Nyctanthes arbor-tristis positively affects immunopathology of malaria-infected mice prolonging its survival.

In order to search for new products that display antimalarial and immunomodulatory mechanisms that complement direct antiparasitic activity, a set of in vitro and in vivo experiments were designed to evaluate the effect of Nyctanthes arbor-tristis in Plasmodium berghei infected mice. Three extracts of N. arbor-tristis leaves from varying concentrations of alcohol and water were considered for their potential to suppress expression of pro-inflammatory mediators from macrophages primed with lipopolysaccharide. The ethanolic extract, which lowered the pro-inflammatory mediators [tumour necrosis factor (TNF), 13.52-55.83 %; interleukin-6 (IL-6), 0-17.29 %; and NO, 39.37-81.63 %], was selected to be examined in malaria (P. berghei) infected mice. Corroborating the in vitro results, it was observed that the extract could normalise the TNF (78 %) and IL-6 (70.35 %) optimally at 1 g/kg, thus retarding the pathological process in infected mice and increasing the mean survival time from 10.6 to 15.6 days. There were no signs of toxicity in the acute oral toxicity test up to 2 g/kg. (1)H NMR of the biologically active extract was obtained to ensure the presence of the compound of interest, i.e., iridoid glycoside. The quality and the reproducibility of results were ensured by means of achieving characteristic high-performance liquid chromatography fingerprint of the extract.