Ameliorating effect of S-Allyl cysteine (Black Garlic) on 6-OHDA mediated neurotoxicity in SH-SY5Y cell line

Therapeutic approaches based on isolated compounds derived from natural products are more common in preventing diseases involving inflammation and oxidative stress at present. S-allyl cysteine (SAC) is a promising garlic-derived organosulfur compound with many positive effects in cell models and living systems. SAC has biological activity in various fields, enclosing healing in learning and memory disorders, neurotrophic effects, and antioxidant activity. In this study, we purposed to identify the neuroprotective activity of SAC toward 6-OHDA-induced cell demise in the SH-SY5Ycell line. For this purpose, 6-OHDA-induced cytotoxicity, and biochemical, and gene expression changes were evaluated in SH-SY5Y cells. SH-SY5Y cells grown in cell culture were treated with SAC 24 h before and after 6-OHDA application. Then, cell viability, antioxidant parameters, and gene expressions were measured. Finally, immunofluorescence staining analysis was performed. Our results showed that SAC increased cell viability by 144 % at 80 µg/mL with pre-incubation (2 h). It was observed that antioxidant levels were significantly increased and oxidative stress marker levels were decreased in cells exposed to 6-OHDA after pre-treatment with SAC (p<0.05). SAC supplementation also suppressed the increase in pro-inflammation levels (TNF-α/IL1/IL8) caused by 6-OHDA (p < 0.05). While 8-OHdG and Nop10 expressions were observed at a mild level in SAC pretreatment depending on the dose, 8-OHdG, and Nop10 expressions were observed at a moderate level in SAC treatment after 6-OHDA application (p<0.05). Our findings demonstrate the positive effect of pretreatment with SAC on SH-SY5Y cells injured by 6-OHDA, suggesting that SAC may be beneficial for neuroprotection in regulating oxidative stress and neuronal survival in an in vitro model of Parkinson's disease.