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

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 IC50 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

Anti-<em>Plasmodium falciparum</em> Activity of Extracts from 10 Cameroonian Medicinal Plants

Background: In the midst of transient victories by way of insecticides against mosquitoes or drugs against malaria, the most serious form of malaria, caused by Plasmodium falciparum, continues to be a major public health problem. The emergence of drug-resistant malaria parasites facilitated by fake medications or the use of single drugs has worsened the situation, thereby emphasizing the need for a continued search for potent, safe, and affordable new antimalarial treatments. In line with this need, we have investigated the antiplasmodial activity of 66 different extracts prepared from 10 different medicinal plants that are native to Cameroon. Methods: Extracts were evaluated for their capacity to inhibit the growth of the chloroquine-sensitive (Pf3D7) and resistant (PfINDO) strains of P. falciparum using the SYBR green fluorescence method. The cytotoxicity of promising extracts against human embryonic kidney cells (HEK293T) mammalian cells was assessed by MTT assay. Results: The antiplasmodial activity (50% inhibitory concentration, IC50) of plant extracts ranged from 1.90 to &gt;100 μg/mL against the two strains. Six extracts exhibited good activity against both Pf3D7 and PfINDO strains, including cold water, water decoction, and ethyl acetate extracts of leaves of Drypetes principum (Müll.Arg.) Hutch. (IC503D7/INDO = 4.91/6.64 μg/mL, 5.49/5.98 μg/mL, and 6.49/7.10 μg/mL respectively), water decoction extract of leaves of Terminalia catappa L. (IC503D7/INDO = 6.41/8.10 μg/mL), and water decoction extracts of leaves and bark of Terminalia mantaly H.Perrier (IC503D7/INDO = 2.49/1.90 μg/mL and 3.70/2.80 μg/mL respectively). These promising extracts showed no cytotoxicity against HEK293T up to 200 μg/mL, giving selectivity indices (SIs) in the range of &gt;31.20–80.32. Conclusions: While providing credence to the use of D. principum, T. catappa, and T. mantaly in the traditional treatment of malaria, the results achieved set the stage for isolation and identification of active principles and ancillary molecules that may provide us with new drugs or drug combinations to fight against drug-resistant malaria