Study of Antiparasitic and Cytotoxicity of the Aqueous, the 80% Methanol Extract and Its Fractions, and the Acute Toxicity of the Aqueous Extract of Brucea sumatrana (Simaroubaceae) Leaves Collected in Mai-Ndombe, Democratic Republic of Congo

Results from the in vitro evaluation of the antiparasitaire activity of the aqueous extract, the 80% methanol extract and its fractions from the leaves of Brucea sumatrana against Trypanosoma brucei brucei, T. cruzi, Leishmania infantum, the multidrug-resistant K1 and chloroquine-sensitive NF54 strains of Plasmodium falciparum indicated that all samples from the leaves extract presented interesting antiparasitaire activity at different extents. The 80% methanol extract, its chloroform acid, petroleum ether and 80% methanol soluble fractions and the aqueous extract exhibited strong activity against Trypanosoma b. brucei, T. cruzi, L. infantum and the multidrug-resistant K1 strain of P. falciparum with IC50 values from <0.25 to 4.35 μg/ml as well as against chloroquine-sensitive NF54 strain of P. falciparum with IC50 values ranging from <0.02 to 2.0.4 μg/ml. Most samples were cytotoxic against MRC-5 cell lines (0.2 50) < 34.24 μg/ml) and showed good selective effect against all tested parasites. In acute toxicity, the aqueous extract was found to be non-toxic and its LD50 was estimated to be greater than 5 g/kg. In addition, it did not significantly modify the concentration levels of some evaluated biochemical and hematological parameters in treated rats. These results constitute a scientific validation supporting and justifying the traditional use of the leaves of B. sumatrana for the treatment of malaria, sleeping sickness and at some extent Chagas disease.

Antioxidant and Cytotoxic Diarylheptanoids Isolated from Zingiber officinale Rhizomes

One new diarylheptanoid, namely （4E,6E）-7-（3,4-dihydroxy-5-methoxyphenyl）-1-（4-hydroxy-3-methoxyphenyl）- hepta-4,6-dien-3-one （1）, was isolated from the rhizomes of Zingiber officinale, along with ten known ones, tetra- hydrocurcumin （2）, curcumin （3）, 5-hydroxy-1,7-bis（4-hydroxy-3-methoxyphenyl）heptan-3-one （4）, gingerenone A （5）, 7-（3,4-dihydroxyphenyl）-5-hydroxy-1-（4-hydroxy-3-methoxyphenyl）heptan-3-one （6）, （E）-1,7-bis（4-hydroxy- 3-methoxyphenyl）hept-1-ene-3,5-dione （7）, （E）-7-（4-hydroxy-3-methoxyphenyl）-1-（4-hydroxyphenyl）-hept-l-ene- 3,5-dione （8）, shogasulfonic acid A （9）, 1,5-epoxy-3-hydroxy-1-（3,4-dihydroxy-5-methoxyphenyl）-7-（4-hydroxy-3- methoxyphenyl）heptane （10）, and （3S, SS）-3,5-diacetoxy-1,7-bis（3,4-dihydroxyphenyl）heptane （11）. Their structures were elucidated on the basis of spectral evidence and comparisons with literature data. The free radical scavenging activity of 1--11 was evaluated by the 1,l-diphenyl-2-picrylhydrazyl （DPPH） assay. Most of the isolated com- pounds were found to be better antioxidants than the positive control ascorbic acid. These compounds were also evaluated for their cytotoxicity against HeLa and MNK-45 cells using the MTT assay. Our results suggest that com- pounds 3 and 5-8 inhibited HeLa cells, and 3, 5, 7 and 8 inhibited MNK-45 cells. It was found that compound 5 was markedly cytotoxic against HeLa and MNK-45 cell lines with ICs0 values of 6.4 and 7.8 μmol/L, respectively.