In Vitro Anthelmintic Activity of Three Tropical Plant Extracts on Haemonchus contortus

To evaluate the anthelmintic activity of Anacardium occidentale shell, Illicium verum fruit, and Artocarpus heterophyllus seed to substantiate their traditional use against helminths.

In vitro anthelmintic activity of hydroalcoholic extracts of three plants was evaluated against eggs, infective larvae (L3), adult, and lactate dehydrogenase (LDH) of Haemonchus contortus of naturally infected sheep.

The three extracts exhibited significant (P < 0.001) dose-dependent anthelmintic responses by inhibiting egg hatching and causing paralysis of larvae and mortality of worms. The extracts were most effective on egg and adult stage of H. contortus than on L3 stage at a higher concentration of 6 mg/mL. Anacardium occidentale shell exhibited maximum activity with 100% paralysis of L3 larvae. Probit analysis revealed that the extracts of A. Occidentale shell induced 50% egg hatch inhibition (LD50 = 0.0255 mg/mL), larval paralysis (LD50 = 0.196 mg/mL), and adult worm mortality (LD50 = 1.0365 mg/mL) at a lower concentration (LD50) compared with those of I. verum fruit and A. heterophyllus seed extracts. Further, all extracts significantly (P < 0.01) inhibited the LDH activity catalyzing the oxidation of lactate in adult H. contortus, with maximum level of inhibition caused by A. occidentale shell extract.

Phytochemical screening of the extracts revealed the presence of alkaloids, flavonoids, tannins, saponins, and amino acids that could be responsible for the anthelmintic effects noticed. The results warrant further in vivo evaluation of these plants for potential use as anthelmintic agents.