How can Mentha piperita oil affect Trichinella spiralis adults and larvae? In vitro and in vivo studies

Abstract

The alarming concerns of the current anti-trichinosis therapeutics; low efficacy against encysted larvae, serious side effects, and resistance emergence necessitate seeking an alternative therapeutic option. The well-reported therapeutic potentials of peppermint essential oil (PEO) in multiple disorders involving parasitic infections inspired us to explore its anti-trichinosis capacity. This study assessed the in-vitro impact of PEO on Trichinella spinalis adult worms and muscle larvae at three concentrations (2.5 %, 5 %, 10 %) for two durations (4, 24 h). Additionally, its in-vivo efficacy against intestinal, muscle invasion, and late convalescent phases were evaluated in experimentally-infected mice. The phytochemical analysis of PEO revealed high content of menthone, menthol, total phenolic acid, and total flavonoids. It had potent antioxidant properties evidenced by monitoring DPPH scavenging activity (73.6 %) and NO serum levels. In-vitro, PEO had significantly-affected the survival and the cuticular ultrastructure of adults and muscle larvae, inducing the highest mortality rate and the most obvious damage at 10 % after 24 h. In-vivo, PEO treatment induced a significant reduction in parasite burden in the different stages of infection. PEO exhibited a superior activity over albendazole against invasive and encapsulated larvae. Histopathologically, PEO showed a marvelous amelioration of inflammatory infiltration and tissue damage in intestines and muscles and significantly reduced CD3⁺ immune-stained T-lymphocyte percentage. In conclusion, PEO revealed an obvious anti-trichinosis activity both in-vitro and in-vivo. The antioxidant capabilities and the anti-inflammatory possessions qualified it to be a promising, safe, therapeutic alternative for trichinosis. However, further studies should be conducted to standardize its dose and duration in human.