Antioxidant, α-Glucosidase and Xanthine Oxidase Inhibitory Activity of Bioactive Compounds From Maize (Zea maysL.)

Structurally diverse specialized metabolites of maize and their extensive biological functions

Maize originated in southern Mexico and various hybrid varieties have been bred during domestication. All maize tissues are rich in specialized plant metabolites (SPMs), which allow the plants to resist the stresses of herbivores and pathogens or environmental factors. To date, a total of 95 terpenoids, 91 phenolics, 31 alkaloids, and 6 other types of compounds have been identified from maize. Certain volatile sesquiterpenes released by maize plants attract the natural enemies of maize herbivores and provide an indirect defensive function. Kauralexins and dolabralexins are the most abundant diterpenoids in maize and are known to regulate and stabilize the maize rhizosphere microbial community. Benzoxazinoids and benzoxazolinones are the main alkaloids in maize and are found in maize plants at the highest concentrations at the seedling stage. These two kinds of alkaloids directly resist herbivory and pathogenic infection. Phenolics enhance the cross-links between maize cell walls. Meanwhile, SPMs also regulate plant-plant relationships. In conclusion, SPMs in maize show a large diversity of chemical structures and broad-spectrum biological activities. We use these to provide ideas and information to enable the improvement of maize resistances through breeding and to promote the rapid development of the maize industry.

Use of human Caco-2 cells and HPAE-PAD for α-glucosidase assay

To measure α-glucosidase activity, rat intestinal acetone powder is commonly used as a source of α-glucosidase, and the mutarotase-glucose oxidase (GOD) methods commonly used to quantitate glucose produced by enzymatic hydrolysis of the substrates. In this study, we compared human Caco-2 cell extracts with rat intestinal acetone powder extracts. We also compared high-performance anion-exchange chromatography with pulsed amperometric detection (HPAE-PAD) with the mutarotase-GOD method. The sensitivity of HPAE-PAD was higher than that of mutarotase-GOD. The glucose concentration quantified by HPAE-PAD was similar to that quantified using the mutarotase-GOD method. In the maltase reaction, 1-deoxynojirimycin (1-DNJ) exerted a more potent inhibitory effect on human enzymes than on rat enzymes. This order was reversed during the sucrase reaction. These results suggested that the combined use of Caco-2 cell extracts and HPAE-PAD is advantageous for use in α-glucosidase-related basic research.

Ethnoveterinary practises of medicinal plants used for the treatment of different cattle diseases: A case study in East Khasi Hill district of Meghalaya, North East India

Introduction

For generations, the inhabitants of Meghalaya have relied on medicinal plants to maintain the health of their livestock and treat various illnesses that may afflict their animals. Due to the lack of survey for use and documentation, these plants have never been undertaken. Therefore, it is imperative to explore the diversity, utilization, and phytochemical profile of these plants and quantitatively analyse the data to identify important medicinal plants. By doing so, we can better understand the potential of these plants for developing novel drugs.

Methods

Frequent field trips were made for the collection of ethnoveterinary data of medicinal plants from local animal-keepers, traditional healers (THs) and inhabitants of different age groups. This information was gathered through semi-structured interviews, individual discussions, direct field-use observation, and questionnaires. A total of 52 informants (35 females and 17 males) were interviewed from seven rural villages and the information obtained from them were quantitatively analysed using the informant consensus factor (ICF), and fidelity level (FL). Additionally, for each documented plant, available published literature was extensively surveyed to identify the presence of bioactive chemical compounds responsible for their therapeutic effects.

Results

During the present study, a total 96 plants, distributed into 87 genera and 43 families were identified and recorded for their use in ethnoveterinary practices against more than 25 diseases. Out of the recorded plant species, the Fabaceae family was found to be the most dominant with seven species, followed by Poaceae and Lamiaceae with six species each, and Moraceae with five species. The leaves (50.00%) and seeds (12.50%) were the most frequently used plant parts, while the paste (30 species) was the common mode of application. Aegle marmelos Correa exhibited a fidelity level (FL) of 100% for indigestion, while Tagetes erecta L. had a fidelity level of 94.11% for wound treatment, making them the most promising candidates for further study. The highest FIC value of 1.00 was recorded for the treatment of neurological disorder (1.00), followed by foot and mouth disease (FIC 0.91), which depicted that some species were frequently utilized to treat multiple livestock ailments.

Conclusion

The study presents trustworthy information about medicinal plants and their associated indigenous ethnoveterinary knowledge. It has been scientifically proven that these plants contain bioactive compounds responsible for their therapeutic properties. However, this knowledge is in danger of being lost due to factors like socioeconomic changes, environmental and technological alterations, and lack of interest from younger generations. Therefore, it is essential to document this empirical folklore knowledge systematically and take measures to protect and conserve it.

Antidiabetic and anti-obesity properties of a polyphenol-rich flower extract from Tagetes erecta L. and its effects on Caenorhabditis elegans fat storages

Diabetes mellitus (DM) is a metabolic disease characterized by a high blood sugar level that can cause severe complications to the organism or even death when not treated. However, certain dietary habits and foods may have beneficial effects on this condition. A polyphenolic-rich extract (containing hyperoside, isoquercitrin, quercetin, ellagic acid, and vanillic acid) of Tageres erecta L. (T. erecta) was obtained from yellow and orange flowers using an ethanolic Soxhlet extraction. These extracts were screened for antidiabetic and anti-obesity properties using in vitro and in vivo procedures. The capacity to inhibit the enzymes lipase and α-glucosidase, as well as the inhibition of advance glycation end-products (AGEs) was tested in vitro. Caenorhabditis elegans (C. elegans) was used as an obesity in vivo model to assess extracts effects on fat accumulation using the wild-type strain N2 and a mutant with no N3 fatty acid desaturase activity BX24. Extracts from both cultivars (yellow and orange) T. erecta presented in vitro inhibitory activity against the enzymes lipase and α-glucosidase, showing lower IC₅₀ values than acarbose (control). They also showed important activity in preventing AGEs formation. The polyphenol-rich matrices reduced the fat content of obese worms in the wild-type strain (N2) down to levels of untreated C. elegans, with no significant differences found between negative control (100% reduction) and both tested samples (p < 0.05). Meanwhile, the fat reduction was considerably lower in the BX24 mutants (fat-1(wa-9)), suggesting that N3 fatty acid desaturase activity could be partially involved in the T. erecta flower effect. Our findings suggested that polyphenols from T. erecta can be considered candidate bioactive compounds in the prevention and improvement of metabolic chronic diseases such as obesity and diabetes.

Xanthine oxidase inhibitory study of eight structurally diverse phenolic compounds

This project was designed to explore the xanthine oxidase (XO) inhibitory mechanism of eight structurally diverse phenolic compounds [quercetin: C1, quercetin-3-rhamnoside: C2, 4, 5-O-dicaffeoylquinic acid: C3, 3, 5-O-dicaffeoylquinic acid: C4, 3, 4-O-di-caffeoylquinic acid: C5, 4-O-caffeoylquinic acid (C6), 3-O-caffeoylquinic acid: C7, and caffeic acid: C8]. For this purpose, in-vitro and different computational methods were applied to determine the xanthine oxidase (XO) inhibitory potential of eight structurally diverse phenolic compounds. The results revealed that phenolic compounds (C1–C8) possess strong to weak XO inhibitory activity. These results were further confirmed by atomic force microscopy (AFM) and ¹H NMR analysis. Furthermore, computational study results revealed that phenolic compounds (C1–C8) bind with the surrounding amino acids of XO at the molybdenum (MO) site. These in-vitro and in-silico results divulge that phenolic compounds have a strong potential to lower uric acid levels via interacting with the XO enzyme and can be used to combat hyperuricemia.

Korean naked waxy barley (saechalssal) extract reduces blood glucose in diabetic mice by modulating the PI3K-Akt-GSK3β pathway

Saechalssal barley is Korea's representative naked waxy barley. This study investigated the anti-diabetic effect of the extract derived from saechalssal and its mechanism. The prethanol extract of saechalssal (SPE) showed greater α-glucosidase inhibitory activity in vitro and a more significant lowering of the postprandial blood glucose levels in normal mice compared to its water extract (SWE). When mice with type 2 diabetes (T2DM) induced by a high-fat diet and streptozotocin were fed SPE (200 mg/kg/day) for six weeks, the fasting blood glucose and serum free fatty acid levels were significantly lower than those of the control group. SPE significantly elevated the hepatic glycogen accumulation with increasing glycogen synthesis-related gene (GYS2 and UGP2) levels compared to the control group. SPE stimulated the expression of the hepatic glycolysis-related genes (GK, PFK1, and PK) and suppressed the gluconeogenesis-related genes (G6Pase, FBP1, and PEPCK). SPE up-regulated the phosphorylation of phosphatidylinositol 3-kinase (PI3K) and protein kinase B (Akt), whereas it down-regulated the phosphorylation of glycogen synthase kinase 3 beta (GSK3β) compared to the control. The major flavonoids of SPE were naringin, prunin, and catechin, while its phenolic acids were ferulic acid and vanillic acid. These phytochemical compounds may contribute to the anti-hyperglycemic effects of SPE in diabetes. Overall, these results suggest that SPE has potential anti-diabetic activity through the regulating the PI3K/Akt/GSK3β pathway.

In vitro α-glucosidase inhibitory activity of Tamarix nilotica shoot extracts and fractions

α-glucosidase inhibitors represent an important class of type 2 antidiabetic drugs and they act by lowering postprandial hyperglycemia. Today, only three synthetic inhibitors exist on the market, and there is a need for novel, natural and more efficient molecules exhibiting this activity. In this study, we investigated the ability of Tamarix nilotica ethanolic and aqueous shoot extracts, as well as methanolic fractions prepared from aqueous crude extracts to inhibit α-glucosidase. Both, 50% ethanol and aqueous extracts inhibited α-glucosidase in a concentration-dependent manner, with IC₅₀ values of 12.5 μg/mL and 24.8 μg/mL, respectively. Importantly, α-glucosidase inhibitory activity observed in the T. nilotica crude extracts was considerably higher than pure acarbose (IC₅₀ = 151.1 μg/mL), the most highly prescribed α-glucosidase inhibitor on the market. When T. nilotica crude extracts were fractionated using methanol, enhanced α-glucosidase inhibitory activity was observed in general, with the highest observed α-glucosidase inhibitory activity in the 30% methanol fraction (IC₅₀ = 5.21 μg/mL). Kinetic studies further revealed a competitive reversible mechanism of inhibition by the plant extract. The phytochemical profiles of 50% ethanol extracts, aqueous extracts, and the methanolic fractions were investigated and compared using a metabolomics approach. Statistical analysis revealed significant differences in the contents of the crude extracts and fractions and potentially identified the molecules that were most responsible for these observed variations. Higher α-glucosidase inhibitory activity was associated with an enrichment of terpenoids, fatty acids, and flavonoids. Among the identified molecules, active compounds with known α-glucosidase inhibitory activity were detected, including unsaturated fatty acids, triterpenoids, and flavonoid glycosides. These results put forward T. nilotica as a therapeutic plant for type 2 diabetes and a source of α-glucosidase inhibitors.

Inhibitory activities of grape bioactive compounds against enzymes linked with human diseases

A quest for identification of novel, safe and efficient natural compounds, as additives in the modern food and cosmetic industries, has been prompted by concerns about toxicity and side effects of synthetic products. Plant phenolic compounds are one of the most documented natural products due to their multifarious biological applications. Grape (Vitis vinifera) is an important source of phenolic compounds such as phenolic acids, tannins, quinones, coumarins and, most importantly, flavonoids/flavones. This review crisply encapsulates enzyme inhibitory activities of various grape polyphenols towards different key human-ailment-associated enzymes: xanthine oxidase (gout), tyrosinase (hyperpigmentation), α-amylase and α-glucosidase (diabetes mellitus), pancreatic lipase (obesity), cholinesterase (Alzheimer's disease), angiotensin i-converting enzymes (hypertension), α-synuclein (Parkinson's disease) and histone deacetylase (various diseases). The review also depicts the enzyme inhibitory mechanism of various grape polyphenols and briefly discusses their stature as potential therapeutic and drug development candidates. KEY POINTS: • Nineteen major bioactive polyphenols from the grape/grape products and their disease targets are presented • Sixty-two important polyphenols as enzyme inhibitors from grape/grape products are presented • A thorough description and graphical presentation of biological significance of polyphenols against various diseases.

Antidiabetic Medicinal Plants Used in Democratic Republic of Congo: A Critical Review of Ethnopharmacology and Bioactivity Data

Several studies have been conducted and published on medicinal plants used to manage Diabetes Mellitus worldwide. It is of great interest to review available studies from a country or a region to resort to similarities/discrepancies and data quality. Here, we examined data related to ethnopharmacology and bioactivity of antidiabetic plants used in the Democratic Republic of Congo. Data were extracted from Google Scholar, Medline/PubMed, Scopus, ScienceDirect, the Wiley Online Library, Web of Science, and other documents focusing on ethnopharmacology, pharmacology, and phytochemistry antidiabetic plants used in the Democratic Republic of Congo from 2005 to September 2021. The Kew Botanic Royal Garden and Plants of the World Online web databases were consulted to verify the taxonomic information. CAMARADES checklist was used to assess the quality of animal studies and Jadad scores for clinical trials. In total, 213 plant species belonging to 72 botanical families were reported. Only one plant, Droogmansia munamensis, is typically native to the DRC flora; 117 species are growing in the DRC and neighboring countries; 31 species are either introduced from other regions, and 64 are not specified. Alongside the treatment of Diabetes, about 78.13% of plants have multiple therapeutic uses, depending on the study sites. Experimental studies explored the antidiabetic activity of 133 plants, mainly in mice, rats, guinea pigs, and rabbits. Several chemical classes of antidiabetic compounds isolated from 67 plant species have been documented. Rare phase II clinical trials have been conducted. Critical issues included poor quality methodological protocols, author name incorrectly written (16.16%) or absent (14.25%) or confused with a synonym (4.69%), family name revised (17.26%) or missing (1.10%), voucher number not available 336(92.05%), ecological information not reported (49.59%). Most plant species have been identified and authenticated (89.32%). Hundreds of plants are used to treat Diabetes by traditional healers in DRC. However, most plants are not exclusively native to the local flora and have multiple therapeutic uses. The analysis showed the scarcity or absence of high-quality, in-depth pharmacological studies. There is a need to conduct further studies of locally specific species to fill the gap before their introduction into the national pharmacopeia.

Natural Products and Extracts as Xantine Oxidase Inhibitors - A Hope for Gout Disease?

Xanthine oxidase (EC 1.17.3.2) (XO) is one of the main enzymatic sources that create reactive oxygen species (ROS) in the living system. It is a dehydrogenase enzyme that performs electron transfer to nicotinamide adenine dinucleotide (NAD+), while oxidizing hypoxanthin, which is an intermediate compound in purine catabolism, first to xanthine and then to uric acid. XO turns into an oxidant enzyme that oxidizes thiol groups under certain stress conditions in the tissue. The last metabolic step, in which hypoxanthin turns into uric acid, is catalyzed by XO. Uric acid, considered a waste product, can cause kidney stones and gouty-type arthritis as it is crystallized, when present in high concentrations. Thus, XO inhibitors are one of the drug classes used against gout, a purine metabolism disease that causes urate crystal storage in the joint and its surroundings caused by hyperuricemia. Urate-lowering therapy includes XO inhibitors that reduce uric acid production as well as uricosuric drugs that increase urea excretion. Current drugs that obstruct uric acid synthesis through XO inhibition are allopurinol, febuxostat, and uricase. However, since the side effects, safety and tolerability problems of some current gout medications still exist, intensive research is ongoing to look for new, effective, and safer XO inhibitors of natural or synthetic origins for the treatment of the disease. In the present review, we aimed to assess in detail XO inhibitory capacities of pure natural compounds along with the extracts from plants and other natural sources via screening Pubmed, Web of Science (WoS), Scopus, and Google Academic. The data pointed out to the fact that natural products, particularly phenolics such as flavonoids (quercetin, apigenin, and scutellarein), tannins (agrimoniin and ellagitannin), chalcones (melanoxethin), triterpenes (ginsenoside Rd and ursolic acid), stilbenes (resveratrol and piceatannol), alkaloids (berberin and palmatin) have a great potential for new XO inhibitors capable of use against gout disease. In addition, not only plants but other biological sources such as microfungi, macrofungi, lichens, insects (silk worms, ants, etc) seem to be the promising sources of novel XO inhibitors.

Targeting Xanthine Oxidase by Natural Products as a Therapeutic Approach for Mental Disorders

Mental disorders comprise diverse human pathologies, including depression, bipolar affective disorder, schizophrenia, and dementia that affect millions of people around the world. The causes of mental disorders are unclear, but growing evidence suggests that oxidative stress and the purine/adenosine system play a key role in their development and progression. Xanthine oxidase (XO) is a flavoprotein enzyme essential for the catalysis of the oxidative hydroxylation of purines -hypoxanthine and xanthine- to generate uric acid. As a consequence of the oxidative reaction of XO, reactive oxygen species (ROS) such as superoxide and hydrogen peroxide are produced and, further, contribute to the pathogenesis of mental disorders. Altered XO activity has been associated with free radical-mediated neurotoxicity inducing cell damage and inflammation. Diverse studies reported a direct association between an increased activity of XO and diverse mental diseases including depression or schizophrenia. Small-molecule inhibitors, such as the well-known allopurinol, and dietary flavonoids, can modulate the XO activity and subsequent ROS production. In the present work, we review the available literature on XO inhibition by small molecules and their potential therapeutic application in mental disorders. In addition, we discuss the chemistry and molecular mechanism of XO inhibitors, as well as the use of structure-based and computational methods to design specific inhibitors with the capability of modulating XO activity.

Delphinidin-3-O-sambubioside: a novel xanthine oxidase inhibitor identified from natural anthocyanins

Objectives

This study was conducted to investigate the xanthine oxidase (XO) inhibitory activities of 18 monomeric anthocyanins from berry fruits and roselle, and to illustrate the underlying mechanism of the most active anthocyanin delphinidin-3-O-sambubioside.

Materials and Methods

Eighteen monomeric anthocyanins were prepared and purified in our laboratory. The inhibitory properties of anthocyanins were investigated by in vitro inhibitory activity studies and fluorescence quenching studies; the inhibitory mechanism was explored through kinetic studies, fluorescence quenching studies, circular dichroism analysis and computational docking simulations.

Results

XO inhibitory activities of anthocyanins were related to the structures of B rings and glycosides. Among all the tested anthocyanins, delphinidin-3-O-sambubioside showed the most potent inhibitory activity with an IC50 of 17.1 μM, which was comparable to the positive control allopurinol. Spectroscopic results revealed that delphinidin-3-O-sambubioside could spontaneously interact with XO and induce conformational changes. Computational docking study indicated that delphinidin-3-O-sambubioside could bind to XO with a proper orientation, stably formed π–π interactions and hydrogen bonds with key residues, thus preventing the substrate from entering the active pocket.

Conclusions

In brief, our study identified delphinidin-3-O-sambubioside as a potent XO inhibitor from natural anthocyanins, which is potentially applicable for prevention and treatment of hyperuricemia.

Kinetic analysis of inhibition of α-glucosidase by leaf powder from Morus australis and its component iminosugars

Abbreviations

1-DNJ: 1-deoxynojirimycin; GAL-DNJ: 2-O-α-D-galactopyranosyl-DNJ

Lipidome, nutraceuticals and nutritional profiling of Pyrus pashia Buch.-ham ex D. Don (Kainth) seeds oil and its antioxidant potential

Kainth fruit, as traditional medicine, has been used in the Himalayan region for its health-promoting properties. However, the phytochemicals and lipidomes of Kainth Seed Oil (KSO) are still scarce. Here, we investigated the physicochemical characterization of KSO and its nutraceuticals, antioxidant potentials. Kainth seeds contain 19-20% oil rich in polyunsaturated fatty acids (PUFA, 82.22%), particularly linoleic acid (C18:2). Lipidome analysis of KSO using high-resolution mass spectrometry showed that trilinoleate (C54:6) was the dominant triacylglycerol (TAG) species. Further, the characteristics of PUFA-rich oil were validated by Fourier transforms infrared spectroscopy (FTIR) and Differential Scanning calorimetry (DSC). The nutraceuticals profiling of KSO depicted the presence of tocopherols (86.72 mg) and phytosterols (32.25 mg) in 100 g oil with significant antioxidant activity. The oil cake contained 19.09% protein and minerals and can be a source for dietary protein. Collectively these results suggest that KSO will be a suitable source for PUFA and nutraceuticals potential.

Traditional Use of Medicinal Plants in South-Eastern Serbia (Pčinja District): Ethnopharmacological Investigation on the Current Status and Comparison With Half a Century Old Data

Balkan Peninsula is one of the most important biodiversity centers in Europe. Despite that, the usage of plant species in the traditional medicine of some Balkan regions remained largely unexplored in the past. This study aimed to collect and document data on the traditional use of medicinal plants in Pčinja district in South-Eastern Serbia, which is among the least developed regions in Serbia. Also, comparison with data collected by Dr. Jovan Tucakov, in a book called Herbal therapy was conducted. The survey was carried out using semi-structured interviews and 113 informants were interviewed. Quantitative ethnobotany factors were calculated, allowing us discussing the results. The informants reported data on 86 medicinal plants belonging to 43 families in Pčinja district. Lamiaceae, Asteraceae, and Rosaceae were the dominant locally used families. The species with the highest number of use reports were Mentha piperita, Matricaria chamomilla, and Hypericum perforatum. Gastrointestinal ailments, respiratory problems and skin diseases were the most frequently reported indications. Usually, the administration was primarily oral followed by topical applications. Leaves were dominantly exploited plant parts and the most frequent preparation form was infusion. Medicinal plants in Pčinja district are mainly used as a mode of primary health care for treating minor health issues. After comparing our results with the ones collected half a century ago by Dr. Jovan Tucakov we can conclude that plant species mentioned in our investigation previously had a much wider spectrum of application.

Assessment of the Phenolic Profiles, Hypoglycemic Activity, and Molecular Mechanism of Different Highland Barley (Hordeum vulgare L.) Varieties

The phenolic profiles, hypoglycemic activity, and molecular mechanism of the effect on type 2 diabetes mellitus (T2DM) of four highland barley varieties were investigated in the present study. The fundamental phenolics in highland barley were ferulic acid, naringin, and catechin, which mainly existed in bound form. These varieties showed favorable hypoglycemic activity via inhibition of α-glucosidase and α-amylase activities, enhancement of glucose consumption, glycogen accumulation and glycogen synthase 2 (GYS2) activity, and down-regulation of glucose-6-phosphatase (G6Pase) and phosphoenolpyruvate carboxykinase (PEPCK) activities. Specifically, ZQ320 variety exhibited the strongest hypoglycemic activity compared to the other varieties. Highland barley phenolics could inhibit gluconeogenesis and motivate glycogen synthesis via down-regulating the gene expression of G6Pase, PEPCK, and glycogen synthase kinase 3β (GSK3β), while activating the expression of insulin receptor substrate-1 (IRS-1), phosphatidylinositol 3 kinase (PI3K), serine/threonine kinase (Akt), GYS2, and glucose transporter type 4 (GLUT4). Therefore, phenolics from highland barley could be served as suitable candidates for therapeutic agent in T2DM to improve human health.

Alpha Glucosidase Inhibitory Activities of Plants with Focus on Common Vegetables

Type-2 diabetes mellitus is one of the most prevalent metabolic diseases in the world, and is characterized by hyperglycemia (i.e., high levels of glucose in the blood). Alpha-glucosidases are enzymes in the digestive tract that hydrolyze carbohydrates into glucose. One strategy that has been developed to treat type-2 diabetes is inhibition of the activity of alpha-glucosidases using synthetic drugs. However, these inhibitors are usually associated with gastrointestinal side effects. Therefore, the development of inhibitors from natural products offers an alternative option for the control of hyperglycemia. In recent years, various studies have been conducted to identify alpha-glucosidases inhibitors from natural sources such as plants, and many candidates have transpired to be secondary metabolites including alkaloids, flavonoids, phenols, and terpenoids. In this review, we focus on the alpha-glucosidases inhibitors found in common vegetable crops and the major classes of phytochemicals responsible for the inhibitory activity, and also as potential/natural drug candidates for the treatment of type-2 diabetes mellitus. In addition, possible breeding strategies for production of improved vegetable crops with higher content of the inhibitors are also described.

Antihyperuricemic effect of dietary polyphenol sinapic acid commonly present in various edible food plants

The present study was conducted to evaluate the antihyperuricemic effect of sinapic acid (SA). The results showed that SA potently inhibited xanthine oxidase (XOD) in a dose-dependent manner by entering the enzyme active site and thwarting the entrance of the substrate. These results were further confirmed by the quantum chemical descriptors analysis and ¹ H NMR titration analysis. The in vivo results indicated that SA not only has the potential to inhibit serum and hepatic XOD (p < .05), but also remarkably lowered serum and urine uric acid levels at 50 and 100 mg/kg bw. Furthermore, SA regulated serum creatinine and blood urea nitrogen levels to normal and lowered inflammation in the renal tubules. Thus, the utilization of SA as an antihyperuricemic agent may have considerable potential for the development of functional foods for the possible treatment of hyperuricemia. PRACTICAL APPLICATIONS: Plant-derived bioactive compounds have multiple health benefits. The present study assesses the effects of sinapic acid against hyperuricemia. The results suggested that sinapic acid may have a strong protective effect against uric acid-related complications and may be used for the formulation of functional foods. However, further mechanistic studies are required to verify this hypothesis.

Chemical composition and enzyme inhibition of Phytolacca dioica L. seeds extracts

Phytolacca, which belongs to the family of Phytolaccaceae, are known for their use in popular medicine. Bioactivity of five extracts from Phytolacca dioica seeds were evaluated in four bioassays. A selected group of compounds from the extract that displayed the best bioactivity was analysed. The ethyl acetate extract (EAE) possessed the highest content of phenolics, the highest inhibitory activity on the tyrosinase and xanthine oxidase enzymes and showed a high antioxidant activity. HPLC-DAD-MS was employed to identify the phenolics profile of the most active one (EAE). HSCCC analysis of the EAE led to the isolation of phytolaccoside B and a mixture of 4 isomers, isoamericanol B1, B2, C1 and C2. These isoamericanol isomers presented activity against tyrosinase and xanthine oxidase. Our results revealed for the first time an interesting biological activity of the extract and isolated compounds from P. dioica seeds, which could be considered as a source of bioactive molecules.

Natural compounds with xanthine oxidase inhibitory activity: A review

Hyperuricemia (HUA), a disease due to an elevation of body uric acid level and responsible for various diseases such as gout, cardiovascular disorders, and renal failure, is a major ground debate for the medical science these days. Considering the risk factors linked with allopathic drugs for the treatment of this disease, the debate has now become a special issue. Previously, we critically discussed the role of dietary polyphenols in the treatment of HUA. Besides dietary food plants, many researchers figure out the tremendous effects of medicinal plants-derived phytochemicals against HUA. Keeping in mind all these aspects, we reviewed all possible managerial studies related to HUA through medicinal plants (isolated compounds). In the current review article, we comprehensively discussed various bioactive compounds, chemical structures, and structure-activity relationship with responsible key enzyme xanthine oxidase.

Antioxidant Activity of Zein Hydrolysates from Zea Species and Their Cytotoxic Effects in a Hepatic Cell Culture

In recent years, food proteins with bioactivity have been studied for cancer treatment. Zein peptides have shown an important set of bioactivities. This work compares the cytotoxic activity of zein hydrolyzed, extracted from four Zea species: teosinte, native, hybrid, and transgenic (Teo, Nat, Hyb, and HT) in a hepatic cell culture. Zein fraction was extracted, quantified, and hydrolyzed. Antioxidant capacity and cytotoxicity assays were performed on HepG2 cells. The levels of expression of caspase 3, 8, and 9 were evaluated in zein-treated cell cultures. Zea parviglumis showed the highest zein content (46.0 mg/g) and antioxidant activity (673.40 TE/g) out of all native zeins. Peptides from Hyb and HT showed high antioxidant activity compared to their native counterparts (1055.45 and 724.32 TE/g, respectively). Cytotoxic activity was observed in the cell culture using peptides of the four Zea species; Teo and Nat (IC50: 1781.63 and 1546.23 ng/mL) had no significant difference between them but showed more cytotoxic activity than Hyb and HT (IC50: 1252.25 and 1155.56 ng/mL). Increased expression of caspase 3 was observed in the peptide-treated HepG2 cells (at least two-fold more with respect to the control sample). These data indicate the potential for zein peptides to prevent or treat cancer, possibly by apoptosis induction.

Management of hyperuricemia through dietary polyphenols as a natural medicament: A comprehensive review

Hyperuricemia, a condition due to high serum uric acid level and is notorious to health. It is considered to be a potent risk factor for gout and dramatically associated in the development of many chronic diseases such as malignant tumor, cardiovascular disorders and renal failure. Modern innovative medicinal and therapeutic interventions are underlying these days to combat hyperuricemia. Previously reported studies revealed the significant impact of dietary polyphenols (e.g. anthocyanins, phenolic acids, flavonoids etc.) against hyperurecemia disorder. Dietary plant polyphenols, unlike anti- hyperuricemic agents, are not reported to have any side effects in curing hyperuricemia. The current comprehensive review figure outs the use of dietary polyphenols as a natural remedy for the management of hyperuricemia. The sources, affiliated pathways, mode of actions and factors affecting their efficiency to prevent hyperuricemia are deeply discussed in this article. Additionally, limitations and suggestions regarding previously reported studies are also highlighted.

Antioxidant and xanthine oxidase inhibitory activities of total polyphenols from onion

Onions (Allium cepa L.) comprise a valuable vegetable crop in many countries. Modern scientific research has shown that onions possess many biological activities, including antibacterial, anticancer, hypoglycemic, hypolipidemic, antiplatelet aggregation, and antioxidant activities. The goal of this study was to investigate the impact of total onion polyphenols on antioxidant and xanthine oxidase (XO) inhibitory activities. Total onion polyphenols showed significant antioxidant activity in DPPH, FRAP, and OH-assays (IC₅₀ [µg/mL]), 43.24, 560.61, and 12.97, respectively). In a X/XO system, antioxidant properties of these polyphenols significantly inhibited XO activity (IC₅₀ [µg/mL], 17.36). These results indicated that total onion polyphenols showed promising antioxidant and anti-gout properties and might be used as potential, natural drugs against oxidative diseases after successful studies in vivo as well as clinical trials.

Total phenolics, antioxidant, antitumor, and enzyme inhibitory activity of Indian medicinal and aromatic plants extracted with different extraction methods

The phenolic content, antioxidant, antitumor, and enzyme inhibitory activities of commonly used medicinal herbs from a Unani system of medicine were investigated using four different extraction methods. Among the plants studied, the Hyssopus officinalis L, Origanum vulgare L, and Portulaca oleracea L. extracts showed the highest amount of total phenolics (64.40, 60.35, and 58.81 mg GAE/g) and revealed significant antioxidant activities. The plants also showed a maximum cytotoxic activity as indicated by H. officinalis (82%), O. vulgare (75%), and P. oleracea (72%) showed more than 70% cytotoxicity for breast cancer cells, 82% of the cells were dead at the concentration of 500 mg/mL. The plants H. officinalis, P. oleracea, O. vulgare, and Rubia cordifolia L. revealed more than 80% inhibition towards xanthine oxidase and comprising maximum 70% of inhibition for superoxide dismutase. From results we conclude that there is a strong correlation between phenolic content, antioxidant, and enzyme inhibitory activity among these plants, indicating phenolics are the major compounds for these biological activities. Furthermore, this study provides the basis for the therapeutic importance of studied plants as latent inhibitors of oxidative stress and antitumor cell proliferation which correlate with the ethnobotanical data contained in the Unani system of medicine.

Phenolic Elderberry Extracts, Anthocyanins, Procyanidins, and Metabolites Influence Glucose and Fatty Acid Uptake in Human Skeletal Muscle Cells

Uptake of glucose and fatty acids in skeletal muscle is of interest for type 2 diabetes treatment. The aim was to study glucose and fatty acid uptake in skeletal muscle cells, antioxidant effects, and inhibition of carbohydrate-hydrolyzing enzymes by elderberries. Enhanced glucose and oleic acid uptake in human skeletal muscle cells were observed after treatment with phenolic elderberry extracts, anthocyanins, procyanidins, and their metabolites. The 96% EtOH and the acidified MeOH extracts were highly active. Of the isolated substances, cyanidin-3-glucoside and cyanidin-3-sambubioside showed highest stimulation of uptake. Phloroglucinol aldehyde was most active among the metabolites. Isolated anthocyanins and procyanidins are strong radical scavengers and are good inhibitors of 15-lipoxygenase and moderate inhibitors of xanthine oxidase. As α-amylase and α-glucosidase inhibitors, they are considerably better than the positive control acarbose. The antidiabetic property of elderberry phenolics increases the nutritional value of this plant and indicates potential as functional food against diabetes.

The Effect of Yokukansan, a Traditional Herbal Preparation Used for the Behavioral and Psychological Symptoms of Dementia, on the Drug-Metabolizing Enzyme Activities in Healthy Male Volunteers

The concomitant use of herb and prescription medications is increasing globally. Herb-drug interactions are therefore a clinically important problem. Yokukansan (YKS), a Japanese traditional herbal medicine, is one of the most frequently used herbal medicines. It is effective for treating the behavioral and psychological symptoms of dementia. We investigated the potential effects of YKS on drug-metabolizing enzyme activities in humans. An open-label repeat-dose study was conducted in 26 healthy Japanese male volunteers (age: 22.7±2.3 years) with no history of smoking. An 8-h urine sample was collected after a 150-mg dose of caffeine and a 30-mg dose of dextromethorphan before and after the administration of YKS (2.5 g, twice a day for 1 week). The activities of cytochrome P450 (CYP) 1A2, CYP2D6, CYP3A, xanthine oxidase (XO) and N-acetyltransferase 2 (NAT2) were assessed based on the urinary metabolic indices of caffeine and dextromethorphan, and the urinary excretion ratio of 6β-hydroxycortisol to cortisol. There were no statistically significant differences in the activities of the examined enzymes before or after the 7-d administration of YKS. Although further studies assessing the influence of YKS on the pharmacokinetics and pharmacodynamics of the substrates of the drug-metabolizing enzymes are needed to verify the present results, YKS is unlikely that a pharmacokinetic interaction will occur with concomitantly administered medications that are predominantly metabolized by the CYP1A2, CYP2D6, CYP3A, XO and NAT2.

Chemical Evidence for Potent Xanthine Oxidase Inhibitory Activity of Ethyl Acetate Extract of Citrus aurantium L. Dried Immature Fruits

Xanthine oxidase is a key enzyme which can catalyze hypoxanthine and xanthine to uric acid causing hyperuricemia in humans. Xanthine oxidase inhibitory activities of 24 organic extracts of four species belonging to Citrus genus of the family Rutaceae were assayed in vitro. Since the ethyl acetate extract of C. aurantium dried immature fruits showed the highest xanthine oxidase inhibitory activity, chemical evidence for the potent inhibitory activity was clarified on the basis of structure identification of the active constituents. Five flavanones and two polymethoxyflavones were isolated and evaluated for inhibitory activity against xanthine oxidase in vitro. Of the compounds, hesperetin showed more potent inhibitory activity with an IC₅₀ value of 16.48 μM. For the first time, this study provides a rational basis for the use of C. aurantium dried immature fruits against hyperuricemia.

HPLC Analysis, Antioxidant, Anti-inflammatory and Xanthine Oxidase Inhibitory Activity of Cudrania tricuspidata

Cudrania tricuspidata is a plant used in folk medicine in Korea for treatment of diseases related to oxidative stress and inflammation. In this study the leaf and shoot extract was studied for its antioxidant, anti-inflammatory, and xanthine oxidase (XO) inhibitory activities. The extract with predominant phenolics was quantified using HPLC-DAD. Antioxidant activity was measured using ABTS [2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) and FRAP (ferric ion reducing antioxidant power), and anti-inflammatory activity by diene-conjugate and β-glucuronidase assays. The average antioxidant effects of C. tricuspidata extracts (1–2 mg/mL) revealed significant activity of 32.5% to 50.2% (ABTS) and 24.2 to 40.5% (FRAP) compared with Trolox, having 55.1% (ABTS) and 42.6% (FRAP) activity, respectively. The anti-inflammatory activities showed as 26.5% to 40.5% (DC) and 40.2% to 70.2% (βG) inhibition compared with the control {phenylbutazone; 42.1% (DC) and 80.2% (βG) inhibition, respectively}. The XO inhibitory activity of the plant extract revealed 90.5% inhibition of that of the control (allopurinol) (97% inhibition at 100 μg/mL concentration). The kinetic parameters of XO inhibition revealed a noncompetitive type of inhibition, where, K m and V max of C. tricuspidata extracts (25 to 100 μg/mL) were 0.25 mM/mL and 0.040, 0.036, 0.032, and 0.030 (μg/min), while for the positive control K m and V max the values were 0.30 mM/mL and 0.045 (μg/min), respectively. Results suggest that C. tricuspidata can be exploited against diseases associated with free radical formation and xanthine oxidase activity.

In vitro and in vivo studies on adlay-derived seed extracts: phenolic profiles, antioxidant activities, serum uric acid suppression, and xanthine oxidase inhibitory effects

This study aimed to explore the potential of polished adlay, brown adlay, adlay bran, and adlay hull to prevent and treat hyperuricemia. Brown adlay extract effectively decreased the serum uric acid levels of oxonate-induced hyperuricemic rats. Free and bound phenolic extracts from these materials contained significant amounts of phenolics, with free phenolics dominated by chlorogenic acid and p-coumaric acid while bound phenolics dominated by p-coumaric acid and ferulic acid. Free and bound phenolics of adlay bran exhibited significant xanthine oxidase inhibition activities, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, oxygen radical absorbance capacities, and superoxide radical scavenging activities. Adlay bran phenolics could be effective xanthine oxidase inhibitors and radical scavengers. p-Coumaric acid is a xanthine oxidase inhibitor with strong superoxide radical scavenging activity. However, ferulic acid is a xanthine oxidase inhibitor with weak superoxide radical scavenging activity. Chlorogenic acid is a superoxide radical scavenger with weak xanthine oxidase inhibitory activity.