Anti-proliferative cassane-type diterpenoids from the seeds of Caesalpinia minax

Abstract

The seeds of Caesalpinia minax Hance have shown anti-tumor potential, while the chemical principle is still unknown. In a search for anti-tumor compounds, six new cassane-type diterpenoids, 12-demethylcaesalpin G (1), caesalpinolide H (2), 12-demethylcaesalpin H (3), caesalpinolide J (4), 12-O-ethyl neocaesalpin B (5), and 3-deacetyldecapetpene B (6), were isolated from the seeds of C. minax Hance, along with fifteen known analogues. The structures of the new compounds were established by means of spectroscopic techniques (NMR, HRESIMS and IR). The absolute configurations of the new compounds were determined by their ECD spectra. All of the new compounds were tested for their anti-proliferative activity against human lung cancer A549 cells, breast cancer MCF-7 cells, and ovarian cancer HEY cells. The results indicated that only compound 6 displayed moderate cytotoxicity against three cancer cell lines. Thus, the opening of furan ring in cassane-type diterpenoids might enhance the cytotoxic activity.

Graphical Abstract

Keywords:

• Caesalpinia minax
• Fabaceae
• cassane diterpenoids
• cytotoxic activity

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Financial support by University of Macau (File no. MYRG2017-00109-ICMS and MYRG2018-00037-ICMS), National Natural Science Foundation of China (81872754), Key-Area Research and Development Program of Guangdong Province, China (2020B1111110003) and the Open Research Fund of Chengdu University of Traditional Chinese Medicine Key Laboratory of Systematic Research of Distinctive Chinese Medicine Resources in Southwest China (2020GZ2011011) are gratefully acknowledged.