Anti-malarial activity of <it>Holarrhena antidysenterica </it>and <it>Viola canescens</it>, plants traditionally used against malaria in the Garhwal region of north-west Himalaya

Abstract

Abstract Background The increasing number of multidrug-resistant Plasmodium strains warrants exploration of new anti-malarials. Medicinal plant research has become more important, particularly after the development of Chinese anti-malarial drug artemisnin from Artemisia annua. The present study shows evaluation of anti-malarial effects of two plants commonly used against malaria in the Garhwal region of north-west Himalaya, in order to discover the herbal-based medicine. Methods In vitro anti-plasmodial sensitivity of plant extracts was assessed using schizont maturation and parasite lactate dehydrogenase (pLDH) assay. Cytotoxic activities of the examined extracts were determined on L-6 cells of rat skeletal muscle myoblast. The 4-day test for anti-malarial activity against a chloroquine sensitive Plasmodium berghei NK65 strain in Swiss albino mice was used for monitoring in vivo activity of plant extracts. Results Chloroform extract of H. antidysenterica (HA-2) and petroleum ether extract of V. canescens (VC-1) plants significantly reduced parasitaemia in P. berghei infected mice. The extract HA-2 showed in vitro anti-plasmodial activity with its IC50 value 5.5 μg/ml using pLDH assay and ED50 value 18.29 mg/kg in P. berghei infected Swiss albino mice. Similarly petroleum ether extract of V. canescens (VC-1) showed in vitro anti-plasmodial activity with its IC50 value 2.76 μg/ml using pLDH assay and ED50 15.8 mg/kg in P. berghei infected mice. The extracts coded as HA-2 at 30 mg/kg and VC-1 at 20 mg/kg exhibited parasite inhibition in mice: 73.2% and 63.0% respectively. Of these two plant extracts, petroleum ether extract of V. canescens was found slightly cytotoxic. Conclusion The present investigation reflects the use of these traditional medicinal plants against malaria and these plants may work as potential source in the development of variety of herbal formulations for the treatment of malaria.