Geissospermiculatine, a New Alkaloid from Bark.

A new alkaloid, geissospermiculatine was characterized in A. H. Gentry bark (Apocynaceae). Here, following a simplified isolation protocol, the structure of the alkaloid was elucidated through GC-MS, LC-MS/MS, 1D, and 2D NMR (COSY, ROESY, HSQC, HMBC, H-N HMBC). Cytotoxic properties were evaluated in vitro on malignant THP-1 cells, and the results demonstrated that the cytotoxicity of the alkaloid (30  μg/mL) was comparable with staurosporine (10  μM). Additionally, the toxicity was tested on zebrafish () embryos in vivo by monitoring their development (0-72 h); toxicity was not evident at 30  μg/mL.