Screening and Characterization of Bioactive Molecules Derived From Medicinal Plants for Antileishmanial Activities for Leishmania donovani

Abstract

Abstract- Leishmaniasis is a vector-borne disease caused by genus Leishmania. It causes significant morbidity and mortality in the endemic areas of several developing countries. Due to multidrug resistance in Leishmania sp and unavailability of an effective vaccine, discovery of new drugs is urgently needed. The aim of the present study was screening of medicinal plants used as Indian traditional medicine for leishmanicidal activity. Promastigote forms of Leishmania parasite were cultured in-vitro in NNN medium and further sub-cultured and maintained in RPMI-1640 medium containing 10% Fetal Bovine Serum for the screening of medicinal plants. A total of 26 medicinal plants were collected and screened for leishmanicidal activity. The methanolic extracts showing antileishmanial activity were subjected to LC-MS analysis to identify the major phyto-constituents in the crude methanolic extracts. The compounds were detected in the LC-MS of active extracts. The plant extract showing maximum antileishmanial activity was further fractionated to isolate the major compound(s).The compound isolated was characterised by IR, Mass spectrometry and subjected to in vitro antileishmanial activity against L. donovani promastigotes. In vitro antileishmanial assay revealed that crude methanolic extracts of 2/10 plants were active against L. donovani promastigotes. Methanolic root extracts of Inula racemosa were found active (54.83%) against the parasite while T. Terrestris were found least active with such as toxicity, percent inhibition 43.10% at concentration of 500 μg/ml. Inula racemosa methanolic extract further fractionated subjected for LC-MS analysis. The compound isolated from the methanolic root extract of I. racemosa was isoalantolactone, which did not show any antileishmanial activity against L. donovani. The study suggested that crude extract of Inula racemosa and T. Terrestris have shown potent antileishmanial activity while extracted bioactive molecules does not show efficacy against Leishmania parasite. Hence the antileishmanial activity could be due to any other compound which could not be detected, so further study is undertaken.