Effects of Peanut-Skin Procyanidin A1 on Degranulation of RBL-2H3 Cells

Autophagy: A potential target for natural products in the treatment of ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disease primarily affecting the mucosa of the colon and rectum. UC is characterized by recurrent episodes, often necessitating lifelong medication use, imposing a significant burden on patients. Current conventional and advanced treatments for UC have the disadvantages of insufficient efficiency, susceptibility to drug resistance, and notable adverse effects. Therefore, developing effective and safe drugs has become an urgent need. Autophagy is an intracellular degradation process that plays an important role in intestinal homeostasis. Emerging evidence suggests that aberrant autophagy is involved in the development of UC, and modulating autophagy can effectively alleviate experimental colitis. A growing number of studies have established that autophagy can interplay with endoplasmic reticulum stress, gut microbiota, apoptosis, and the NLRP3 inflammasome, all of which contribute to the pathogenesis of UC. In addition, a variety of intestinal epithelial cells, including absorptive cells, goblet cells, and Paneth cells, as well as other cell types like neutrophils, antigen-presenting cells, and stem cells in the gut, mediate the development of UC through autophagy. To date, many studies have found that natural products hold the potential to exert therapeutic effects on UC by regulating autophagy. This review focuses on the possible effects and pharmacological mechanisms of natural products to alleviate UC with autophagy as a potential target in recent years, aiming to provide a basis for new drug development.

Phenolic Fraction from Peanut (Arachis hypogaea L.) By-product: Innovative Extraction Techniques and New Encapsulation Trends for Its Valorization

Peanut skin is a by-product rich in bioactive compounds with high nutritional and pharmaceutical values. The phenolic fraction, rich in proanthocyanidins/procyanidins, is a relevant class of bioactive compounds, which has been increasingly applied as functional ingredients for food and pharmaceutical applications and is mostly recovered from peanut skins through low-pressure extraction methods. Therefore, the use of green high-pressure extractions is an interesting alternative to value this peanut by-product. This review addresses the benefits of the phenolic fraction recovered from peanut skin, with a focus on proanthocyanin/procyanidin compounds, and discusses the improvement of their activity, bioavailability, and protection, by methods such as encapsulation. Different applications for the proanthocyanidins, in the food and pharmaceutical industries, are also explored. Additionally, high-pressure green extraction methods, combined with micro/nanoencapsulation, using wall material derived from peanut industrial processing, may represent a promising biorefinery strategy to improve the bioavailability of proanthocyanidins recovered from underutilized peanut skins.

Extracts of Peanut Skins as a Source of Bioactive Compounds: Methodology and Applications

Peanut skins are a waste product of the peanut processing industry with little commercial value. They are also significant sources of the polyphenolic compounds that are noted for their bioactivity. The extraction procedures for these compounds range from simple single solvent extracts to sophisticated separation schemes to isolate and identify the large range of compounds present. To take advantage of the bioactivities attributed to the polyphenols present, a range of products both edible and nonedible containing peanut skin extracts have been developed. This review presents the range of studies to date that are dedicated to extracting these compounds from peanut skins and their various applications.

Localization of Flavan-3-ol Species in Peanut Testa by Mass Spectrometry Imaging

Flavan-3-ols, procyanidins and their monomers are major flavonoids present in peanuts that show a wide range of biological properties and health benefits, based on their potent antioxidant activity. Procyanidin oligomers, especially A-type, are reportedly abundant in peanut skin; however, their localization in the raw peanut testa remains poorly understood. Therefore, we performed matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) to investigate the localization of flavan-3-ols in peanut testa. 1,5-Diaminonaphthalene was coated onto the peanut section by matrix vapor deposition/recrystallization, and MALDI-MSI measurements were performed in the negative-ion mode. Peaks matching the m/z values of flavan-3-ol [M - H]^- ions were observed in the mass spectrum extracted from the outer epidermis of the peanut testa, using the region of interest function. Catechin and/or epicatechin, five A-type, and one B-type procyanidins were assigned by the fragment ions generated by retro-Diels-Alder, heterocyclic ring fission, and quinone methide reactions detected in MALDI-tandem MS spectra. These flavan-3-ols were localized in the outer epidermis of the peanut testa. This information will contribute to improving the extraction and purification efficiencies of flavan-3-ols from peanut testa. As flavan-3-ols display anti-microbial activity, it is speculated that flavan-3-ols present in the outer epidermis of peanut testa act to prevent pathogen infection.

Inhibitory effect of aqueous extract of Cuminum cyminum L. seed on degranulation of RBL-2H3 cells and passive cutaneous anaphylaxis reaction in mice

Cuminum cyminum L. (cumin) seed is used as a spice in various countries. Although several functions of the components in cumin seed have been reported, the anti-allergic effect of the water-soluble component in cumin seed has not been reported yet. In this study, we focused on the suppressive effect of cumin seed aqueous extract on degranulation in order to reveal the anti-allergic effect of cumin. Cumin seed aqueous extract significantly suppressed the antigen-induced degranulation of rat basophilic leukemia cell line RBL-2H3 cells in a dose-dependent manner without cytotoxicity. The extract also inhibited the elevation of the intracellular calcium ion concentration induced by antigen. Immunoblot analysis revealed that the extract suppresses phosphorylation of phosphatidylinositol 3-kinase, Bruton's tyrosine kinase, phospholipase C-γ1/2, and Akt in the signaling pathways activated by antigen induction via FcεRI. Furthermore, the extract suppressed microtubule formation induced by antigen. In addition, oral administration of cumin seed aqueous extract significantly suppressed the passive cutaneous anaphylaxis reaction in BALB/c mice. Our findings suggest that cumin seed contains water-soluble components with the anti-allergic effect. Therefore, cumin seed has potential as anti-allergic functional food.

Cinnamtannin B-1, a novel antioxidant for sperm in red deer

Cinnamtannin B-1 (CNB-1) is a naturally occurring trimeric A-type proanthocyanidin contained in several plants such as cinnamon (Cinnamomum zeylanicum). It is considered to be a potent antioxidant. The protective effect of CNB-1 against oxidative stress was assessed in red deer epididymal sperm incubated at 37 °C. Cryopreserved sperm from six stags were thawed, pooled and extended to 400 × 10⁶ sperm/ml in BGM (bovine gamete medium). After being aliquoted, the samples were supplemented with different concentrations of CNB-1 (0, 0.1, 1, 10 and 100 μg/mL), with or without induced oxidative stress (100 μM Fe²⁺/ascorbate). The samples were evaluated after 0, 2 and 4 h of incubation at 37 °C. This experiment was replicated six times. Spermmotility (CASA), viability, mitochondrial membrane potential, acrosomal status, lipoperoxidation (C11 BODIPY 581/591), intracellular reactive oxygen species (ROS) production and DNA status (TUNEL) were assessed. After 4 h of incubation, CNB-1 prevented the deleterious effects of oxidative stress, thus improved sperm progressivity and velocity (P<0.05). Furthermore, 1 and 10 μM CNB-1 improved sperm linearity, even when compared to those samples that had not been subjected to oxidative stress (P<0.05). The greatest concentration, 100 μM, prevented sperm lipoperoxidation and reduced ROS production in samples subjected to oxidative stress.

A novel mode of stimulating platelet formation activity in megakaryocytes with peanut skin extract

We report in this study novel biochemical activities of peanut skin extract (PEXT) on thrombocytopoiesis. Peanut skin, derived from Arachis hypogaea L., is a traditional Chinese medicine that is used to treat chronic hemorrhage. We have shown that oral administration of PEXT increases the peripheral platelet levels in mice. Recently, we reported a liquid culture system that is useful for investigating megakaryocytopoiesis and thrombocytopoiesis from human CD34⁺ cells. In this liquid culture system, PEXT was shown to enhance the formation of CD41⁺/DAPI^- cells (platelets), but had no effect on the formation of CD41⁺/DAPI⁺ cells (megakaryocytes) or on the DNA content. Furthermore, PEXT selectively stimulated proplatelet formation from cultured mature megakaryocytes and phorbol 12-myristate 13 acetate (PMA)-induced formation of platelet-like particles from Meg01 cells. Despite having no influence on the formation of megakaryocyte colony forming units (CFUs), PEXT increased the size of megakaryocytes during their development from CD34⁺ cells. PEXT showed no effect on the GATA-1 and NF-E2 mRNA levels, which are known to play an important role in thrombocytopoiesis and, based on the results of a pMARE-Luc (pGL3-MARE-luciferase) assay, had no influence on NF-E2 activation in Meg01 cells. These results suggest that PEXT accelerates proplatelet formation from megakaryocytes but does not influence the development of hematopoietic stem cells into megakaryocytes.

Procyanidins Mitigate Osteoarthritis Pathogenesis by, at Least in Part, Suppressing Vascular Endothelial Growth Factor Signaling

Procyanidins are a family of plant metabolites that have been suggested to mitigate osteoarthritis pathogenesis in mice. However, the underlying mechanism is largely unknown. This study aimed to determine whether procyanidins mitigate traumatic injury-induced osteoarthritis (OA) disease progression, and whether procyanidins exert a chondroprotective effect by, at least in part, suppressing vascular endothelial growth factor signaling. Procyanidins (extracts from pine bark), orally administered to mice subjected to surgery for destabilization of the medial meniscus, significantly slowed OA disease progression. Real-time polymerase chain reaction revealed that procyanidin treatment reduced expression of vascular endothelial growth factor and effectors in OA pathogenesis that are regulated by vascular endothelial growth factor. Procyanidin-suppressed vascular endothelial growth factor expression was correlated with reduced phosphorylation of vascular endothelial growth factor receptor 2 in human OA primary chondrocytes. Moreover, components of procyanidins, procyanidin B2 and procyanidin B3 exerted effects similar to those of total procyanidins in mitigating the OA-related gene expression profile in the primary culture of human OA chondrocytes in the presence of vascular endothelial growth factor. Together, these findings suggest procyanidins mitigate OA pathogenesis, which is mediated, at least in part, by suppressing vascular endothelial growth factor signaling.

Bacillus cereus Response to a Proanthocyanidin Trimer, a Transcriptional and Functional Analysis

Proanthocyanidins are abundant in peanut skin, and in this study, the antibacterial effects of a peanut skin extract (PSE) against food-borne bacteria were investigated to find its minimum inhibitory concentration. Food-borne gram-positive bacteria, and in particular Bacillus cereus, was more sensitive to PSE. In particular, the inhibitory activity of epicatechin-(4β → 6)-epicatechin-(2β → O→7, 4β → 8)-catechin (EEC), a proanthocyanidin trimer from peanut skin, against B. cereus was stronger than that of procyanidin A1, a proanthocyanidin dimer. DNA microarray analysis of B. cereus treated with EEC was carried out, with a finding that 597 genes were significantly up-regulated. Analysis of the up-regulated genes suggested that EEC disrupted the normal condition of the cell membrane and wall of B. cereus and alter its usual nutritional metabolism. Moreover, treatment of B. cereus with EEC inhibited glucose uptake, suggesting that EEC affects the cell-surface adsorption.

Comparative proteomic analysis and IgE binding properties of peanut seed and testa (skin)

To investigate the protein composition and potential allergenicity of peanut testae or skins, proteome analysis was conducted using nanoLC-MS/MS sequencing. Initial amino acid analysis suggested differences in protein compositions between the blanched seed (skins removed) and skin. Phenolic compounds hindered analysis of proteins in skins when the conventional extraction method was used; therefore, phenol extraction of proteins was necessary. A total of 123 proteins were identified in blanched seed and skins, and 83 of the proteins were common between the two structures. The skins contained all of the known peanut allergens in addition to 38 proteins not identified in the seed. Multiple defense proteins with antifungal activity were identified in the skins. Western blotting using sera from peanut-allergic patients revealed that proteins extracted from both the blanched seed and skin bound significant levels of IgE. However, when phenolic compounds were present in the skin protein extract, no IgE binding was observed. These findings indicate that peanut skins contain potentially allergenic proteins; however, the presence of phenolic compounds may attenuate this effect.

Value-added processing of peanut skins: antioxidant capacity, total phenolics, and procyanidin content of spray-dried extracts

To explore a potential use for peanut skins as a functional food ingredient, milled skins were extracted with 70% ethanol and filtered to remove insoluble material; the soluble extract was spray-dried with or without the addition of maltodextrin. Peanut skin extracts had high levels of procyanidin oligomers (DP2-DP4) but low levels of monomeric flavan-3-ols and polymers. The addition of maltodextrin during spray-drying resulted in the formation of unknown polymeric compounds. Spray-drying also increased the proportion of flavan-3-ols and DP2 procyanidins in the extracts while decreasing larger procyanidins. Spray-dried powders had higher antioxidant capacity and total phenolics and increased solubility compared to milled skins. These data suggest that spray-dried peanut skin extracts may be a good source of natural antioxidants. Additionally, the insoluble material produced during the process may have increased value for use in animal feed due to enrichment of protein and removal of phenolic compounds during extraction.