Phytochemical screening and evaluation of cytotoxicity of stem bark extracts of Genus dolichocarpa and Duguetia chrysocarpa (Annonaceae)

Purpose: To investigate the phytochemistry and cytotoxic activity of stem bark extracts from Genus dolichocarpa and Duguetia chrysocarpa - two species of the Annonaceae family. Methods: The crude ethanol bark extracts (EtOH) of the plants were obtained by maceration. The crude extracts were suspended in a mixture of methanol (MeOH) and water (H2O) (proportion 3:7 v/v) and partitioned with hexane, chloroform (CHCl3) and ethyl acetate (AcOEt) in ascending order of polarity to obtain the respective fractions. The extracts were evaluated on thin layer chromatography (TLC) plates of silica gel to highlight the main groups of secondary metabolites. Cytotoxicity was tested against human tumor cell lines - OVCAR-8 (ovarian), SF-295 (brain) and HCT-116 (colon) - using 3- (4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Results: The screening results demonstrated that all the extracts were positive for the presence of flavonoids and tannins. The presence of alkaloids also was detected in some extracts. The hexane extract of A. dolichocarpa showed the strongest cytotoxicity against HCT-116 with cell growth inhibition of 89.02 %. Conclusion: The findings demonstrate for the first time the cytotoxic activity of the extracts of A. dolichocarpa and D. chrysocarpa, thus providing some evidence that plants of the Annonaceae family are a source of active secondary metabolites with cytotoxic activity.

Leishmanicidal and cytotoxic activity of extracts and saponins from Ilex laurina (Aquifoliaceae)

Purpose: To evaluate the leishmanicidal and cytotoxic activity of alcohol and non-alcohol extracts and saponins from Ilex laurina . Methods: Extracts were obtained by percolation with solvents of different polarities: hexane, dichloromethane, ethyl acetate and ethanol. The ethyl acetate extract was subjected to silica gel column chromatography eluting with a step gradient of dichloromethane-methanol. All products were evaluated in vitro for leishmanicidal activity against amastigotes of leishmania panamensis and cytotoxicity on U- 937 cells. Results: Two saponins were isolated from the ethyl acetate extract. The ethyl acetate extract showed high leishmanicidal activity against intracellular amastigotes of L. panamensis (EC50, 7.5 ± 1.5 μg/mL) and low activity against axenic amastigotes (EC50, 52.8 ±1.6 μg/mL); this extract showed also high cytotoxicity (LC50, 57.7 ± 12.1 μg/mL). Saponin 2 exhibited high activity against intracellular amastigotes (EC50, 5.9 ± 0.5 μg/mL) but also showed high cytotoxicity on U-937 cells (EC50, 25.7 ± 6.1 μg/mL). This compound showed similar leishmanicidal activity and cytotoxicity to meglumine antimoniate and amphotericin B, respectively, drugs currently used for the treatment of leishmaniasis. Conclusions: Based on these results, Ilex laurina is a potential source of compounds that can lead to the development of new therapeutic alternatives against leishmaniasis.