Abstract
Medicinal plants have been of great importance to many traditional communities for many generations. However, there is need to carry out scientific studies in order to confirm the medicinal properties of many plants used traditionally. <i>Cosmos sulphureus</i> (Asteraceae) used by local communities for the treatment of various diseases has showed antioxidant, antibacterial, antifungal and antiplasmodial properties although there are no studies demonstrating its antionchocerca activity. The present study was undertaken to investigate the antionchocerca potential of crude extracts and chromatographic fractions of <i>C. sulphureus</i> using <i>Onchocerca ochengi</i>, a bovine filarial closest in phylogeny to <i>Onchocerca volvulus</i>. Solvent extraction of the parts of <i>C. sulphureus</i> was performed using distilled water, 70% EtOH, MeOH, CH<sub>2</sub>Cl<sub>2</sub> and a mixture of MeOH/CH<sub>2</sub>Cl<sub>2</sub> (v/v). Anthelmintic assay was evaluated on adult worms of <i>O. ochengi</i> and worm viability was assessed biochemically using the dimethylthiazol (MTT) formazan assay. Acute and sub-acute oral toxicities of the promising extract was investigated in mice. The chemical composition of extracts was revealed. EtOH extract of roots showed highest anthelmintic activity with an LC<sub>50</sub> value of 31.01±1.17 μg/mL which was more significant than the one of ivermectin (LC<sub>50</sub>=42.78 μg/mL) used as standard. The other extracts show moderate activities. The most active fraction obtained from EtOH extract of roots had an LC<sub>50</sub> value of 19.10 μg/mL on male worm. For acute toxicity, a single dose of 2000 mg/kg used induced no critical behavioral changes or death. In sub- acute toxicity, daily oral administration of hydro-ethanolic extracts of roots at the dose of 250, 500 and 750 mg/kg revealed disturbances in the normal growth of animals as well as liver and kidney alterations. These results unfold potential sources of novel anti-onchocerca lead compounds and validate the traditional use of the plants in onchocerciasis treatment.
Highlights
Onchocerciasis, well known as river blindness, is a debilitating insect-borne parasitic disease caused by Onchocerca volvulus and transmitted to human by Simulium species that breed in fast flowing rivers and streams
The use of nematicidal bio-products obtained from plants is an alternative control method that could partially replace the use of chemical anthelmintic drugs against animal’s parasites. This is the first attempt at using C. sulphureus against O. ochengi
A total of 15 extracts were prepared from different parts of C. sulphureus using solvents of different polarities: methylene chloride (CH2CL2) followed by mixture (MeOH) / (CH2CL2) (v/v), ethanol 70% (EthOH), methanol and distilled water (H2O)
Summary
Onchocerciasis, well known as river blindness, is a debilitating insect-borne parasitic disease caused by Onchocerca volvulus and transmitted to human by Simulium species (black flies) that breed in fast flowing rivers and streams. River blindness has an important socio-economic impact on affected populations It creates stigma and generates and perpetuates poverty [9]. Current efforts to control onchocerciasis are almost exclusively dependent on controlling transmission using mass distribution of ivermectin. This drug is only a microfilaricide, and a major challenge with this treatment is the fact that it kills Loa loa mf in blood, a situation that often leads to severe adverse effects (encephalopathy and death) in individuals with high L. loa mf load [11]. There is a need for a safe and effective macrofilaricidal drug against onchocerciasis that will be able to cure the infection and break transmission cycles, or at least, an alternative microfilaricide that does not kill L. loa mf
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
