Diterpenoids as potential anti-malarial compounds from Andrographis paniculata

Abstract

The objectives of the current study are to evaluate the traditionally used medicinal plants Andrographis paniculata for in vitro anti-malarial activity against human malarial parasite Plasmodium falciparum and to further characterize the anti-malarial active extract of A. paniculata using spectroscopic and chromatographic methods. The chloroform extract of A. paniculata displayed anti-malarial activity with IC50 values 6.36\u2009μg/ml against 3D7 strain and 5.24\u2009μg/ml against K1 strains respectively with no evidence of significant cytotoxicity against mammalian cell line (CC50 >\u2009100\u2009μg/ml). LC-MS analysis of the extract led to the identification of 59 compounds based on their chromatographic and mass spectrometric features (a total of 35 compounds are present in positive ion and 24 compounds in negative ion mode). We have identified 5 flavonoids and 30 compounds as diterpenoids in positive ion mode, while in the negative mode all identified compounds were diterpenoids. Characterization of the most promising class of compound diterpenoids using HPLC-LC-ESI-MS/MS was also undertaken. The in vitro results undoubtedly validate the traditional use of A. paniculata for the treatment of malaria. The results have led to the identification of diterpenoids from IGNTU_06 extract as potential anti-malarial compounds that need to be further purified and analyzed in anti-malarial drug development programs.