Antioxidation Abilities of Sesquiterpenoids from Curcuma aromatica in vitro

In our previous study, 21 sesquiterpenoids with different skeleton types were isolated from the radix of Curcuma aromatica Salisb., a traditional Chinese medicine used for treating depression and qi and blood stasis. C. aromatica enhanced PC12 cell viability upon damage by H₂O₂. The aim of this study was to elucidate the antioxidation capability of these sesquiterpenoids using a model of H₂O₂-induced PC12 cells and analyze the correlation between their structure and bio-activity.

PC12 cells were simultaneously treated with 400 μM H2O2 and sesquiterpenoid compounds or vitamin E (used as a positive control) for 24 h. The activities of GSH-Px, LDH, CAT, and SOD were detected by ELISA kits. The reactive oxygen species (ROS) level in the cells was determined by the fluorescence probe DCFH-DA. [Ca²⁺]i was detected based on the Fluo 2-AM fluorescence labeling assay. The structures of sesquiterpenoids were featured with 41 selected molecular descriptors, and the relationship between active parameters and structural features was determined by the partial least squares (PLS) analysis.

All twenty-one sesquiterpenoids from the radix of C. aromatica increased the activities of GSH-Px, CAT, and SOD, and decreased the LDH leakage, and levels of ROS level and [Ca²⁺]i to different degrees. Some relationships were observed between the molecular descriptors featured by the sesquiterpenoids and GSH-Px, CAT, SOD, LDH, ROS, and [Ca²⁺]i by PLS analysis.

Twenty-one sesquiterpenoids showed different antioxidation abilities as measured by a model of H₂O₂-induced PC12 cells. Five molecular descriptors were positively correlated with GSH-Px, CAT, SOD, and were negatively correlated with LDH and [Ca²⁺].