Hum Exp Toxicol. 2011 (Sep); 30 (9): 1382–1391
de Oliveira DM1, Barreto G, Galeano P, Romero JI, Holubiec MI,
Badorrey MS, Capani F, Alvarez LD.
Laboratório de Neuroquímica e Biologia Celular,
Instituto de Ciências da Saúde,
Universidade Federal da Bahia (UFBA),
Campus do Canela, Salvador, Bahia, Brasil.
This study has me excited about the potential long-term effects of this novel new ingredient. Because guaraná has powerful antioxidant properties, these researchers wanted to explore its impact on neurodegenerative disorders like Parkinson's disease (PD). PD begins with the degeneration of a portion of the brain called the substantia nigra (SN) because of oxidative damage. The SN produces a neurotransmitter called dopamine. Loss of these dopamine-secreting neurons causes the muscle tremors and motor impairments most associated with PD; however dopamine also plays other important roles in personal motivation, behavior, pleasure arousal, mood, and learning.
To test their hypothesis, they treated human dopaminergic brain cells with a toxic insecticide called rotenone over 48 hours. Then they treated those same cells with guaraná extract, at 2 different concentrations. Post-testing showed that guaraná significantly increased cell viability, in a dose-dependent manner. Although this is a basic cell culture study, it does suggest that guaraná provides important neuro-protective effects which need to be explored further.
Paullinia cupana Mart. var. Sorbilis, commonly known as Guaraná, is a Brazilian plant frequently cited for its antioxidant properties and different pharmacological activities on the central nervous system. The potential beneficial uses of Guaraná in neurodegenerative disorders, such as in Parkinson's disease (PD), the pathogenesis of which is associated with mitochondrial dysfunction and oxidative stress, has not yet been assessed. Therefore, the main aim of the present study was to evaluate if an extract of commercial powdered seeds of Guaraná could protect human dopaminergic neuroblastoma SH-SY5Y cell line against rotenone-induced cytotoxicity. Two concentration of Guaraná dimethylsulfoxide extract (0.312 and 0.625 mg/mL) were added to SH-SY5Y cells treated with 300 nM rotenone for 48 h, and the cytoprotective effects were assessed by means of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, measuring lactate dehydrogenase (LDH) levels, and analyzing nuclear integrity with Hoechst33258 stain. Results showed that the addition of Guaraná extract significantly increased the cell viability of SH-SY5Y cells treated with rotenone, in a dose-dependent manner. On the other hand, LDH levels were significantly reduced by addition of 0.312 mg/mL of Guaraná, but unexpectedly, no changes were observed with the higher concentration. Moreover, chromatin condensation and nuclear fragmentation were significantly reduced by addition of any of both concentrations of the extract. The results obtained in this work could provide relevant information about the mechanisms underlying the degeneration of dopaminergic neurons in PD and precede in vivo experiments. Further studies are needed to investigate which active constituent is responsible for the cytoprotective effect produced by Paullinia cupana.
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