In vitro and in vivo evaluation of the leishmanicidal and cytotoxic activities of chitosan and chitosan–amphotericin B

Cutaneous leishmaniasis (CL), classified as a neglected tropical disease (NTD), is a significant public health concern caused by Leishmania protozoa. It is transmitted through the bites of infected female sandflies and manifests in various forms, ranging from localized skin ulcers to social stigma due to scarring. Numerous reports highlight the life-threatening side effects of glucantim, the first-line treatment for this disease, indicating a pressing need foralternative drugs. This experimental study aims to assess the anti-leishmanial effects of chitosan and chitosan- amphotericin B against Leishmania major (L. major) in vitro and in vivo. Chitosan and amphotricine B were purchased, and different concentrations were prepared. L. major promastigotes were cultured in RPMI-1640 medium. In vitro anti-leishmanial activity was assessed against the promastigotes of L. major using vital staining. For the in vivo assessment, lesion sizes were measured before and after ointment treatments in Bagg Albino mice (BALB/c). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H-tetrazolium bromide (MTT) assay was utilized to evaluate the cytotoxic effects of chitosan and chitosan-amphotericin B at varying concentrations on the L929 cell line. Additionally, the in vitro hemolytic activity was measured using a spectrophotometric method. The in vitro and in vivo experiments demonstrated that chitosan-amphotericin B exhibited superior inhibitory effects against L. major compared to either chitosan or amphotericin B alone, and even against the positive control, particularly at higher concentrations (P < 0.05). Furthermore, cytotoxicity tests indicated that both chitosan and amphotericin, whether used separately or in combination, had no cytotoxic effects on the L929 cell line or human blood samples in vitro and did not impact liver enzymes in vivo (P < 0.05). The findings from this in vitro and in vivo study highlighted the impressive anti-leishmanial effects of chitosan, which were further enhanced with the addition of amphotericin B.