Anthelmintic Activity, Acute Toxicity of Anacardium occidentale L. (Anacardiaceae) on Onchocerca ochengi and Caenorhabditis elegans

Aim: The objective was to evaluate the anthelmintic activity of the ethanolic stem bark of A. occidentale.

Study Design: Ethanolic extract of stem barks of Anacardium occidentale was tested in vitro against the cattle filarial parasite Onchocerca ochengi and the wild type, the drug resistant strains of the free living nematode Caenorhabditis elegans.

Place and Duration of Study: The work took place at the Laboratory of Applied Zoology of the Faculty of the University of Ngaoundere between May 2016 and March 2017.

Methodology: Adults of O. ochengi were incubated in RPMI-1640 medium supplemented with penicillin/streptomycin and plant extract or drugs. C. elegans was incubated at 20°C with plant extract or drugs in M9-medium. Worm mortality was determined biochemically by MTT/formazan colorimetry after 24, 48 and 72 h. Ivermectin and levamisole were used as positive control and DMSO as negative control. Acute toxicity on mice (Mus musculus) and phytochemical compounds were also determined.

Results: Ethonolic stem bark extract (SBE) of Anacardium occidentale was active against worms. O. ochengi was the most affected by the extract with the LC50 values of 88 ± 0.16 µg/mL, 3.18 ±0.17 µg/mL and 2.76 ± 0.10 µg/mL respectively after 24, 48 and 72h of incubation. The quantitative phyto-constituents screening has revealed the presence of tannins, phenolic acids, saponins and flavonoids. Tannins (107.16 mg GAE/ 100 g) were the most quantified compound followed by phenolic acid (26.23 mg/g GAE), saponins (9.33 mg/g) and flavonoids (0.16 mg of rutin/100 g). The acute toxicity study has demonstrated that at short term (14 days), oral intake of ethanolic stem bark extract was not toxic up to a dose of 1600 mg/kg by weight.

Conclusion: This study justifies the use of this plant by traditional health practitioners in managing the disease, and also suggests a source of compounds against Onchocerca volvulus.