Activity of Herbal Medicines on Plasmodium falciparum Gametocytes: Implications for Malaria Transmission in Ghana

• Published in: PloS one Vol. 10; no. 11; p. e0142587
• Main Authors: Amoah, Linda Eva, Kakaney, Courage, Kwansa-Bentum, Bethel, Kusi, Kwadwo Asamoah
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 12.11.2015; Public Library of Science (PLoS)
• Subjects: Aloe; Analysis of Variance; Antimalarial agents; Antimalarials - therapeutic use; Artemisinin; Disease transmission; Drug sensitivity testing; Drugs; Effectiveness; Erythrocytes; Gametocytes; Ghana; Health sciences; Herbal medicine; Herbal Medicine - methods; Immunology; Inhibition; Inhibitory Concentration 50; Insecticides; Malaria; Malaria, Falciparum - parasitology; Malaria, Falciparum - prevention & control; Malaria, Falciparum - transmission; Medical research; Microscopy; Mosquitoes; Parasites; Parasitic Sensitivity Tests - methods; Plant Extracts - therapeutic use; Plants, Medicinal - chemistry; Plasmodium falciparum; Plasmodium falciparum - drug effects; Plasmodium falciparum - growth & development; Studies; Survival; Vector-borne diseases; Ghana
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0142587

Malaria still remains a major health issue in Ghana despite the introduction of Artemisinin-based combination therapy (ACT) coupled with other preventative measures such as the use of insecticide treated nets (ITNs). The global quest for eradication of malaria has heightened the interest of identifying drugs that target the sexual stage of the parasite, referred to as transmission-blocking drugs. This study aimed at assessing the efficacy and gametocydal effects of some commonly used herbal malaria products in Ghana. After identifying herbal anti-malarial products frequently purchased on the Ghanaian market, ten of them were selected and lyophilized. In vitro drug sensitivity testing of different concentrations of the herbal products was carried out on asexual and in vitro generated gametocytes of the 3D7 strain of Plasmodium falciparum. The efficacies of the products were assessed by microscopy. Cultures containing low dose of RT also produced the least number of late stage gametocytes. Two of the herbal products CM and RT inhibited the growth of late stage gametocytes by > 80% at 100 μg/ml whilst KG was the most inhibitory to early stage gametocytes at that same concentration. However at 1 μg/ml, only YF significantly inhibited the survival of late stage gametocytes although at that same concentration YF barely inhibited the survival of early stage gametocytes. Herbal product RT (Aloe schweinfurthii, Khaya senegalensis, Piliostigma thonningii and Cassia siamea) demonstrated properties of a highly efficacious gametocydal product. Low dose of herbal product RT exhibited the highest gametocydal activity and at 100 μg/ml, RT exhibited >80% inhibition of late stage gametocytes. However inhibition of asexual stage parasite by RT was not optimal. Improving the asexual inhibition of RT could convert RT into an ideal antimalarial herbal product. We also found that generally C. sanguinolenta containing herbal products exhibited gametocydal activity in addition to high asexual efficacy. Herbal products with high gametocydal activity can help in the fight to reduce malaria transmission.