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An investigation of the antiplatelet effects of succinobucol (AGI-1067)

Houston SA, Ugusman A, Gnanadesikan S, Kennedy S

Platelets, 2017 May;28(3):295-300.
PMID: 27681689 DOI: 10.1080/09537104.2016.1218456

Succinobucol is a phenolic antioxidant with anti-inflammatory and antiplatelet effects. Given the importance of oxidant stress in modulating platelet-platelet and platelet-vessel wall interactions, the aim of this study was to establish if antioxidant activity was responsible for the antiplatelet activity of succinobucol. Platelet aggregation in response to collagen and adenosine diphosphate (ADP) was studied in rabbit whole blood and platelet-rich plasma using impedance aggregometry. The effect of oxidant stress on aggregation, platelet lipid peroxides, and vascular tone was studied by incubating platelets, washed platelets or preconstricted rabbit iliac artery rings respectively with a combination of xanthine and xanthine oxidase (X/XO). To study the effect of succinobucol in vivo, anaesthetized rats were injected with up to 150 mg/kg succinobucol and aggregation measured in blood removed 15 mins later. Succinobucol (10-5-10-4M) significantly attenuated platelet aggregation to collagen and ADP in whole blood and platelet-rich plasma. X/XO significantly increased aggregation to collagen and platelet lipid peroxides and this was reversed by succinobucol. Addition of X/XO to denuded rabbit iliac arteries caused a dose-dependent relaxation which was significantly inhibited by succinobucol. In vivo administration up to 150 mg/kg had no effect on heart rate or mean arterial blood pressure but significantly inhibited platelet aggregation to collagen ex vivo. In conclusion, succinobucol displays anti-platelet activity in rabbit and rat blood and reverses the increase in platelet aggregation in response to oxidant stress.

Matched MeSH terms: Xanthine Oxidase/antagonists & inhibitors; Xanthine Oxidase/pharmacology
Flavonoids and phenylethanoid glycosides from Lippia nodiflora as promising antihyperuricemic agents and elucidation of their mechanism of action

Cheng LC, Murugaiyah V, Chan KL

J Ethnopharmacol, 2015 Dec 24;176:485-93.
PMID: 26593216 DOI: 10.1016/j.jep.2015.11.025

ETHNOPHARMACOLOGICAL RELEVANCE: Lippia nodiflora has been traditionally used in the Ayurvedic, Unani, and Sidha systems, as well as Traditional Chinese Medicine (TCM) for the treatment of knee joint pain, lithiasis, diuresis, urinary disorder and swelling.
AIM OF THE STUDY: The present study aims to investigate the antihyperuricemic effect of the L. nodiflora methanol extract, fractions, and chemical constituents and their mechanism of action in the rat model.
MATERIALS AND METHODS: The mechanisms were investigated by performing xanthine oxidase inhibitory, uricosuric, and liver xanthine oxidase/xanthine dehydrogenase (XOD/XDH) inhibitory studies in potassium oxonate- and hypoxanthine-induced hyperuricemic rats. The plant safety profile was determined using acute toxicity study. The molecular docking of the active compound to the xanthine oxidase was simulated using computer aided molecular modeling analysis.
RESULTS: Oral administration of methanol extract showed a dose-dependent reduction effect on the serum uric acid level of hyperuricemic rats. F3 was the most potent fraction in lowering the serum uric acid level of hyperuricemic rats. Bioactivity-guided purification of F3 afforded two phenylethanoid glycosides, arenarioside (1) and verbascoside (2) and three flavonoids, 6-hydroxyluteolin (3), 6-hydroxyluteolin-7-O-glycoside (4), and nodifloretin (5). The highest serum uric acid reduction effect was exhibited by 3 (66.94%) in hyperuricemic rats, followed by 5 (55.97%), 4 (49.16%), 2 (29.03%), and 1 (22.08%) at 0.2 mmol/kg. Dose-response investigation on 3 at doses of 0.05, 0.1, and 0.3 mmol/kg produced a significant dose-dependent reduction on the serum uric acid level of hyperuricemic rats. Repeated administration of F3 or 3 to the hyperuricemic rats for 10 continuous days resulted in a significant and progressive serum uric acid lowering effect in hyperuricemic rats. In contrast, methanol extract and F3 did not reduce serum uric acid level of normoruricemic rats. In addition, F4 significantly increased the uric acid excretion of hyperuricemic rats at 200mg/kg. No toxic effect was observed in rats administered with 5000 mg/kg of methanol extract or F3.
CONCLUSION: The potential application of L. nodiflora against hyperuricemia in the animal in accordance with its traditional uses has been demonstrated in the present study for the first time. The antihyperuricemic effect possessed by L. nodiflora was contributed mainly by liver XOD/XDH inhibitory activities and partially by uricosuric effect. Flavonoids mainly accountable for the uric acid lowering effect of L. nodiflora through the inhibition of XOD/XDH activities.
KEYWORDS: Antihyperuricemic; Hypoxanthine-induced hyperuricemic rat; Lippia nodiflora; Liver xanthine oxidase and xanthine dehydrogenase; Serum uric acid; Uric acid excretion

Matched MeSH terms: Xanthine Oxidase/metabolism
Chelation therapy with desferrioxamine does not normalize ferritin level but attenuates oxidative damage and improves total antioxidant level in Malaysian Chinese beta-thalassaemia major patients

Kuppusamy UR, Tan JA

West Indian Med J, 2011 Jan;60(1):3-8.
PMID: 21809703

Beta-thalassaemia major causes severe anaemia and patients with it may be transfusion-dependent for life. Regular blood transfusions cause iron-overload that leads to oxidative damage which can hasten mortality. The objective of this research was to study the oxidant-antioxidant indices in beta-thalassaemia major patients at the University of Malaya Medical Centre (UMMC) who were on desferrioxamine-chelation or without chelation therapy. Blood was collected from 39 Chinese patients and 20 controls. Plasma and peripheral blood mononuclear cell lysates (PBMC) were extracted and biochemical tests to evaluate oxidative stress were performed. Oxidative stress was evident in these patients as advanced oxidized protein products (AOPP) and lipid hydroperoxides were elevated, whereas glutathione peroxidase activity and the ferric reducing antioxidant power (FRAP) were reduced. The catalase activity in the patients' PBMC was elevated, possibly as a compensatory mechanism for the reduced glutathione peroxidase activity in both red blood cells and PBMC. The lower FRAP and higher AOPP levels in the non-chelated patients compared with the chelated patients were indicative of a lower oxidative stress level in the chelated patients. The ferritin levels in the chelated and non-chelated patients were high and the mean levels of liver enzyme activities in the majority of patients were elevated regardless of chelation therapy. In conclusion, this study indicates that desferrioxamine chelation therapy does not normalize ferritin level but attenuates oxidative damage and improves total antioxidant level in Malaysian Chinese beta-thalassaemia major patients.

Matched MeSH terms: Xanthine Oxidase/blood
Glycaemic control in relation to xanthine oxidase and antioxidant indices in Malaysian Type 2 diabetes patients

Kuppusamy UR, Indran M, Rokiah P

Diabet Med, 2005 Oct;22(10):1343-6.
PMID: 16176194 DOI: 10.1111/j.1464-5491.2005.01630.x

Aims: Increased oxidative stress and oxidative damage are present in Type 2 diabetes mellitus (DM). The aim of this study was to assess the oxidative stress levels in the three major ethnic groups in Malaysia and to study the association between glycaemic control and oxidant-antioxidant levels in these patients.

Methods: Oxidative indices and glycaemic control were assessed in 650 Type 2 DM patients and 280 healthy age-matched controls by known established methods.

Results: Type 2 DM patients had significantly lower levels of antioxidant enzymes and non-enzymatic antioxidant (FRAP) and increased levels of HbA(1c), fasting blood glucose (FBG), malondialdehyde (MDA) and xanthine oxidase (XO) when compared with control subjects. Markers of oxidative stress were more apparent in Indian patients compared with Malay and Chinese patients. Correlation analysis of oxidant-antioxidant parameters as a function of HbA(1c) in each ethnic group revealed a strong association of HbA(1c) with oxidative indices.

Conclusions: The present study provides evidence for the possible contribution of XO to oxidative stress and the pathophysiology of diabetes. HbA(1c) remains an important marker of glycaemic control for the management of Type 2 DM, but other confounding factors that predispose or lead to oxidative stress should also be taken into consideration.

Matched MeSH terms: Xanthine Oxidase/blood*
Biological Activities of Isolated Compounds from Three Edible Malaysian Red Seaweeds, Gracilaria changii, G. manilaensis and Gracilaria sp

Andriani Y, Syamsumir DF, Yee TC, Harisson FS, Herng GM, Abdullah SA, et al.

Nat Prod Commun, 2016 Aug;11(8):1117-1120.
PMID: 30725572

Gracilaria species are red marine macroalgae that are found abundantly in Malaysia. Gracilaria changii from Morib, Selangor, G. nanilaensis and Gracilaria sp. from Gelang Patah, Johor were used in this study. Five compounds were successfully isolated and identified as hexadecanoic acid (1), cholest-5-en-3-ol (2), 2-hydroxymyristic acid (3), cholesteryl myristate (4) and 1-(4'-methoxyphenyl)-3-(2",4",6"-trihydroxyphenyl)-3-hydroxypropanone (5) based on spectral data analysis (IR, UV, GC-MS, 'H NMR, "C NMR, HMQC and HMBC). All compounds isolated were tested for cytotoxicity (MTT assay for HL-60 and MCF-7 cell lines), and antibacterial (disc diffusion method), antioxidant (DPPH free radical scavenging assay and xanthine oxidase inhibitory assay) and acetylcholinesterase inhibitory (AChE) activity (TLC bioautographic method). Compounds I and 3 exhibited strong cytotoxic activity against HL-60 and MCF-7 cell lines. Compound 5 showed high antioxidant activity in both the DPPH free radical scavenging and xanthine oxidase inhibition assays. Compound I showed positive activity for AChE inhibitory with a minimum inhibition dose of 0.625 tg sample. All compounds demonstrated antibacterial activity producing 8 to 14 mm inhibition zones. A positive control was applied to all bioassays and experiments were performed with three replicates. Results demonstrated that three edible red seaweeds are rich sources of bioactive compounds with potential application for pharmaceutical purposes.

Matched MeSH terms: Xanthine Oxidase
Antioxidant and anti-inflammatory activities contribute to the prophylactic effect of semi-purified fractions obtained from the crude methanol extract of Muntingia calabura leaves against gastric ulceration in rats

Balan T, Sani MH, Mumtaz Ahmad SH, Suppaiah V, Mohtarrudin N, Zakaria ZA

J Ethnopharmacol, 2015 Apr 22;164:1-15.
PMID: 25540923 DOI: 10.1016/j.jep.2014.12.017

In traditional medicine, the leaves, flowers, barks and roots of Muntingia calabura L. (Muntingiaceae) have been employed as a treatment for various ailments including dyspepsia and to relieve pain caused by gastritis and peptic ulcer disease. The methanolic extract of Muntingia calabura leaves (MEMC) has been proven in the previous study to possess significant antiulcer activity. In this study, we attempted to determine the prophylactic effect of the fractions obtained from MEMC against ethanol-induced gastric lesion in rats and the involvement of antioxidants and anti-inflammatory mediators.

Matched MeSH terms: Xanthine Oxidase/metabolism
Fulltext Mechanism(s) of action involved in the gastroprotective activity of Muntingia calabura

Zakaria ZA, Balan T, Suppaiah V, Ahmad S, Jamaludin F

J Ethnopharmacol, 2014 Feb 12;151(3):1184-1193.
PMID: 24380736 DOI: 10.1016/j.jep.2013.12.045

ETHNOPHARMACOLOGICAL RELEVANCE: Muntingia calabura L. (Muntingiaceae) is locally known as kerukup siam. Its leaves, flowers, barks and roots have been used traditionally in East Asia and South America to treat various diseases including ulcer-related diseases. The present study aimed to investigate the mechanism(s) of gastroprotective effect of methanol extract of Muntingia calabura leaves (MEMC) using the pylorus ligation induced gastric ulceration in rats.
MATERIALS AND METHODS: Five groups of rats (n=6) were administered orally once daily for 7 days with 8% Tween 80 (negative control), 100 mg/kg ranitidine (positive control), or MEMC (100, 250 or 500 mg/kg), followed by the ulcer induction via ligation of the pyloric part of the rat's stomach. This was followed by the macroscopic analysis of the stomach, evaluation of gastric content parameters, and quantification of mucus content. The antioxidant (measured using the superoxide anion and 2,2-diphenyl-1-picrylhydrazyl (DPPH)-radical scavenging, oxygen radical absorbance capacity (ORAC) and total phenolic content (TPC) assays), anti-inflammatory (evaluated using the in vitro lipoxygenase and xanthine oxidase assays), phytoconstituents and HPLC analysis of MEMC were also carried out.
RESULTS: The MEMC significantly (p<0.05) reduced gastric lesion in this model. Furthermore, the extract also significantly (p<0.01) reduced the volume of gastric content whereas the total acidity was significantly (p<0.05) reduced in the doses of 100 and 500 mg/kg MEMC. Moreover, the mucus content increased significantly (p<0.01) in MEMC-treated rats. The extract also showed high antioxidant and anti-inflammatory activities in all assays tested, and demonstrated the presence of high tannins and saponins followed by flavonoids.
CONCLUSION: The MEMC exerted gastroprotective effect via several mechanisms including the anti-secretory, antioxidant and anti-inflammatory activities. These activities could be attributed to the presence of tannins, saponins and flavonoids (e.g. rutin, quercitrin, fisetin and dihydroquercetin).

Matched MeSH terms: Xanthine Oxidase/metabolism
Fulltext Palm vitamin E reduces catecholamines, xanthine oxidase activity and gastric lesions in rats exposed to water-immersion restraint stress

Mohd Fahami NA, Ibrahim IA, Kamisah Y, Mohd Ismail N

BMC Gastroenterol, 2012;12:54.
PMID: 22639913 DOI: 10.1186/1471-230X-12-54

This study examined the effects of Palm vitamin E (PVE) and α-tocopherol (α-TF) supplementations on adrenalin, noradrenalin, xanthine oxidase plus dehydrogenase (XO + XD) activities and gastric lesions in rats exposed to water-immersion restraint stress (WIRS).

Matched MeSH terms: Xanthine Oxidase/metabolism*
Mechanisms of antihyperuricemic effect of Phyllanthus niruri and its lignan constituents

Murugaiyah V, Chan KL

J Ethnopharmacol, 2009 Jul 15;124(2):233-9.
PMID: 19397979 DOI: 10.1016/j.jep.2009.04.026

ETHNOPHARMACOLOGICAL RELEVANCE: Phyllanthus niruri Linn. (Euphorbiaceae) is used as folk medicine in South America to treat excess uric acid. Our initial study showed that the methanol extract of Phyllanthus niruri and its lignans were able to reverse the plasma uric acid of hyperuricemic animals.
AIM OF THE STUDY: The study was undertaken to investigate the mechanisms of antihyperuricemic effect of Phyllanthus niruri and its lignan constituents.
MATERIAL AND METHODS: The mechanisms were investigated using xanthine oxidase assay and uricosuric studies in potassium oxonate- and uric acid-induced hyperuricemic rats.
RESULTS: Phyllanthus niruri methanol extract exhibited in vitro xanthine oxidase inhibition with an IC50 of 39.39 microg/mL and a moderate in vivo xanthine oxidase inhibitory activity. However, the lignans display poor xanthine oxidase inhibition in vitro and a relatively weak in vivo inhibitory activity at 10mg/kg. On the other hand, intraperitoneal treatment with Phyllanthus niruri methanol extract showed 1.69 folds increase in urinary uric acid excretion when compared to the hyperuricemic control animals. Likewise, the lignans, phyllanthin, hypophyllanthin and phyltetralin exhibited up to 2.51 and 11.0 folds higher in urinary uric acid excretion and clearance, respectively. The co-administration of pyrazinamide with phyllanthin exhibited a significant suppression of phyllanthin's uricosuric activity resembling that of pyrazinamide with benzbromarone.
CONCLUSIONS: The present study showed that the antihyperuricemic effect of Phyllanthus niruri methanol extract may be mainly due to its uricosuric action and partly through xanthine oxidase inhibition, whereas the antihyperuricemic effect of the lignans was attributed to their uricosuric action.

Matched MeSH terms: Xanthine Oxidase/antagonists & inhibitors*
Fulltext The Antioxidant and Xanthine Oxidase Inhibitory Activity of Plumeria rubra Flowers

Mohamed Isa SSP, Ablat A, Mohamad J

Molecules, 2018 Feb 13;23(2).
PMID: 29438299 DOI: 10.3390/molecules23020400

Plumeria rubra Linn of the family Apocynaceae is locally known in Malaysia as "Kemboja". It has been used by local traditional medicine practitioners for the treatment of arthritis-related disease. The LCMS/MS analysis of the methanol extract of flowers (PR-ME) showed that it contains 3-O-caffeyolquinic acid, 5-caffeoquinic acid, 1,3-dicaffeoquinic acid, chlorogenic acid, citric acid, 3,3-di-O-methylellagic acid, kaempferol-3-O-glucoside, kaempferol-3-rutinoside, kaempferol, quercetin 3-O-α-l-arabinopyranoside, quercetin, quinic acid and rutin. The flower PR-ME contained high amounts of phenol and flavonoid at 184.632 mg GAE/g and 203.2.2 mg QE/g, respectively. It also exhibited the highest DPPH, FRAP, metal chelating, hydrogen peroxide, nitric oxide superoxide radical scavenging activity. Similarly, the XO inhibitory activity in vitro assay possesses the highest inhibition effects at an IC50 = 23.91 μg/mL. There was no mortality or signs of toxicity in rats at a dose of 4 g/kg body weight. The administration of the flower PR-ME at doses of 400 mg/kg to the rats significantly reduced serum uric acid 43.77%. Similarly, the XO activity in the liver was significantly inhibited by flower PR-ME at doses of 400 mg/kg. These results confirm that the flower PR-ME of P. rubra contains active phytochemical compounds as detected in LCMS/MS that contribute to the inhibition of XO activity in vitro and in vivo in reducing acid uric level in serum and simultaneously scavenging the free radical to reduce the oxidative stress.

Matched MeSH terms: Xanthine Oxidase/antagonists & inhibitors*; Xanthine Oxidase/metabolism

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