Neurodegenerative diseases are multifactorial debilitating disorders of the nervous system affecting approximately 30 million individuals worldwide. Mitochondrial dysfunction and oxidative stress have also been implicated in causing neurodegeneration. As life expectancy is increasing, neurodegenerative disorders are becoming a major social issue. None of the drugs currently available for treatment are capable of healing the patient. This means that new molecules should be explored. Plants have been used for treatment of countless medical conditions and extensive research is being carried out on species of the Myrtaceae family, widely used in traditional medicine. To date, Myrciaria plinioides D. Legrand has not been studied for its therapeutic use. To evaluate the neuroprotective effect of aqueous and ethanol extracts of this plant, we investigated the protective effects in human neuroblastoma cells (SH-SY5Y). High-performance liquid chromatography fingerprinting of extracts revealed the presence of phenolic compounds and flavonoids. Extracts showed antioxidant activity in the ORAC, DPPH, FRAP and GAE methods. Ethanol extract presented a strong inhibitory activity toward p38 and JNK3 MAPKs and AChE activity and also toward TNF-α release in human whole blood. None of the extracts significantly affected cell viability; the ethanol extract, however, reversed 6-OHDA-induced toxicity. Particularly the ethanol extract suggests neuroprotective effects by preventing membrane depolarization and by significantly decreasing H2O2 production and caspase-3 activity. The present results indicate that the ethanol extract protects SH-SY5Y cells against oxidative damage and apoptosis, as shown by the antioxidative activity of the extract as well as by the inhibition of important proteins such as caspase-3, p38 and JNK3 and the cytokine TNF-α.
Keywords: 6-Hydroxydopamine; Human neuroblastoma cells; MAPK; Medicinal plants; Neurodegenerative diseases.