced cell migration. The extract modulated the activity of key metabolic enzymes restoring glucose-6-phosphate dehydrogenase and enolase activity, while supporting glycolytic flux through pyruvate kinase and lactate dehydrogenase. PCA and Pearson correlation analyses confirmed a treatment-dependent modulation of the metabolic and redox profile, suggesting a regulatory role beyond a mere scavenging effect. These findings highlight the nutraceutical potential of feijoa polyphenols, not only as direct antioxidants but also as modulators of cellular metabolism and redox homeostasis, supporting their application in gastrointestinal disorders with oxidative or inflammatory components. Full article

Ethnographic sources provide information about several dye plants that produced reddish colors; however, there is no information on how this process is accomplished. Combining information from written sources with the results of dyeing experiments enables a deeper understanding of the dyeing methods employed in the past. This paper gives insight into the effect of using alkali on obtaining reddish tones in dyeing with Potentilla erecta and Rumex sp. In dyeing experiments, wool yarn was dyed with plant extracts, and the chemical compositions were studied both in plant extracts and in extracts obtained from wool after dyeing. As a result, the red/red-brown color is obtained only under the influence of alkali. Analytical studies of procyanidin (PC) extracts from rhizomes and yarns were performed using infrared spectroscopy (FTIR-ATR) and liquid chromatography coupled with mass spectrometric detection (LC-DAD-MS). Procyanidin extracts of P. erecta and R. acetosa contained monomers identified as (+)-catechin and (-)-epicatechin, as well as dimeric procyanidins of type-A (m/z 575 [M−H]⁻) and type-B (m/z 577 [M−H]⁻), along with various types of trimers (m/z 865 [M−H]⁻; m/z 863 [M−H]⁻), which were also isolated from dyed wool yarns with a similar composition. The conducted research on the use of alkali with tannin-containing plants contributes to deepening our understanding of the perception of color that existed in the ancient rural environment. Full article

Bud paradormancy has been widely studied in perennial deciduous woody species, but little attention has been paid to paradormancy set and release in perennial evergreen tree species. Here, shoot bud paradormancy in Camellia sinensis cv. Huangdan was studied by untargeted metabolomics. We found that after removing the axillary floral buds for one day, the paradormancy of the axillary shoot buds was released. The paradormant shoot buds had lower glucose-1-phosphate, fructose, and D-(-)-tagatofuranose content but higher trehalose, raffinose, galactinol, and α-D-xylopyranose content. Meanwhile, high levels of asparagine were accumulated. Flavonoids were differentially accumulated, and higher levels of three flavone glycosides (C-diglucosylapigenin, apigenin 6-C-glucoside 8-C-arabinoside, and prunin) and four proanthocyanidins (Procyanidin trimer isomer 1, Galloylprocyanidin dimer, Procyanidin trimer isomer 3, and Galloylated trimeric proanthocyanidin) were accumulated in paradormant shoot buds. During the paradormancy-to-growth transition, all these metabolites were reversed. These data suggest that the reconfiguration of carbon, nitrogen, and flavonoid metabolism could be an important aspect for the paradormancy set and release of tea axillary shoot buds. This study provided novel insights into shoot bud paradormancy set and release in a perennial evergreen tree species. Full article

Jatobá (Hymenaea courbaril) is a native tree abundant in Brazil. The fruit coat is an industrial by-product of jatobá flour processing, typically discarded. Presently, within the circular bioeconomy concept, there are efforts underway that aim at finding economically viable applications for the bio-residues of jatobá. Within this context, the present work attempts to find possible applications for the jatobá coat in glycemic control through inhibition of α-amylase activity. Aqueous and hydroethanolic extracts were used. In vitro experiments included detailed kinetic studies with an α-amylase catalyzed reaction. Starch absorption in vivo was assessed by means of a starch tolerance test in mice. Both extracts inhibited α-amylase. The IC₅₀ values for the aqueous and hydroalcoholic extracts were 81.98 ± 3.53 µg/mL and 51.06 ± 0.42 µg/mL, respectively. The inhibition was of the non-competitive type. Both extracts reduced hyperglycemia caused by starch administration in mice, the aqueous extract being effective over a larger dose range. This action can be attributed to the α-amylase inhibition. In silico studies suggested that procyanidin dimers, taxifolin 7-O-rhamnoside, and quercetin 7-rhamnoside contribute, but several other not-yet-identified substances may be involved. The findings suggest that aqueous and hydroalcoholic extracts from jatobá coat warrant further investigations as potential modulators of glycemia following starch ingestion. Full article

Geoffroea decorticans (Gill. ex Hook. & Arn) Burk. is a native tree of the dry areas of Northwestern and Central Argentina. Its seeds are considered waste material. The flour of seeds was analyzed as a source of nutritional and bioactive compounds. It has a low carbohydrate content, containing about 9% protein and between 10 and 14% fat. Approximately 82–84% of the fatty acids were unsaturated (oleic and linoleic acids). A high polyphenol and dietary fiber content was detected. Flavonoids and condensed tannins were the dominant phenolics. Polyphenol-enriched extracts were obtained from seed flour. The HPLC–ESI-MS/MS analysis of these concentrated extracts allowed for the identification of six compounds including C-glycosyl flavones (vitexin and isovitexin), type A procyanidins (dimer and trimer), and epicatequin gallate. Polyphenolic extracts showed antioxidant capacity and were able to inhibit enzymes (α-glucosidase and α-amylase) related to carbohydrate metabolism and (lipoxygenase) pro-inflammatory enzymes and were not toxic. Flour and polyphenolic extract from chañar seeds could be considered as new alternative ingredients for the formulation of functional foods, nutraceuticals, or food supplements. The use of the seed flour in addition to the pulp of the fruit along with the rest of the plant would encourage the propagation of this species resistant to extreme arid environments for commercial and conservation purposes to boost the regional economies of vulnerable areas of South America. Full article

Coffee pulp, which accounts for approximately 40% of the dry weight of coffee cherries, is one of the many byproducts produced by the world’s most popular beverage, coffee. Such neglected waste represents an interesting source of bioactive compounds, such as procyanidins, which have antioxidant, anti-inflammatory, and neuroprotective properties. This study aims to develop an efficient method for procyanidins extraction from Coffea arabica pulp using a novel microwave–ultrasound hybrid method of extraction. Microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE) and a novel hybrid method (MAE–UAE) were comparatively analyzed. Using Box–Behnken design, the hybrid extraction method was optimized, giving a procyanidin yield of 60.88 mg/g (under these conditions: ~60 °C, ~21 min, ~1:13 solid-to-liquid ratio). The purification was carried out through a Sephadex LH-20 packed column chromatography, and the identified procyanidin dimers and trimers were confirmed by HPLC/ESI-MS. The hybrid extract’s acetonic fraction’s DPPH and ABTS tests revealed that procyanidins had a greater capacity to scavenge radicals than Trolox (p < 0.05). The findings highlight the potential of sustainable extraction methods for valorizing coffee pulp in functional food and pharmaceutical applications. Full article