A triterpenoid saponin, Spergulin-A from Glinus oppositifolius is a potent immunostimulator and antileishmanial agent

Present chemotherapeutics are inadequate against visceral leishmaniasis (VL) an immunosuppressive ailment caused by Leishmania donovani. Despite the interest in plant-based drug development, an antileishmanial drug from plant source is unavailable. Glinus oppositifolius had been reported in favor of being immunomodulators along with other traditional uses. Novel anti-VL therapies can rely on host immune-modulation with associated leishmanicidal action. With this rationale, an n-BuOH fraction of the methanolic extract of the plant and isolated triterpenoid saponin Spergulin-A were evaluated against acellular and intracellular L. donovani. Immunostimulatory activity of them was confirmed by elevated TNF-α and extracellular NO production from treated MФs and was found nontoxic to the host cells. Identification and structure confirmation for isolated Spergulin-A was performed by ESI-MS,13C, and 1H NMR. Spergulin-A was found ineffective against the acellular forms while, against the intracellular parasites at 30μg/ml, the reduction was 92.6% after 72h. Spergulin-A enhanced ROS and nitric oxide (NO) release and changes in Gp91-phox, i-NOS, and pro and anti-inflammatory cytokines elaborated its intracellular anti-leishmanial activity. The results supported that G. oppositifolius and Spergulin-A can potentiate new lead molecules for the development of alternative drugs against VL.