Mentha villosa Hubs., M. x piperita and their bioactives against gastrointestinal nematodes of ruminants and the potential as drug enhancers.

Parasitic diseases caused by gastrointestinal nematodes (GIN) are responsible for a major impact on ruminant welfare. Although the available anthelmintics have a safe margin of toxicity to the animals, their indiscriminate use has increased the selection of resistant parasite populations. In this scenario, essential oils (EO) stand out as a promising ecofriendly therapeutic alternative against GIN. The objective of this work was to determine the effect of the EO of Mentha villosa Hubs (MVEO) collected in 2017 and 2018, M. x piperita (MPEO) and their main components, carvone and limonene, against the third stage larvae (L3) of Haemonchus spp. and Trichostrongylus spp. The solutions, including in nanoemulsion preparations, were tested in a range of concentrations using the larval migration inhibition test (LMIT). The EO and carvone were also tested in combination with nitroxynil (NTX) to determine their effect as drug enhancers (additive or synergy). MVEO/2017, MVEO/2018, MPEO and carvone showed 70.6 (73.4 mg/mL), 86.3 (74.9 mL/mL), 95.5 (143.6 mg/mL), and 88.2 % (38.3 mg/mL) efficacy against L3, respectively. Carvone alone had approximately a 3-fold higher efficacy when compared to its concentration in each EO: 68.8 % in MVEO/2017 and 83.9 % in MVEO/2018. Limonene did not show any significant effect on inhibiting L3 migration. The combination of MPEO and NTX, and carvone and NTX showed a statistically significantly (P <  0.05) synergic and additive effect, respectively, when compared to the isolated treatment. The nanoemulsion of MVEO/2017 at 0.367 mg/mL, inhibited L3 migration by 83.1 %, demonstrating to be highly effective (concentration ratio of 1:0.004), when compared to the MVEO/2017 (70.6 % at 73.4 mg/mL) extraction. The in vitro data from the combination of MPEO or carvone plus NTX suggest that these products can be considered for in vivo experiments against the most important GIN of ruminants as drug enhancers, possibly reducing the final concentration of NTX`. The efficacy of carvone was higher (EC50 = 1.96 mg/mL) than its expected efficacy, based on its concentrations on both EO. Therefore, this component does not need the entire EO composition to exert its L3 motility action. The remarkable efficacy demonstrated by the MVEO/2017/nanoemulsion (EC50 = 0.10 mg/mL), supports its potential to be a candidate to the next-generation therapy to alleviate clinical parasite infections and combat GIN resistant populations.

Trachyspermum ammi (L.) Sprague, superb essential oil and its major components on peptic ulcers: in vivo combined in silico studies.

BACKGROUND: Trachyspermum ammi (L.) Sprague is used for treating gastrointestinal disorders. Several studies indicated gastric antiulcer activity of T. ammi extract, yet the effect of its essential oil has not been studied on. OBJECTIVES: The present study evaluates chemical composition of T. ammi essential oil and anti-peptic ulcer effect of the essential oil as well as its three major components in ethanol induced-gastric ulcers in rats. METHODS: Primarily chemical composition of the essential oil was analyzed by gas chromatography-mass spectrometry (GC/MS). Rats received the essential oil (500, 250, 125, 62.5, 31.25 mg/kg), thymol (30, 100 mg/kg), para-cymene (100, 150 mg/kg) and gamma-terpinene (100, 150 mg/kg) using gavage tube along with ethanol 80%. Finally, dissected stomachs were assessed both macroscopically and microscopically to evaluate anti-ulcerative effect of the essential oil and the pure compounds. Moreover, molecular docking was utilized to explore the interactive behavior of the main components with active site residues of H+/K+ ATPase. RESULTS: Analysis of the essential oil indicated that para-cymene (37.18%), gamma-terpinene (35.36%) and thymol (20.51%) are the main components. Administration of different doses of the essential oil noticeably diminished the number of peptic ulcers in a dose-dependent manner. Among the main components, thymol was more potent than para-cymene and gamma-terpinene. Administration of the essential oil (500 mg/kg) and thymol (100 mg/kg) observed maximum inhibition percentage (98.58% and 79.37%, respectively). Molecular docking study provides the evidence of thymol ability to inhibit H+/K+ ATPase. CONCLUSIONS: The findings revealed that T. ammi essential oil can be applied to treat gastric ulcer as a natural agent. Graphical abstract.