title: Protective effects of baicalein against excess L-DOPA-induced dopamine quinone neurotoxicity.
abstract: OBJECTIVE
  Baicalein, a flavonoid derived from the root of Scutelaria baicalensis Georgi, possesses anti-oxidative properties including reactive oxygen species scavenging and lipid peroxidation inhibiting activities. The present study was undertaken  to investigate the neuroprotective effect of baicalein against dopamine (DA) neurotoxicity induced by exposure to a synthetic DA precursor, L-3,4-dihydroxyphenylalanine (L-DOPA), in cultured dopaminergic CATH.a cells.
  
  
  RESULTS
  Exposure to L-DOPA for 24 hours reduced the  number of viable cells and enhanced protein-bound quinone (quinoprotein) formation in the cell. Both effects were prevented by simultaneous treatment with baicalein. In addition, baicalein prevented the formation of DA semiquinone radicals from DA in an in vitro cell-free system. Long-term  baicalein treatment for 96 hours also protected against excess L-DOPA-induced cell death, and also increased glutathione (GSH) levels in CATH.a cells.
  
  
  CONCLUSIONS
  Our results indicate that baicalein has neuroprotective properties against excess L-DOPA-induced DA neurotoxicity through  the suppression of DA quinone formation. Furthermore, the long-term treatment of baicalein upregulates intracellular GSH contents, which may also exert neuroprotective effects against oxidative stress-induced neuronal damage.
authors.affiliation: School of Food and Nutrition Science, Kyushu Nutrition Welfare University, Fukuoka, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Takeshima
authors.forename: Maiko
authors.initials: M
authors.lastname: Murata
authors.forename: Natsuho
authors.initials: N
authors.lastname: Urasoe
authors.forename: Shinki
authors.initials: S
authors.lastname: Murakami
authors.forename: Ikuko
authors.initials: I
authors.lastname: Miyazaki
authors.forename: Masato
authors.initials: M
authors.lastname: Asanuma
authors.forename: Taizo
authors.initials: T
authors.lastname: Kita
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology / Q000627:therapeutic use; D000978:Antiparkinson Agents / Q000493:pharmacokinetics / Q000633:toxicity*; D002460:Cell Line; D004298:Dopamine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity; D044950:Flavanones / Q000494:pharmacology* / Q000627:therapeutic use; D007980:Levodopa / Q000493:pharmacokinetics / Q000633:toxicity*; D051379:Mice; D018696:Neuroprotective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D009498:Neurotoxins / Q000037:antagonists & inhibitors*
chemical_list: D000975:Antioxidants; D000978:Antiparkinson Agents; D044950:Flavanones; D018696:Neuroprotective Agents; D009498:Neurotoxins; D007980:Levodopa; C006680:baicalein; C104705:dopamine quinone; D004298:Dopamine