Curtisia dentata (Cornaceae) leaf extracts and isolated compounds inhibit motility of parasitic and free-living nematodes

Onderstepoort Journal of Veterinary Research, 76:249–256 (2009) Curtisia dentata (Cornaceae) leaf extracts and isolated compounds inhibit motility of parasitic and free-living nematodes L.J. SHAI1, 2*, E.S. BIZIMENYERA1, 3, V. BAGLA1, L.J. MCGAW1 and J.N. ELOFF1 ABSTRACT SHAI, L.J., BIZIMENYERA, E.S., BAGLA, A.V., McGAW, L.J. & ELOFF, J.N. 2009. Curtisia dentata (Cornaceae) leaf extracts and isolated compounds inhibit motility of parasitic and free-living nematodes. Ondesterpoort Journal of Veterinary Research, 76:249–256 Haemonchus contortus and Trichostrongylus colubriformis are among the most important parasitic nematodes of small ruminants. Caenorhabditis elegans, a free-living nematode, is used as a model for evaluating anthelmintic activity of a variety of test substances. Extracts of several medicinal plants are useful in vitro and in vivo against nematode development. Extracts of Curtisia dentata, a South African medicinal plant, and compounds isolated from leaves of this plant were investigated for anthelmintic activity against T. colubriformis, H. contortus and C. elegans. The acetone and dichloromethane extracts were active against all nematodes at concentrations as low as 160 μg/mℓ. Betulinic acid and lupeol were active against the parasitic nematodes only at the high concentrations of 1 000 and 200 μg/mℓ, respectively. All compounds were effective against C. elegans with active concentrations as low as 8 μg/mℓ. Betulinic acid was less active than lupeol and ursolic acid against C. elegans. The acetone and dichloromethane extracts were also active against C. elegans with a concentration of 0.31 mg/mℓ resulting in almost 80 % inhibition of larval motility. The use of free-living nematodes may provide information on the activity of potential anthelmintics against parasitic nematodes. Extracts of various medicinal plant species may provide solutions to ill-health of small ruminants caused by parasitic nematodes in poor communities of southern Africa. Keywords: Anthelmintic, betulinic acid, Curtisia dentata, lupeol, ursolic acid INTRODUCTION Helminthosis, caused by parasitic gastrointestinal nematodes, remains a major constraint to livestock 1 Phytomedicine Programme, Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, 0110 South Africa 2 Department of Biochemistry, Faculty of Science and Agriculture, University of Limpopo, P.O. Box 235, Medunsa, 0204 South Africa 3 Department of Agriculture and Animal Health, UNISA, Private Bag X6, Florida 1710 * Author to whom correspondence is to be directed. Email: Accepted for publication 13 October 2008—Editor production across the tropical and subtropical regions, with Haemonchus contortus and Trichostrongylus colubriformis listed among the top ten most important parasites of ruminants (Perry & Randolph 1999; Chiejina 2001; Hounzangbe-Adote, Paolini, Fouraste, Moutairou & Hoste 2005). Trichostrongylus colubriformis causes parasitic enteritis that predisposes ruminants to diarrhoea, weakness and death. This parasite is frequently found infecting cattle and sheep in South Africa, causing loss in production (Horak 2003; Horak, Evans & Purnell 2004). Haemonchus contortus causes anaemia, haemorrhagic gastroenteritis, hypoproteinaemia partly manifested as submandibular oedema or ‘bottle jaw’ and sudden death, or chronic emaciation 249 Curtisia dentata (Cornaceae) leaf extracts and isolated compounds inhibit motility of nematodes in affected livestock (Urquhart, Armour, Duncan, Dunn & Jennings 1996). In southern Benin, the prevalence of H. contortus was estimated at 92.5 % in goats and sheep (Salifou 1996). The usual mode of control of these parasitic diseases relies on the repeated and strategic use of proprietary anthelmintic drugs. However, these drugs are often so highly priced that they are not accessible to subsistence and small-scale livestock farmers in developing countries (Hounzangbe-Adote et al. 2005). Extensive use of drugs by commercial farmers has created anthelmintic resistance that has become cosmopolitan. The emergence of resistance of gastrointestinal nematodes to conventional anthelmintics and resulting economic and production losses emphasize the need to search for alternative methods of worm control (Prichard 1990; Wolstenholme, Fairweather, Prichard, Von SamsonHimmelstjerna & Sangster 2004; Jabbar, Iqbal, Kerboeuf, Muhammad, Khan & Afaq 2006). One of the alternative methods of worm control is the use of medicinal plants. In many parts of the developing world, small-scale and subsistence farmers rely on traditional methods of deworming that include the administration of remedies derived from plants (Hammond, Fielding & Bishop 1997; Danø & Bøgh 1999). The scientific evidence of the efficacy and safety to support widespread use of plant-based remedies as anthelmintics is still scanty (Hammond et al. 1997). Extracts of several African plant species are active against parasitic and free-living nematodes (Hammond et al. 1997; Enwerem, Okogun, Wambebe, Okorie & Akah 2001; Bizimenyera, Githiori, Eloff & Swan 2006). Extracts of Artemisia sp. have shown activity against Haemonchus sp. (Idris, Adam & Tartour 1982; Iqbal, Lateef, Ashraf & Jabbar 2004) and Trichostrongylus species (Sharma 1993). Furthermore, Hördegen, Hertzberg, Heilmann, Langhans & Maurer (2003) demonstrated anthelmintic activity of ethanolic extracts of several plant species in an in vivo sheep model. Some compounds and plant extracts that possess anthelmintic activity also have antifungal efficacy. In 1993, Padmaja, Thankamany & Hisham reported that extracts of the root bark of Uvaria hookeri and Uvaria narum, together with the isolated acetogenins, have antifungal, antibacterial and anthelmintic activities. Benzimidazole carbamates, a class of anthelmintics used in human and veterinary medicine have antifungal activity (Murray, Hudson & Yassa 1992; Katiyar, Gordon, McLaughlin & Edlind 1994). Polyphenols isolated from the leaves of Piper betle had both antifungal and anthelmintic activity (Evans, 250 Bowers & Funk 1984). The extracts of C. dentata leaves showed antifungal activity against Candida albicans and several other fungal species (Shai 2007; Shai, McGaw, Masoko & Eloff 2008). We investigated anthelmintic activity in C. dentata extracts and compounds isolated from the leaves of the plant to discover potential correlations with known antifungal activity. Curtisia dentata is traditionally used in humans for stomach ailments and diarrhoea, as a blood strengthener and an aphrodisiac (Hutchings, Scott, Lewis & Cunningham 1996; Pujol 2000). It is also used in the treatment of heartwater in cattle in the Eastern Cape Province (Dold & Cocks 2001) and as a pimple treatment (Grierson & Afolayan 1999). The anthelmintic activity of C. dentata extracts has not been reported in available literature. Betulinic acid is one of the compounds isolated from C. dentata leav (...truncated)