Antiparasitic activities of hydroethanolic extracts of Ipomoea imperati (Vahl) Griseb. (Convolvulaceae)

Ipomoea imperati is widely used in tropical areas to treat several pathological conditions. The effect of this plant against parasitic species has not been investigated even being used for this purpose in the Brazilian northeastern. This study aimed to evaluate the anthelmintic and acaricide potential of a hydroethanolic extract of I. imperati leaves and stolons. I. imperati leaves and stolons were crushed and subjected to maceration in ethanol 70% (v/v), after which the solvent was removed using a rotary evaporator. The chromatographic profile of the extract was obtained by UV Spectrum high-performance liquid chromatography and compounds were identified by liquid chromatography/electrospray ionization tandem mass spectrometry. Identification of the compounds present in the extract was achieved by comparing their retention times and UV spectra with data in the literature. Anthelmintic activity was evaluated by larval exsheathment inhibition assays using Haemonchus contortus larvae and five concentrations of each extract ranging from 0.07 to 1.2 mg/mL. Acaricide activity was evaluated via larval immersion of Rhipicephalus microplus in eight concentrations of each extract ranging from 5.0 to 25.0 mg/mL. Live and dead larvae were counted after 24 hours. The median inhibitory concentration (IC(50)) for H. contortus larvae and the median lethal concentration (LC(50)) for R. microplus larvae were calculated. Twelve compounds were observed in the hydroethanolic extract of leaves, with a predominance of the aglycone form of flavonoids and tannins. This extract was effective against H. contortus larvae, presenting an average inhibitory concentration of 0.22 mg/mL, but showed no activity toward R. microplus larvae. The stolon hydroethanolic extract presented 11 compounds, with phenolic acids and glycosylated flavonoids prevailing. This extract showed low activity on R. microplus and no effect on inhibiting H. contortus larval exsheathment at the concentrations tested. This study is the first to assess the anthelmintic and acaricidal activities of I. imperati. Data reported confirm promising potential of I. imperati leaves hydroethanolic extract against H. contortus. This effect could be due to its secondary compounds presents in this extract, such as procyanidin, kaempferol, isoquercitrin and rutin.