Grape seed extract-soluplus dispersion and its antioxidant activity

Depolymerized peanut skin-derived proanthocyanidins alleviate cognitive dysfunction by inhibiting Aβ42 aggregation in Alzheimer's disease

Peanut skin proanthocyanidins (PSP) are natural polyphenols with antioxidant properties that mitigate Alzheimer's disease (AD), a complex progressive neurodegenerative disorder whose underlying biological mechanisms includes the aggregation of insoluble amyloid plaques. However, the high degree of polymerization of PSP, extracted using conventional methods, limits its bioavailability. This study established the optimal processes for ultrasound-assisted alkaline depolymerization to produce oligomeric proanthocyanidins (OPSP) from PSP content (2.7 mg/mL), depolymerization temperature (54.8 °C), ultrasonic power (480 W, 28 Hz), ultrasonic duration (28.7 min), and pH (12.1). Under these conditions, the degree of polymerization of the proanthocyanidins decreased from 6.74 to 2.87. Physicochemical characteristics of PSP and OPSP were analyzed. Both PSP and OPSP exhibited shared structural bonding and a repeating 288 Da unit, with Proanthocyanidin A identified as the predominant type. Furthermore, compared with PSP, OPSP demonstrated enhanced stability and antioxidant activity. Using in vitro detection of amyloid-beta (Aβ42) inhibition, this study demonstrated that OPSP exhibited greater inhibition of Aβ42 fibrillogenicity than underpolymerized PSP, and OPSP significantly inhibited Aβ42-induced cytotoxicity. In addition, the effect of OPSP was investigated in a rat model of Alzheimer's disease. The results indicated that OPSP improved the memory performance of AD rats in the water maze and decreased the levels of inflammatory factors IL-6, IL-1β, and TNF-α. Moreover, OPSP ameliorated histopathological changes and reduced Aβ42 plaque deposition in the brains of AD rats. These findings regarding OPSP are anticipated to facilitate high-value utilization of peanut by-products, expand their applications, and provide guidance for the use of OPSP in the development of natural healthcare pharmaceuticals and mitigation and treatment of Alzheimer's disease.

Optimization of Ultrasonic-Enzyme Synergistic Extraction of Proanthocyanidins from Jujube: Purification, Characterization, and Bioactivity Study

Proanthocyanidins have received extensive attention due to their high functional value, but their sources are limited. Therefore, this experiment studied the preparation, biological activities, and characterization of proanthocyanidins from Chinese jujube (Ziziphus jujuba Mill. cv. Muzao) at different periods, aiming to explore a new source of proanthocyanidins and enhance their utilization value. Through ultrasonic-assisted enzymatic extraction, the optimal extraction conditions for PC from Muzao were determined, yielding a proanthocyanidin content of 2.01%. Purification using AB-8 macroporous resin increased the proanthocyanidin content by 11 times. The bioactivity results indicated that proanthocyanidins demonstrated significant in vitro antioxidant activity (scavenging rate ≥ 83.4%) and blood glucose-lowering activity (inhibition rate ≥ 84.7%). Both activities decreased with maturity, while the degree of polymerization also exhibited a positive effect. Mass spectrometry identified a total of 102 compounds, with cyanidin-based compounds being the most abundant, comprising 28 species. The comprehensive research results indicate that the oligomeric proanthocyanidins extracted, purified, and isolated from Muzao during the young fruit stage exhibit diverse biological activities and are abundant in content. They can be utilized for the extraction and purification of proanthocyanidins, offering a reference for the expansion of natural sources of proanthocyanidins and the development of functional foods.

Sensory Characteristics and Impact of Flavanol-Rich Grape and Blueberry Extract on Blood Flow Velocity and Oxidative Stress

BACKGROUND

Several epidemiological studies and intervention trials have demonstrated that grapes and blueberries, which are rich in flavanols, can lower the risk of cardiovascular disease. However, the mechanisms of action of these compounds remain unclear due to their low bioavailability.

OBJECTIVE

This study aimed to characterize the sensory properties, blood flow velocity, and oxidative stress of a polyphenol rich grape and blueberry extract (PEGB) containing approximately 16% flavanols (11% monomers and 4% dimers).

METHOD

A sensory property of PEGB was compared with quercetin at uniform concentration using healthy young subjects. In addition, the reactivity of PEGB with O2•- was also compared with quercetin utilizing a luminescence method. Furthermore, the effect of a single administration of PEGB on the blood flow velocity of skeletal muscle arterioles was investigated using a laser Doppler method in rats.

RESULTS

At a concentration where quercetin was barely tasteful, flavanol in PEGB exhibited a robust astringent taste. Furthermore, under pH conditions mimicking the oral cavity and intestinal tract, PEGB promoted O2•- production at low concentrations and scavenging O2•- at high concentrations. In contrast, quercetin demonstrated antioxidant activity. A single oral administration of PEGB significantly increased the blood flow velocity of skeletal muscle arterioles.

CONCLUSION

The results demonstrate that PEGB exhibited a pronounced astringent taste, O2•- production at low concentrations in neutral pH environments, and significantly enhanced blood flow to skeletal muscle following a single administration to rats. These findings highlight the necessity for further investigation into the causal relationships between oral perception, redox properties, and bioactivity of polyphenols.

Pressurized liquid extraction of bioactive compounds from grape peel and application in pH-sensing carboxymethyl cellulose films: A promising material to monitor the freshness of pork and milk

This study produced pH-sensing carboxymethyl cellulose (CMC) films functionalized with bioactive compounds obtained by pressurized liquid extraction (PLE) of grape peel to monitor the freshness of pork and milk. A semi-continuous PLE was conducted using hydroethanolic solution (70:30, v/v) at a flow rate of 5 mL/min, 15 MPa, and 60 °C. The films were produced by the casting technique using CMC (2.5 %, w/v), glycerol (1 %, v/v), and functionalized with 10, 30, and 50 % (v/v) grape peel extract. From the results obtained, LC-MS/MS revealed that PLE extracted twenty-seven phenolic compounds. The main phenolic compounds were kaempferol-3-glucoside (367.23 ± 25.88 µg/mL), prunin (270.23 ± 3.62 µg/mL), p-coumaric acid (236.43 ± 26.02 µg/mL), and procyanidin B1 (117.17 ± 7.29 µg/mL). The CMC films presented suitable color and mechanical properties for food packaging applications. The addition of grape peel extract promoted the pH-sensing property, showing the sensitivity of anthocyanins to pH changes. The films functionalized with grape peel extract presented good release control of bioactive compounds, making them suitable for food packaging applications. When applied to monitor the freshness of pork and milk, the films exhibited remarkable color changes associated with the pH of the food during storage. In conclusion, PLE is a sustainable approach to obtaining bioactive compounds from the grape peel, which can be applied in the formulation of pH-sensing films as a promising sustainable material to monitor food freshness during storage.

Mixed micelles loaded with hesperidin protect against acetaminophen induced acute liver injury by inhibiting the mtDNA-cGAS-STING pathway

Excessive acetaminophen (APAP) is the main cause of drug-induced acute liver failure, and the pathogenesis has not been elucidated and there is a lack of effective drugs. Hesperidin (Hes), a rich flavanone in citrus peel with excellent biological activities, is a potential agent for treatment liver injury. Due to poor water solubility of Hes, this study prepared mixed micelles using polyvinyl pyrrolidone (PVP K17) and poloxamer 188, and encapsulated Hes (Hes-MMs). The results showed that Hes-MMs exhibited a uniform spherical shape with a particle size of 66.80 ± 0.83 nm, and Hes-MMs significantly improved the dispersibility, antioxidant activity, and cellular uptake of Hes. In vitro results showed that Hes-MMs protected the proliferation inhibition of HepG2 cells induced by APAP, inhibited the production of reactive oxygen species (ROS) and the damage of mitochondrial membrane potential (MMP) induced by APAP. Furthermore, Hes-MMs exerted liver protective effects by inhibiting APAP induced mtDNA release and activating the cGAS-STING pathway. In vivo results demonstrated that Hes-MMs showed protective and therapeutic effects on APAP induced liver injury, and their mechanisms were related to the mtDNA-cGAS-STING signaling pathway. In summary, our study demonstrated that the mtDNA-cGAS-STING pathway was involved in APAP induced acute liver injury, and Hes-MMs might be a potential therapeutic agent for treating APAP induced acute liver injury.

Plant Polyphenols Attenuate DSS-induced Ulcerative Colitis in Mice via Antioxidation, Anti-inflammation and Microbiota Regulation

The pathogenesis of ulcerative colitis (UC) is associated with inflammation, oxidative stress, and gut microbiota imbalance. Although most researchers have demonstrated the antioxidant bioactivity of the phenolic compounds in plants, their UC-curing ability and underlying mechanisms still need to be further and adequately explored. Herein, we studied the antioxidation-structure relationship of several common polyphenols in plants including gallic acid, proanthocyanidin, ellagic acid, and tannic acid. Furthermore, the in vivo effects of the plant polyphenols on C57BL/6 mice with dextran-sulfate-sodium-induced UC were evaluated and the action mechanisms were explored. Moreover, the interplay of several mechanisms was determined. The higher the number of phenolic hydroxyl groups, the stronger the antioxidant activity. All polyphenols markedly ameliorated the symptoms and pathological progression of UC in mice. Furthermore, inflammatory cytokine levels were decreased and the intestinal barrier was repaired. The process was regulated by the antioxidant-signaling pathway of nuclear-erythroid 2-related factor 2. Moreover, the diversity of the intestinal microbiota, Firmicutes-to-Bacteroides ratio, and relative abundance of beneficial bacteria were increased. An interplay was observed between microbiota regulation and oxidative stress, immunity, and inflammatory response. Furthermore, intestinal barrier repair was found to be correlated with inflammatory responses. Our study results can form a basis for comprehensively developing plant-polyphenol-related medicinal products.

Antioxidant Properties Mediate Nephroprotective and Hepatoprotective Activity of Essential Oil and Hydro-Alcoholic Extract of the High-Altitude Plant Skimmia anquetilia

There are many high-altitude plants such as Skimmia anquetilia that are unexplored for their possible medicinal values. The present study was conducted to examine the antioxidant activities of Skimmia anquetilia (SA) using in vitro and in vivo models. The SA hydro-alcoholic extracts were investigated using LC-MS for their chemical constituents. The essential oil and hydro-alcoholic extracts of SA were evaluated for pharmacological properties. The antioxidant properties were evaluated using in vitro DPPH, reducing power, cupric reducing antioxidant power, and metal chelating assays. The anti-hemolytic activity was carried out using a human blood sample. The in vivo antioxidant activities were evaluated using CCL₄-induced hepatotoxicity and nephrotoxicity assay. The in vivo evaluation included histopathological examination, tissue biochemical evaluation such as the kidney function test, catalase activity, reduced glutathione activity, and lipid peroxidation estimation. The phytochemical investigation showed that the hydro-alcoholic extract contains multiple important active constituents such as L-carnosine, acacetin, linoleic acid, leucylleucyl tyrosine, esculin sesquihydrate, etc., similar to the components of SA essential oil reported in a previous study. The high amount of total phenolic content (TPC) and total flavonoid content (TFC) reflect (p < 0.001) a high level of reducing power, cupric reducing, and metal chelating properties. This significantly (p < 0.001) inhibited enlargement of the liver, with a significant reduction in ALT (p < 0.01) and AST (p < 0.001). Highly significant improvement in the functioning of the kidney was noted using the blood urea and creatinine (p < 0.001) levels. Tissue-based activities showed a major rise in catalase, reduced glutathione, and reduced lipid peroxidation activities. We conclude from this study that the occurrence of a high quantity of flavonoid and phenolic contents had strong antioxidant properties, leading to hepatoprotective and nephroprotective activity. Further active constituent-specific activities should be evaluated.

The benefits of grape seed extract in neurological disorders and brain aging

Common neurological disorders, including neurodegenerative diseases, stroke, epilepsy, autism and psychiatric disorders, affect many people worldwide and threaten their lives and health by inducing movement disorders, behavioral disorders, or a combination of both. Oxidative stress and neuroinflammation play a central role in neuronal damage and neurological diseases induction and progression. In addition, protein homeostasis (proteostasis) impairment occurs in many neurodegenerative diseases, which plays a critical role in the progression of the pathology. Grape seed contains several flavonoids and non-flavonoids and exerts potent antioxidant and anti-inflammatory effects. In addition, polyphenols and flavanols can maintain cellular proteostasis. Since impaired proteostasis is closely involved in all amyloid diseases, particularly neurodegenerative diseases, grape seeds extract can be a valuable therapeutic agent. Therefore, this review discusses the protective and therapeutic mechanisms of grape seed against neurological disorders and, in the end, links GSE to microRNAs as future therapeutic developments.

Stearoyl-CoA Desaturases1 Accelerates Non-Small Cell Lung Cancer Metastasis by Promoting Aromatase Expression to Improve Estrogen Synthesis

Metastases contribute to the low survival rate of non-small cell lung cancer (NSCLC) patients. Targeting lipid metabolism for anticancer therapies is attractive. Accumulative evidence shows that stearoyl-CoA desaturases1 (SCD1), a key enzyme in lipid metabolism, enables tumor metastasis and the underlying mechanism remains unknown. In this study, immunohistochemical staining of 96 clinical specimens showed that the expression of SCD1 was increased in tumor tissues (p < 0.001). SCD1 knockdown reduced the migration and invasion of HCC827 and PC9 cells in transwell and wound healing assays. Aromatase (CYP19A1) knockdown eliminated cell migration and invasion caused by SCD1 overexpression. Western blotting assays demonstrated that CYP19A1, along with β-catenin protein levels, was reduced in SCD1 knocked-down cells, and estrogen concentration was reduced (p < 0.05) in cell culture medium measured by enzyme-linked immunosorbent assay. SCD1 overexpression preserving β-catenin protein stability was evaluated by coimmunoprecipitation and Western blotting. The SCD1 inhibitor A939572, and a potential SCD1 inhibitor, grape seed extract (GSE), significantly inhibited cell migration and invasion by blocking SCD1 and its downstream β-catenin, CYP19A1 expression, and estrogen concentration. In vivo tumor formation assay and a tail vein metastasis model indicated that knockdown of SCD1 blocked tumor growth and metastasis. In conclusion, SCD1 could accelerate metastasis by maintaining the protein stability of β-catenin and then promoting CYP19A1 transcription to improve estrogen synthesis. SCD1 is expected to be a promised therapeutic target, and its novel inhibitor, GSE, has great therapeutic potential in NSCLC.

Pterostilbene-Loaded Soluplus/Poloxamer 188 Mixed Micelles for Protection against Acetaminophen-Induced Acute Liver Injury

Excessive acetaminophen (APAP) induces excess reactive oxygen species (ROS), leading to liver damage. Pterostilbene (PTE) has excellent antioxidant and anti-inflammatory activities, but poor solubility limits its biological activity. In this study, we prepared PTE-loaded Soluplus/poloxamer 188 mixed micelles (PTE-MMs), and the protective mechanism against APAP-induced liver injury was investigated. In vitro results showed that PTE-MMs protected H₂O₂-induced HepG2 cell proliferation inhibition, ROS accumulation, and mitochondrial membrane potential destruction. Immunofluorescence results indicated that PTE-MMs significantly inhibited H₂O₂-induced DNA damage and cGAS-STING pathway activation. For in vivo protection studies, PTE-MMs (25 and 50 mg/kg) were administered orally for 5 days, followed by APAP (300 mg/kg). The results showed that APAP significantly induced injury in liver histopathology as well as an increase in serum aspartate aminotransferase and alanine aminotransferase levels. Moreover, the above characteristics of APAP-induced acute liver injury were inhibited by PTE-MMs. In addition, APAP-induced changes in the activities of antioxidant enzymes such as SOD and GSH in liver tissue were also inhibited by PTE-MMs. Immunohistochemical results showed that PTE-MMs inhibited APAP-induced DNA damage and cGAS-STING pathway activation in liver tissues. For in vivo therapeutic effect study, mice were first given APAP (300 mg/kg), followed by oral administration of PTE-MMs (50 mg/kg) for 3 days. The results showed that PTE-MMs exhibited promising therapeutic effects on APAP-induced acute liver injury. In conclusion, our study shows that the Soluplus/poloxamer 188 MM system has the potential to enhance the biological activity of PTE in the protection and therapeutic of liver injury.

Antimicrobial Potential, Antioxidant Activity, and Phenolic Content of Grape Seed Extracts from Four Grape Varieties

The aim of this study was to evaluate the total phenolic content, composition, and antioxidant and antibacterial activities of four grape seed extracts (Cabernet Sauvignon, Marselan, Pinot Noir, and Tamyanka). The total phenolic content (TPC) and flavonoid, anthocyanin, procyanidin, ascorbic acid, DPPH, and ABTS antioxidant capacities of the grape seed extracts (GSEs) were determined. The extracts showed high TPC values (79.06-111.22 mg GAE/g). The individual components in the GSEs were determined using HPLC. High contents of catechin, epicatechin, and procyanidin B1 were found in the extracts. The antimicrobial activity of the obtained GSEs against Staphylococcus aureus, Bacillus cereus, and Escherichia coli was evaluated using the agar diffusion test and a test to determine the minimum inhibitory concentration (MIC). According to the effect on the growth of pathogens, the extracts were ranked in the following order: Pinot Noir > Marselan > Cabernet Sauvignon > Tamyanka. The tested bacteria showed high sensitivity to the extracts (MIC = 0.12-0.50 mg/mL). According to the MIC values, the bacteria were in the following order: S. aureus > B. cereus > E. coli. A correlation was found between the phenolic content of the GSEs and their antibacterial potential. The obtained results show that the studied GSEs have good potential as antioxidant and antimicrobial agents.

Formulation of water-soluble Buddleja globosa Hope extracts and characterization of their antimicrobial properties against Pseudomonas aeruginosa

Buddleja globosa Hope (BG) extracts are traditionally used to treat skin and gastric ulcers due to their healing properties. Non-aqueous solvents such as ethanol and DMSO are usually used to extract naturally occurring compounds. However, the cytotoxicity of these solvents and the low water solubility of the extracted compounds can hinder their biomedical applications. To overcome the limited solubility of the BG extracts, we aimed to enhance the solubility by processing a standardized hydroalcoholic extract (BG-126) through spray drying (SD), with and without two solubility enhancers. Spray-dried BG (BG-SD) extracts and spray-dried BG extracts plus polyvinylpyrrolidone (BG-SD PVP) and Soluplus® (BG-SD SP) were developed starting from BG-126 (containing 53% ethanol). These four formulations were characterized by total phenolic content, water solubility at 25°C and 37°C, and antimicrobial properties against Pseudomonas aeruginosa. All the SD formulations presented a solubility that allowed them to reach maximum concentrations of 1,024 μg/ml catechin for BG-SD and 2,048 μg/ml catechin for BG-SD PVP and BG-SD SP for antimicrobial testing. BG-SD showed the highest antimicrobial potency with a minimum inhibitory concentration (MIC) of 512 μg/ml catechin, followed by BG-126 with a MIC of 1,024 μg/ml catechin and SP. BG-126 was also shown to inhibit biofilm formation, as well as the excipients PVP and SP. The spray-dried BG (BG-SD) extract represents a promising natural active component with enhanced antimicrobial properties against P. aeruginosa for further research and the development of novel phytopharmaceuticals.

Hormetic response to B-type procyanidin ingestion involves stress-related neuromodulation via the gut-brain axis: Preclinical and clinical observations

B-type procyanidins, a series of catechin oligomers, are among the most ingested polyphenols in the human diet. Results of meta-analyses have suggested that intake of B-type procyanidins reduces cardiovascular disease risk. Another recent focus has been on the effects of B-type procyanidins on central nervous system (CNS) function. Although long-term B-type procyanidin ingestion is linked to health benefits, a single oral intake has been reported to cause physiological alterations in circulation, metabolism, and the CNS. Comprehensive analyses of previous reports indicate an optimal mid-range dose for the hemodynamic effects of B-type procyanidins, with null responses at lower or higher doses, suggesting hormesis. Indeed, polyphenols, including B-type procyanidins, elicit hormetic responses in vitro, but animal and clinical studies are limited. Hormesis of hemodynamic and metabolic responses to B-type procyanidins was recently confirmed in animal studies, however, and our work has linked these effects to the CNS. Here, we evaluate the hormetic response elicited by B-type procyanidins, recontextualizing the results of intervention trials. In addition, we discuss the possibility that this hormetic response to B-type procyanidins arises via CNS neurotransmitter receptors. We have verified the direction of future research for B-type procyanidins in this review.

Byproducts (Flour, Meals, and Groats) from the Vegetable Oil Industry as a Potential Source of Antioxidants

The present study presents the use of photochemiluminescence assay (PCL) and 2,2 diphenyl-1-picryl-hydrazyl (DPPH), 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), the ferric reducing antioxidant power (FRAP), and cupric ion reducing antioxidant capacity (CUPRAC) methods for the measurement of lipid-soluble antioxidant capacity (ACL) of 14 different byproducts obtained from the vegetable oil industry (flour, meals, and groats). The research showed that the analyzed samples contain significant amounts of phenolic compounds between 1.54 and 74.85 mg gallic acid per gram of byproduct. Grape seed flour extract had the highest content of total phenolic compounds, 74.85 mg GAE/g, while the lowest level was obtained for the sunflower groats, 1.54 mg GAE/g. DPPH values varied between 7.58 and 7182.53 mg Trolox/g of byproduct, and the highest antioxidant capacity corresponded to the grape seed flour (7182.53 mg Trolox/g), followed by walnut flour (1257.49 mg Trolox/g) and rapeseed meals (647.29 mg Trolox/g). Values of ABTS assay of analyzed samples were between 0 and 3500.52 mg Trolox/g of byproduct. Grape seed flour had the highest value of ABTS (3500.52 mg Trolox/g), followed by walnut flower (1423.98) and sea buckthorn flour (419.46). The highest values for FRAP method were represented by grape seed flour (4716.75 mg Trolox/g), followed by sunflower meals (1350.86 mg Trolox/g) and rapeseed flour (1034.92 mg Trolox/g). For CUPRAC assay, grape seed flour (5936.76 mg Trolox/g) and walnut flour (1202.75 mg Trolox/g) showed the highest antioxidant activity. To assess which method of determining antioxidant activity is most appropriate for the byproducts analyzed, relative antioxidant capacity index (RACI) was calculated. Depending on the RACI value of the analyzed byproducts, the rank of antioxidant capacity ranged from −209.46 (walnut flour) to 184.20 (grape seed flour). The most sensitive methods in developing RACI were FRAP (r = 0.5795) and DPPH (r = 0.5766), followed by CUPRAC (r = 0.5578) and ABTS (r = 0.4449), respectively. Strong positive correlations between the antioxidant capacity of lipid-soluble compounds measured by PCL and other methods used for determining antioxidant activity were found (r > 0.9). Analyses have shown that the different types of byproducts obtained from the vegetable oil industry have a high antioxidant activity rich in phenolic compounds, and thus their use in bakery products can improve their nutritional quality.

Repeated Oral Administration of Flavan-3-ols Induces Browning in Mice Adipose Tissues through Sympathetic Nerve Activation

We previously found increases in uncoupling protein (Ucp)-1 transcription in brown adipose tissue (BAT) of mice following a single oral dose of flavan 3-ol (FL)s, a fraction of catechins and procyanidins. It was confirmed that these changes were totally reduced by co-treatment of adrenaline blockers. According to these previous results, FLs possibly activate sympathetic nervous system (SNS). In this study, we confirmed the marked increase in urinary catecholamine (CA) s projecting SNS activity following a single dose of 50 mg/kg FLs. In addition, we examined the impact of the repeated administration of 50 mg/kg FLs for 14 days on adipose tissues in mice. In BAT, FLs tended to increase the level of Ucp-1 along with significant increase of thermogenic transcriptome factors expressions, such as peroxisome proliferator-activated receptor γ coactivator (PGC)-1α and PR domain-containing (PRDM)1. Expression of browning markers, CD137 and transmembrane protein (TMEM) 26, in addition to PGC-1α were increased in epididymal adipose (eWAT) by FLs. A multilocular morphology with cell size reduction was shown in the inguinal adipose (iWAT), together with increasing the level of Ucp-1 by FLs. These results exert that FLs induce browning in adipose, and this change is possibly produced by the activation of the SNS.