감귤류 과피는 플라보노이드의 중요 급원 중의 하나로 아시아에서 민간 의약품으로서 오래전부터 사용되어 왔다. 본 연구에서는 진귤(Citrus sunki Hort. ex Tanaka) 과피에서 HPLC-MS/MS를 이용하여 9종의 플라보노이드 성분을 동정하였으며, hydroxypentamethoxyflavone과 dihydroxytetramethoxyflavone은 진귤에서 처음으로 확인되었다. 총 플라보노이드의 항산화 활성은 25~500 mg/L 의 농도범위에서 DPPH·, ABTS·+, NO· 소거능 및 환원력에 의해 측정되었으며, 시료의 첨가량이 많아짐에 따라 항산화 활성은 유의적으로 증가하였다.

The peel of Citrus sunki exhibits multiple biological activities such as anti-oxidant, anti-inflammation and anti-obesity, but little is known about neurodegeneration-related activities. In this study, we investigated the protective effect of ethanolic extract from both immature and mature Citrus sunki peel on neuronal cell death. Treatment of the neuroblastoma cell line SH-SY5Y with MPP+, an inducer of Parkinson disease model, increased cell death in a dose dependent manner. Increased levels of active caspase-3 and cleaved PARP were detected. Treatment with immature Citrus sunki peel extract significantly reduced MPP+-induced neurotoxicity. Cytoprotection with immature Citrus sunki peel extract was associated with a decrease in caspase-3 activation and PARP cleavage. In contrast, mature Citrus sunki peel extract had no significant effects. These data suggest that immature Citrus sunki peel extract may exert anti-apoptotic effect through the inhibition of caspase-3 signaling pathway on MPP+-induced neuronal cell death.