iridoids and Malaria

Heinsia crinita is used in traditional medicine for the treatment of febrile illness and erectile dysfunction. Its stem bark powder is found in some peripheral markets in the Democratic Republic of the Congo (DRC) as a remedy against malaria. Investigations were conducted on crude extracts of leaves, fruits and stem barks in view to validate their use and to determine which plant part possesses the best antiplasmodial properties.. Different plant parts were extracted with methanol, ethanol and dichloromethane. Based on the preliminary assays, the dichloromethane extract of the stem bark was subjected to fractionation using preparative HPLC system and column chromatography. This step led to the isolation of two new iridoids which had their structures elucidated by NMR, UV, MS and FT-IR spectroscopic techniques. Extracts and pure compounds were tested in vitro against the 3D7 strain of Plasmodium falciparum. The inhibition of the parasite growth was evaluated in vitro by colorimetric method (p-LDH assay) and their cytotoxicity evaluated in vitro against the human non-cancer fibroblast cell line (WI38) through WST1 assay. The in vivo antiplasmodial activity was assessed by the inhibition of Plasmodium berghei growth in infected mice treated with the ethanol extract of H. crinita stem bark at the concentrations of 200 and 300mg/Kg/day per os, using a protocol based on the 4-d suppressive test of Peters and compared to a non-treated negative control group of mice (growth =100%). Finally the antioxidant activity of the same extract was evaluated using ABTS, DPPH and cell-based assays.. The results showed that H. crinita extracts possess antimalarial activity and contain some unusual iridoids with moderate antiplasmodial activity, therefore justifying to some extent its traditional use by the local population in DRC for this purpose. This is the first report of the isolation and antiplasmodial activity of these two new iridoids.

Topics: Animals; Antimalarials; Cell Line; Cell Survival; Female; Fruit; HL-60 Cells; Humans; Iridoids; Malaria; Mice; Plant Bark; Plant Extracts; Plant Leaves; Plasmodium berghei; Plasmodium falciparum; Reactive Oxygen Species; Rubiaceae