Mechanisms underlying quercetin-induced vasorelaxation in aorta of subchronic diabetic rats: an in vitro study

In this study, the mechanisms involved in vasorelaxant effect of the flavonoid quercetin was investigated in isolated aortic rings from streptozotocin (STZ)-diabetic rats. After 4 weeks, addition of quercetin (0.1 muM-1 mM) caused a significant dose-dependent relaxation of noradrenaline (NA)- and KCl-preconstricted rings in both control and diabetic groups with a significant inter-group difference of P<0.01. Furthermore, both nitro-L-arginine-methyl ester (L-NAME, 100 muM) and indomethacin (10 muM) markedly attenuated the vasorelaxant responses following quercetin application. Meanwhile, endothelium removal significantly attenuated the quercetin-induced vasorelaxation. It is concluded that the quercetin can relax the preconstricted rings of aorta in subchronic STZ-diabetic rats through nitric oxide- and prostaglandin-mediated pathways, which themselves could be considered as endothelium-dependent. (C) 2004 Elsevier Inc. All rights reserved

Endothelium-dependent attenuating effect of Trigonella foenum-graecum on the contractile vascular reactivity of diabetic rats

The present study was undertaken to determine whether two-month treatment of streptozotocin (STZ)-diabetic rats with aqueous leaf extract of Trigonella foenum-graecum (TFG; 200 mg/kg; i.p.) could improve thoracic aortic responsiveness and to evaluate its endothelium dependency. For this purpose, vascular responses to KCl and noradrenaline (NA) were measured. Diabetic state significantly increased contractile responses to KCl and NA in aortic rings in both endothelium-intact and -denuded rings. Extract-treated diabetic rats showed a significant lower maximal contractile response to KCl only in endothelium-intact rings as compared to diabetic rings. It is concluded that intraperitoneal administration of aqueous leaf extract of TFG for two months could improve some functional indices of the vascular system in diabetic state and the integrity of the endothelium is essential for its beneficial effects

The Flavonoid Hesperetin Alleviates Behavioral Abnormality in 6-Hydroxydopamine Rat Model of Hemi-Parkinsonism

ABSTRACTParkinson’s disease (PD) is a neuropathological and debilitating disorder involving the degeneration of mesencephalic dopaminergic neurons. Neuroprotective effect of hesperetin has already been reported, therefore, this study examined whether the administration of this flavonoid would attenuate behavioral abnormalities in an experimental model of PD in rat. For this purpose, unilateral intrastriatal 6-hydroxydopamine (6-OHDA, 12.5 μg/5μl of saline-ascorbate)-lesioned rats were pretreated i.p. with hesperetin (10 mg/kg). It was found out that hesperetin administration attenuates the rotational behavior in lesioned rats. In summary, hesperetin administration attenuates behavioral abnormality in hemiparkinsonian rats and this may be of benefit, along with other therapies, in neurodegenerative disorders including PD

Green Tea Polyphenol Epigallocatechin-3-Gallate Attenuates Behavioral Abnormality in Hemi-Parkinsonian Rat

ABSTRACT Background: Epigallocatechin gallate (EGCG), a major constituent of green tea, has been introduced as a potent free radical scavenger and can effectively reduce free radical-induced lipid peroxidation. Since free radical injury plays an important role in neuronal damage in Parkinson&apos;s disease (PD), this study examined whether EGCG administration would reduce functional asymmetry in an experimental model of PD in male Wistar rats. Methods: For this purpose, unilateral intrastriatal 6-hydroxydopamine-lesioned rats were intraperitoneally pretreated with EGCG (40 mg/Kg) 2 hours before surgery and daily (20 mg/Kg) for a period of 2 weeks post-surgery. Apomorphine-and amphetamine-induced rotations were measured pre-and postsurgery after 2 weeks. Results: The results showed that there are 35.1% (P&lt;0.05) and 33.2% (P&lt;0.05) reductions in controversies apomorphine-and ipsiversive amphetamine-induced rotations in EGCG-treatedlesioned group respectively as compared to the untreated lesioned group at 2 nd week post-surgery. Conclusion: Taken together, these results showed that two-week administration of EGCG could attenuate the drug-induced behavioral abnormalities in this model of PD

The Flavonoid Hesperetin Alleviates Behavioral Abnormality in 6-Hydroxydopamine Rat Model of Hemi-Parkinsonism

ABSTRACTParkinson’s disease (PD) is a neuropathological and debilitating disorder involving the degeneration of mesencephalic dopaminergic neurons. Neuroprotective effect of hesperetin has already been reported, therefore, this study examined whether the administration of this flavonoid would attenuate behavioral abnormalities in an experimental model of PD in rat. For this purpose, unilateral intrastriatal 6-hydroxydopamine (6-OHDA, 12.5 μg/5μl of saline-ascorbate)-lesioned rats were pretreated i.p. with hesperetin (10 mg/kg). It was found out that hesperetin administration attenuates the rotational behavior in lesioned rats. In summary, hesperetin administration attenuates behavioral abnormality in hemiparkinsonian rats and this may be of benefit, along with other therapies, in neurodegenerative disorders including PD

The Flavonoid Hesperetin Alleviates Behavioral Abnormality in 6-Hydroxydopamine Rat Model of Hemi-Parkinsonism

Parkinson's disease (PD) is a neuropathological and debilitating disorder involving the degeneration of mesencephalic dopaminergic neurons. Neuroprotective effect of hesperetin has already been reported, therefore, this study examined whether the administration of this flavonoid would attenuate behavioral abnormalities in an experimental model of PD in rat. For this purpose, unilateral intrastriatal 6-hydroxydopamine (6-OHDA, 12.5 μg/5μl of saline-ascorbate)-lesioned rats were pretreated i.p. with hesperetin (10 mg/kg). It was revealed that hesperetin administration attenuates the rotational behavior in lesioned rats. In summary, hesperetin administration attenuates behavioral abnormality in hemiparkinsonian rats and this may be of benefit, along with other therapies, in neurodegenerative disorders including PD

Protective effects of aqueous extract of silybum marianum in 6-hydroxydopamine-induced model of parkinsonism in male rat: a behavioral, biochemic and histological study

Introduction : Parkinson,s disease (PD) is a common neurological disorder due to degeneration of substantia nigra pars compacta degeneration. With regard to protective effect of silybum marianum, this study was conducted to evaluate the protective effect of aqueous extract of this plant in an experimental model of PD . Materials and Methods: Forty male rats were randomly divided into 4 groups; sham-operated(SH), extract-treated sham-operated (E+SH), lesion (L) and extract-treated lesion(E+L) groups. The hemi-PD model was induced by unilateral intrastriatal injection of 6-hydroxydopamine (6-OHDA, 12.5 g/ l of saline-ascorbate).The E+SH and E+L groups received intra-peritoneal pretreatment of aqueous extract of silybummarianum (200mg/kg/daily) for one week before surgery. Two weeks after surgery, the animals were tested for rotational behavior by apomorphine hydrochloride and the number of nissle-stained neurons in the substantia nigra pars compacta (SNC). Results: Two weeks after surgery, apomorphine caused a significant contralateral turning (P<0.0001) and reduction in the number of neurons on the left side of the SNC in the L group in comparison with SH group (P<0.05). Administration of aqueous extract of silybum marianum decreased the rotational behavior in lesioned rats and attenuated the reduction of number of SNC neurons (P<0.05). On the other hand, treatment of SH group with extract of silybum marianum had no significant effect on the number of apomophine-induced rotation and neurons of SNC . Conclusion: Our finding shows in experimental model of PD, intra-peritoneal administration of aqueous extract of silybum marianum has protective effects against 6-OHDA toxicity

The Anticonvulsant and Antioxidant Effects of Berberine in Kainate-induced Temporal Lobe Epilepsy in Rats

Introduction: Temporal lobe epilepsy(TLE) is a long lasting neurological disorder in which patients suffer from spontaneous seizures. New treatments with novel mechanisms of action are needed to help those patients whose seizures are resistant to available drugs. In this study, we investigated the possible neuroprotective effect of berberine in an intrahippocampal kainate model of TLE in rat. Methods: In the present study, the anticonvulsant and antioxidant effects of intraperitoneal administration of berberine(25, 50 and 100 mg/kg), was evaluated in intrahippocampal kainate(4g)-induced TLE in rats. Results: The results showed that the kainate rats exhibit acute and spontaneous seizures in 24 hours and two weeks after intrahippocampal kainic acid injection. Administration of berberine, significantly decreased Racine score and rate of incidence of seizure in kainate rats(P<0.05). On the other hand, berberine ameliorated the lipid peroxidation(P<0.001) and nitrite(P<0.001) level, but had no effect on SOD activity. Discussion: These data suggest that berberine pretreatment could attenuate spontaneous recurrent seizures. Since, administration of berberine decreased lipid peroxidation in kainate rats, it seems that berberine,s favourable effect is due to its effectiveness in lessening of oxidative stress in rat. Key words: Kainic acid, Berberine, Seizure, Hippocampus, Oxidative stress, Ra