Limonium brasiliense rhizomes extract against virulence factors of Porphyromonas gingivalis: Inhibition of gingipains, bacterial adhesion, and biofilm formation.

Periodontitis is clinically characterized by destruction of the tooth support system and tooth loss. Porphyromonas gingivalis (Pg) plays a dominant role in periodontitis. Fractions and isolated compounds from an acetone-water extract of the roots of Limonium brasiliense (Lb) were tested in vitro for their anti-adhesive capacity against Pg on human KB buccal cells, influence on gingipains, the main virulence factors of Pg, and biofilm formation. Fractions EAF and FLB7 (50 µg/mL) reduced the bacterial adhesion of Pg to KB cells significantly (63 resp. 70%). The proanthocyanidin samarangenin A inhibited the adhesion (72%, 30 µM), samarangenin B (71%, 20 µM), and the flavan-3-ol epigallocatechin-3-O-gallate (79%, 30 µM). Fraction AQF, representing hydrophilic compounds, reduced the proteolytic activity of Arginin-specific gingipain (IC50 12.78 µg/mL). Fractions EAF and FLB7, characterized by lipohilic constituents, inhibited Arg-gingipain (IC50 3 µg/mL). On Lysine-specific gingipain, AQF has an IC50 15.89, EAF 14.15, and FLB7 6 µg/mL. The reduced bacterial adhesion is due to a strong interaction of proanthocyanidins with gingipains. AQF, EAF, and FLB7 significantly inhibited biofilm formation: IC50 11.34 (AQF), 11.66 (EAF), and 12.09 µg/mL (FLB7). In silico analysis indicated, that the polyphenols act against specific targets of Pg, not affecting mammalian cells. Therefore, Lb might be effective for prevention of periodontal disease by influencing virulence factors of Pg.

Synthesis and Isolation of Phenol- and Thiol-Derived Epicatechin Adducts Prepared from Avocado Peel Procyanidins Using Centrifugal Partition Chromatography and the Evaluation of Their Antimicrobial and Antioxidant Activity.

Polyphenols from agro-food waste represent a valuable source of bioactive molecules that can be recovered to be used for their functional properties. Another option is to use them as starting material to generate molecules with new and better properties through semi-synthesis. A proanthocyanidin-rich (PACs) extract from avocado peels was used to prepare several semi-synthetic derivatives of epicatechin by acid cleavage in the presence of phenol and thiol nucleophiles. The adducts formed by this reaction were successfully purified using one-step centrifugal partition chromatography (CPC) and identified by chromatographic and spectroscopic methods. The nine derivatives showed a concentration-dependent free radical scavenging activity in the DPPH assay. All compounds were also tested against a panel of pathogenic bacterial strains formed by Listeria monocytogenes (ATCC 7644 and 19115), Staphylococcus aureus (ATCC 9144), Escherichia coli (ATCC 11775 and 25922), and Salmonella enterica (ATCC 13076). In addition, adducts were tested against two no-pathogenic strains, Limosilactobacillus fermentum UCO-979C and Lacticaseibacillus rhamnosus UCO-25A. Overall, thiol-derived adducts displayed antimicrobial properties and, in some specific cases, inhibited biofilm formation, particularly in Listeria monocytogenes (ATCC 7644). Interestingly, phenolic adducts were inactive against all the strains and could not inhibit its biofilm formation. Moreover, depending on the structure, in specific cases, biofilm formation was strongly promoted. These findings contribute to demonstrating that CPC is a powerful tool to isolate new semi-synthetic molecules using avocado peels as starting material for PACc extraction. These compounds represent new lead molecules with antioxidant and antimicrobial activity.

Advances in Extraction Protocols, Degradation Methods, and Bioactivities of Proanthocyanidins.

Proanthocyanidins, natural polyphenolic compounds abundantly present in plants, exhibit diverse bioactivities, including antioxidative, anti-inflammatory, and antibacterial effects. These bioactivities are intricately linked to the degree of polymerization of these compounds. Through a comprehensive analysis of recent domestic and international research, this article synthesizes the latest advancements in the extraction process, degradation methods, as well as the biological activities and underlying mechanisms of proanthocyanidins. Furthermore, future research endeavors should prioritize the refinement of extraction techniques, the elucidation of bioactive mechanisms, and the development of formulations with enhanced potency. This will maximize the utilization of proanthocyanidins across diverse applications.

Optimization of the Extraction of Proanthocyanidins from Grape Seeds Using Ultrasonication-Assisted Aqueous Ethanol and Evaluation of Anti-Steatosis Activity In Vitro.

Conventional extraction methods of proanthocyanidins (PAC) are based on toxic organic solvents, which can raise concerns about the use of extracts in supplemented food and nutraceuticals. Thus, a PAC extraction method was developed for grape seeds (GS) and grape seed powder using food-grade ethanol by optimizing the extraction conditions to generate the maximum yield of PAC. Extraction parameters, % ethanol, solvent: solid (s:s) ratio, sonication time, and temperature were optimized by the central composite design of the response surface method. The yields of PAC under different extraction conditions were quantified by the methylcellulose precipitable tannin assay. The final optimum conditions were 47% ethanol, 10:1 s:s ratio (v:w), 53 min sonication time, and 60 °C extraction temperature. High-performance liquid chromatography analysis revealed the presence of catechin, procyanidin B2, oligomeric and polymeric PAC in the grape seed-proanthocyanidin extracts (GS-PAC). GS-PAC significantly reduced reactive oxygen species and lipid accumulation in the palmitic-acid-induced mouse hepatocytes (AML12) model of steatosis. About 50% of the PAC of the GS was found to be retained in the by-product of wine fermentation. Therefore, the developed ethanol-based extraction method is suitable to produce PAC-rich functional ingredients from grape by-products to be used in supplemented food and nutraceuticals.

Neuroprotective Effects of B-Type Cinnamon Procyanidin Oligomers on MPP+-Induced Apoptosis in a Cell Culture Model of Parkinson's Disease.

Cinnamon procyanidin oligomers (CPOs) are water-soluble components extracted from cinnamon. This study aims to explore the neuroprotection of B-type CPO (CPO-B) against 1-methyl-4-phenylpyridinium (MPP+)-mediated cytotoxicity and the molecular mechanisms underlying its protection. The results demonstrated that CPO-B showed protection by increasing cell viability, attenuating an intracellular level of reactive oxygen species, downregulating cleaved caspase-3 expression, and upregulating the Bcl-2/Bax ratio. Moreover, CPO-B completely blocked the dephosphorylation of extracellular, signal-regulated kinase 1 and 2 (Erk1/2) caused by MPP+. Treatment with an Erk1/2 inhibitor, SCH772984, significantly abolished the neuroprotection of CPO-B against MPP+. Taken together, we demonstrate that CPO-B from cinnamon bark provided protection against MPP+ in cultured SH-SY5Y cells, and the potential mechanisms may be attributed to its ability to modulate the dysregulation between pro-apoptotic and anti-apoptotic proteins through the Erk1/2 signaling pathway. Our findings suggest that the addition of cinnamon to food or supplements might benefit patients with PD.

Validation of a high-throughput method for the quantification of flavanol and procyanidin biomarkers and methylxanthines in plasma by UPLC-MS.

Nutritional biomarkers are critical tools to objectively assess intake of nutrients and other compounds from the diet. In this context, it is essential that suitable analytical methods are available for the accurate quantification of biomarkers in large scale studies. Recently, structurally-related (-)-epicatechin metabolites (SREMs) and 5-(3',4'-dihydroxyphenyl)-γ-valerolactone metabolites (gVLMs) were identified as biomarkers of intake of flavanols and procyanidins, a group of polyphenol bioactives. This study aimed at validating a high throughput method for the quantification of SREMs and gVLMs in plasma along with methylxanthines (MXs), dietary compounds known to interact with flavanol and procyanidin effects. To accomplish this, a full set of authentic analytical standards were used to optimize a micro solid phase extraction method for sample preparation coupled to HPLC-MS detection. Isotopically-labelled standards for all analytes were included to correct potential matrix effects on quantification. Average accuracies of 101%, 93% and 103% were obtained, respectively, for SREMs, gVLMs and MXs. Intra- and inter-day repeatability values were <15%. The method showed linear responses for all analytes (>0.993). Most SREMs and gVLMs had limits of quantifications <5 nM while limits of quantification of MXs were 0.2 µM. All analytes were stable under different tested processing conditions. Finally, the method proved to be suitable to assess SREMs, gVLMs and MXs in plasma collected after single acute and daily intake of cocoa-derived test materials. Overall, this method proved to be a valid analytical tool for high throughput quantification of flavanol and procyanidin biomarkers and methylxanthines in plasma.

A Prospective of Multiple Biopharmaceutical Activities of Procyanidins-Rich Uapaca togoensis Pax Extracts: HPLC-ESI-TOF-MS Coupled with Bioinformatics Analysis.

The article reports the chemical composition, antioxidant, six key enzymes inhibitory and antimicrobial activities of two solvent extracts (water and methanol) of leaves and stem bark of Uapaca togoensis. For chemical composition, methanol extract of stem bark exhibited significant higher total phenolic (129.86 mg GAE/g) and flavanol (10.44 mg CE/g) contents. Methanol extract of leaves and water extract of stem bark showed high flavonoids (20.94 mg RE/g) and phenolic acid (90.40 mg CAE/g) content, respectively. In addition, HPLC-ESI-TOF-MS analysis revealed that U. togoensis was rich in procyanidins. The methanol and water extracts of stem bark had overall superior antioxidant activity; however, only methanol extract of stem bark showed higher inhibition of cholinesterase (AChE: 2.57 mg GALAE/g; BChE: 4.69 mg GALAE/g), tyrosinase (69.53 mg KAE/g) and elastase (2.73 mmol CE/g). Potent metal chelating ability was showed by water extract of leaves (18.94 mg EDTAE/g), higher inhibition of amylase was detected for water extracts of leaves (0.94 mmol ACAE/g) and stem bark (0.92 mmol ACAE/g). The tested extracts have shown wide-spectrum antibacterial properties and these effects have shown to be more effective against Aspergillus ochraceus, Penicillium funiculosum, Trichoderma viride, Bacillus cereus, Escherichia coli and Pseudomonas aeruginosa. The results revealed that the antioxidant, enzyme inhibitory and antimicrobial activities depended on the extraction solvents and the parts of plant. Bioinformatics analysis on the 17 major compounds showed modulation of pathway associated with cancer. In brief, U. togoensis might be valuable as potential source of natural agents for therapeutic application.

Proanthocyanidins isolated from the leaves of Photinia × fraseri block the cell cycle and induce apoptosis by inhibiting tyrosinase activity in melanoma cells.

Tyrosinase is considered a molecular marker of melanoma, and few natural antitumor drugs targeting tyrosinase have been identified. In this study, proanthocyanidins (PAs) were isolated from the leaves of Photinia × fraseri and their structures were characterized by high performance liquid chromatography-electrospray ionization mass spectrometry (HPLC-ESI-MS), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and the effects of antityrosinase activity were investigated. The results showed that the basic structural units of PAs are composed of catechin and epicatechin and that oligomer is the main component. PAs exhibited better antityrosinase activity via chelation of copper ions and by disturbing o-quinone production. Furthermore, analyses of the cell cycle, apoptosis rate, and regulation of melanin protein expression revealed preliminarily that PAs could affect melanin production by downregulating microphthalmia transcription factor (MITF) expression and by inhibiting the activities of tyrosinase and tyrosinase related protein 1 (TRP-1), leading to cell cycle arrest and apoptosis of melanoma cells. Collectively, our study demonstrated that PAs are potential tyrosinase inhibitors and have good antimelanoma effects. These findings provide a theoretical support for the application of tyrosinase inhibitors and for further drug development.

A Study of the Therapeutic Potential of Lentinus squarrosulus (Agaricomycetes) from Gabon.

Lentinus squarrosulus is a mushroom widely used in Gabon for its culinary and medicinal properties. The bioactive potential of mushrooms might be attributable to the presence of several pharmaceutically important mycocompounds that need to be ascertained scientifically. A study of the therapeutic potential of L. squarrosulus, the species of lignicolous fungus exploited in Gabon, was carried out on the basis of a chemical screening performed on three extracts in order to highlight different important chemical groups. This chemical screening was followed by a study of the fungus's antioxidant activity and prediction of its additional pharmacological activities. Chemical screening revealed that three extracts (aqueous, hydroethanolic, and ethanolic) of L. squarrosulus were almost free of tannins and were poor in total flavonoids and moderately rich in reducing sugars. Aqueous and ethanolic extracts were rich in total polyphenols, whereas aqueous and hydroethanolic extracts were rich in alkaloids. The aqueous extract was rich in saponosides and the hydroethanolic extract was rich in coumarins. The dosage of phenolic compounds confirmed the fungus's richness in total polyphenols, especially for aqueous and ethanolic extracts, its poverty in flavonoids and absence of tannins in ethanolic and hydroethanolic extracts. Regarding antioxidant activities, the results obtained for diphenyl picryl hydrazyl trapping tests showed that the different extracts tested had antioxidant activity ranging from low to moderate (0.12 ≤ antioxidant activity index [IAA] ≤ 0.6); the greatest activity was obtained with ethanolic extract (IAA = 0.6). Hence, we conclude that L. squarrosulus extracts can be used as easily accessible sources of natural antioxidants for potential preventative therapies.

Polyphenol Profiling of Chestnut Pericarp, Integument and Curing Water Extracts to Qualify These Food By-Products as a Source of Antioxidants.

Plant polyphenols have beneficial antioxidant effects on human health; practices aimed at preserving their content in foods and/or reusing food by-products are encouraged. The impact of the traditional practice of the water curing procedure of chestnuts, which prevents insect/mould damage during storage, was studied to assess the release of polyphenols from the fruit. Metabolites extracted from pericarp and integument tissues or released in the medium from the water curing process were analyzed by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) and electrospray-quadrupole-time of flight-mass spectrometry (ESI-qTOF-MS). This identified: (i) condensed and hydrolyzable tannins made of (epi)catechin (procyanidins) and acid ellagic units in pericarp tissues; (ii) polyphenols made of gallocatechin and catechin units condensed with gallate (prodelphinidins) in integument counterparts; (iii) metabolites resembling those reported above in the wastewater from the chestnut curing process. Comparative experiments were also performed on aqueous media recovered from fruits treated with processes involving: (i) tap water; (ii) tap water containing an antifungal Lb. pentosus strain; (iii) wastewater from a previous curing treatment. These analyses indicated that the former treatment determines a 6-7-fold higher release of polyphenols in the curing water with respect to the other ones. This event has a negative impact on the luster of treated fruits but qualifies the corresponding wastes as a source of antioxidants. Such a phenomenon does not occur in wastewater from the other curing processes, where the release of polyphenols was reduced, thus preserving the chestnut's appearance. Polyphenol profiling measurements demonstrated that bacterial presence in water hampered the release of pericarp metabolites. This study provides a rationale to traditional processing practices on fruit appearance and qualifies the corresponding wastes as a source of bioactive compounds for other nutraceutical applications.

Proanthocyanidins from Chinese berry leaves modified the physicochemical properties and digestive characteristic of rice starch.

Proanthocyanidins extracted from Chinese berry leaves (CBLPs) were heated with rice starch in aqueous solution to prepare polyphenols-starch complexes. The physicochemical properties of the complexes were characterized with XRD, DSC, RVA and FT-IR and starch constituents were also analyzed with an enzyme method. Results indicated that the addition of CBLPs destroyed the long ordered structure of rice starch rather than the short ordered structure, since the crystallinity decreased from 21.96% to 18.90% and the ratio of 1047 cm-1/1022 cm-1 showed little difference, consistent with the lower ΔH of complexes with higher CBLPs content. Additionally, the CBLPs-rice starch complexes showed a significantly lower content of rapidly digested starch (RDS, 45.64 ± 3.25%) than that of the native rice starch (67.76 ± 2.15%). These results indicated that CBLPs complexes with rice starch might be a novel way to prepare functional starch with slower digestion.

Screening active components from Rubus amabilis for pancreatic ß-cells protection.

CONTEXT: Rubus species (Rosaceae) have been used in folk medicine to treat diabetes due to their hypoglycaemic activity. OBJECTIVE: To screen the active components that act as hypoglycaemic agents in Rubus amabilis Focke and the underlying mechanisms. MATERIALS AND METHODS: Aqueous stem extract of R. amabilis was incubated with MIN6 ß-cells, PBS was used as the blank control. Then the cells were washed, cell membrane-bound components were dissociated and identified by UPLC/MS. Total procyanidins (PCs) in R. amabilis was enriched and the cytotoxicity and anti-proliferation on ß-cell were evaluated by MTT assay. PCs at 25, 50, and 75 µg/mL was applied for 24 h to determine its effects on palmitate (PA)-induced apoptosis and GSIS. Western blotting was employed to detect the protein expression of PI3K/Akt/FoxO1 signalling. The antioxidant indices were also measured. RESULTS: ß-Cell membrane-bound components were identified as three procyanidin B dimers and a C trimer. PCs showed no significant cytotoxicity up to a concentrations of 100 µg/mL. PCs treatment reversed the elevated apoptosis rate and impaired GSIS induced by PA. PCs markedly decreased the intracellular ROS and MDA production and increased the SOD activity. Moreover, PCs promoted the phosphorylation of Akt and FoxO1, and regulated Pdx-1 and Bax expression in MIN6 cells. Discussion and conclusion: The active components that act as hypoglycaemic agents in R. amabilis are procyanidins, which protected MIN6 cells against PA-induced apoptosis by activating PI3K/Akt/FoxO1 signalling. These results indicate that ß-cell extraction, combined with UPLC/MS, is a valid method for screening antidiabetic components from herbal medicines.

Preparative Separation of Procyanidins from Cocoa Polyphenolic Extract: Comparative Study of Different Fractionation Techniques.

To provide further insight into the antioxidant potential of procyanidins (PCs) from cocoa beans, PC extract was fractionated by several methodologies, including solid phase extraction, Sephadex LH-20 gel permeation, and preparative HPLC using C18 and diol stationary phases. All the isolated fractions were analyzed by UHPLC-QTOF-MS to determine their relative composition. According to our results, classical techniques allowed good separation of alkaloids, catechins, dimers, and trimers, but were inefficient for oligomeric PCs. Preparative C18-HPLC method allowed the attainment of high relative composition of fractions enriched with alkaloids, catechins, and PCs with degree of polymerization (DP) < 4. However, the best results were obtained by preparative diol-HPLC, providing a separation according to the increasing DP. According to the mass spectrometry fragmentation pattern, the nine isolated fractions (Fractions II-X) consisted of exclusively individual PCs and their corresponding isomers (same DP). In summary, an efficient, robust, and fast method using a preparative diol column for the isolation of PCs is proposed. Regarding DPPH• and ABTS•+ scavenging activity, it increases according to the DP; therefore, the highest activity was for cocoa extract > PCs > monomers. Thereby, cocoa procyanidins might be of interest to be used as alternative antioxidants.

Proanthocyanidins: Components, Pharmacokinetics and Biomedical Properties.

Proanthocyanidins (PAs) are a group of polyphenols enriched in plant and human food. In recent decades, epidemiological studies have upheld the direct relationship between PA consumption and health benefits; therefore, studies on PAs have become a research hotspot. Although the oral bioavailability of PAs is quite low, pharmacokinetics data revealed that some small molecules and colonic microbial metabolites of PAs could be absorbed and exert their health beneficial effects. The pharmacological effects of PAs mainly include anti-oxidant, anticancer, anti-inflammation, antimicrobial, cardiovascular protection, neuroprotection, and metabolism-regulation behaviors. Moreover, current toxicological studies show that PAs have no observable toxicity to humans. This review summarizes the resources, extraction, structures, pharmacokinetics, pharmacology, and toxicology of PAs and discusses the limitations of current studies. Areas for further research are also proposed.

Optimizing Water-Based Extraction of Bioactive Principles of Hawthorn: From Experimental Laboratory Research to Homemade Preparations.

Hawthorn (Crataegus) is used for its cardiotonic, hypotensive, vasodilative, sedative, antiatherosclerotic, and antihyperlipidemic properties. One of the main goals of this work was to find a well-defined optimized extraction protocol usable by each of us that would lead to repeatable, controlled, and quantified daily uptake of active components from hawthorn at a drinkable temperature (below 60 °C). A thorough investigation of the extraction mode in water (infusion, maceration, percolation, ultrasounds, microwaves) on the yield of extraction and the amount of phenolic compounds, flavonoids, and proanthocyanidin oligomers as well as on the Ultra High Performance Liquid Chromatography (UHPLC) profiles of the extracted compounds was carried out. High-resolution Fourier transform ion cyclotron resonance mass spectrometry was also implemented to discriminate the different samples and conditions of extraction. The quantitative and qualitative aspects of the extraction as well as the kinetics of extraction were studied, not only according to the part (flowers or leaves), the state (fresh or dried), and the granulometry of the dry plant, but also the stirring speed, the temperature, the extraction time, the volume of the container (cup, mug or bowl) and the use of infusion bags.

Investigation of Antibacterial and Antiinflammatory Activities of Proanthocyanidins from Pelargonium sidoides DC Root Extract.

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-1ß, iNOS, and surface presentation of CD80 and CD86 in LPS + IFNγ-treated macrophages, and IL-1ß 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.

Isolation and characterization of a novel oligomeric proanthocyanidin with significant anti-cancer activities from grape stems (Vitis vinifera).

Novel proanthocyanidin fractions from grape stem extracts were purified using Amberlite XAD-1180N, Sephadex-LH-20, Toyopearl HW40F and reverse phase high-performance liquid chromatography. Two key compounds were estimated as epigallocatechin-(epicatechin)7 gallate using electron-spray ionization time-of-flight mass spectrometry. Epigallocatechin-(epicatechin)7 gallate (compound 1) showed significant anti-cancer activity in PC-3 prostate cancer cells. In particular, compound 1 suppressed the gene expression of fatty acid-binding protein 5 (FABP5), which is involved in promoting cell proliferation and metastasis in prostate cancer cells.

Litchi (Litchi chinensis Sonn.) flower proanthocyanidin fraction exhibited protective efficacy to suppress nickel-induced expression for vascular endothelial growth factor in HepG2 cells.

The protective efficacy of litchi (Litchi chinensis Sonn.) flower proanthocyanidin fraction (LFPF) composed of (-)-epicatechin and proanthocyanidin A2 against vascular endothelial growth factor (VEGF) generation induced by nickel (Ni) in hepatocellular carcinoma (Hep G2) cells was studied. VEGF is an angiogenic inducer, which promotes tumor angiogenesis, leading to rapid tumor growth and metastasis. VEGF could be substantially induced in the Ni-mediated Hep G2 cells. Through LFPF treatment, the Ni-induced VEGF generation could be suppressed significantly. The inhibition of HIF-1α expression by blocking phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathways, and the suppression of Janus kinase 2 (JAK2)/signal transducers and activators of transcription 3 (STAT 3), and Raf-1 proto-oncogene, serine/threonine kinase (RAF1)/mitogen-activated protein kinase (MEK1/2)/extracellular-signal-regulated kinase (ERK1/2) pathways are important molecular mechanisms for the LFPF action. LFPF should probably reduce the risk of liver cancer in Ni-contaminated environments by inhibiting VEGF expression. PRACTICAL APPLICATIONS: LFPF mainly contained (-)-epicatechin and proanthocyanidin A2. Our results demonstrated that LFPF considerably suppressed the Ni-induced VEGF expression through inhibition of JAK2/STAT 3 and RAF1/MEK1/2/ERK1/2 pathways and prohibited HIF-1α expression through blocking PI3K/AKT/mTOR pathway. Litchi flowers might have the potential to diminish the liver cancer risk in a Ni-contaminated environment through suitable treatment.

Revisiting the chemistry of apple pomace polyphenols.

Hot water is an easily implementable process for polyphenols extraction. To evaluate the effect of this process on apple pomace, the overall polyphenolic composition was assessed before and after hot water extraction, followed by extractions with aqueous/organic solutions. As determined by UHPLC-DAD, flavan-3-ols were the main apple native polyphenols. Their amount decreased 50% after hot water extraction, while the other classes remained unchanged. Dihydrochalcones and hydroxycinnamic acid oxidation products, were also observed, alongside with non-extractable oxidised procyanidins that represented more than 4-fold the amount of native apple polyphenols in the pomace. Microwave superheated-water extraction of the insoluble cell wall material in water/acetone solutions and the high amounts of polyphenols that were insoluble in water/ethanol solutions suggested that oxidised procyanidins could be covalently linked to polysaccharides. These complexes represented up to 40% of the available polyphenols from apple pomace, potentially relevant for agro-food waste valuation.

The Proanthocyanidin-Rich Fraction Obtained from Red Rice Germ and Bran Extract Induces HepG2 Hepatocellular Carcinoma Cell Apoptosis.

This study aims to determine the anti-carcinogenic effects of the proanthocyanidin-rich fraction (PRFR) obtained from red rice germ and bran extract on HepG2 cells. The PRFR obtained from red rice germ and bran extract could reduce the cell viability of HepG2 cells as shown by the IC50 value at 20 µg/mL. Notably, PRFR concentrations at 20 and 40 µg/mL significantly increased the number of cells in the G2/M phase from 25.7% ± 1.4%in the control group to 36.2% ± 3.4% (p < 0.01) and 48.9% ± 2.6% (p < 0.0001), respectively, suggesting that the cells were arrested in this phase, which was confirmed by the reduction of survival proteins, including cyclin B1 and cdc25. Moreover, the PRFR at 20 and 40 µg/mL could induce cell death via the apoptosis cascade, indicated by the percentage of total apoptotic cells from 9.9% ± 3.1% in the control group to 41.1 ± 3.9 (p < 0.0001) and 82.2% ± 5.8% (p < 0.0001), respectively. This was clarified by increasing apoptotic proteins (such as cleaved PARP-1, cleaved caspase-8 and cleaved caspase-3) and decreasing anti-apoptotic protein survivin without p53 alterations. These results demonstrated that the PRFR obtained from red rice germ and bran extract could inhibit cell proliferation and induce cell apoptosis in HepG2 cells via survivin, which could potentially serve as a new target for cancer therapeutics making it an excellent "lead candidate" molecule for in vivo proof-of concept studies.