Monoterpenoid indole alkaloids with potential neuroprotective activities from the stems and leaves of Melodinus cochinchinensis

A chemical study on the stems and leaves of Melodinus cochinchinensis resulted in the isolation and identification of a new monoterpenoid indole alkaloid, melodicochine A (1), together with seven known monoterpenoid indole alkaloids (2-8). The chemical structure of 1 was elucidated on the basis of extensive spectral data analyses and the known compounds were identified by comparing their experimental spectral data with the reported data in the literature. All isolated indole alkaloids were evaluated for their neuroprotective effects against 6-hydroxydopamine induced cell death in human neuroblastoma SH-SY5Y cells in vitro. Monoterpenoid indole alkaloids 1-8 exhibited notable neuroprotective effects with EC50 values in range of 0.72 ± 0.06 to 17.89 ± 0.16 μM.