**Table 1.**

*Medicinal plants from Ghana with anthelmintic and anti-schistosomal activity.*

*The Ghanaian Flora as a Potential Source of Anthelmintic and Anti-Schistosomal Agents DOI: http://dx.doi.org/10.5772/intechopen.97417*

After a two-week period of treatment, the mean number of worms recovered from *A. indica*-treated mice was 19.80 ± 8.194 which was significantly lesser than that of the untreated mice (40.20 ± 3.072) [73].

The effect of the extract on the weight of spleen and liver of infected mice were all significantly lesser in the *A. indica*-treated group than that of the untreated group (*p* < 0.05). Organ histology also revealed only few granulomas which were smaller in diameter in the treatment groups whereas those in the untreated were severe (*p* < 0.05). Treated cercariae-infected mice group also had relatively less severe inflammatory cell infiltration compared with untreated group [73].

#### **3.2** *Dichapetalum crassifolium* **Chodat (Dichapetalaceae)**

*Dichapetalum crassifolium* is a scandent shrub, about 1.5 m tall usually found growing in the rain forest, shady places, primitive woods and rocky areas of African countries including Ghana, Angola, Benin, Cameroon, Ivory Coast, Liberia, Nigeria, Sierra Leone, Tanzania, Togo and Zambia [74].

Crude extracts (pet-ether, ethyl acetate and methanol) and isolated triterpenoids from the stems and roots of *D. crassifolium* were investigated for antischistosomal activity against eggs obtained from clinical isolates of *Schistosoma haematobium* using the 96-well plate-egg hatch assay [75].

For the stem extracts, the ovicidal potency was in the following order petroleum ether (IC50 = 443.70) > EtOAc (IC50 = 638.00) > MeOH (IC50 = 893.70 μg/mL). The IC50 values for the root extracts were 248.60, 546.40, and 566.30 μg/mL respectively for the EtOAc, pet-ether and MeOH extracts.

The isolated compounds (Friedelan-3-one, β-Sitosterol/stigmasterol, Dichapetalin M and Dichapetalin A) showed higher ovicidal activity than the extracts though activities for both extracts and compounds were lower compared to the standard drug, praziquantel. The highest ovicidal potency was exhibited by β-sitosterol/stigmasterol mixture with an IC50 of 177.90 μg/mL which was about 11 times less potent than praziquantel (15.47 ± 0.06 μg/mL). The next highest was dichapetalin A (151.10 μg/mL) whiles friedelan-3-one showed the least potency with IC50 of 378.10 μg/mL. From the root extract, Dichapetalin M showed ovicidal effect with IC50 of 191.00 μg/mL [75].

#### **3.3** *Erythrophleum ivorense* **Afzel (Euphorbiaceae)**

*E. ivorense* is a large tree which grows to about 40 m tall, with a cylindrical bole, sometimes fluted at the base. It is widely distributed in the evergreen primary and secondary forests of tropical Africa where it is commonly called by names like 'forest ordeal tree', 'red water tree' and 'sasswood tree'. Among the Akan tribe in Ghana, it is known as '*potrodum'*. The stem-bark and roots are usually employed in the treatment of epilepsy, emesis, pain, oedema, constipation and worm infestations [76].

The cercaricidal activity of the leaf and stem bark extracts of *E. ivorense* was investigated against two developmental stages of *Schistosoma mansoni* namely: the post-infective larvae (schistosomule) and the adult parasite. Various solvent fractions were assayed against the schitosomules at a concentration range of 0.31– 100 μg/mL and against adult parasites at 1.25 mg/mL. The acetone fractions of both leaf and bark demonstrated the highest anti-schistosomal activity causing severe phenotypic alterations (immobility/inactivity, change in shape, translucence, surface disintegration) and death of schistosomules at all dilutions (except 0.31 g/mL) at 24 h and 48 h. For adult parasites, severe phenotypic changes specifically damage to the adult parasite's tegument (surface) was observed for the acetone fraction of

the stem bark extract. The adult worms were observed to be uncoordinated by 5 h, darkened in color by 24 h and died at 48 h exhibiting tegumental damage [77].

In another study, the *in vitro* cercaricidal activity of solvent fractions and isolated compounds from the root bark of *E. ivorense* was investigated against freshly shed cercariae from *Schistosoma haematobium*. Whereas the cercariae showed normal viability without any morphological changes (tail loss) throughout the entire duration of the experiment in the untreated group, exposure of cercariae to the crude hydro-ethanolic extract, its fractions and compounds caused a concentration and time-dependent decrease in viability of cercariae. Within two hours of incubation, all cercariae died at the various concentrations of test compounds and extracts. Eriodictyol, was the most potent compound with an IC50 of 1.23 ± 0.05 μg/ mL. All test samples exhibited a much higher cercaricidal activity than the standard drug praziquantel which caused only 40% mortality of cercariae at the highest concentration tested (IC50 = 695.50 ± 0.05 μg/mL) [78].

#### **3.4** *Holarrhena floribunda* **(G. Don) Dur. & Schinz. (Apocynaceae)**

*Holarrhena floribunda* is native to West Africa and is known in Ghana as '*osese'* among the Akans. The plant is traditionally used in the treatment of malaria, fever and bareness in females. It has antifungal, antibacterial and antidiabetic properties [79, 80].

The hydroethanolic and alkaloidal extracts from the stem bark of *H. floribunda* were tested on cercariae from *Schistosoma haematobium* at concentrations between 15.625 and 500.00 μg/mL. After 180 mins of contact with test samples, the ethanolic extract exhibited the highest cercaricidal potency with an IC50 of 20.09 ± 1.11 μg/ mL higher than the effect of paraziquantel (IC50 = 695.50 ± 1.12). The alkaloidal extract also exhibited cercaricidal potency with an IC50 of 53.20 ± 1.33 μg/mL. The isolated compounds: holonamine, holadienine and conessine exhibited cercaricidal potency with IC50 values of 53.24 ± 1.28, 470.80 ± 1.00 and 33.28 ± 1.04 respectively. The results confirmed the activity of *Holarrhena floribunda* against *S. heamatobium* ceracriae [81].

#### **3.5** *Morinda lucida* **Benth (Rubiaceae)**

[Refer to Section 2.8 for plant description].

In a previous study, the cercaricidal activity of the methanol stem bark extract of *M. lucida* was carried out. The extract at a concentration of 500 μg/mL elicited 100% mortality of *S. mansoni* cercariae within 120 mins of exposure giving an IC50 value of 262.3 μg/mL, which was however lower than the effect of the positive control *Balanites aegyptiaca* (IC50 of 5.95 μg/mL). Further, the *in vitro* adulticidal effect of the stem bark extract on adult schistosome worms revealed that at a concentration of 125–1000 μg/mL, the extract was found to be lethal to the adult worms within 120 h of exposure [73].

#### **3.6** *Nauclea latifolia* **Carl Lin. (Rubiaceae)**

*Nauclea latifolia*, commonly called the African peach, is a deciduous shrub with an open canopy distributed throughout tropical and savanna regions of Africa and Asia. It varies widely in height from around 10–30 m according to soil and moisture conditions. The plant is used against various medical conditions such as diabetes, fever, indigestion and cough [82].

Previous studies on the cercaricidal activity the methanolic extract of stem bark of *N. latifolia* revealed 100% mortality of *S. mansoni* cercariae at a concentration

of 250 μg/mL at 120 min (IC50 = 195.9 μg/mL). Further the extract was found to exhibit schistomicidal effect being lethal to the adult incopula worms at a concentration range of 500–1000 μg/mL within 120 mins of exposure [73].
