Neuroprotective effects of extracts from the radix Curcuma aromatic on H2O2-induced damage in PC12 cells.

Aim & objectives: Curcumins, also known as diarylheptanoids, are regarded as characteristic constituents in Curcuma, which have obviously neuroprotective activities against oxidative stress. As one of Traditional Chinese Medicines from Curcuma, the radix of Curcuma aromatic is also rich in curcumins, but its neuroprotective activity and underlying mechanism remains unknown. The aim of current study is to evaluate the neuroprotective effects of different extracts from the radix of C. aromatic (ECAs) on hydrogen peroxide (H2O2) -damaged PC12 cells.

MATERIAL AND METHODS: The model of oxidative stress damage was established by treatment of 400 µM hydrogen peroxide (H2O2) on PC12 to induce cell damage. After the treatment of ECWs for 24 h, the cell viability, the release rate of lactate dehydrogenase (LDH), and the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione (GSH) were measured to evaluate the neuroprotection of ECAs on that model. The possibly protecting mechanism of oxidative damage by measurement of level of ROS, cell apoptosis rate, mitochondrial membrane potential (MMP), morphologic change, the intracellular Ca2+ content (F340/F380) and the expressions of Bcl-2, Bax and Caspase-3. Additionally, the constituents from those extracts were analyzed by HPLC-DAD-Q-TOF-MS method.

RESULTS: Compared with a positive control, Vitamin E, 10 µg/ml of 95 % EtOH extract (HCECA) and 75 % EtOH extract (MCECA) can markedly increase the rate of cell survival and enhance the antioxidant enzyme activities of SOD, CAT, increase the levels of GSH, decrease LDH release and the level of ROS, attenuate the intracellular Ca2+ overloading, reduce the cell apoptotic rate and stabilize MMP, down-regulate Bcl-2 expression, up-regulate Bax and caspase-3 expression, improve the change of cell morphology. The chemical analysis showed diarylheptanoids and sesquiterpenoids are the major chemicals in those extracts and the former was richer in HCECA and MCECA than others.

CONCLUSIONS: These findings indicated that the effects of HCECA and MCECA on inhibiting the cells damage induced by H2O2 in PC12 are better than other extracts from the radix of C. aromatic through the mechanisms of apoptosis inhibition in PC12, and the active constituents with neuroprotective effects consisting in those two extracts are diarylheptanoids.