In vitro anti-plasmodial activity of three selected medicinal plants that are used in local traditional medicine in Amhara region of Ethiopia.

Background: The plants Aloe weloensis, Lepidium sativum, and Lobelia gibberoa have been used in Ethiopian folklore medicine to treat various diseases including malaria.

Method: The in vitro anti-plasmodial activity of the three crude extracts was evaluated using parasite lactate dehydrogenase assay against the chloroquine (CQ)-sensitive D10 and the chloroquine (CQ)-resistant W2 strains.

Result: The methanolic extract of L. gibberoa roots showed the highest in vitro anti-plasmodial effect against both D10 and W2 Plasmodium falciparum strains with IC₅₀ value of 103.83 ± 26.17 µg/mL and 47.11 ± 12.46 µg/mL, respectively. However, the methanolic extract of L. sativum seeds and the leaf latex of A. weloensis were not active with an IC₅₀ value > 200 µg/mL against both D10 and W2 strains.

Conclusion: The methanolic extract of L. gibberoa roots showed a promising in vitro anti-plasmodial activity against the CQ-sensitive (D10) and CQ-resistant (W2) strains of P. falciparum. Thus, the anti-plasmodial activity of this plant partly justifies and may also support the traditional use against malaria. However, the methanolic extract of L. sativum seeds and the leaf latex of A. weloensis did not exert suppressive activity on the growth of P. falciparum strains.