Bioassay directed antiplasmodial constituents from <i>Clerodendrum infortunatum</i> L. (Lamiaceae), an ethnomedicinal plant of Assam

Eight compounds have been identified from the bioactive fractions of <i>Clerodendrum infortunatum</i> L. leaf and root. NMR experiments and HRMS data were used to confirm the structures of the isolated compounds, and data compared to the existing literature. Among eight compounds, 3β-hydroxy-30-<i>nor</i>-urs-21-en-20-one (<b>3</b>) and 22-dehydroclerosterol-3-<i>O</i>-β-D-glucopyranoside (<b>8</b>) have considerable antiplasmodial activities against 3D7 strain of <i>Plasmodium falciparum</i> with IC ₅₀ value 13.82 and 11.42 μM respectively compared to the positive control value 0.892 μM. The remarkable antiplasmodial property of these two compounds lends credence to the use of <i>C.infortunatum</i> L. against malaria and thus provides a new template for the design of an antiplasmodial molecule. This is the first report of compounds such as (24S)-ethylcholesta-5, 22, 25-triene-3β-ol (<b>2</b>), 3β-hydroxy-30-<i>nor</i>-urs-21-en-20-one (<b>3</b>), Clerosterol (<b>4</b>) and 22-dehydroclerosterol-3-<i>O</i>-β-D-glucopyranoside (<b>8</b>) exhibiting antiplasmodial properties.