Twelve undescribed bisindole alkaloids, tabernaemontines A-L, were simultaneously isolated from the leaves of Tabernaemontana bovina and their structures were elucidated by spectroscopic methods. All alkaloids consist of two Aspidosperma-type units with various intramolecular linkages. Particularly, tabernaemontines A-D were assembled through C-3/14 ' with a large angle strain, whilst tabernaemontines E-K adopted a preferential conformation. Tabernaemontine L was assembled via a C-14/10 ' connection. Tabernaemontines F, K and L showed good inhibition of microglial activation. As a representative of Aspidosperma-type dimers, the P38 MAPK activation inhibition properties of tabernaemontine F were tested. The promising results revealed this compound as a potential candidate for the treatment of chronic neurodegenerative diseases.