ABSTRACT
Title
Evidences for neuroprotective effect of bergamot juice in an in vitro model of experimental Parkinson's disease
Authors
G. Lo Surdo1, E. Trapasso1, M. R. Ursino1, G. Calapai2, M. Navarra1,3
1Pharmaco-Biological Dept., School of Pharmacy, University of Messina, Italy
2Dept. of Clinical and Experimental Medicine and Pharmacology, School of Medicine, University of Messina, Messina
3IRCCS Centro Neurolesi "Bonino-Pulejo", Messina
1Pharmaco-Biological Dept., School of Pharmacy, University of Messina, Italy
2Dept. of Clinical and Experimental Medicine and Pharmacology, School of Medicine, University of Messina, Messina
3IRCCS Centro Neurolesi "Bonino-Pulejo", Messina
Abstract
It is known that high levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS) are involved in numerous neurodegenerative processes such as Parkinson's disease (PD). Etiopathogenesis of PD seems to be partially related to the oxidative stress due to the excessive hydrogen peroxide (H2O2) formation caused by increased dopamine turnover. Mitochondrial dysfunction and inflammation can also contribute to ROS production and has been implicated in the pathologenic mechanism of PD (Drechsel and Patel, 2008). Disruption in the balance of ROS and RNS contributes to oxidative damage of cellular macromolecules ultimately leading to cell death.
Several experimental evidences have demonstrated that vegetable molecules commonly present in the diet may prevent a number of diseases associated with oxidative stress (Espín et al., 2007). Over the past few years, following the growing interest about the antioxidant activity of compounds present in the diet, bergamot juice (BJ) has attracted attention as a result of its remarkable flavonoids content.
Citrus bergamia Risso et Poiteau (bergamot) is a small tree belonging to the family Rutaceae, growing almost exclusively in Calabria region (Italy). Bergamot fruit is used mostly for the extraction of its essential oil from the peel, widely used in perfumery industry. On the contrary, BJ, obtained from the endocarp after essential oils extraction, is considered just a secondary and discarded product.
Aim of the present study was to evaluate the cytoprotective effect of BJ in an in vitro toxin-based models to induce experimental PD. Experiments were performed on the catecholaminergic SH-SY5Y neuroblastoma cell cultures by using 6-hydroxydopamine (6-OHDA) as a selective catecholaminergic neurotoxin able to generate ROS in neurons.
Treatment of SHSY-5Y with 6-OHDA (50 and 100 µM) resulted in significant cytotoxic effects, as assessed 24 hours later by MTT reduction assay (P<0.001 vs untreated cultures). Pre-incubation with BJ (0,5% and 1%) 1 hour prior to the exposure to 6-OHDA exhibited significant concentration-dependent prevention on 6-OHDA-induced cell death (P<0.001vs 6-OHDA-treated cells). BJ alone caused a significant reduction of metabolic activity at concentration equal or greater than to 5% (P<0.05 and P<0.001, respectively). Furthermore, 10-min incubation of SH-SY5Y cells with 30 μM 6-OHDA significantly increased ROS production (P<0.05) that was completely abolished by BJ (P<0.001). Furthermore, cytofluorimetric studies (Annexin-V test and cell cycle analysis) suggest that BJ can inhibit apoptosis induced by 6-OHDA. Evidences that BJ protects SHSY-5Y cells against H2O2-induced ROS generation and cell death suggests its antioxidant capability, as further assessed by both the DPPH and the reducing power tests.
Collectively, our study indicate that the antioxidant propertiesof BJ may be responsible of its neuroprotective effect in vitro, while other mechanisms of action cannot be excluded.
Drechsel and Patel (2008). Free Radic Biol Med. 44 (11),1873-1886.
Espín et al. (2007). Phytochemistry. 68 (22-24), 2986-3008.
Several experimental evidences have demonstrated that vegetable molecules commonly present in the diet may prevent a number of diseases associated with oxidative stress (Espín et al., 2007). Over the past few years, following the growing interest about the antioxidant activity of compounds present in the diet, bergamot juice (BJ) has attracted attention as a result of its remarkable flavonoids content.
Citrus bergamia Risso et Poiteau (bergamot) is a small tree belonging to the family Rutaceae, growing almost exclusively in Calabria region (Italy). Bergamot fruit is used mostly for the extraction of its essential oil from the peel, widely used in perfumery industry. On the contrary, BJ, obtained from the endocarp after essential oils extraction, is considered just a secondary and discarded product.
Aim of the present study was to evaluate the cytoprotective effect of BJ in an in vitro toxin-based models to induce experimental PD. Experiments were performed on the catecholaminergic SH-SY5Y neuroblastoma cell cultures by using 6-hydroxydopamine (6-OHDA) as a selective catecholaminergic neurotoxin able to generate ROS in neurons.
Treatment of SHSY-5Y with 6-OHDA (50 and 100 µM) resulted in significant cytotoxic effects, as assessed 24 hours later by MTT reduction assay (P<0.001 vs untreated cultures). Pre-incubation with BJ (0,5% and 1%) 1 hour prior to the exposure to 6-OHDA exhibited significant concentration-dependent prevention on 6-OHDA-induced cell death (P<0.001vs 6-OHDA-treated cells). BJ alone caused a significant reduction of metabolic activity at concentration equal or greater than to 5% (P<0.05 and P<0.001, respectively). Furthermore, 10-min incubation of SH-SY5Y cells with 30 μM 6-OHDA significantly increased ROS production (P<0.05) that was completely abolished by BJ (P<0.001). Furthermore, cytofluorimetric studies (Annexin-V test and cell cycle analysis) suggest that BJ can inhibit apoptosis induced by 6-OHDA. Evidences that BJ protects SHSY-5Y cells against H2O2-induced ROS generation and cell death suggests its antioxidant capability, as further assessed by both the DPPH and the reducing power tests.
Collectively, our study indicate that the antioxidant propertiesof BJ may be responsible of its neuroprotective effect in vitro, while other mechanisms of action cannot be excluded.
Drechsel and Patel (2008). Free Radic Biol Med. 44 (11),1873-1886.
Espín et al. (2007). Phytochemistry. 68 (22-24), 2986-3008.