Intracellular anti-leishmanial effect of Spergulin-A, a triterpenoid saponin of Glinus oppositifolius

Infect Drug Resist. 2019 Sep 17:12:2933-2942. doi: 10.2147/IDR.S211721. eCollection 2019.

Abstract

Background: Many of present chemotherapeutics are inadequate and also resistant against visceral leishmaniasis (VL), an immunosuppressive ailment caused by Leishmania donovani. Despite the interest in plant-based drug development, no antileishmanial drugs from plant source are currently available. Glinus oppositifolius had been reported in favor of being immune modulators along with other traditional uses. Novel anti-VL therapies can rely on host immune-modulation with associated leishmanicidal action.

Objective: Discovery of novel plant-based antileishmanial compound from G. oppositifolius having permissible side effects.

Methods: With this rationale, an n-BuOH fraction of the methanolic extract of the plant and obtained 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.

Results: Spergulin-A was found ineffective against the acellular forms while, against the intracellular parasites at 30 μg/mL, the reduction was 92.6% after 72 hrs. 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.

Conclusion: The results supported that G. oppositifolius and Spergulin-A can potentiate new lead molecules for the development of alternative drugs against VL.

Keywords: Glinus oppositifolius; anti-amastigote; immunostimulation; macrophage; spergulin-A; visceral leishmaniasis.