en Original Original <p style="DIRECTION: ltr" align="justify"><strong>Abstract<br>Introduction:</strong> Parkinson's disease (PD) is a neuropathological disorder involving the degeneration of dopaminergic neurons in the substantia nigra, with the subsequent loss of their terminals in the striatum. Quercetin, a natural flavonoid, is a strong antioxidant and radical scavenger. Therefore, its neuroprotective effect in a model of Parkinson’s disease in rat was evaluated.<br><strong>Methods:</strong> For this purpose, unilateral intrastriatal 6-hydroxydopamine (6-OHDA)-lesioned rats were pretreated with quercetin (20 mg/kg i.p.) 1 hour before surgery and treated once a day for one month. Nissl-stained neurons of substantia nigra pars compacta (SNC) were counted. <br><strong>Results:</strong> Number of Nissl-stained neurons in left side of SNC of lesion group was lower relative to sham-operated group (p<0.005) and it was higher in quercetin-treated lesion group as compared to untreated lesion group (p<0.01).<br><font face="tahoma,arial,helvetica,sans-serif"><strong><span style="LINE-HEIGHT: 115% FONT-FAMILY: "><font size="2" face="tahoma,arial,helvetica,sans-serif">Discussion</font></span>:</strong></font> Flavonoid quercetin administration for one month could protect the neurons of SNC against 6-OHDA toxicity.  <br></p> Quercetin, 6-Hydroxydopamine, Parkinson’s disease, Rat 3 6 http://bcn.iums.ac.ir/browse.php?a_code=A-10-1-1&slc_lang=en&sid=1 Mehdi Mehdizadeh 137003194753284600302 137003194753284600302 Yes Mohammad Taghi Joghataei 137003194753284600303 137003194753284600303 No Maliheh Nobakht 137003194753284600304 137003194753284600304 No Roya Aryanpour 137003194753284600305 137003194753284600305 No