In vivo antimalarial and acute toxicity properties of hexane and chloroform extracts from Clausena anisata (Willd.) Benth.

Abstract

Malaria is a disease caused by Plasmodium parasites and, though preventable and curable, is still one of the greatest global public health problems, especially in sub- Saharan Africa. This can be partly attributed to malaria in endemic areas. Unfortunately, recent reports indicate a decline in efficacy of artemisinin derivatives along the Thai-Cambodia border, a site historically known for the recurrent emergence of drug-resistant malaria parasites (Dondorp et al, 2009; Noedl et al, 2008). New classes of antimalarial agents are therefore urgently needed, given that drug resistance is likely to eventually compromise the efficacy of currently available antimalarial drugs; identification of lead antimalarial agents from medicinal plants could boost the search.

Clausena anisata in vivo antimalarial activity and acute toxicity of C. anisata extracts were investigated. The plant was selected as it has been traditionally used to treat malaria (Kokwaro, 2009; Beentje, 1994). (Willd.) Benth is a deciduous shrub/tree whose leaves are aromatic. In Kenya, it is known locally as Mjarikali (Swahili) and Mutathi (Kikuyu). Traditionally, soup boiled with the roots of the plant was given to women after birth to cleanse the uterus. This soup is also highly recommended for headaches, malaria, influenza, and indigestion. Twigs are used as toothbrushes and are believed to cure a toothache. Decoctions of the root are also drunk to treat syphilis (Kokwaro, 2009; Beentje, 1994; Gachathi, 1989).

Pharmacological activities associated with extracts from this plant include antifungal and antibacterial activity (Senthilkumar and Venkatesalu, 2009; Hamza et al, 2006; Gundidza et al, 1994), antidiabetic activity (Ojewole, 2002), anticonvulsant activity (Makanju, 1983), angiotensin converting enzyme (ACE) inhibitory activity (Duncan et al, 1999), and antiviral activity (Ayisi and Nyadedzor, 2003). Phytochemical investigations indicate carbazole alkaloids as the major component of this plant (Ito et al, 2000; Ito et al, 2009).

Coumarins and limonoids have also been isolated (Ngadjui et al, 1991; Ngadjui et al, 1989; Lakshmia et al, 1984). Pharmacological activities associated with carbazole alkaloids include antifungal, antibacterial, and antiviral activities (Ito et al, 2009; Ito et al, 2000; Chakraborty et al, 1995). Coumarins are reported to have anticoagulant properties (Emerole et al, 1981). Steam distillation of fresh leaves yielded sweet-smelling, brownish-yellow oil whose major component is the acute toxin estragole (Okunade, 1987).

As part of our continuing efforts to identify antimalarial agents from medicinal plants, in vivo antimalarial activity and acute toxicity of C. anisata extracts were investigated. The plant was selected as it has been traditionally used to treat malaria (Kokwaro, 2009; Beentje, 1994).