Neuroprotective effect of Perilla extracts on PC12 cells

Perilla frutescens (L.) Britton contains rosmarinic acid, luteolin and linoleic acid which had neuroprotective actions. This study was aimed to investigate the effect of Perilla extracts on neuroprotection, antioxidation and neurite outgrowth in PC¹² cells. Freeze-dried ethnolic extract from Perilla leaves and cold-pressed oil from seed at dose of 50,100,200 mg/ml were tested. Cells were pretreated with each extract 10 min then incubated with beta-amyloid protein 20µM for 24h to induce toxicity. Cell viability, antioxidant enzyme (SOD) activity and inhibition on tau-protein hyperphosphorylation were analyzed [1]. In cell cultured in serum free media associated with 2 ng/ml of nerve growth factor, followed by adding each extract, the neurite outgrowth bearing cells and MEK-1protein production were investigated [2]. Dulbecco's Modified Eagle's Medium and rosmarinic acid were used as normal and positve controls respectively. Results revealed that induction of toxicity by beta-amyloid protein in PC12 cells: (i) the cell viability decreased to 60% of control (ii) the cell viability increased in culture pretreated with Perilla leaf extract 200 mg/ml and seed oil 50 mg/ml; (iii) given Perilla leaf extract at dose of 100, 200 mg/ml and each dose of seed oil to cells could decrease SOD activity; (iv) tau phosphorylation at Thr 205 and Ser 396 was decreased by pretreating cells with Perilla seed oil at dose of 50 mg/ml. Moreover, given Perilla leaf extract or seed oil to PC12 culture, the amount of neurite outgrowth bearing cells were shown to increase harmoniously with the amount of MEK-1 protein. In summary, Perilla leaf extract and seed oil reversed the effect of beta-amyloid induced toxicity by decreasing oxidative stress as well as inhibition of tau-protein hyperphosphorylation. The enhancement of neurite outgrowth by Perilla extracts was also revealed. These preliminary results imply the neuroprotective effect of Perilla as a functional food.

Acknowledgements: This research was supported by grant from National Research Council of Thailand, 2014 – 2015. Thanks to Professor Dr.Maitree Suttajit for providing the Perilla extracts.

Keywords: Perilla frutescens, neuroprotection.

References:

[1] Park SY, Kim HS, Cho EK, Kwon BY, Phark S, Hwang KW, et al. Curcumin protected PC12 cells against beta-amyloid-induced toxicity through the inhibition of oxidative damage and tau hyperphosphorylation. Food Chem Toxicol 2008; 46: 2881 – 2887

[2] Yamazaki M, Chiba K, Mohri T. Fundamental role of nitric oxide in neuritogenesis of PC12h cells. Br J Pharmacol 2005; 146: 662 – 669