In vitro action of Mimosa caesalpinifolia ketone extract on Haemonchus contortus and Trichostrongylus colubriformis

Abstract

This study aimed to evaluate the in vitro anthelmintic activity of Mimosa caesalpinifolia (sabiá) ketone extract, which is rich in condensed tannins (CT), on Haemonchus contortus and Trichostrongylus colubriformis. The leaves and stems of M. caesalpinifolia were collected, dried in the shade, and ground to a dry powder from which ketone extracts were obtained for in vitro assays. The extracts were diluted in 5% acetone and PBS to concentrations in the range 0.25-2.80 mg mL-¹ and the inhibition of egg hatchability was assayed. Feces collected from goats naturally infected with H. contortus (55%) and T. colubriformis (45%) were macerated and the helminth eggs were collected to conduct in vitro egg hatchability tests. Nematode larvae collected from the feces were used for a larval exsheathment inhibition assay of M. caesalpinifolia leaf and M. caesalpinifolia leaf and stem ketone extracts at concentrations of 0.6 and 1.2 mg mL-¹; three replicates were performed for each concentration. PBS was used as a negative control. Polyvinylpolypyrrolidone (PVPP) was added to the extracts to assess the effect of phenolic compounds on anthelmintic activity. An inhibitory effect of 80.7% and 82.3% was observed on hatchability after treatment with 1.0 and 2.0 mg mL-¹ M. caesalpinifolia leaf ketone extract, respectively. An inhibition rate lower than 75% was observed for 1.0 mg mL-¹ M. caesalpinifolia leaf and stem ketone extract. The M. caesalpinifolia leaf ketone extract larval exsheathment assay resulted in inhibition of 97.3% and 99.8% at concentrations of 0.6 and 1.2 mg mL-¹, respectively. For the leaf and stem ketone extract, the larval exsheathment inhibition was 94.3% at 1.2 mg mL-¹. The leaf and leaf and stem extracts showed no inhibitory effects on larval exsheathment after the addition of PVPP. These results showed that cuticular loss was related to the action of the phenolic compounds in the M. caesalpinifolia extracts. M. caesalpinifolia leaf ketone extract inhibited egg hatchability, but the leaf and stem extract showed lower efficiency, which indicated a greater abundance of active compounds in the leaves. The M. caesalpinifolia ketone extracts were effective in the inhibition of larval exsheathment at the highest concentration tested. Based on these results, in vivo studies should be performed to demonstrate the anthelmintic activity of this plant in goats.