Guided Isolation of New Cytotoxic Cassane Diterpenoids from Caesalpinia sappan

Guided by an MS/MS-based molecular networking, six undescribed cassane diterpenoids and three known ones were isolated and identified from the seeds of Caesalpinia sappan. Their structures were unequivocally elucidated by extensive spectroscopic analyses and electronic circular dichroism (ECD) calculations. Cytotoxic evaluation showed that phanginin JA exhibited significant antiproliferative activities against human non-small cell lung cancer (A549) cells with IC50 values of 16.79 +/- 0.83 mu M. Further flow cytometry analysis revealed that phanginin JA could exert apoptotic effect of A549 cells by arresting cell cycle in G0/G1 phase.