**2.2** *Alstonei boonei* **De Wild (Apocynaceae)**

*Alstonia boonei* is an indigenous African tree mostly distributed in the evergreen rain forest of tropical West Africa. In Ghana it is locally called '*Nyame dua'* meaning God's tree in the Akan language. In the western coastal regions of Africa, this plant is well known for its extensive use in traditional medicine for treating rheumatism, general body pains, worm infestation and diabetes. A cold infusion of the fresh or dried bark is used as a vermifuge to expel intestinal worms and other intestinal parasites in children [34].

The methanol extracts (50–150 mg/mL) of the stem bark and roots of *A. boonei* were investigated *in vitro* for anthelmintic effects against the adult Indian earthworm, *Pheretima posthuma* by direct exposure of worms to the extracts. The stem bark extract exhibited a concentration dependent anthelmintic activity causing paralysis of worms within 15–55 mins and death within approximately 100 mins which was significant (*p <* 0.01) compared to the untreated group. The stem bark extract had a better anthelmintic effect than the root bark [35].

In another study, the aqueous and ethanolic stem bark extracts (50–200 mg/mL) of *A. boonei* demonstrated significant anthelmintic activity against *Lubricus terretris*.

While worms in the untreated group saw no paralysis or death after 120 mins of exposure, the extract-treated worms were paralyzed within 8–16 minutes of exposure and died within approximately 21–27 minutes of exposure [36].
