Rapid determination of total flavonoid content, xanthine oxidase inhibitory activities, and antioxidant activity in Prunus mume by near-infrared spectroscopy.

Evaluating the quality of herbal medicine based on the content and activity of its main components is highly beneficial. Developing an eco-friendly determination method has significant application potential. In this study, we propose a new method to simultaneously predict the total flavonoid content (TFC), xanthine oxidase inhibitory (XO) activity, and antioxidant activity (AA) of Prunus mume using near-infrared spectroscopy (NIR). Using the sodium nitrite-aluminum nitrate-sodium hydroxide colorimetric method, uric acid colorimetric method, and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) free radical scavenging activity as reference methods, we analyzed TFC, XO, and AA in 90 P. mume samples collected from different locations in China. The solid samples were subjected to NIR. By employing spectral preprocessing and optimizing spectral bands, we established a rapid prediction model for TFC, XO, and AA using partial least squares regression (PLS). To improve the model's performance and eliminate irrelevant variables, competitive adaptive reweighted sampling (CARS) was used to calculate the pretreated full spectrum. Evaluation model indicators included the root mean square error of cross-validation (RMSECV) and determination coefficient (R2) values. The TFC, XO, and AA model, combining optimal spectral preprocessing and spectral bands, had RMSECV values of 0.139, 0.117, and 0.121, with RCV2 values exceeding 0.92. The root mean square error of prediction (RMSEP) for the TFC, XO, and AA model on the prediction set was 0.301, 0.213, and 0.149, with determination coefficient (RP2) values of 0.915, 0.933, and 0.926. The results showed a strong correlation between NIR with TFC, XO, and AA in P. mume. Therefore, the established model was effective, suitable for the rapid quantification of TFC, XO, and AA. The prediction method is simple and rapid, and can be extended to the study of medicinal plant content and activity.

A strategy to boost xanthine oxidase and angiotensin converting enzyme inhibitory activities of peptides via molecular docking and module substitution.

Molecular docking and activity evaluation screened the dipeptide module GP with low xanthine oxidase (XOD) inhibitory activity and modules KE and KN with high activity, and identified them as low- and high-contribution modules, respectively. We hypothesized the substitution of low-contribution modules in peptides with high contributions would boost their XOD inhibitory activity. In the XOD inhibitory peptide GPAGPR, substitution of GP with both KE and KN led to enhanced affinity between the peptides and XOD. They also increased XOD inhibitory activity (26.4% and 10.3%) and decreased cellular uric acid concentrations (28.0% and 10.4%). RNA sequencing indicated that these improvements were attributable to the inhibition of uric acid biosynthesis. In addition, module substitution increased the angiotensin-converting enzyme inhibitory activity of GILRP and GAAGGAF by 84.8% and 76.5%. This study revealed that module substitution is a feasible strategy to boost peptide activity, and provided information for the optimization of hydrolysate preparation conditions.

Phytochemical and Bioactivity Studies on Hedera helix L. (Ivy) Flower Pollen and Ivy Bee Pollen.

Bee pollen, known as a 'life-giving dust', is a product of honeybees using flower pollen grains and combining them with their saliva secretions. Thus, flower pollen could be an indicator of the bee pollen botanical source. Identification of bee pollen sources is a highly crucial process for the evaluation of its health benefits, as chemical composition is directly related to its pharmacological activity. In this study, the chemical profiles, contents of phenolic marker compounds and pharmacological activities of Hedera helix L. (ivy) bee pollen samples from Türkiye and Slovenia, as well as ivy flower pollen grains, were compared. High-performance thin-layer chromatography (HPTLC) analyses revealed that pollen samples, regardless of where they were collected, have similar chemical profiles due to the fact that they have the same botanical origins. Marker compounds afzelin, platanoside and quercetin-3-O-ß-glucopyranosyl-(1→2)-ß-galactopyranoside, common to both bee pollen and flower pollen, were isolated from bee pollen, and their structures were elucidated by nuclear magnetic resonance (NMR) and mass spectrometry (MS). These three compounds, as well as chlorogenic acid and 3,5-dicaffeoylquinic acid (found in flower pollen), were quantified using high-performance liquid chromatography (HPLC) analyses. In vitro tests and effect-directed analyses were used to evaluate the xanthine oxidase inhibition and antioxidant activity of the marker compounds and extracts from flower pollen and bee pollen. This is the first report comparing chemical profiles and related bioactivities of the flower pollen and bee pollen of the same botanical origin, as well as the first report of the chemical profile and related bioactivities of ivy flower pollen.

Purification and identification of xanthine oxidase inhibitory peptides from enzymatic hydrolysate of α-lactalbumin and bovine colostrum casein.

The development of food-derived Xanthine Oxidase (XO) inhibitors is critical to the treatment of hyperuricemia and oxidative stress-related disease. Few studies report on milk protein hydrolysates' XO inhibitory activity, with the mechanism of their interaction remaining elusive. Here, different commercial enzymes were used to hydrolyze α-lactalbumin and bovine colostrum casein. The two proteins hydrolyzed by alkaline protease exhibited the most potent XO inhibitory activity (bovine casein: IC50 = 0.13 mg mL-1; α-lactalbumin: IC50 = 0.28 mg mL-1). Eight potential XO inhibitory peptides including VYPFPGPI, GPVRGPFPIIV, VYPFPGPIPN, VYPFPGPIHN, QLKRFSFRSFIWR, LVYPFPGPIHN, AVFPSIVGR, and GFININSLR (IC50 of 4.67-8.02 mM) were purified and identified from alkaline protease hydrolysates by using gel filtration, LC-MS/MS and PeptideRanker. The most important role of inhibiting activity of peptides is linked to hydrophobic interactions and hydrogen bonding based on the results of molecular docking and molecular dynamics simulation. The enzymatic hydrolysate of α-lactalbumin and bovine colostrum casein could be a competitive candidates for hyperuricemia-resisting functional food.

Bioactivity assays and phytochemical analysis upon Alcea glabrata; focusing on xanthine oxidase inhibitory and antimalarial properties.

Alcea glabrata from the family Malvaceae, was selected for evaluating its xanthine oxidase inhibitory, anti-malarial, and antioxidant activities. In addition, some phytochemical analysis upon different extracts of A. glabrata were performed. Aerial parts of the collected A. glabrata plant material were dried and solvent extracted via soxhlet apparatus using different solvents. Various chromatographic techniques were used for extra fractionation of the achieved extracts. Xanthine oxidase (XO) inhibitory, antimalarial and antioxidant activity assays upon different A. glabrata extracts and fractions were carried out and reported in terms of IC50s. Total phenolic and flavonoid contents of the A. glabrata methanol extract (MeOH) were determined using the 2,2-Di Phenyl-1-Picryl Hydrazyl (DPPH) assay, aluminum chloride colorimetric, and Folin-Ciocalteu reagents, respectively. In addition, A. glabrata essential oil was obtained through hydrodistillation by a Clevenger apparatus. Analysis and identification of essential oil compounds were carried out through gas chromatography mass spectrometry (GC-MS) analysis. MeOH extract showed the highest XO inhibitory activity with the IC50 of 0.37 ± 0.12 mg/mL antioxidant activity with the RC50 of 0.24 ± 0.06 mg/mL. While, chloroform extract revealed the strongest antimalarial activity with the IC50 of 0.4 ± 0.05 mg/mL. The total flavonoid and phenolic contents of the A. glabrata methanol extract were 39.8 mg quercetin equivalent and 6.1 g gallic acid equivalent per 100 g of dry plant material, respectively. GC-MS analysis showed that the monoterpenes were prevailing in A. glabrata essential oil where the major constituents: octacosane (30.7%), eugenol (12.3%), and anethole (12.0%). Concerning the results of this study, A. glabrata extracts and its ingredients could be considered as a novel promising herbal medicine in the design and also treatment of new drugs for the relief of gout and malaria diseases.

Xanthine Oxidase Inhibitory Activity and Chemical Composition of Pistacia chinensis Leaf Essential Oil.

Gout is a common metabolic disease caused by abnormal purine metabolism that promotes the formation and deposition of monosodium urate crystals within joints that causes acute arthritis and can seriously affect the daily life of patients. Pistacia chinensis is one of the traditional medicinal plants of the Anacardiaceae family, and there have been many studies on its biological activity, including anti-inflammatory, antidepressant, antibacterial, antioxidant, and hypoglycemic activities. The aim of this study was to evaluate the antigout effect of P. chinensis leaf essential oil and its constituents through xanthine oxidase inhibition. Leaf essential oil showed good xanthine oxidase inhibitory activity for both substrates, hypoxanthine and xanthine. Six fractions were obtained from open column chromatography, and fraction E1 exhibited the best activity. The constituents of leaf essential oil and fraction E1 were analyzed by GC-MS. The main constituents of both leaf essential oil and fraction E1 were limonene and 3-carene; limonene showed a higher inhibitory effect on xanthine oxidase. Based on the enzyme kinetic investigation, limonene was the mixed-type inhibitor against xanthine oxidase. The results revealed that Pistacia chinensis leaf essential oil and limonene have the potential to act as natural remedies for the treatment of gout.

Novel xanthine oxidase inhibitory peptides derived from whey protein: identification, in vitro inhibition mechanism and in vivo activity validation.

As the development of hyperuricemia (HUA) and gout continues to accelerate worldwide, there is increasing interest in the use of xanthine oxidase (XO) inhibitors as therapeutic agents for the management of HUA and gout. In the present study, XO inhibitory peptides were identified from whey protein isolate (WPI) hydrolysates, and the underlying inhibitory mechanism and in vivo activities was investigated. WPI hydrolysates were isolated and purified, and two peptides (ALPM and LWM) with lower binding energy were screened by molecular docking. The result showed that these two peptides interacted with residues around the active site of XO through hydrogen bond and hydrophobic interaction. The IC50 values of ALPM and LWM were 7.23 ± 0.22 and 5.01 ± 0.31 mM, respectively. According to the Lineweaver-Burk curve, the inhibition types of ALPM and LWM were non-competitive inhibition. Circular dichroism (CD) spectra indicated ALPM and LWM could change the secondary structure of XO. Molecular dynamics simulations revealed that XO-peptide complexes were more stable and compact than XO. Moreover, animal studies have shown that ALPM and LWM have anti-hyperuricemia effects in vivo. This study suggested that ALPM and LWM can be considered as natural XO inhibitors for the treatment of HUA.

Synthesis of New Pyrazole Hybrids as Potential Anticancer Agents with Xanthine Oxidase Inhibitory Activity.

AIMS: The study aims to synthesize hybrid molecules containing pyrazole and aryldiazenyl/arylhydrazono fragments with promising anticancer activity. BACKGROUND: The clinical effectiveness of anticancer drugs is limited by their adverse side effects and patient resistance. Therefore, the development of safer classes of drugs through rational drug design is imperative. OBJECTIVE: Considering the anticancer potential of the pyrazole moiety, the study was carried out with the objective of synthesizing some hybrid pyrazole derivatives with anticancer potential. METHODS: The anticancer potential of these pyrazolyl analogues were evaluated by sulforhodamine B assay using three cancer cell lines MCF-7, HepG2, and HCT-116. RESULTS: HCT-116 was the most sensitive cell line against these pyrazolyl analogues. Among these newly synthesised derivatives, 1-(4-((4-bromophenyl)diazenyl)-3,5-dimethyl-1H-pyrazol-1-yl)-2-(naphthalen-2-yloxy)ethan-1-one (5e) emerged as a promising anticancer agent (IC50 3.6-24.6 µM), having a xanthine oxidase inhibitory effect (IC50 10.87 µM). To obtain further insights into the binding interactions of these molecules, molecular docking studies were also carried out. CONCLUSION: In summary, our findings suggest that these hybrid pyrazolyl derivatives can be considered as potential lead molecules for anticancer agents.

Purification and Identification of Novel Xanthine Oxidase Inhibitory Peptides Derived from Round Scad (Decapterus maruadsi) Protein Hydrolysates.

The objective of the present study was to investigate the xanthine oxidase (XO) inhibitory effects of peptides purified and identified from round scad (Decapterus maruadsi) hydrolysates (RSHs). In this study, RSHs were obtained by using three proteases (neutrase, protamex and alcalase). Among them, the RSHs of 6-h hydrolysis by neutrase displayed the strongest XO inhibitory activity and had an abundance of small peptides (<500 Da). Four novel peptides were purified by immobilized metal affinity chromatography and identified by nano-high-performance liquid chromatography mass/mass spectrometry. Their amino acid sequences were KGFP (447.53 Da), FPSV (448.51 Da), FPFP (506.59 Da) and WPDGR (629.66 Da), respectively. Then the peptides were synthesized to evaluate their XO inhibitory activity. The results indicated that the peptides of both FPSV (5 mM) and FPFP (5 mM) exhibited higher XO inhibitory activity (22.61 ± 1.81% and 20.09 ± 2.41% respectively). Fluorescence spectra assay demonstrated that the fluorescence quenching mechanism of XO by these inhibitors (FPSV and FPFP) was a static quenching procedure. The study of inhibition kinetics suggested that the inhibition of both FPSV and FPFP was reversible, and the type of their inhibition was a mixed one. Molecular docking revealed the importance of π-π stacking between Phe residue (contained in peptides) and Phe914 (contained in the XO) in the XO inhibitory activity of the peptides.

The influence of chemical composition of potent inhibitors in the hydrolyzed extracts of anti-hyperuricemic plants to their xanthine oxidase activities.

ETHNOPHARMACOLOGICAL RELEVANCE: Anti-hyperuricemic plant parts that were selected for this study, are traditionally used to treat gout in Malaysia. Caffeic acid (a hydroxycinnamic acid), apigenin (a flavone), myricetin, quercetin and kaempferol (flavonols), were reported to act as potent xanthine oxidase inhibitors. These compounds can be found in some of the selected ethnomedicinal plants. However, there is still lack of published research works on the quantification of these inhibitors from these urate-lowering phytotherapies. AIMS OF THE STUDY: The compounds were quantified from 21 hydrolyzed extracts of the phytotherapies for gout. The activity-content contributions of the compounds to the potent extracts were determined. MATERIALS AND METHODS: The anti-hyperuricemic activities of the extracts and the compounds were determined using a xanthine oxidase inhibitory assay. Ultra-Performance Liquid Chromatography (UPLC) coupled with Photodiode Array Detector (PDA) was used to quantify the compounds in the extracts. RESULTS: The results revealed higher activity of the hydrolyzed extracts. The hydrolyzed extract of the flower bud of Syzygium aromaticum Merr. & L.M.Perry exhibited the highest activity (EC50 = 39.58 ± 0.10 µg/mL) due to the highest content of myricetin (42,297.55 ± 159.47 µg/g). The activity-content contribution of myricetin was 7.69%. Due to the highest activity of apigenin (EC50 = 3.27 ± 0.09 µg/mL), the highest contribution of this flavone (29.96%) to the hydrolyzed extract of Orthosiphon aristatus (Blume) Miq. was observed. CONCLUSION: The results revealed different contents and activities of xanthine oxidase inhibitors in the hydrolyzed extracts of anti-hyperuricemic plants can play a major role to influence the activity.

Action mechanisms and interaction of two key xanthine oxidase inhibitors in galangal: Combination of in vitro and in silico molecular docking studies.

Galangal extract (GE)-based hypouricemic functional food is under-developed due to ambiguous quality control standard that is closely associated with action mechanisms and interaction of key xanthine oxidase (XO) inhibitors (kaempferide and galangin) in GE. In terms of kinetics analysis, fluorescence quenching and molecular docking, kaempferide and galangin showed similar docking posture to xanthine in molybdopterin center, and formed flavonol-XO complexes driven by hydrogen bonding, hydrophobic interaction and van der Waals force, competitively inhibiting XO. Kaempferide, had stronger binding affinity for XO and three more hydrogen bonds with XO than galangin, interacting with critical amino acid residues (Arg880 and Glu802) in catalysis reaction of XO and showing stronger XO inhibitory activity than galangin. The combination of kaempferide and galangin enhanced their binding affinities for XO, showing synergistic inhibition on XO at optimal molar ratio 1:4 that could be quality control standard for GE. This study provided new insights into structure-XO inhibitory activity relationship of methoxylated flavonoids and quality control standard for GE-based hypouricemic functional food.

New prenylflavonol glycosides with xanthine oxidase inhibitory activity from the leaves of Cyclocarya paliurus.

Eight new prenylflavonol glycosides (1-8), along with five known analogues (9-13) were isolated from the n-butanol extract of the dried leaves of Cyclocarya paliurus (family Juglandaceae) for the first time. The structures of these compounds were characterized by comprehensive analysis of 1D, 2D NMR, HRESIMS, UV data and acid hydrolysis. In bioassay, all these thirteen prenylflavonol glycosides exhibited inhibitory effects on xanthine oxidase (XOD) activity. Especially compounds 2 and 7, showed outstanding IC50 values of 31.81 ± 2.20 and 29.71 ± 3.69 µM, respectively.

Study on in vitro Inhibitory Activity of the Extracts from 9 Kinds of TCM for Dredging Collaterals and Dispelling Wind on Xanthine Oxidase / 中国药房

OBJECTIVE：To study in vi tro inhibitory act ivities of 9 kinds of TCM for dredging collaterals and dispelling wind on xanthine oxidase （XO），and to screen TCM with outstanding activity. METHODS ：Using xanthine as substrate and xanthinase as reaction enzyme ，allopurinol as positive control ，with water extract and methanol extract （hereinafter referred to as “ethanol extract”）from the stem and leaves of Hedera nepalensis ，the whole plant of Piper wallichii ，the fruits of Rubus corchorifolius ，the root of Caragana sinica ，the root of Wisteria sinensis ，the root of Rubus crataegifolius ，the bark of Catalpa ovata ，the root of Campsis grandiflora ，the stem of P. hancei （hereinafter referred to by plant name ）and petroleum ether ，dichloromethane，ethyl acetate，n-butanol and water fraction of active extract as the objects ，inhibition rate of each sample to XO was detected by spectrophotometry；IC50values were calculated with Graphpad prism 6.0 software to screen active extract/fraction. Double reciprocal method was used to determine the type of enzyme inhibition. RESULTS ：Among 9 kinds of TCM and 18 kinds of the extracts ，the inhibitory rates to XO of 500 μg/mL extracts from each TCM（except for ethanol extract of P. wallichii ），250 μg/mL water extract and ethanol extract of H. nepalensis ，P. wallichii ，R. corchorifolius and P. hancei ，250 μg/mL water extract of C. ovata ，250 μ g/mL ethanol extract of C. sinica ，R. crataegifolius and C. grandiflora ，125 μ g/mL ethanol extract of C. sinica and R. crataegifolius，62.5 μg/mL ethanol extract of C. sinica were more than 50％. The IC 50 value of the ethanol extract from C. sinica was 43.43 μg/mL，which was lower than the extracts of other TCM ，and which was the active extract. The IC 50 values of petroleum ether，dichloromethane，ethyl acetate ，n-butanol and water fracti on of ethanol extract from C. sinica were ＞200，193.35，7.67， 14.80 and ＞200 μg/mL，respectively. The IC 50 value of ethyl XO was competitive-noncompetitive inhibition ， which was different from competi tive inhibition of positive control. CONCLUSIONS：The ethanol extracts of C. sinica ，R. crataegifolius ，P. wallichii ，R. corchorifolius ，P. hancei ，H. nepalensis and the water extracts of H. nepalensis ，P. wallichii ，C. ovata show certain inhibitory activity in vitro to XO ，especially ethanol extract of C. sinica . The ethyl acetate fraction of the ethanol extract of C. sinica has similar inhibitory activity to allopurinol but their inhibition types are different.

Chemical investigation of Hyptis suaveolens seed, a potential antihyperuricemic nutraceutical, with assistance of HPLC-SPE-NMR.

The seed of Hyptis suaveolens, commonly known as wild flour ball (san fen yuan) in Taiwan, serves as a main refreshing drink substance in several regions. This study investigated firstly its secondary metabolites, leading to the isolation of five major caffeoylquinic acid derivatives (1-5) from the ethanol extract. In addition, ten minors, including three caffeoylquinic acid derivatives (12-14), were characterized via assistance of HPLC-SPE-NMR. Of these isolates, sodium 4,5-dicaffeoylquinate (2) and methyl 3,5-dicaffeoylquinate (4) showed moderate inhibitory activity against xanthine oxidase with the respective IC50 values of 69.4 µM and 92.1 µM (c.f. allopurinol IC50 28.4 µM). Quantitative HPLC analysis of the EtOH extract indicates the content of sodium 3,5-dicaffeoylquinate (1) and sodium 4,5-dicaffeoylquinate (2) to be 0.1% and 0.08% (w/w, dry seed), respectively. This study not only discloses the bioactive constituents, but also demonstrates the potential of H. suaveolens seed as an antihyperuricemic nutraceutical.

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.

Purification of Periploca forrestii total flavonoids and assay for the in vitro inhibitory activity on xanthine oxidase / 国际药学研究杂志

Objective: To extract and purify total flavonoids from Periploca forrestii Schltr.(P. forrestii),and test the in vitro inhibitory activity of the total flavonoids and two flvaonoidal compounds in P. forrestii,so as to provide a reference for studies on the related medicinal substances in P. forrestii. Methods: Total flavonoids were extracted from P. forrestii and then purified by the column chromatography on macroporous resin and polyamide columns. The content of total flavonoids was determined according to the Lambert-Beer’s law. The in vitro xanthine oxidase(XOD)inhibitory ac- tivity was assayed for total flavonoids and the two flavonoidal compounds by the ultraviolet spectrophotometry. Results The purified total flavonoids had a content of more than 95%. The total flavonoids and two flavonoidal compounds all showed an inhibitory effect on XOD in vitro,with the inhibitory rate enhanced with increasing concentration. The IC50 of the total flavonoids as well as the two flavonoidal compounds,quercetin-3-O-α-L-pyranoside(QP)and quercetin-7-O-β- D-glucopyranoside(QG)were 608.9,221.2 and 261.2 μg/ml,respectively. Conclusion: The total flavonoids as well as the two flvaonoidal compounds QP and QG in P. forrestii all showed the in vitro inhibitory activity on XOD.

Xanthine Oxidase Inhibitory Activity and Thermostability of Cinnamaldehyde-Chemotype Leaf Oil of Cinnamomum osmophloeum Microencapsulated with ß-Cyclodextrin.

The xanthine oxidase inhibitory activity and thermostability of Cinnamomum osmophloeum leaf oil microencapsulated with ß-cyclodextrin were evaluated in this study. The yield of leaf oil microcapsules was 86.3% using the optimal reaction conditions at the leaf oil to ß-cyclodextrin ratio of 15:85 and ethanol to water ratio ranging from 1:3 to 1:5. Based on the FTIR analysis, the characteristic absorption bands of major constituent, trans-cinnamaldehyde, were confirmed in the spectra of leaf oil microcapsules. According to the dry-heat aging test, ß-cyclodextrin was thermostable under the high temperature conditions, and it was beneficial to reduce the emission of C. osmophloeum leaf oil. Leaf oil microcapsules exhibited high xanthine oxidase inhibitory activity, with an IC50 value of 83.3 µg/mL. It is concluded that the lifetime of C. osmophloeum leaf oil can be effectively improved by microencapsulation, and leaf oil microcapsules possess superior xanthine oxidase inhibitory activity.

Identification of the free phenolic profile of Adlay bran by UPLC-QTOF-MS/MS and inhibitory mechanisms of phenolic acids against xanthine oxidase.

Adlay bran free phenolic extract has been previously demonstrated to possess potent xanthine oxidase (XOD) inhibitory activity. The aims of this study were to characterize the free phenolic profile of adlay bran and investigate the structure-activity relationship, underlying mechanism and interaction of phenolic acids as XOD inhibitors. A total of twenty phenolics including ten phenolic acids, two coumarins, two phenolic aldedhyes and six flavonoids were identified in a phenolic compound-guided separation by UPLC-QTOF-MS/MS. Adlay bran free phenolic extract possessed strong XOD inhibitory activity related to hydroxycinnamic acids with methoxyl groups. The hydrogen bonding and hydrophobic interactions were the main forces in the binding of adlay phenolics to XOD. Sinapic acid, identified in adlay bran for the first time, possessed strong XOD inhibitory activity in a mixed non-competitive manner, and synergistic effects with other adlay phenolic acids at low concentrations, and would be a promising agent for preventing and treating hyperuricemia.

New phenolic glycosides from Curculigo orchioides and their xanthine oxidase inhibitory activities.

Seven new phenolic glycosides including two heterocyclic phenolic derivatives orcinosides I-J (1-2) and five chlorophenolic glycosides curculigines J-N (3-7), together with nineteen known compounds were isolated from the rhizome of Curculigo orchioides. Based on extensive spectroscopic analyses (UV, IR, HRESIMS, 1D and 2D NMR), the structures of the new compounds were identified. Orcinoside I (1) and J (2) displayed xanthine oxidase inhibitory activities with IC50 values 0.25 and 0.62mM respectively.

Investigation of a green process for the polymerization of catechin.

Flavonoids are polyphenolic secondary plant metabolites which possess antioxidant and anti-inflammatory properties. Besides, they have been shown to exhibit increased antioxidant properties in their polymerized form. Catechins are one of the attractive class of flavonoids which belong to the group of flavan-3-ols. Polymerization of catechins have been investigated in numerous studies indicating the requirement of certain amount of organic solvent to provide the solubility of the monomer. However, many research projects have been conducted recently to replace toxic organic contaminants of the processes with environmentally friendly solvents. In this aspect, deep eutectic solvents (DESs) that are regarded as "green solvents" have been studied extensively in various enzyme catalyzed reactions. In the present study, we focused on establishing a green pathway for laccase catalyzed polycatechin synthesis by replacing organic solvent content with DESs as green solvents. For this aim, various parameters were investigated, such as DES types and concentrations laccase amount and reaction time. Consequently, the highest molecular weight polycatechin was obtained using 5% (v/v) B-M, 125 U laccase in 1 hr of reaction time, at 30°C, as 4,354 ± 678 g mol-1. Corresponding X/XO inhibitory activity and superoxide radical scavenging activities were achieved as, 59 and 50%, respectively.