Lamoussa Paul Ouattara

Fungi and their toxins have an impact on the hygienic standards and market value of corn (Zea Mayas L.) in Burkina Faso. Though effective, other pesticides have been shown to be harmful. This study aims to aid in the management of corn diseases by assessing the effectiveness of bio-fungicide formulations. In this study, the blotter method was used to assess the antifungal activity at doses of 0.5% (5 g/kg) and 1% (10 g/kg) of powdered formulations of Cymbopogon giganteus (F1) and Eucalyptus camaldulensis (F2) essential oils on the fungal flora of a corn sample. Untreated controls were also observed. The results of this study demonstrated that Aspergillus flavus and Aspergillus parasiticus, which could produce aflatoxin, were more susceptible to the 0.5% dose at F1 than at F2. Though Aspergillus niger and Rhizopus sp. were resistant to 0.5% of F1 and 0.5% of F2, while Fusarium sp. was resistant to 0.5% of F1. All of the above fungi were vulnerable to 1% of F1 and F2. Therefore, these two formulations could be utilized successfully to combat the decline in the hygienic, nutritional, and market value of corn in Burkina Faso caused by aflatoxin contamination and other toxins produced by these fungi. However, it would be important to evaluate the synergistic effect of these biofungicide formulations in situ and on a large scale. Key words: Antifungal, Cymbopogon giganteus, Eucalyptus camaldulensis, essential oil, biofungal formulation, corn. Fungi and their toxins have an impact on the hygienic standards and market value of corn (Zea Mayas L.) in Burkina Faso. Though effective, other pesticides have been shown to be harmful. This study aims to aid in the management of corn diseases by assessing the effectiveness of bio-fungicide formulations. In this study, the blotter method was used to assess the antifungal activity at doses of 0.5% (5 g/kg) and 1% (10 g/kg) of powdered formulations of Cymbopogon giganteus (F1) and Eucalyptus camaldulensis (F2) essential oils on the fungal flora of a corn sample. Untreated controls were also observed. The results of this study demonstrated that Aspergillus flavus and Aspergillus parasiticus, which could produce aflatoxin, were more susceptible to the 0.5% dose at F1 than at F2. Though Aspergillus niger and Rhizopus sp. were resistant to 0.5% of F1 and 0.5% of F2, while Fusarium sp. was resistant to 0.5% of F1. All of the above fungi were vulnerable to 1% of F1 and F2. Therefore, these two formulations could be utilized successfully to combat the decline in the hygienic, nutritional, and market value of corn in Burkina Faso caused by aflatoxin contamination and other toxins produced by these fungi. However, it would be important to evaluate the synergistic effect of these biofungicide formulations in situ and on a large scale. Key words: Antifungal, Cymbopogon giganteus, Eucalyptus camaldulensis, essential oil, biofungal formulation, corn.

Malaria remains a major public health problem due to the emergence and spread of Plasmodium falciparum drug resistance. There is an urgent need to investigate new sources of antimalarial drugs which are more effective against Plasmodium falciparum. One of the potential sources of antimalarial drugs is traditional medicinal plants. In this work, we studied the in vitro antiplasmodial activity of chloromethylenic, methanolic, and MeOH/H₂O (1/1) crude extracts and decoction obtained from eight medicinal plants collected in Burkina Faso and of total alkaloids for five plants. Extracts were evaluated in vitro for efficacy against Plasmodium falciparum strain K1, which is resistant to chloroquine, pyrimethamine and proguanil using the fluorescence-based SYBR Green I assay. The antiproliferative activity on human-derived hepatoma cell line HepG2 and Chinese hamster ovary (CHO) cells was evaluated using the 3-[4,5-dimethylthyazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test in order to determine the selectivity index. Among the plant extracts tested for in vitro antiplasmodial activity, 16 were considered to be inactive (with IC₅₀ > 10 μg/ml), six showed a moderate activity (5 < IC₅₀ ≤ 10 μg/ml), and six were found to have a good in vitro activity with IC₅₀ value ≤ 5 μg/ml. The highest antiplasmodial activity was found for extracts from: the alkaloid leaf extract and the chloromethylenic extracts of Combretum fragrans (IC₅₀ = 3 μg/ml, IC₅₀ = 5 μg/ml), the total alkaloids and the chloromethylenic leaf extracts of Combretum collinum (IC₅₀ = 4 μg/ml), the MeOH/H₂O leaf extract of Terminalia avicennioides (IC₅₀ = 3.5 μg/ml), and the alkaloid leaf extract of Pavetta crassipes (IC₅₀ = 5 μg/ml). Three other extracts showed moderate antiplasmodial activity (5 < IC₅₀ ≤ 10 μg/ml): Terminalia avicennioides and Combretum fragrans methanolic extracts and Acacia kirkii alkaloid leaf extract (IC₅₀ = 6.5, 9 and 10 μg/ml respectively). The Terminalia avicennioides crude MeOH/H₂O (80:20 v/v) extract of the leaves was submitted to a successive liquid/liquid extraction with ethylacetate and n-butanol respectively. The extracts were investigated for in vitro antiplasmodial activity and antioxidant properties using DPPH^●, ABTS⁺ and FRAP methods. The ethylacetate extract showed the best antiplasmodial activity (7 μg/ml) and the active constituent was isolated as ellagic acid by bioguided fractionation with an IC₅₀ = 0.2 μM on Plasmodium falciparum and SI = 152. Besides, Terminalia avicennioides leaf extract and ellagic acid showed a good antioxidant activity. Our finding confirms the importance of investigating the antimalarial activity of plant species used in traditional medicine. Overall, two plants belonging to the Combretaceae family, Combretum fragrans and Combretum collinum appeared to be the best candidates and will be further investigated for their antiplasmodial properties, in order to isolate the molecules responsible for the antiplasmodial activity.