Evaluation of antiplasmodial potential of Cissampelos pareira L.: Characterization and quantification of isoquinoline alkaloids responsible for the biological activity

Abstract

Globally, based on traditional knowledge, different parts of Cissampelos pareira plant are being used individually or in combination in various forms to manage malaria. However, the scientific investigation for validating the most effective part of this plant against malaria parasite has not been done. Thus, the study aims to explore the antiplasmodial potential of different parts of the plant against malaria parasite by bio-assay guided isolation of compounds from different extracts and fractions. Antiplasmodial activities of the whole plant parent extract and its fractions along with decoctions (roots, stem, leaves and whole plant) and isolated molecules were evaluated against chloroquine-sensitive Pf3D7 and chloroquine-resistant PfINDO strains of Plasmodium falciparum. A UPLC-DAD based method was developed to quantify the marker compounds in all samples by utilizing isolated molecules as analytical standards. The chloroform fraction of the whole plant was found to be the most potent with IC50 (µg/mL) of 0.79 (Pf3D7) and 2.26 (PfINDO) followed by root decoction with IC50 (µg/mL) 10.22 (Pf3D7) and 7.7 (PfINDO). Further, phytochemical analysis of active chloroform fraction led to the isolation of two potent bisbenzylisoquinoline compounds, namely O,O-dimethylcurine (1) [IC50 (µM) 1.46 (Pf3D7) and 0.51 (PfINDO)], and curine (2) [IC50 (µM) 1.46 (Pf3D7) and 0.51 (PfINDO)]. Analysis of developed UPLC-DAD method showed the highest quantities of curine (2) (∼107 mg/g) and O,O-dimethylcurine (1) (∼15 mg/g) in chloroform fraction which might be responsible for its potent activity. This study showed that the root decoction was more effective than decoctions of each of the other parts of the plant and the whole plant hydroalcoholic extract.