Proanthocyanidin Extract Research Articles

Grape-Seed Proanthocyanidin Extract (GSPE) Modulates Diurnal Rhythms of Hepatic Metabolic Genes and Metabolites, and Reduces Lipid Deposition in Cafeteria-Fed Rats in a Time-of-Day-Dependent Manner.

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global health issue with increasing prevalence. Polyphenols, such as grape seed proanthocyanidin extract (GSPE), are bioactive compounds present in plants and represent an interesting therapeutical approach for MASLD. This study questioned whether the timing of GSPE administration impacts liver diurnal metabolism and steatosis in a rat obesity model. Results from hepatic lipid profiling and diurnal metabolic gene expression and metabolomics reveal that rats fed with a cafeteria (CAF) diet show impaired glucose homeostasis and enhanced lipogenesis in the liver, contributing to liver steatosis. Chronic consumption of GSPE in the inactive or active phase is associated with beneficial effects as the restoration of rhythms of transcripts and metabolites is observed. However, only when given in the active phase, GSPE treatment decreases hepatic triglyceride levels. Using an in vitro hepatocyte model, the study identifies that catechin, one of the main phenolic compounds found in the GSPE extract, is a potential mediator in ameliorating the effects of CAF-induced liver steatosis. Taken altogether, the findings show that the beneficial effects of GSPE on MASLD development depend on the treatment time.

Evaluation of the antioxidant activity and prebiotic properties of mangosteen peel proanthocyanidin extracts through simulated in vitro digestion and colonic fermentation

The biological activity of mangosteen peel proanthocyanidin extracts is related to digestive properties and colonic metabolism. Therefore, the study's aim was to investigate the dynamics of proanthocyanidin extracts during in vitro digestion and colonic fermentation, their protective effects against oxidative damage in PEC-J2 cells, and their interactions with the intestinal flora. The results showed that epicatechin and proanthocyanidin B2 were the most abundant in proanthocyanidin. In addition, the catechin was increased by 27.7 ± 0.2 μg/mL. The total phenol content, total flavonoid content, and proanthocyanidin content of mangosteen peel were reduced by 32.36%, 90.63%, and 78.06%, respectively. However, the antioxidant capacity was increased by two-fold, protecting against oxidative damage in cells. Proanthocyanidin polymers that are not digested by the gastrointestinal tract go to the colon, where they are metabolized by microorganisms to produce short-chain fatty acids (SCFAs). Proanthocyanidin extracts modulated the microbial flora structure: the relative abundance of Phascolarctobacterium, Roseburia, Faecalibacterium, Coprococcu, and Clostridium sensu stricto all increased significantly. The ratio of Bacteroides to Firmicutes increased, and Bifidobacterium grew and multiplied. This study improves the utilization of mangosteen peel and provides a theoretical basis for the scientific evaluation of the antioxidant activity and gut microbiota modulation of mangosteen peel.

Electron beam irradiation coupled ultrasound-assisted natural deep eutectic solvents extraction: A green and efficient extraction strategy for proanthocyanidin from walnut green husk

Proanthocyanidin (PAC) is recognized as a potent natural antioxidant that prevents various diseases. As societal awareness increases, eco-friendly and efficient natural product extraction technologies are gaining more attention. In this study, an electron beam irradiation (EBI) coupled with ultrasound-assisted natural deep eutectic solvents (NADES) extraction method was developed to enable the green and highly efficient extraction of PAC from walnut green husk (WGH). NADES, prepared with choline chloride and ethylene glycol, demonstrated excellent extraction capacity and storage stability for PAC. Molecular dynamics simulations elucidated the high compatibility between NADES and PAC, attributed mainly to a higher SASA value (207.85 nm2), a greater number of hydrogen bonds (330.99), an extended hydrogen bonding lifetime (4.54 ps), and lower inter-molecular interaction energy. Based on these findings, the optimal conditions (13 kGy EBI, 42 mL/g liquid-solid ratio, 38 °C extraction temperature, 70 min extraction time) resulted in a maximum PAC extraction yield of 56.34 mg/g. Notably, this yield was 32.93 % higher than that observed in samples not treated with EBI and ultrasound-assisted extraction (UAE). Analysis of tissue morphology, extract functional groups and thermal behavior suggested a possible mechanism for the synergistically enhanced PAC extraction by the EBI-NADES-UAE method. Additionally, the PAC extracted using the NADES by the EBI coupled with ultrasound-assisted method exhibited outstanding antioxidant activity (comparable to Vc), digestive enzyme inhibition (IC50: 17–0.61 mg/mL), and anti-glycation capacity (IC50: 86.49 μg/mL). Overall, this work provided a green and efficient strategy for PAC extraction from WGH, elucidated the extraction mechanism and bioactivities, and offered valuable insights for potential industrial applications.

Effects of grape seed proanthocyanidin extract on cholesterol metabolism and antioxidant status in finishing pigs

Grape seed proanthocyanidin extract (GSPE) is a natural polyphenolic compound, which plays an important role in anti-inflammatory and antioxidant. The present study aimed to investigate the effects of GSPE supplementation on the cholesterol metabolism and antioxidant status of finishing pigs. In longissimus dorse (LD) muscle, the data showed that GSPE significantly decreased the contents of total cholesterol (T-CHO) and triglyceride (TG), and decreased the mRNA expression of 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMG-CoAR) and Fatty acid synthase (FAS), while increased the mRNA expression of carnitine palmitoyl transferase-1b (CPT1b), peroxisome proliferator-activated receptors (PPARα) and peroxisome proliferator activated receptor-γ coactivator-1α (PGC-1α). GSPE also reduced the enzyme activities of HMG-CoAR and FAS, and meanwhile amplified the activity of CPT1b in LD muscle of finishing pigs. Furthermore, dietary GSPE supplementation increased the serum catalase (CAT) and total antioxidant capacity (T-AOC), serum and liver total superoxide dismutase (T-SOD) and glutathione peroxidase (GSH-Px) levels, while reduced serum and liver malondialdehyde (MDA) level in finishing pigs. In the liver, Superoxide Dismutase 1 (SOD1), catalase (CAT), glutathione peroxidase 1 (GPX1), Nuclear Factor erythroid 2-Related Factor 2 (NRF2) mRNA levels were increased by GSPE. In conclusion, this study showed that GSPE might be an effective dietary supplement for improving cholesterol metabolism and antioxidant status in finishing pigs.

Effect of Grape Seed Proanthocyanidins Supplement on the Incidence of Recurrent Urinary Tract Infections in a Sample of Iraqi Diabetic Patients

Background: Proanthocyanidin is often used to prevent urinary tract infections (UTIs) in susceptible E. coli strains. Objective: To explore how grape seed proanthocyanidin extract (GSPE) affects type 2 diabetic patients (T2DM) with recurrent urinary tract infections (rUTIs). Method: The efficacy of GSPE in the treatment of T2DM with rUTIs was assessed in this randomized, single-blind controlled study. Sixty adults with diagnosed T2DPs and urinary tract infections were randomly assigned to treatment for 12 weeks with metformin (0.5 g t.i.d.) in Group A (Control Group) and a combination of GSPE (300 mg q.d.) and metformin (0.5 g t.i.d.), Group B, with the end of follow-up being 24 weeks, according to the study. Results: The medicinal plant GSPE reduces the recurrence of urinary tract infections in patients with T2DM after 12 weeks of treatment, compared with pre-treatment values and the control group. After 12 weeks of treatment for T2DM, fasting plasma glucose levels, creatinine, urea, and uric acid in both groups decreased non-significantly compared to control. There were fewer recurrent UTIs in the intervention group (77.8%), the control group (48.1%), and the GSPE (7.1%), compared to the control group (12.7%), the GSPE (7.1%), and the intervention group (33.7%) over the course of 24 weeks. Conclusions: Utilizing GSPE to treat, prevent, and minimize recurrent urinary tract infections in T2DM will help them better grasp the benefits and hazards associated with the daily administration of an appropriate GSPE dose.

Sex Differences in the Absorption, Disposition, Metabolism, and Excretion of Grape Seed Proanthocyanidins in Prepubescent Rats.

The absorption, disposition, metabolism, and excretion (ADME) of phenolic compounds are key factors in determining their bioactivity. The group demonstrates that the ADME of a Grape Seed Proanthocyanidin Extract (GSPE) depends on sex in adult rats and specifically, methylated metabolites are only quantified in brain male adult rats. The aim of this study is to determine whether these differences exist before puberty. Prepubescent 4-week-old male and female Wistar rats are administered GSPE at a dose of 1000mgkg-1. Plasma, liver, mesenteric white adipose tissue (MWAT), brain, and kidneys are extracted excised 2h after GSPE administration, and the PAs metabolite profile is studied by HPLC-ESI-MS/MS. Moreover, plasma estradiol and brain and liver catechol-O-methyltransferase (COMT) protein levels are also studied. Results showed that there are no differences in plasma and brain among sexes and only differences are observed in liver, MWAT, and kidney with individual metabolites. This agrees with the lack of differences in estradiol and COMT levels among sexes. However, the ADME of PAs metabolites is higher in male rats. The results demonstrate lack of sex-dependence in metabolite profile in prepubescent rats, suggesting that sex differences in the metabolism of GSPE occur due to puberty.

Grape Seed Proanthocyanidin Extract Attenuates Cafeteria-Diet-Induced Liver Metabolic Disturbances in Rats: Influence of Photoperiod.

This study investigated the influence of photoperiod (day length) on the efficacy of grape seed proanthocyanidin extract (GSPE) in mitigating metabolic disorders in obese rats fed a cafeteria diet. Rats were exposed to standard (L12), long (L18), or short (L6) photoperiods and treated with GSPE or vehicle. In the standard photoperiod, GSPE reduced body weight gain (50.5%), total cholesterol (37%), and triglycerides (34.8%), while increasing the expression of hepatic metabolic genes. In the long photoperiod, GSPE tended to decrease body weight gain, increased testosterone levels (68.3%), decreased liver weight (12.4%), and decreased reverse serum amino acids. In the short photoperiod, GSPE reduced glycemia (~10%) and lowered triglyceride levels (38.5%), with effects modified by diet. The standard photoperiod showed the greatest efficacy against metabolic syndrome-associated diseases. The study showed how day length affects GSPE's benefits and underscores considering biological rhythms in metabolic disease therapies.

Evaluating the Renal and Splenic Protective Effects of Grape Seed Proanthocyanidin Extract in Diethylnitrosamine-Induced Male Sprague Dawle

Evaluating the Renal and Splenic Protective Effects of Grape Seed Proanthocyanidin Extract in Diethylnitrosamine-Induced Male Sprague Dawle

Grape seed proanthocyanidin extract promotes skeletal muscle fiber type transformation through modulation of cecal microbiota and enhanced butyric acid production.

The conversion of fast-twitch fibers into slow-twitch fibers within skeletal muscle plays a crucial role in improving physical stamina and safeguarding against metabolic disorders in individuals. Grape seed proanthocyanidin extract (GSPE) possesses numerous pharmacological and health advantages, effectively inhibiting the onset of chronic illnesses. However, there is a lack of research on the specific mechanisms by which GSPE influences muscle physiology and gut microbiota. This study aims to investigate the role of gut microbiota and their metabolites in GSPE regulation of skeletal muscle fiber type conversion. In this experiment, 54 male BALB/c mice were randomly divided into three groups: basal diet, basal diet supplemented with GSPE, and basal diet supplemented with GSPE and antibiotics. During the feeding period, glucose tolerance and forced swimming tests were performed. After euthanasia, samples of muscle and feces were collected for analysis. The results showed that GSPE increased the muscle mass and anti-fatigue capacity of the mice, as well as the expression of slow-twitch fibers. However, the beneficial effects of GSPE on skeletal muscle fibers disappeared after adding antibiotics to eliminate intestinal microorganisms, suggesting that GSPE may play a role by regulating intestinal microbial structure. In addition, GSPE increased the relative abundance of Blautia, Muribaculaceae, and Enterorhabdus, as well as butyrate production. Importantly, these gut microbes exhibited a significant positive correlation with the expression of slow-twitch muscle fibers. In conclusion, supplementation with GSPE can increase the levels of slow-twitch fibers by modulating the gut microbiota, consequently prolonging the duration of exercise before exhaustion. PRACTICAL APPLICATION: This research suggests that grape seed proanthocyanidin extract (GSPE) has potential applications in improving physical stamina and preventing metabolic disorders. By influencing the gut microbiota and increasing butyric acid production, GSPE contributes to the conversion of fast-twitch muscle fibers into slow-twitch fibers, thereby enhancing anti-fatigue capacity and exercise endurance. While further studies are needed, incorporating GSPE into dietary supplements or functional foods could support individuals seeking to optimize their exercise performance and overall metabolic health.

Hawthorn Proanthocyanidin Extract Inhibits Colorectal Carcinoma Metastasis by Targeting the Epithelial-Mesenchymal Transition Process and Wnt/β-Catenin Signaling Pathway.

Colorectal carcinoma (CRC) is a major global health concern, with cancer metastasis being the main cause of patient mortality, and current CRC treatments are challenged by drug resistance. Although natural compounds, especially in foods like hawthorn proanthocyanidin extract (HPOE), have good anticancer activity, their effects on CRC metastasis remain unknown. Therefore, our objective was to investigate the impact and potential mechanisms of HPOE on the movement and infiltration of cells in the HCT116 CRC cells. Firstly, scratch-healing experiments confirmed the anti-migratory and anti-invasive capabilities of HPOE. Then, network pharmacology identified 16 possible targets, including MMP-9. Subsequently, RT-qPCR and Western blotting experiments confirmed that HPOE downregulated epithelial-mesenchymal transition-related factors (N-cadherin and MMP-9) and inhibited Wnt/β-catenin pathway activation. Finally, these results were experimentally validated using the Wnt pathway activator Licl and inhibitor XAV939. It was confirmed that HPOE had a certain inhibitory effect on the activation of the Wnt signaling pathway caused by the activator Licl and could enhance the inhibitory effect of the inhibitor XAV939. Our findings provide a basis for developing functional foods or dietary supplements, especially positioning HPOE as a functional food raw material for adjuvant treatment of CRC, given its ability to inhibit metastasis through the Wnt/β-catenin pathway.

Grape Seed Proanthocyanidins Protect Pancreatic β Cells Against Ferroptosis via the Nrf2 Pathway in Type 2 Diabetes

Pancreatic β cell damage is the primary contributor to type 2 diabetes mellitus (T2DM); however, the underlying mechanism remains nebulous. This study explored the role of ferroptosis in pancreatic β cell damage and the protective effects of grape seed proanthocyanidin extract (GSPE). In T2DM model rats, the blood glucose, water intake, urine volume, HbA1c, and homeostasis model assessment-insulin resistance were significantly increased, while the body weight and the insulin level were significantly decreased, indicating the successful establishment of the T2DM model. MIN6 mouse insulinoma β cells were cultured in high glucose and sodium palmitate conditions to obtain a glycolipid damage model, which was administered with GSPE, ferrostatin-1 (Fer-1), or nuclear factor erythroid 2-related factor 2 (Nrf2) small interfering (si) RNA. GSPE and Fer-1 treatment significantly improved pancreatic β-cell dysfunction and protected against cell death. Both treatments increased the superoxide dismutase and glutathione activity, reduced the malondialdehyde and reactive oxygen species levels, and improved iron metabolism. Furthermore, the treatments reversed the expression of ferroptosis markers cysteine/glutamate transporter (XCT) and glutathione peroxidase 4 (GPX4) caused by glycolipid toxicity. GSPE treatments activated the expression of Nrf2 and related proteins. These effects were reversed when co-transfected with si-Nrf2. GSPE inhibits ferroptosis by activating the Nrf2 signaling pathway, thus reducing β-cell damage and dysfunction in T2DM. Therefore, GSPE is a potential treatment strategy against T2DM.Graphical

Dietary short-term supplementation of grape seed proanthocyanidin extract improves pork quality and promotes skeletal muscle fiber type conversion in finishing pigs

Plant extracts are commonly used as feed additives to improve pork quality. However, due to their high cost, shortening the duration of supplement use can help reduce production costs. In this study, we aimed to investigate the effects of grape seed proanthocyanidin extract (GSPE) on meat quality and muscle fiber characteristics of finishing pigs during the late stage of fattening, which was 30 days in our experimental design. The results indicated that short-term dietary supplementation of GSPE significantly reduced backfat thickness, but increased loin eye area and improved meat color and tenderness. Moreover, GSPE increased slow myosin heavy chain (MyHC) expression and malate dehydrogenase (MDH) activity, while decreasing fast MyHC expression and lactate dehydrogenase (LDH) activity in the Longissimus thoracis (LT) muscle. Additionally, GSPE increased the expression of Sirt1 and PGC-1α proteins in the LT muscle of finishing pigs and upregulated AMP-activated protein kinase α 1 (AMPKα1), AMPKα2, nuclear respiratory factor 1 (NRF1), and calcium/calmodulin-dependent protein kinase kinase β (CaMKKβ) mRNA expression levels. These findings suggest that even during the late stage of fattening, GSPE treatment can regulate skeletal muscle fiber type transformation through the AMPK signaling pathway, thereby affecting the muscle quality of finishing pigs. Therefore, by incorporating GSPE into the diet of pigs during the late stage of fattening, producers can enhance pork quality while reducing production costs.

Grape seed proanthocyanidin extract alleviates inflammation in experimental colitis mice by inhibiting NF-κB signaling pathway.

Ulcerative colitis (UC) is a complex inflammatory disease of colorectum that induces abnormal immune responses and severely affects the quality of life of the patients. Grape seed proanthocyanidin extract (GSPE) exerts anti-inflammatory and antioxidant functions in many inflammatory diseases. The objective of this study was to investigate the potential therapeutic effects and underlying mechanisms of GSPE in UC using a dextran sodium sulfate (DSS)-induced mouse UC model and a lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage model. In this study, we found that the GSPE markedly prevented DSS-induced weight loss and colon length shortening in UC mice. Further investigations showed that GSPE significantly attenuated the expression of pro-inflammatory cytokines TNF-α, IL-6, and IL-1β, and elevated the expression of anti-inflammatory cytokine IL-10 in the colon tissues and serum of DSS-induced colitis mice by suppressing NF-κB signaling pathway. Furthermore, LPS-induced inflammation in RAW264.7 cells was also reversed by GSPE. Taken together, our results confirm that GSPE can ameliorate inflammatory response in experimental colitis via inhibiting NF-κB signaling pathway. This study advances the research progress on a potentially effective therapeutic strategy for inflammatory bowel diseases.

Immunomodulatory effects of aflatoxin B1 (AFB1) and the use of natural products to ameliorate its immunotoxic effects: A review

Aflatoxin B1 (AFB1), a potent mycotoxin, is known to be an immunotoxic agent that causes various immune system disorders. It can cause immunosuppression by direct toxic effect on the host or by its ability to interfere with the immune response and thereby lead to secondary infections. The immunomodulatory effects of AFB1 and its metabolites have been reported in many studies. Yet, the exact mechanisms responsible for these immunomodulatory effects are still obscure. This review summarizes the current findings on the interaction between AFB1 and the host immune system, while also highlighting other potential mechanisms involved in AFB1-induced immunosuppression. These potential mechanisms include modulation of cytokine production, production of inflammatory mediators and their receptors, activation of pro-inflammatory pathways, alteration in cell surface receptors involved in T cell activation and regulation of apoptosis. The review also discusses recent findings on natural products that have been found capable of inhibiting AFB1-induced immunosuppression in various animal models. With the latest exploration of natural products as a solution, the burden of aflatoxicosis in society is likely to subdue. Some of the promising natural products that have been highlighted to have ameliorative effects include grape seed proanthocyanidin extract (GSPE), bentonite clay, NovaSil Clay and Spirulina plantesis among others. Considering the seriousness of aflatoxicosis in the public domain and lack of effective management approaches, there is an urgent need for more research to understand AFB1-induced immunotoxicity and possible remedies.

Abrupt Photoperiod Changes Differentially Modulate Hepatic Antioxidant Response in Healthy and Obese Rats: Effects of Grape Seed Proanthocyanidin Extract (GSPE)

Disruptions of the light/dark cycle and unhealthy diets can promote misalignment of biological rhythms and metabolic alterations, ultimately leading to an oxidative stress condition. Grape seed proanthocyanidin extract (GSPE), which possesses antioxidant properties, has demonstrated its beneficial effects in metabolic-associated diseases and its potential role in modulating circadian disruptions. Therefore, this study aimed to assess the impact of GSPE administration on the liver oxidant system of healthy and diet-induced obese rats undergoing a sudden photoperiod shift. To this end, forty-eight photoperiod-sensitive Fischer 344/IcoCrl rats were fed either a standard (STD) or a cafeteria diet (CAF) for 6 weeks. A week before euthanizing, rats were abruptly transferred from a standard photoperiod of 12 h of light/day (L12) to either a short (6 h light/day, L6) or a long photoperiod (18 h light/day, L18) while receiving a daily oral dose of vehicle (VH) or GSPE (25 mg/kg). Alterations in body weight gain, serum and liver biochemical parameters, antioxidant gene and protein expression, and antioxidant metabolites were observed. Interestingly, GSPE partially ameliorated these effects by reducing the oxidative stress status in L6 through an increase in GPx1 expression and in hepatic antioxidant metabolites and in L18 by increasing the NRF2/KEAP1/ARE pathway, thereby showing potential in the treatment of circadian-related disorders by increasing the hepatic antioxidant response in a photoperiod-dependent manner.

Dietary grape seed proanthocyanidin extract improved the chemical composition, antioxidant capacity, myofiber growth and flesh quality of Nile tilapia muscle

The effects of dietary grape seed proanthocyanidin extract (GSPE) supplementation (0, 100, 200, and 400 mg/kg) on the stress response, antioxidant status, myofiber growth, and meat quality of Nile tilapia were investigated in present study. Dietary GSPE lowered serum stress-related parameters (cortisol, glucose, Na+, and lactate) and improved the total antioxidant capability with enhanced superoxide dismutase and catalase activities and reduced levels of reactive oxygen species. Meanwhile, myoglobin content, pH, color, tenderness, the water-holding capacity were improved. Dietary GSPE also increased the contents of delicious amino acids, flavor amino acids, and total amino acids, C18:3n-3 (ALA), C20:5n-3 (EPA), n-3 poly-unsaturated fatty acids, decreasing off-flavor compounds such as aldehydes and alcohols. Moreover, GSPE supplementation improved myofiber growth and muscle protein deposition likely via the activation of the IGFs/PI3K/Akt/TOR/S6K1/4E-BP1 pathway, contributing to the enhanced growth performance of Nile tilapia (Oreochromis niloticus). Together, GSPE is a promising natural food additive that enhances various important meat quality parameters of fish, and the optimal dietary GSPE requirement for maximum growth and muscle protein deposition was approximately 280 mg/kg.

Grape seed proanthocyanidin extract modulates cigarette smoke extract-induced epithelial cell apoptosis by inhibiting oxidative stress in chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a progressive, irreversible, inflammatory lung disease characterized by airway inflammation and emphysema. Cigarette smoke-induced oxidative stress and apoptosis of alveolar epithelial cells (AECs) are key factors in COPD pathogenesis. We investigated the effects of grape seed proanthocyanidin extract (GSPE) on cigarette smoke extract (CSE)-induced AEC apoptosis, emphysema, and inflammation. We exposed mice to CSE and evaluated histological changes, reactive oxygen species production, proinflammatory cytokine expression, and apoptosis levels in the lungs and AECs. GSPE exerted protective effects against CSE-induced COPD. The levels of reactive oxygen species were by GSPE in vitro and in vivo. GSPE significantly decreased the levels of reactive oxygen species in vitro and in vivo and reduced the number of macrophages, neutrophils and levels of cytokines in the bronchoalveolar lavage fluid and AECs, ameliorating lung inflammation. GSPE ameliorated the CSE-induced COPD development by inhibiting oxidative stress-induced epithelial cell apoptosis.

Exploring separation patterns and mechanisms of proanthocyanidins in grape seeds and pomace with diverse molecular weights, compositions, and structures

The function of proanthocyanidins (PAs) relies on their structure and requires high-purity PAs. Though Sephadex LH-20 gel permeation chromatography (GPC) is expected to separate PAs based on structure, its usage rules and mechanisms remain unclear. This study delves into the PAs separation patterns on Sephadex LH-20, first confirming the purification mechanisms of PAs with various mean degrees of polymerization (DP) using the adsorption kinetic model. The study found that an increase in the molecular weight or mean DP of PAs results in decreased polarity, reduced hydrogen bonding actions, and intensified hydrophobic effect, causing delayed extraction of PAs on Sephadex LH-20, with galloylated PA as an exception, which was extracted first despite its high DP. Additionally, the principles for separating specific composition, such as monomers, dimers, etc., were evaluated. The study sheds light on enhancing the purification efficiency of PAs, thus advancing the precise separation technology of diverse proanthocyanidins.

Proanthocyanidin-rich extract from Pinus radiata bark: Mild-alkaline extraction and characterization

This study assessed the efficacy of mild-alkaline extraction from P. radiata bark in obtaining proanthocyanidin (PA)-rich extracts. When the bark was treated with three types of bases—Na2CO3, NaHCO3, and NaOH—at varying concentrations, the extract yields increased with higher concentrations. When the pH of the extracts exceeded 7, the PA content and antioxidant activity were remarkably reduced. This result suggests that the pH holds a greater effect in the alkaline extraction of the bark rather than the type of base used. Among the bases used, NaHCO3 was selected and the extraction conditions of pine bark were examined at a concentration where the pH of the extract did not exceed 7. The extraction time during mild-alkaline extraction using 0.2% NaHCO3 was reduced compared to water-only extraction at the same temperature. Moreover, the extract yields were over 10% higher than those of water extraction, and the dried extracts exhibited good solubility in water. The mild-alkaline extracts were characterized using FT-IR and 13C NMR spectroscopic techniques, and acidic alcoholysis. Analyses of the spectra of the mild-alkaline extracts showed similarities to that of pure PA and hot water extract. This result indicated that PA in the bark was not significantly affected during mild-alkaline extraction.

Performance of microwave-assisted extraction of proanthocyanidins from red sorghum grain in various power and citric acid concentration

Performance of microwave-assisted extraction of proanthocyanidins from red sorghum grain in various power and citric acid concentration