Anti-Onchocerca activity and phytochemical analysis of an essential oil from Cyperus articulatus L

Abstract

BackgroundThe lack of a safe and effective adult worm drug 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 onchocerciasis. The present study was undertaken to investigate the acclaimed anti-Onchocerca activity of the roots/rhizomes of Cyperus articulatus in the traditional treatment of onchocerciasis in North Western Cameroon and to assess the plant as a new source of potential filaricidal lead compounds.MethodsCrude extracts were prepared from the dried plant parts using hexane, methylene chloride and methanol. The antifilarial activity was evaluated in vitro on microfilariae (Mfs) and adult worms of the bovine derived Onchocerca ochengi, a close relative of Onchocerca volvulus. The viabilities of microfilariae and adult male worms were determined based on motility reduction, while for the adult female worms the viability was based on the standard MTT/formazan assay. Cytotoxicity of the active extract was assessed on monkey kidney epithelial cells in vitro and the selectivity indices (SI) were determined. Acute toxicity of the promising extract was investigated in mice. Chemical composition of the active extract was unraveled by GC/MS analysis.ResultsOnly the hexane extract, an essential oil exhibited anti-Onchocerca activity. The oil killed both the microfilariae and adult worms of O. ochengi in a dose manner dependently, with IC50s of 23.4 μg/ml on the Mfs, 23.4 μg/ml on adult male worms and 31.25 μg/ml on the adult female worms. Selectivity indices were 4, 4, and 2.99 for Mfs, adult males and adult females, respectively. At a single limit dose of 2000 mg/kg body weight, none of 6 mice that received the essential oil by gavage died. GC/MS analysis revealed the presence of terpenoids, hydrocarbons and fatty acids or fatty acid derivatives as components of the oil.ConclusionsThe essential oil from the roots/rhizomes of Cyperus articulatus is active against O. ochengi microfilariae and adult worms in vitro in a dose dependent manner, hence may provide a source of new anti-filarial compounds. The results also support the traditional use of C. articulatus in the treatment of human onchocerciasis.

In vitro and in vivo antimalarial activity of the volatile oil of Cyperus articulatus (Cyperaceae)

“…Our results for the cytotoxicity tests and the acute lethal toxicity of VOCA were similar to those reported by Metuge et al (2014) for C. articulatus from Cameroon, who found an IC 50 = 93.7 µg ml -1 using monkey kidney cells to assess cytotoxicity and also determined the toxic dose in mice to be greater than 2,000 mg kg -1 under acute exposure conditions. Rukunga et al (2008) described the antiplasmodial activity of two sesquiterpenes isolated from the chloroform extract of the rhizomes of C. articulatus from Kenya: corymbolone (IC 50 = 1.07 and 1.92 µg ml -1 ) and mustakone (IC 50 = 0.14 and 0.25 µg ml -1 ) against NF 54 and ENT 36 cell strains, respectively.…”

Antifilarial Activity of Cucurbita pepo ovifera var ovifera (Cucurbitaceae) on Onchocerca ochengi Adult Worms

“…In the present work, ethanolic extracts of Cucurbita ovifera, plant used in traditional medicine in Cameroon was tested for its anthelmintic activity. [9][10][11][12][13] and close species to C. pepo ovifera var ovifera such as Cucurbita moschata for its inhibiting actions on the blossoming of eggs in Haemonchus contortus [18]. All those studies reported are not directly comparable to our results, due to differences in plant materials.…”

“…The appearance of toxic symptoms such as behavioural changes, locomotion, convulsions and mortality, were observed and recorded. Animals were observed constantly for the first 30 min after administration and thereafter every 4 h up to 24 h and subsequently once a day for up to 14 days [9,21]. There is no law yet regulating animal research in Cameroon [12].…”

“…The antifilarial activities of some medicinal plants from Cameroon have been reported on Onchocerca ochengi [7,[9][10][11][12][13]. Both parasites O. volvulus and O. ochengi are evolutionary closely related and are transmitted to their human and bovine host by the same blackfly vector Simulium damnosum, their microfilariae being equally sensitive to ivermectin [14].…”

Targeting Human Onchocerciasis: Recent Advances Beyond Ivermectin

“…Such forms of medicine have been practiced for hundreds or even thousands of years and are a valuable repository of human knowledge and possibly sources of future drugs. 48 In this sense, Metuge et al 49 investigated the acclaimed anti-onchocerca activity of the roots/rhizomes of Cyperus articulatus in the traditional treatment of onchocerciasis in North Western Cameroon with the purpose of identifying potential filaricidal lead compounds. The essential oil from the roots/rhizomes of C. articulatus was found to be active against O. ochengi microfilariae and adult worms in a dose-dependent manner in vitro.…”