(R)-3-(8'-Hydroxyfarnesyl)-indole and other chemical constituents from the flowers of Anomianthus dulcis and their antimalarial and cytotoxic activities

Abstract

A new farnesylindole, (R)-3-(8'-hydroxyfarnesyl)-indole (1), as a scalemic mixture (33% ee) along with nine known compounds (2-10), including one farnesylindole, three flavanones, three flavone derivatives and two chalcone derivatives were isolated from the methanolic crude extract of the flowers from Anomianthus dulcis. All compounds were purified by appropriate chromatographic techniques and their structures elucidated by spectroscopic methods. Compounds 1, 2 and 8 showed moderate antiplasmodial activities against TM4/8.Two and K1CB1 strains of which compound 2 displayed the best activity with IC₅₀ values of 27.9 ± 2.57 and 21.4 ± 1.68 µM, respectively. In addition, compound 1 also presented modest cytotoxicity against a KB cell line with an IC₅₀ value of 22.3 ± 0.39 µM. None of these compounds showed cytotoxicity against Vero cells.

Graphical Abstract

Keywords:

• Anomianthus dulcis
• farnesylindole
• antiplasmodial activities
• cytotoxicity

Acknowledgements

TP thanks the Science Achievement Scholarship of Thailand (SAST). We would like to thank Chiang Mai University and the Center of Excellence for Innovation in Chemistry (PERCH-CIC) for partial support and Mr. Phorn Prommaharaj, Chiang Mai University, Thailand, for collecting the plant material. SK thanks Research Chair Grant (no. P1850116) from NSTDA, Thailand.

Disclosure statement

The authors declare no conflict of interest