Onchocerciasis or River Blindness is the second leading infectious cause of blindness to humans. The lack of a safe and effective drug against the adult Ochocerca worm and the emergence of resistant animal parasite strains to the only recommended drug, the microfilaricide, ivermectin put many at risk of the devastating effects of the disease.
Although many plants are used traditionally for the treatment of Onchocerciasis, the prevalence of the disease has not dropped in many of these communities. This has led to a scientific study of these plants, where crude extracts and pure compounds isolated from them, have been tested on the adult worms both in vitro and in situ. Adult onchocerca worms have been kept in culture for up to seven days. Many crude extracts are active on the adult worms but isolated pure compounds are less active. Some of the crude extracts and pure compounds have been observed to be toxic at filaricidal doses. The continuous consumption of these plants as herbal medicines may be hazardous in the long term due to cumulative toxicity effects. Combinations of active pure compounds may be more effective than single compounds. Where pure compounds are active against adult worms and microfilarae, the challenge is to explain their mode or mechanism of action. In silico methods can be used to predict the targets of the active pure compounds and their possible toxicity effects