Purification and identification of buckwheat hull flavonoids and its comparative evaluation on antioxidant and cytoprotective activity in vitro

Inhibition mechanism of buckwheat hulls polyphenols on α-amylase and α-glucosidase using kinetics, spectroscopics and molecular docking approaches

The work investigated the activity inhibition of phenolic compounds in buckwheat (Fagopyrum esculentum Moench) hulls (BH) on α-amylase and α-glucosidase, and clarified their possible mechanisms based on kinetics, spectroscopics and molecular docking analysis. The total polyphenols (BHP) from BH using an ultrasound-assisted alcohol extraction method was 210.50 mg GAE/g DW. The study identified a total of 33 polyphenolic compounds in the extracts of BH using UPLC-Q-Exactive Orbitrap/MS, revealing that sixteen of these were novel polyphenolic substances not previously documented in this plant. BHP demonstrated significant inhibitory effects on both α-amylase and α-glucosidase enzymes, with IC50 values recorded at 27.16 μg/mL and 7.00 μg/mL, respectively, suggesting noncompetitive and mixed-type inhibition mechanisms. The fluorescence intensity of the enzymes was effectively quenched by BHP through a combination of dynamic and static quenching mechanisms, driven predominantly by hydrophobic interactions. BHP's interaction with the enzymes resulted in conformational changes that reduced their enzymatic activities. Molecular docking further revealed that six polyphenolic components of BHP had a strong affinity for binding with the active sites nestled in the enzymes' hydrophobic cavities, inhibiting their activity and potentially contributing to a reduction in blood glucose levels. The results could provide perspective for using BHP in the functional components of sugar-controlling foods.

Potential Implications of Hyperoside on Oxidative Stress-Induced Human Diseases: A Comprehensive Review

Hyperoside is a flavonol glycoside mainly found in plants of the genera Hypericum and Crataegus, and also detected in many plant species such as Abelmoschus manihot, Ribes nigrum, Rosa rugosa, Agrostis stolonifera, Apocynum venetum and Nelumbo nucifera. This compound exhibits a multitude of biological functions including anti-inflammatory, antidepressant, antioxidative, vascular protective effects and neuroprotective effects, etc. This review summarizes the quantification, original plant, chemical structure and property, structure-activity relationship, pharmacologic effect, pharmacokinetics, toxicity and clinical application of hyperoside, which will be significant for the exploitation for new drug and full utilization of this compound.

Cytotoxic flavone-C-glycosides from the leaves of Dypsis pembana (H.E.Moore) Beentje & J.Dransf., Arecaceae: in vitro and molecular docking studies

BACKGROUND

Cancer poses a health threat, with an increased incidence worldwide. Thus, it is essential to develop new natural anticancer agents. Dypsis pembana (H.E.Moore) Beentje & J.Dransf (DP) is an ornamental plant belonging to the family Arecaceae. This study aimed to isolate and identify phytoconstituents from the leaves of this plant and evaluate their in vitro cytotoxic activities.

METHODS

Different chromatographic techniques were applied to fractionate the hydro-alcoholic extract of DP and separate the major phytoconstituents. The isolated compounds were structurally elucidated based on their physical and spectroscopic data. The in vitro cytotoxic activities of the crude extract and fractions thereof were evaluated against human colon carcinoma (HCT-116), human breast carcinoma (MCF-7), and human hepatocellular carcinoma (HepG-2) cell lines via MTT assay. Moreover, selected isolates were tested against HepG-2 cell line. Molecular docking analysis was performed to investigate the interactions of these compounds with two potential targets, the human topoisomerase IIα and cyclin-dependent kinase 2 enzymes.

RESULTS

Thirteen diverse compounds were reported for the first time from DP, providing significant chemotaxonomic biomarkers. Among tested compounds, vicenin-II (7) was the most cytotoxic against HepG-2 cell line, with an IC₅₀ value of 14.38 µg/mL, followed by isovitexin (13) (IC₅₀ of 15.39 µg/mL). These experimental findings were complemented by molecular docking, which demonstrated that vicenin-II exhibited superior enzyme-binding affinities to the studied vital targets and shed light on the structure-activity relationships among the investigated flavone-C-glycosides members.

CONCLUSION

The phytochemical profile of DP was characterized for the first time, reflecting chemotaxonomic data about the concerned species, genus, or even the family. Biological and computational findings revealed that vicenin-II and isovitexin are possible lead structures as inhibitors of the human topoisomerase IIα and cyclin-dependent kinase 2 enzymes.

Optimization of Extraction of Compound Flavonoids from Chinese Herbal Medicines Based on Quantification Theory and Evaluation of Their Antioxidant Activity

Plant-derived flavonoids have been attracting increasing research interest because of their multiple health promoting effects, where numerous investigations were carried out on the optimization of extraction and bioactivities. This study aims to optimize the extraction process of compound flavonoids (CFs) from Chinese herbal medicines and detect their antioxidant activity in vitro. CFs were extracted from the raw materials named “medicine food homology,” composed of hawthorn, lotus leaf, tartary buckwheat, cassia seed, Lycium barbarum, and Poria cocos in a mass ratio of 4 :  2 :  2 :  1.5 :  1 :  1. L9 (34) orthogonal design, level effect and engineering average estimation, and quantification theory were utilized to improve the extraction method of CFs, and the predictive model for CFs yield was constructed. The 2,2ʹ-diphenyl-1-picrylhydrazyl (DPPH), 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS), hydroxyl radical scavenging rate, and reducing power of CFs were measured. The highest CFs yield was obtained under the following extraction condition: liquid-solid ratio of 35 : 1 mL/g, extraction temperature of 75°C, extraction duration of 75 min, and extraction mode enzyme-assisted extraction. The forecasted yield was 37.62%. The result was accurate and the established prediction equation was reliable (R = 0.95). The antioxidant activity of CFs was significantly positively correlated with the concentration from 0.05 to 0.4 mg/mL. The DPPH, ABTS, hydroxyl radical scavenging abilities, and the reducing power of CFs were 81.82 ± 1.75%, 49.35 ± 0.09%, 89.78 ± 0.66%, and 0.232 ± 0.001 at the concentration of 0.4 mg/mL, respectively. CFs could be exploited as natural antioxidants in pharmaceuticals and functional foods.

Buckwheat Hull-Enriched Pasta: Physicochemical and Sensory Properties

This work aimed to evaluate the effect of partial replacement of semolina with 0, 1, 5, 10, 15, and 20% of ground buckwheat hull (BH) on the chemical composition, antioxidant properties, color, cooking characteristics, and sensory properties of wheat pasta. Pasta samples were prepared by dough lamination (tagliatelle shape) and dried at 55 °C until the moisture content was 11–12% (wet basis). Analyses of samples showed that the addition of BH caused an increase in fiber content in pasta from 4.31% (control pasta) to 14.15% (pasta with 20% of BH). Moreover, the brightness and yellowness of BH-enriched products were significantly decreased compared to the control sample, and the total color difference ranged from 23.84 (pasta with 1% of BH) to 32.56 (pasta with 15% BH). In addition, a decrease in optimal cooking time, as well as an increased weight index and cooking loss, was observed in BH-enriched pasta samples. Furthermore, BH-enriched cooked pasta had significantly higher total phenolic content and antioxidant activity but an unpleasant smell and taste, especially if the level of BH was higher than 10%.

A Risk and Hazard Analysis Model for the Production Process of a New Meat Product Blended With Germinated Green Buckwheat and Food Safety Awareness

This study was specifically designed for a small-scale meat processing enterprise “DARIYA” to set up a specific HACCP plan for the new product (patties) made from mixed horsemeat with vegetable components developed in the Department of Technology of Food Production and Biotechnology, Shakarim University of Semey. Critical control points (CCPs) were identified and applied in the HACCP plan. The different hazards were detected at each processing step, whereas each CCP in the HACCP plan was identified and accompanied with the appropriate significant hazard, critical limit, monitoring of the CCP, and corrective actions, confirming that the enterprise has fully employed the HACCP methodology and ISO 22000:2018. Our results indicate that during almost 1 year following the implementation of ISO 22000:2018, the coliform level of tested patties significantly dropped (p < 0.05) after 6 months of implementation (coliform count dropped from 4.4 MPN/g to 1.8 MPN/g). The rapid screening of the bacterial count, heavy metals, pesticide residue, and physical contamination levels also improved monitoring assertiveness, allowing them to deal with foreseeable issues linking to resources and guarantee product quality. Cesium-137 was recorded as 5.4 ± 2.9627 Bq/kg in horsemeat and 6.7 ± 2.7045 in poultry. The activity of cesium-137 did not exceed the MAC. This result discloses that prompt screening is the foremost and necessary step for small enterprises. According to this study, the “acceptance of raw materials” is the most important CCP, and their control, particularly in small-scale meat processing enterprises, can actually prevent many negative outcomes. The implementation of both standards improved food quality by declining the flaw rates for patties, and the number of flow inconsistencies needed for correction in the process also dropped significantly (p < 0.05), demonstrating that safety and quality points were improving. If the application of the HACCP plan were to continue over an extended period of time, the Food Safety Management System's (FSMS) benefits would be more substantial improvements to a greater number of items being monitored. The process of implementing HACCP principles and ISO 22000:2018 could be arduous but achievable enough to be used in small industries with significant outcomes.

Postharvest UV-C irradiation inhibits blackhead disease by inducing disease resistance and reducing mycotoxin production in 'Korla' fragrant pear (Pyrus sinkiangensis)

Blackhead disease is a major fungal disease causing the quality deterioration of postharvest 'Korla' fragrant pear. In this study, the relationships of resistance to blackhead disease with the enzyme activity, phenolic compounds, and mycotoxin metabolism of 'Korla' fragrant pear were investigated, through UV-C irradiation of 0.12, 0.24, 0.36, 0.48, 0.72 and 1.08 kJ/m² on 'Korla' fragrant pear inoculated with Alternaria alternata (Fries) Keissler (A. alternata). The results showed that the low-dose UV-C irradiation (0.36 kJ/m²) effectively controlled blackhead disease. The activities of chitinase (CHI), β-1,3-glucanase (GLU), peroxidase (POD), superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), phenylalanine ammonia-lyase (PAL), and the content of phenolic compounds in fruit were enhanced, whereas the activities of lipoxygenase (LOX), polyphenol oxidase (PPO), and the contents of hydrogen peroxide (H₂O₂) and mycotoxins (including AOH, AME, and TeA) were decreased. Therefore, the low-dose UV-C irradiation could improve the resistance to blackhead disease and reduce the production of mycotoxins in 'Korla' fragrant pear. This study proves that UV-C irradiation may be a potentially effective strategy for the control of blackhead disease and the improvement of quality of postharvest 'Korla' fragrant pear.

Hepatoprotective effects of flavonoids from common buckwheat hulls in type 2 diabetic rats and HepG2 cells

Flavonoids from common buckwheat hulls (BHFs) show significant antioxidant and antidiabetic potential. However, their hepatoprotective property is yet to be defined. This study aims to examine the hepatoprotective effect of BHFs in type 2 diabetes mellitus (T2DM) rats and chronic high glucose-damaged HepG2 cells. Results showed that BHF treatment significantly relieves the state of insulin resistance, thereby reducing blood glucose and improving oxidative stress in T2DM rats. It is worth mentioning that BHF treatment improved diabetes-induced liver damage disorders, manifested as the clearance of liver fat and the decline of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. In vitro, HepG2 cells pretreated with BHFs maintained higher superoxide dismutase (SOD), glutathione peroxidase (GSH-px), and catalase (CAT) activities than the unprotected group. In parallel, compared with the unprotected group, BHFs significantly reduced the leakage of ALT and AST in pre-protected group dose-dependently. These results indicated that BHFs had considerable antioxidant and hepatoprotective potential and could be promising to be used as nutraceuticals and dietary supplements to prevent and/or protect against liver disorders.

Flavonoids derived from buckwheat hull can break advanced glycation end-products and improve diabetic nephropathy

Diabetic nephropathy (DN) is the most important complication in patients with diabetes. The accumulation of advanced glycation end-products (AGEs) is the main reason for the development of DN. In this study, we investigated the mechanism of buckwheat hull flavonoids to break AGEs in vitro by measuring fluorescence analysis, three-dimensional fluorescence, protein molecular weight, free amino groups, and the sulfhydryl group content. Proteomics analysis was used to determine the effect of total buckwheat hull flavonoids (TBHF) intervention on protein differential expression in the kidney of db/db mice. The results showed that buckwheat hull flavonoids were potent in breaking AGEs in vitro, and they protected mice kidneys by regulating the renal AGE-RAGE pathway. This study lays a strong experimental and theoretical foundation for the development of new lysing agents to break AGEs. The findings should make an important contribution to the field of flavonoids in improving the application of diabetic nephropathy in the diet.