In rye, there is a considerable variety of grain color which is determined by the diversity of compounds localized in different parts of the grain (caryopsis) - pericarp, testa, and aleurone. The localization of anthocyanins and proanthocyanidins was analyzed in 26 rye samples with identified anthocyanin genes, along with the analysis of CIE color coordinates. The Grain Scan program [1] was used to analyze images of individual grains. The localization of anthocyanins and proanthocyanidins was studied on longitudinal and cross sections of grains using light microscopy and MALDI-imaging. The violet-grained samples contain anthocyanins in the pericarp, and the green-grained samples contain anthocyanins in the aleurone layer. The green, violet and yellow-grained rye, with the exception of two anthocyaninless mutants vi3 and vi6, shows the presence of proanthocyanidins in the brown-colored testa. Four main color groups of the rye grains (yellow, green, brown, violet) could be differentiated using the color coordinate h° (hue angle). Interspecies and intraspecies variability for the localization of colored flavonoids in cereal grains is discussed.

One of the richest natural sources of resveratrol - the rhizome of Reynoutria japonica in East Asia is a well-known traditional herb (Hu zhang) used in various inflammatory diseases, infections, skin diseases, scald, hyperlipidemia. Although, it has been recently included in the European Pharmacopoeia, still in Europe is an untapped resource. Some of the therapeutic effects are likely to be influenced by its antioxidant properties and this in turn is frequently associated with a high stilbene content. However, some literatures suggested that other compounds than stilbenes may add to the total antioxidant capacity. Hence, the aim of this research was to examine rhizomes of R. japonica and less studied, morphologically similar species, R. sachalinensis and R. x bohemica for their phytochemical composition and antioxidant activity and to clarify the relationship between the antioxidant activity and compounds by statistical methods. HPLC/UV/ESI-MS studies of three Reynoutria species revealed 171 compounds comprising stilbenes, carbohydrates, procyanidins, flavan-3-ols, anthraquinones, phenylpropanoids, lignin oligomers, hydroxycinnamic acids, naphthalenes and their derivatives. Our studies confirmed the presence of procyanidins with high degree of polymerization, up to decamers in the rhizomes of R. japonica and brings new data on the presence of these compounds in other Reynoutria species. A procyanidin trimer digallate was described for the first time in the studied plants. Moreover, we suggested a presence of new for these species, dianthrone glycosides and previously unrecorded phenylpropanoid disaccharide esters and hydroxycinnamic acid derivatives, mainly in R. sachalinensis. Furthemore, compounds tentatively annotated as lignin oligomers were observed for the first time in studied species. The rhizomes of all Reynoutria species exhibited strong antioxidant activity. Statistical analysis demonstrated that proanthocyanidins should be considered as important contributors to the total antioxidant capacity.

Flavonoids are a biochemically diverse group of specialized metabolites in plants that are derived from phenylalanine. While the biosynthesis of the flavonoid aglycone is highly conserved across species and well characterized, numerous species-specific decoration steps and their relevance remained largely unexplored. The flavonoid biosynthesis takes place at the cytosolic site of the endoplasmatic reticulum (ER), but accumulation of various flavonoids was observed in the central vacuole. A universal explanation for the subcellular transport of flavonoids has eluded researchers for decades. Current knowledge suggests that a glutathione S-transferase-like protein (ligandin) protects anthocyanins and potentially proanthocyanidin precursors during the transport to the central vacuole. ABCC transporters and to a lower extend MATE transporters sequester anthocyanins into the vacuole. Glycosides of specific proanthocyanidin precursors are sequestered through MATE transporters. A P-ATPase in the tonoplast and potentially other proteins generate the proton gradient that is required for the MATE-mediated antiport. Vesicle-mediated transport of flavonoids from the ER to the vacuole is considered as an alternative or additional route.

Sweet cherry pomace is a by-product that can be a source of bioactive phenolic compounds. Usually, polyphenols have been extracted using conventional extraction methodologies. However, a significant fraction, called non-extractable polyphenols (NEPs), remains retained in the conventional extraction residues. Therefore, this work is aimed, for the first time, to investigate the release of NEPs from cherry pomace combining pressurized liquid extraction (PLE) and enzyme-assisted extraction (EAE) using Promod enzyme. A response surface methodology was employed to study the influence of temperature, time, and pH on the NEPs extraction. The response variables were the total phenolic content (TPC) measured by Folin-Ciocalteu method, total proanthocyanidin (PA) content evaluated by vanillin, DMAC, and butanol/HCl assays, and total antioxidant capacity determined by Trolox equivalent antioxidant capacity and inhibition of hydroxyl radical assays. The results indicated that PLE-EAE was more suitable and selective to obtain NEPs from sweet cherry pomace than PLE alone. In fact, the extracts obtained by PLE-EAE displayed higher TPC, PA content, and bioactivity than the extracts obtained by PLE under the same extraction conditions, and those obtained by conventional methods. Moreover, size-exclusion chromatography profiles showed that the combination of PLE and EAE enabled the recovery of NEPs with higher molecular weight than PLE without EAE treatment.

Flavan-3-ols and their oligomeric forms called proanthocyanidins are polyphenolic compounds occurring in several foodstuffs and in many medicinal herbs. Their consumption is associated with numerous health benefits. Their bioactivities include antioxidant, anti-inflammatory, cytoprotective, as well as antimicrobial. The latter property is important in prevention and treatment of periodontal diseases. Periodontitis is a multifactorial polymicrobial infection characterized by a destructive inflammatory process affecting the periodontium. Using non-toxic and efficient natural products such as flavanol derivatives can significantly contribute to alleviating of periodontitis symptoms and prevent the disease progress. In this paper, we systematically review the state-of-the art in antibacterial effects of these compounds from the viewpoint of gum health. There is a significant evidence supporting an importance of antibacterial action exerted by proanthocyanidins from edible fruits, tea and medicinal herbs in inhibition of periodontitis-causing pathogens.

The viability, productivity and survival of higher plants under the adverse factors influence are largely determined by the functional activity of the antioxidant system. The aim of our work was to investigate changes in formation of high-molecular (superoxide dismutase and peroxidase) and low-molecular (phenolics, including flavanols and proanthocyanidins) antioxidants in callus culture of Camellia sinensis under influence of phenolic precursors (L-phenylalanine – 3 mM, trans-cinnamic acid – 1 mM, naringenin – 0.5 mM). According to the data obtained, precursors effect on tea callus cultures did not lead to significant increasing of superoxide dismutase and peroxidase activity in most cases. However, it led to the increased accumulation of the total phenolics content, as well as flavanols and proanthocyanidins contents. For C. sinensis callus cultures, the most promising regulator of phenolic compounds was L-phenylalanine, in the presence of which its content increased almost twice. Thus, the exogenous effect of various precursors is possible to use for the targeted regulation of the certain phenolics classes accumulation in plant cells.

This paper continues the review study on antimicrobial properties relevant to the periodontal diseases. Inflammation as a major response of the periodontal tissues attacked by pathogenic microbes can significantly exacerbate the condition. However, the bidirectional activity of phytochemicals that simultaneously inhibit bacterial proliferation and proinflammatory signaling can provide a substantial alleviation of both cause and symptoms. The modulatory effects on various aspects of inflammatory and overall immune response has been covered, including confirmed and postulated mechanisms of action, structure activity relationships and molecular targets. Further, the clinical relevance of flavan-3-ols and available outcomes from clinical studies has been analyzed and discussed. Among the numerous natural sources of flavan-3-ols and proanthocyanidins the most promising are, similarly to antibacterial properties, constituents of various foods, such as fruits of Vaccinium species, tea leaves, grape seeds, and tannin-rich medicinal herbs. Despite a vast amount of in vitro and cell-based evidence of immunomodulatory there is still much less studies using animal models and only a few clinical studies. Most of the studies, regardless of the used model indicated efficiency of these phytochemicals from cranberries and other Vaccinium species and tea extracts (green or black). Other sources such as grape seeds and traditional medicinal plants, were seldom. In conclusion, the potential of flavan-3-ols and their derivatives in prevention and alleviation of periodontitis is remarkable but clinical evidence is urgently needed for issuing credible dietary recommendation and complementary treatments.

The study explores antibacterial, antiinflammatory and cytoprotective capacity of Pelargonium sidoides DC root extract (PSRE) and proanthocyanidin fraction from PSRE (PACN) under conditions characteristic for periodontal disease. Following previous finding that PACN exerts stronger suppression of Porphyromonas gingivalis compared to the effect on commensal Streptococcus salivarius, the current work continues antibacterial investigation on Staphylococcus aureus, Staphylococcus epidermidis, Aggregatibacter actinomycetemcomitans and Escherichia coli. PSRE and PACN are also studied for their ability to prevent gingival fibroblast cell death in the presence of bacteria or bacterial lipopolysaccharide (LPS), to block LPS- or LPS+IFNγ-induced release of inflammatory mediators, gene expression and surface antigen presentation. Both PSRE and PACN were more efficient in suppressing Staphylococcus and Aggregatibacter compared to Escherichia, prevented A. actinomycetemcomitans- and LPS induced death of fibroblasts, decreased LPS-induced release of interleukin 8 and prostaglandin E2 from fibroblasts and IL-6 from leukocytes, blocked expression of IL-1β, iNOS, and surface presentation of CD80 and CD86 in LPS+IFNγ-treated macrophages, and IL-1β and COX-2 expression in LPS-treated leukocytes. None of the investigated substances affected either the level of secretion or expression of TNFα. In conclusion, PSRE, and especially PACN, possess strong antibacterial, antiinflammatory and gingival tissue protecting properties under periodontitis mimicking conditions and are suggestable candidates for treatment of the disease.

Delivery systems of the biologically active substance such as proanthocyanidins (PCAN) produced through the electrospinning method were designed using a blend of poly(L-lactide-co-glycolide) and poly[(R,S)-3-hydroxybutyrate]. The research involved the structural and thermal characteristics of the developed electrospun three-dimensional fiber matrix, as well as hydrolytic degradation tests performed on them. Additionally, the release profile of PCAN from the electrospun nonwoven was determined using UV–VIS spectroscopy. Approximately 30% of PCAN was released from the tested electrospun nonwoven during the initial 15-20 days of incubation. The chemical structure of water-soluble oligomers that were formed after the hydrolytic degradation of the developed delivery system was identified through electrospray ionization mass spectrometry. Oligomers of lactic acid and OLAGA oligocopolyester, as well as oligo-3-hydroxybutyrate terminated with hydroxyl and carboxyl end groups, were recognized as degradation products released into the water during the incubation time. It was also demonstrated that variations in the degradation rate of individual mat components influenced the degradation pattern, and the number of formed oligomers. The obtained results suggest that the incorporation of proanthocyanidins into the system slowed down the hydrolytic degradation process of the poly(L-lactide-co-glycolide)/poly[(R,S)-3-hydroxybutyrate] three-dimensional fiber matrix. In addition, in vitro cytotoxicity and antimicrobial studies advocate the use of PCAN for biomedical applications with promising antimicrobial activity.