Abstract:
The nematode, Haemonchus contortus, is responsible for major economic losses in the livestock
industry. The management of parasites such as H. contortus has been through the use of
synthetic parasiticides. This has resulted in the presence of residues in meat and milk, which
affects food safety. The development of resistance to available anthelmintics coupled with
their high cost has further complicated matters. This has led to the investigation of alternative
methods to manage nematodes, including the use of plants and plant extracts as a potential
source of novel anthelmintics. Acetone extracts were prepared from 15 South African plant
species and their anthelmintic activity determined using the egg hatch assay (EHA). The leaf
extract of Cleome gynandra had the best inhibitory activity (68% ± 3%) at a concentration of
2.5 mg/mL, followed by the stem extract of Maerua angolensis (65% ± 5%). The extracts had a
relatively low toxicity on Vero cells determined by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-
diphenyltetrazolium bromide) cellular assay.
