Xanthine oxidase inhibitory activity and antihyperuricemic effect of Moringa oleifera Lam. leaf hydrolysate rich in phenolics and peptides

Investigating the Role of Food-Derived Peptides in Hyperuricemia: From Mechanisms of Action to Structural Effects

Hyperuricemia, a disorder of purine metabolism associated with cardiovascular disease, gout, and kidney disease, can be alleviated by food-derived peptides. However, the precise mechanisms remain unclear, hindering their development. This study reviews uric acid-lowering peptides from various sources, focusing on two pathways: inhibiting uric acid production and promoting excretion. Low-molecular-weight peptides (<1000 Da) exhibited superior uric acid-lowering effects. We further explored the relationships between amino acid composition and their target interactions. Peptides rich in cyclic amino acids (tryptophan, phenylalanine, and histidine) and containing small amounts of linear amino acids (leucine, cysteine, and glycine) demonstrated significant potential for lowering uric acid. These findings provide theoretical support for developing novel functional foods for the management of hyperuricemia.

Recent Advances in the Application of Foodborne Substances in Hyperuricemia

Hyperuricemia (HUA) is a purine metabolism disorder characterized by the excessive production or inadequate excretion of uric acid. Current pharmacological strategies targeting uric acid reduction have potential adverse effects. Following the concept of "homology of medicine and food", food ingredients are increasingly being explored to prevent HUA and gout, with xanthine oxidase (XOD) emerging as a crucial therapeutic target in managing HUA. Recent scientific investigations have determined that uric acid-lowering substances come from various food sources, such as seafood, dairy products, and agricultural products. These bioactive substances have attracted wide attention because of their effective antihyperuricemia and XOD inhibitory ability. In this study, the pathogenesis, many side effects of uric acid-lowering drugs, and some components of uric acid-lowering drugs are mainly described, with emphasis on the source, composition, preparation technology, and mechanism of uric acid-lowering peptides.

Regulation of redox enzymes by nutraceuticals: a review of the roles of antioxidant polyphenols and peptides

Redox enzymes are essential components of the cellular defence system against oxidative stress, which is a common factor in various diseases. Therefore, understanding the role of bioactive nutraceuticals in modulating the activity of these enzymes holds immense therapeutic potential. This paper provides a comprehensive review of the regulation of redox enzymes in cell and animal models by food-derived bioactive nutraceuticals, focusing on polyphenols and peptides. Specifically, this paper discusses the regulation of superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase (CAT), NAPDH oxidase, xanthine oxidase (XO), myeloperoxidase (MPO), and haem oxygenase (HO) in cell and animal models. Polyphenols, which are abundant in fruits, vegetables, and beverages, have diverse antioxidant properties, including direct scavenging of reactive oxygen species and regulation of transcription factors such as nuclear factor erythroid 2-related factor 2, which leads to the increased expression of the redoxenzymes SOD, HO, and GPx. Similarly, bioactive peptides from various food proteins can enhance antioxidative enzyme activity by regulating gene expression and directly activating the enzyme CAT. In other cases, an antioxidative response requires the downregulation or inhibition of the redox enzymes XO, MPO, and NAPDH oxidase. This paper highlights the potential of bioactive nutraceuticals in mitigating oxidative stress-related diseases and their mechanisms in modulating the redox enzyme expression or activity. Furthermore, the review highlights the need for further research to uncover new therapeutic strategies using nutraceuticals for enhancing cellular antioxidant defence mechanisms and improving health outcomes.

Food-derived bioactive peptides with anti-hyperuricemic activity: A comprehensive review

Hyperuricemia (HU) is a metabolic disorder caused by the overproduction or underexcretion of uric acid (UA) in the human body. Several approved drugs for the treatment of HU are available in the market; however, all these allopathic drugs exhibit multiple side effects. Therefore, the development of safe and effective anti-HU drugs is an urgent need. Natural compounds derived from foods and plants have the potential to decrease UA levels. Recently, food-derived bioactive peptides (FBPs) have gained attention as a functional ingredient owing to their biological activities. In the current review, we aim to explore the urate-lowering potential and the underlying mechanisms of FBPs. We found that FBPs mitigate HU by reducing blood UA levels through inhibiting key enzymes such as xanthine oxidase, increasing renal UA excretion, inhibiting renal UA reabsorption, increasing anti-oxidant activities, regulating inflammatory mediators, and addressing gut microbiota dysbiosis. In conclusion, FBPs exhibit strong potential to ameliorate HU.

Assessment of oral toxicity of Moringa oleifera Lam aqueous extract and its effect on gout induced in a murine model

Background and Aim

Although widely employed in traditional remedies globally, the safety and efficacy of Moringa oleifera remain inadequately documented through scientific research. This study evaluated the oral toxicity of M. oleifera leaf aqueous extract (MoAE) and its impact on gout-induced rats.

Materials and Methods

2000 mg/kg was given in a single dose during the acute oral toxicity test, while 100 mg/kg, 250 mg/kg, and 500 mg/kg were given daily for 28 days in the repeated dose toxicity test. 100 mg/kg, 250 mg/kg, and 500 mg/kg MoAE doses were administered during the assessment of its impact on gout caused by monosodium urate. In the hyperuricemia model induced by oxonic acid, serum uric acid levels were assessed and pain response was measured through acetic acid-induced writhing.

Results

In acute oral and 28-day repeated dose tests, no indications of toxicity were detected, while MoAE alleviated ankle joint swelling and reduced serum uric acid concentrations in arthritic rats, causing a significant reduction in acetic acid-induced contortions.

Conclusion

No acute oral toxicity or toxicity in 28-day repeated doses was found for MoAE, while it exhibited antiarthritic, antihyperuricemic, and pain-relieving effects in the murine model.

Anti-hyperuricemia bioactive peptides: a review on obtaining, activity, and mechanism of action

Hyperuricemia, a disorder of uric acid metabolism, serves as a significant risk factor for conditions such as hypertension, diabetes mellitus, renal failure, and various metabolic syndromes. The main contributors to hyperuricemia include overproduction of uric acid in the liver or impaired excretion in the kidneys. Despite traditional clinical drugs being employed for its treatment, significant health concerns persist. Recently, there has been growing interest in utilizing protein peptides sourced from diverse food origins to mitigate hyperuricemia. This article provides a comprehensive review of bioactive peptides with anti-hyperuricemia properties derived from animals, plants, and their products. We specifically outline the methods for preparing these peptides from food proteins and elucidate their efficacy and mechanisms in combating hyperuricemia, supported by in vitro and in vivo evidence. Uric acid-lowering peptides offer promising prospects due to their safer profile, enhanced efficacy, and improved bioavailability. Therefore, this review underscores significant advancements and contributions in identifying peptides capable of metabolizing purine and/or uric acid, thereby alleviating hyperuricemia. Moreover, it offers a theoretical foundation for the development of functional foods incorporating uric acid-lowering peptides.

Exploring the Role of Phenolic Compounds in Chronic Kidney Disease: A Systematic Review

Chronic kidney disease (CKD) presents a formidable global health concern, affecting one in six adults over 25. This review explores the potential of phenolic compounds in managing CKD and its complications. By examining the existing research, we highlight their diverse biological activities and potential to combat CKD-related issues. We analyze the nutritional benefits, bioavailability, and safety profile of these compounds. While the clinical evidence is promising, preclinical studies offer valuable insights into underlying mechanisms, optimal dosages, and potential side effects. Further research is crucial to validate the therapeutic efficacy of phenolic compounds for CKD. We advocate for continued exploration of their innovative applications in food, pharmaceuticals, and nutraceuticals. This review aims to catalyze the scientific community's efforts to leverage phenolic compounds against CKD-related challenges.

Therapeutic voyage of synthetic and natural xanthine oxidase inhibitors

Xanthine oxidase (XO) inhibitors are commonly used to treat gout, nephropathy, and renal stone diseases related to hyperuricemia. However, recent research has shown that these inhibitors may also have potential benefits in preventing vascular diseases, including those affecting the cerebrovasculature. This is due to emerging evidence suggesting that serum uric acid is involved in the growth of cardiovascular disease, and XO inhibition can reduce oxidative stress in the vasculature. There is a great interest in the development of new XO inhibitors for the treatment of hyperuricemia and gout. The present review discusses the many synthetic and natural XO inhibitors that have been developed which are found to have greater potency.

Moringa oleifera Lam.: a comprehensive review on active components, health benefits and application

Moringa oleifera Lam. is an edible therapeutic plant that is native to India and widely cultivated in tropical countries. In this paper, the current application of M. oleifera was discussed by summarizing its medicinal parts, active components and potential mechanism. The emerging products of various formats such as drug preparation and product application reported in the last years were also clarified. Based on literature reports, the unique components and biological activities of M. oleifera need to be further studied. In the future, a variety of new technologies should be applied to the development of M. oleifera products, to enrich the varieties of dosage forms, improve the bitter taste masking technology, and make it better for use in the fields of food and medicine.

Alternative Protein Sources and Novel Foods: Benefits, Food Applications and Safety Issues

The increasing size of the human population and the shortage of highly valuable proteinaceous ingredients has prompted the international community to scout for new, sustainable, and natural protein resources from invertebrates (e.g., insects) and underutilized legume crops, unexploited terrestrial and aquatic weeds, and fungi. Insect proteins are known for their nutritional value, being rich in proteins with a good balance of essential amino acids and being a valuable source of essential fatty acids and trace elements. Unconventional legume crops were found rich in nutritional, phytochemical, and therapeutic properties, showing excellent abilities to survive extreme environmental conditions. This review evaluates the recent state of underutilized legume crops, aquatic weeds, fungi, and insects intended as alternative protein sources, from ingredient production to their incorporation in food products, including their food formulations and the functional characteristics of alternative plant-based proteins and edible insect proteins as novel foods. Emphasis is also placed on safety issues due to the presence of anti-nutritional factors and allergenic proteins in insects and/or underutilized legumes. The functional and biological activities of protein hydrolysates from different protein sources are reviewed, along with bioactive peptides displaying antihypertensive, antioxidant, antidiabetic, and/or antimicrobial activity. Due to the healthy properties of these foods for the high abundance of bioactive peptides and phytochemicals, more consumers are expected to turn to vegetarianism or veganism in the future, and the increasing demand for such products will be a challenge for the future.

An Insight into Diverse Activities and Targets of Flavonoids

BACKGROUND

Flavonoids belong to the chemical class of polyphenols and are in the category of secondary metabolites imparting a wide protective effect against acute and chronic diseases.

OBJECTIVE

The study aims to investigate and summarize the information of various flavonoids extracted, isolated from various sources, and possess different pharmacological properties by acting on multiple targets.

METHODS

This comprehensive review summarizes the research information related to flavonoids and their pharmacological action targets from various sources like PubMed, Google Scholar and Google websites.

RESULTS

Extracted information in the paper discusses various therapeutic effects of flavonoids isolated from medicinal plant sources, which have the property to inhibit several enzymes, which finally results in health benefits like anti-cancer, anti-bacterial, antioxidant, anti-allergic, and anti-viral effects. This study also showed the different solvents and methods involved in the extraction and characterization of the isolated phytochemical constituents.

CONCLUSION

The findings showed the contribution of several flavonoids in the management and inhibition of various acute and chronic sicknesses by acting on different sites in the body. This study may lead to gaining interest for more research on the bioactives of different medicinal plants for the discovery of new lead compounds or further improvement of the efficacy of the existing compound.

The Therapeutic Effect and the Potential Mechanism of Flavonoids and Phenolics of Moringa oleifera Lam. Leaves against Hyperuricemia Mice

The aim of this study is to evaluate the anti-hyperuricemia effect and clarify the possible mechanisms of flavonoids and phenolics of MOL (MOL-FP) in mice. Hyperuricemia mice were generated via intraperitoneal (i.p.) administration of potassium oxonate (PO) and oral gavage (p.o.) of hypoxanthine (HX). Serum uric acid (UA), weight, serum XO activity, hepatic XO activity, urea nitrogen (BUN), creatinine (CRE), serum AST level, serum ALT level, mRNA expression of renal urate-anion transporter 1 (URAT1), glucose transporter 9 (GLUT9), organic anion transporters 1 (OAT1), organic anion transporters 3 (OAT3), and ATP-binding cassette transporter G2 (ABCG2) were determined. The molecular docking was conducted using AutoDock Vina 1.2.0 to screen potential XO inhibitors in MOL-FP. Serum metabolomics was established to collect the metabolic profiles of mice and explore the metabolic changes that occurred after MOL-FP treatment. MOL-FP could notably reduce the serum UA level of hyperuricemia mice by inhibiting XO activity and regulating renal urate transporters. Molecular docking studies indicated that 5-p-coumaroylquinic acid, 3-p-coumaroylquinic acid, and catechin could be potential XO inhibitors. Besides, MOL-FP prevented the pathological process of hyperuricemia by regulating biomarkers associated with purine metabolism, amino acid metabolism, and lipid metabolism.

Inhibitory effects of Moringa oleifera leaves extract on xanthine oxidase activity from bovine milk

Moringa oleifera is a tropical plant in the Moringaceae family that contains a lot of bioactive compounds. This study aimed to isolate and characterize the enzyme xanthine oxidase (XO), and conducted inhibitory tests on XO using methanol extracts of M. oleifera leaves. The xanthine oxidase enzyme isolated from bovine milk was characterized to determine the optimum pH, temperature, and substrate concentration. XO inhibition was evaluated by in vitro and in silico methods. The results of XO isolation and characterization of bovine milk showed the optimum conditions at pH 6.5, substrate concentration of 0.1 mM, and temperature 35 °C with an activity rate of 32.47 mU/mL; 21.55 mU/mL, and 21.94 mU/mL. Inhibition analysis results on methanol extract of M. oleifera leaves showed the highest activity decrease at the extract concentration of 160 ppm, with a relative inhibition value of 21.35%, while allopurinol as a positive control has a relative value inhibition of 61.21%. Relative value inhibition indicated the potential of M. oleifera leaves as a source of medicinal plants for gout sufferers. Additionally, a computational analysis was performed to observe the molecular interaction between the primary compounds of M. oleifera leaves, i.e., 5-O-acetyl-thio-octyl-β-L-rhamnofuranoside, quinic acid, and 2-dimethyl(trimethylsilylmethyl)silyloxymethyltetrahydrofuran, and XO using the molecular docking method. The finding implied that these compounds are bound to the catalytic sites of XO by hydrogen bonds and hydrophobic interactions, indicating the primary compounds of M. oleifera leaves could become XO inhibitors to treat gout disease.

Chemical Compounds, Antioxidant Activities, and Inhibitory Activities Against Xanthine Oxidase of the Essential Oils From the Three Varieties of Sunflower (Helianthus annuus L.) Receptacles

Background/Aim: Essential oils of sunflower receptacles (SEOs) have antibacterial and antioxidant potential. However, the differences of biological activities from the different varieties of sunflowers have not been studied till now. The purpose of this study was to compare the differences of chemical compounds, antioxidant activities, and inhibitory activities against xanthine oxidase (XO) of SEOs from the three varieties of sunflowers including LD5009, SH363, and S606.

Methods: SEOs were extracted by using the optimal extraction conditions selected by response surface methodology (RSM). Chemical compounds of SEOs were identified from the three varieties of sunflowers by gas chromatography-mass spectrometry (GC-MS). Antioxidant activities of SEOs were detected by 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and iron ion reduction ability. Inhibitory activities of SEOs against XO were measured by using UV spectrophotometer. XO inhibitors were selected from the main chemical compounds of SEOs by the high-throughput selections and molecular simulation docking.

Results: The extraction yields of SEOs from LD5009, SH363, and S606 were 0.176, 0.319, and 0.580%, respectively. A total of 101 chemical compounds of SEOs were identified from the three varieties of sunflowers. In addition, the results of inhibitory activities against XO showed that SEOs can reduce uric acid significantly. Eupatoriochromene may be the most important chemical compounds of SEOs for reducing uric acid. The results of antioxidant activities and inhibitory activities against XO showed that SEOs of LD5009 had the strongest antioxidant and XO inhibitory activities. The Pearson correlation coefficient (r > 0.95) showed that γ-terpinene, (E)-citral, and L-Bornyl acetate were highly correlated with the antioxidant activities and XO inhibitory ability.

Conclusion: SEOs had antioxidant activities and XO inhibitory ability. It would provide more scientific information for utilization and selection of varieties of sunflowers, which would increase the food quality of sunflowers and incomes of farmers.

Analysis of Risk Factors for Changes in the Renal Two-Dimensional Image in Gout Patients

OBJECTIVE

To explore the effects of different blood uric acid levels in gout patients on the two-dimensional image of the kidney and the risk factors for gout-related kidney damage for providing clinical evidence to enable early prevention and treatment of gout-related kidney damage.

METHODS

We obtained information of 227 patients with primary gout and estimated the association between two-dimensional kidney images and clinical indicators using binary logistic regression.

RESULTS

Our study showed that different uric acid levels, age, disease course, cystatin C (CysC) level, and γ-glutamyl transpeptidase level were correlated with echo of the renal medulla (P < 0.05). CysC level was correlated with the renal cortex thickness and kidney stones in different uric acid-level groups (P < 0.05). Disease course, aspartate transaminase (AST) level, creatinine (CREA) level, and tophi were risk factors for renal cortex thinning in gout patients (P = 0.045, 0.026, 0.004, 0.006, respectively). The disease course, platelet (PLT) count, and high-density lipoprotein (HDL-C) level were risk factors for kidney stone formation in gout patients (P = 0.037, 0.022, 0.023, respectively), while CysC level and C-reactive protein (CRP) level were risk factors for increased renal medulla echo in these patients (P = 0.022, 0.028, respectively).

CONCLUSION

Our study revealed disease course, AST level, CREA level, tophi, PLT count, HDL-C level, CysC level and CRP level may be important predictors of renal image changes.