Identification of antimalarial compounds from Leucas calostachys, using High Performance Liquid Chromatography and Electrospray Ionization Mass Spectrometry

Abstract

Leucas calostachys is widely used in traditional medicine in Kenya for management of various ailments including malaria. Bio-assay guided fractionation of Leucas calostachys extracts was carried out using in-vitro antiplasmodial and β-hematin inhibition assays with semi-preparative high performance liquid chromatography (HPLC). The active methanol fraction was subjected to liquid chromatography tandem mass spectrometry to identify constituent compounds. A total of twenty compounds consisting of eight flavonoids and 12 phenylethanoids were identified from this fraction. The flavonoids included, isorhamnetin, luteolin-7-O-glucoside, luteolin-4′-O-glucoside, luteolin diglucoside, apigenin-O-glucoside, genistein-O-glucoside, chrysoeriol-7-O-glucoside, and chrysoeriol-7-O-glucuronide. Seven of the phenylethanoids were identified as acteoside, isoactoeside, hydroxyacteoside, forthsoside B, samioside, alyssonoside and leucoseptoside A. The antimalarial activity of Leucas calostachys could be linked to presence of flavonoids and phenylethanoids.