In vitro activity of Morinda citrifolia Linn. fruit juice against the axenic amastigote form of Leishmania amazonensis and its hydrogen peroxide induction capacity in BALB/c peritoneal macrophages

Objective: The current treatment of leishmaniasis induces strong side effects and increasing numbers of cases of resistance to reference drugs have been reported. The discovery of the therapeutic properties of active substances in plant extracts represents an interesting field of research into a more efficient treatment against leishmaniasis. Morinda citrifolia, commonly known as noni, has demonstrated promising results as antileishmanial and immunomodulator. Thus, the aim of this work was to evaluate activity against axenic amastigote and hydrogen peroxide induction capacity by M. citrifolia fruit juice.

Results: Phytochemical screening identified anthraquinones, flavonoids, alkaloids, terpenoids, steroids, saponins, coumarins, phenolic compounds, tannins, anthocyanidins and chalcones. Noni juice exhibited dose-dependent activity and an IC₅₀ of 240.1 µg/mL for axenic amastigotes. An absence of endotoxins was observed at the concentrations analyzed, while no cytotoxic effects were identified. Noni juice induced hydrogen peroxide production in BALB/c peritoneal macrophages but not in macrophages infected with Leishmania amazonensis. M. citrifolia fruit juice exhibited antileishmanial activity against L. amazonensis axenic amastigotes and activated macrophages by hydrogen peroxide induction, asserting its potential for further research into new forms of leishmaniasis treatment.