Cytotoxic and larvicidal activities of Stemona alkaloids from the aerial parts and roots of Stemona curtisii Hook.f.

Abstract

A new Stemona alkaloid glycoside derivative, 6-hydroxy-5,6-seco-stemocurtisinoside (4), was isolated from the ethanolic extract of the aerial parts of Stemona curtisii Hook.f., together with stemocurtisine (1), (11Z)-1',2'-didehydrostemofoline (2) and 6-hydroxy-5,6-seco-stemocurtisine (3). Whereas, stemocurtisine (1), stemocurtisinol (5) and oxyprotostemonine (6) were isolated from the roots. Their structures were elucidated using 1D and 2D NMR spectroscopy as well as MS experiments. The extract and the pure isolated compounds were evaluated for their cytotoxicities and their larvicidal activities against the dengue vector, Aedes aegypti. The alkaloid 2 showed the strongest larvicidal activity with a LC₅₀ value of 2.44 µM. While the alkaloid 3 exhibited cytotoxicity against MCF-7 and KB cells (IC₅₀ values of 62.52 and 18.82 µM, respectively) and showed no significant cytotoxicity against Vero cells. Additionally, quantitative analysis of the most active compounds; 2 and 3 in the crude extracts was also performed by HPLC.

Graphical Abstract

Keywords:

• Stemonaceae
• Stemona curtisii Hook.f.
• Stemona alkaloids
• Cytotoxicity
• Larvicidal activity
• MCF-7 cells
• KB cells

Acknowledgements

We acknowledge CMU Mid-Career Research Fellowship program, Chiang Mai University; the Center of Excellence for Innovation in Chemistry (PERCH-CIC), Ministry of Higher Education, Science, Research and Innovation, Thailand and the Environmental Science Research Center (ESRC), Chiang Mai University for their financial support. The Science Achievement Scholarship of Thailand (SAST) and the Graduate School of Chiang Mai University are also acknowledged for the grant of a Ph.D. student. We thank the Office of Disease Prevention and Control, Chiang Mai, Thailand for providing the mosquito eggs and larvae. The facilities for this work were supported by the Environmental Science program and the Department of Chemistry, Faculty of Science, Chiang Mai University.

Disclosure statement

No potential conflict of interest was reported by the authors.