Protective Effects of Extract with Phenolics from Camellia (Camellia japonica) Leaf against Oxidative Stress-induced Neurotoxicity

Abstract

Antioxidant and neuronal cell protective effects of aqueous extract from camellia (Camellia japonica) leaf (CJLE) were evaluated. The 1,1-phenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing/antioxidant power (FRAP) assays of the CJLE were increased in a dose dependent manner. In neuronal cell viability assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium-bromide (MTT), the aqueous extract showed protective effect against H2O2-induced neurotoxicity and lactate dehydrogenase (LDH) release into medium was also inhibited by CJLE (7.13-43.89%). The cell viability of CJLE was higher than vitamin C (200 mu M) by neutral red uptake (NRU) assay at a concentration of 250-1,000 mu g/mL. Phenolics of CJLE were 21.75 mg/g, and major phenolic compounds were quercetin (120.20 mg/100 g) and kaempferol (88.13 mg/100 g). Therefore these data suggested that the CJLE including above phenolics may be useful in the natural antioxidant substance and reduce the risk of neurodegenerative disease such as Alzheimer's disease.