Cytotoxicity and in vitro anthelmintic activity of selected Strychnos species against Pheretima posthuma and Ascaris suum goeze

Objective: This study aimed at testing Strychnos spinosa and Strychnos innocua for cytotoxicity and anthelmintic activities. Methodology: Leaf and bark ethanolic extracts were used for the in vitro testing of both activities. Cytotoxicity testing employed Brine Shrimp Lethality test (BST) on Artemia salina with cyclophosphamide as a reference drug. Anthelmintic activity testing applied Nilan’s team procedure with minor modification on non-pathogenic earth worms Pheretima posthuma and the pathogenic worm Ascaris suum from porcine. Albendazole tablets and albendazole API were used as reference drugs for P. posthuma and A. suum respectively. Results: S. innocua (SIL) and S. spinosa (SSL) leaf extracts were classified as non-toxic towards Artemia salina with LC 50 values of 162.10 and 194.01 (µg/ml) respectively. They also exhibited stronger anthelmintic activity against P. posthuma and A. suum than Albendazole tablets, albendazole API and their respective bark extracts. The order of efficacy found was; SIL extract > SSL extract > Albendazole (API).  At the highest tested concentration (100 mg/ml), the mean paralytic and death times for both SIL and SSL were statistically significant from Albendazole API (p < 0.0001) and matched with PC50 and LC50  (mg/ml) values obtained. Conclusion: Based on results obtained from this work and the fact that, Strychnos genus is rich of many phytochemical of classes, studies on safety evaluation using animal models and identification of bioactive compounds/fractions are ongoing to get new anthelmintic compounds/fractions and to judge their suitability as alternative herbal medicines against worms.