The leishmaniases are severe parasitic diseases that occur worldwide, caused by protozoa of the genus Leishmania. Studies with medicinal plants can lead to a range of possibilities for treating and improving the patients' quality of life. Research on Azadirachta indica fractions and extracts has shown that they have excellent anti-leishmanial activity based on bioactivity-guided fractionation of ethanolic extracts of leaves and seeds and in vitro activity against promastigotes. In this research the most efficient extracts and fractions were selected for tests on intracellular amastigotes of Leishmania amazonensis. The ethanolic extract of the leaves and dichloromethane and chloroform fractions had IC(50) values of 38, 3.9 and 1.2 μg/mL for promastigotes and 9.8, 1.1 and 0.6 μg/mL for amastigotes, respectively, at 72 hours. For the ethanolic extract and dichloromethane fraction from nut tegument, the IC(50) was 2.7 and 2.1 μg/mL for promastigotes and 0.4 and 0.6 μg/mL for amastigotes. The cytotoxicity of the fractions presented selectivity that was between 8 to 32 times more toxic to promastigotes and 15 to 72 times to amastigotes than to macrophages. The extracts and fractions from leaves and fruits were more effective against amastigotes, and the fractionation increased activity against both promastigotes and amastigotes, enabling us to obtain potentially active fractions with low toxicity.

The objective of the study was to compare the effect of organic and conventional cultivation on the antioxidant compound content and antioxidant activity of the Carmen tomato cultivar. Tomatoes were analyzed regarding ascorbic acid, phenolic compounds, lycopene content and antioxidant activity. Organic tomatoes presented higher content of ascorbic acid and total phenolics (641.39 and 4466.66 mg/100 g EAG on dry wt basis) than did the conventional tomatoes (510.16 and 3477.50 mg/100 g EAG on wt dry basis, respectively). There was no difference in lycopene concentrations between the organic and conventional. The ether, alcohol and aqueous extracts obtained from the tomatoes were subjected to the DPPH test and the β-carotene/linoleic acid system assay. The alcohol and aqueous extracts from organic tomatoes presented higher antioxidant activity in the DPPH test (25.43 and 14.28%, respectively) than the conventional tomatoes (19.52 and 11.33%, respectively). Organic tomatoes had higher antioxidant potential probably due to its higher ascorbic acid and total phenolic values