Antileishmanial potential of a marine sponge Haliclona oculata against experimental visceral leishmaniasis

Abstract

Objective: To evaluate the antileishmanial activity of a marine sponge Haliclona oculata. Methods: The crude methanol extract was prepared from the freshly collected sponge and its three fractions were also prepared by maceration method. The antileishmanial activity of these extract and fractions was tested against Leishmania donovani. Results: The antileishmanial activity was tested both in vitro and in vivo. The crude methanol extract exerted almost complete inhibition of promastigotes (81.0% ± 6.9%) and 78.8% ± 5.2% inhibition of intracellular amastigotes at 100 μg/mL with IC₅₀ values of 29.5 μg/mL and 40.6 μg/mL, respectively. The treatment of 500 mg/kg (p.o.) of the crude methanol extract for 5 d for Leishmania donovani infected hamsters resulted in 78.35% ± 10.20% inhibition of intracellular amastigotes. At a lower dose (250 mg/kg), it exhibited poor efficacy. Among the fractions, highest in vitro (>75%) and in vivo (84.3% ± 10.2%) antileishmanial activity was observed in n-chloroform fraction with IC₅₀ values of 54.2 μg/mL and 61 μg/mL against promastigotes and intracellular amastigotes, respectively. Hexane fraction and n-butanol (both insoluble and soluble) fractions were found inactive in vitro and in vivo. Conclusions: Our findings indicate that this marine sponge has the potential to provide new insight toward development of an effective antileishmanial agent and, hence, more exhaustive studies are needed for exploiting the vast marine resources of the world to combat the scourge of several parasitic diseases.