Effect of Methanolic Extract of Some Selected Plants on the Mortality of Leech (Hirudo medicinalis)

Background and Objective: The increased invasiveness of Leeches in many streams, lakes and fishing sites in Bayelsa Staten has called for a prompt control intervention. This study was undertaken to test the effect of the extract of four botanicals, Cassia alata, Costus afer, Ficus sur and Platostoma africanum on the mortality rate of the leech. Materials and Methods: The screening, preparation and extraction of the metabolites from the plant samples followed standard techniques. The leeches were collected from a fishing lake and a stream in Elebele Community of Ogbia, Bayelsa State into a sterilized transparent container using a plastic scoop and transported along with their natural habitat water (stream water) to the Department of Biological Sciences Laboratory. Identification of the leeches followed standard pictorial key. A complete randomized block design was used to set up three treatment groups with varying concentrations of the plant extract. Two hundred and eighty-eight of the leeches previously kept in the aquarium were introduced into the treatments and their death rates were recorded. Results: From the results, five phytochemicals, Alkaloids, Flavonoids, Tannins, Terpenes and Saponins were encountered with the plants. Out of the 288 leeches tested with the plant extract, the mortality rate was 61.5%, with more death recorded with Platostoma africanum. The mean death rate in Cassia alata, Costus afer and Ficus sur and Platostoma africanum ranges from 11.039.11-1000.00, 22.0719.11-1000.00, 11.039.11-1000.00 and 47.8019.22-1000.00, respectively. Conclusion: The mortality rate increases with an increase in extract concentration. The promising anti hirudinicidal activities of these plants should be employed.