Antiplasmodial and cytotoxic activities of secondary metabolites from the leaves of Pleiocarpa bicarpellata Stapf (Apocynaceae).

Abstract

Phytochemical studies of the leaves of Pleiocarpa bicarpellata led to the isolation of a new indole C-glycoside, Bicarpellatoside A (1), along with eight known compounds (2-9), including three indoles, two indolines, an iridoid monoterpenoid, a triterpenoid, and a phenolic acid. The structures of all isolated compounds were elucidated using NMR, MS, and IR spectroscopic data, in comparison with the literature. Compounds 1, 3, and 9 are reported in this genus for the first time. In vitro antiplasmodial activity tests were conducted against both chloroquine-sensitive (3D7) and chloroquine-resistant (Dd2) strains of Plasmodium falciparum, using the crude extract and isolated compounds 1-4. The crude extract exhibited promising activity, with IC₅₀ values of 4.07 ± 0.78 μg/mL (Dd2) and 4.32 ± 0.42 μg/mL (3D7). Bicarpellatoside A (1) showed good activity, with IC₅₀ values of 2.24 ± 0.05 µM and 2.74 ± 0.05 µM against Dd2 and 3D7 strains of P. falciparum, respectively. Compound 4 showed moderate activity (IC₅₀ of 40.93 ± 3.39 µM and 48.13 ± 5.63 µM on Dd2 and 3D7 strains of P. falciparum, respectively, with a high selectivity index of 34.48, indicating potential for further development. Overall, these findings highlight and confirm the antiplasmodial potential of compounds from P. bicarpellata.