Antiplasmodial volatile extracts from Cleistopholis patens Engler & Diels and Uvariastrum pierreanum Engl. (Engl. & Diels) (Annonaceae) growing in Cameroon

Abstract

In a search for alternative treatment for malaria, plant-derived essential oils extracted from the stem barks and leaves of Cleistopholis patens and Uvariastrum pierreanum (Annonaceae) were evaluated in vitro for antiplasmodial activity against the W2 strain of Plasmodium falciparum. The oils were obtained from 500 g each of stem barks and leaves, respectively, by hydrodistillation, using a Clevenger-type apparatus with the following yields: 0.23% and 0.19% for C. patens and 0.1% and 0.3% for U. pierreanum (w/w relative to dried material weight). Analysis of 10% (v/v) oil in hexane by gas chromatography and mass spectrometry identified only terpenoids in the oils, with over 81% sesquiterpene hydrocarbons in C. patens extracts and U. pierreanum stem bark oil, while the leaf oil from the latter species was found to contain a majority of monoterpenes. For C. patens, the major components were α-copaene, δ-cadinene, and germacrene D for the stem bark oil and β-caryophyllene, germacrene D, and germacrene B for the leaf oil. The stem bark oil of U. pierreanum was found to contain mainly β-bisabolene and α-bisabolol, while α-and β-pinenes were more abundant in the leaf extract. Concentrations of oils obtained by diluting 1-mg/mL stock solutions were tested against P. falciparum in culture. The oils were active, with IC 50 values of 9.19 and 15.19 μg/mL for the stem bark and leaf oils, respectively, of C. patens and 6.08 and 13.96 μg/mL, respectively, for those from U. pierreanum. These results indicate that essential oils may offer a promising alternative for the development of new antimalarials. IntroductionA multitude of biological activities have been described for essential oils. The physicochemical properties of these substances, including ready diffusion across cell membranes (acting as drug transport enhancers; Cornwell and Barry 1994) and other specific actions on parasite metabolism, e.g., modulators of P-glycoprotein drug efflux activity (Calcabrini et al. 2004;Munoz-Martinez et al. 2004) and protein isoprenylation (Moura et al. 2001), are likely to explain their biological activities.Malaria is one of the most prevalent infections in the world and constitutes one of the main causes of death in much of the tropics (Walther and Walther 2007;Rowe et al. 2007). Plasmodium falciparum is increasingly resistant to available antimalarial agents, and so, the identification of new compounds that are active against the parasite is an urgent priority.Nonvolatile natural products have been widely investigated for antiplasmodial activity, with encouraging results F. F. Boyom (*) : V. Ngouana : E. A. M. Kemgne :

Ethnopharmacological survey of Annonaceae medicinal plants used to treat malaria in four areas of Cameroon

“…Amongst the extracts with activity, many were volatile extracts from Cleistopholis patens (Boyom et al, 2011b), Xylopia aethiopica, Hexalobus crispiflorus, (Boyom et al, 2003), Xylopia staudtii, Xylopia aethiopica, Xylopia parviflora, Monodora brevipes, Monodora myristica, Polyalthia suaveolens, Annickia chlorantha, Annona senegalensis (Boyom, 2004). Non-volatile extracts from Annickia chlorantha, Annona muricata, Anonidium mannii, Monodora myristica, Polyalthia suaveolens, Uvaria banmanni, Xylopia aethiopica, and Xylopia parviflora also showed potency against Plasmodium falciparum in vitro (Boyom et al, 2009(Boyom et al, , 2011a.…”

In vitro sensitivity of Plasmodium falciparum field isolates to extracts from Cameroonian Annonaceae plants

“…Other types of extracts from Annonaceae species have previously shown antiplasmodial activity (Boyom et al 2011a(Boyom et al , b, 2009Bagavan et al 2010). Available results suggest that this plant family is a promising potential source for antimalarial drugs Acetogenin-rich fractions and interface precipitates were tested in combination with chloroquine against the parasite isolates (Table 3).…”

Anti‐Parasitic Activity of Essential Oils and their Active Constituents against Plasmodium, Trypanosoma and Leishmania

“…& Diels were evaluated in vitro for antiplasmodial activity against W2 strain. The oils showed IC 50 values of 9.19 ± 0.08 μg/mL and 15.19 ± 0.13 μg/mL respectively for the stem bark and leaf oils of Cleistopholis patens and 6.08 ± 0.01 μg/mL and 13.96 ± 0.05 μg/mL respectively for those from Uvariastrum pierreanum (Boyom et al, 2011).…”