Termiticidal lectins from Myracrodruon urundeuva (Anacardiaceae) cause midgut damage when ingested by Nasutitermes corniger (Isoptera: Termitidae) workers

Myracrodruon urundeuva is a hardwood tree, and its bark, heartwood and leaf contain lectins (MuBL, MuHL and MuLL respectively) with termiticidal activity against Nasutitermes corniger. In this work, the effects of these lectins on the midgut of N. corniger workers were evaluated. The insects were supplied with an artificial diet containing the lectins at their respective LC 50 (previously determined). At 48 h after treatment, the midguts were dissected and fixed for histopathology analyses. Toluidine-blue-stained midguts from lectin-treated workers showed disorganisation, with the presence of debris in the lumen and the absence of brush border. Fluorescence microscopy revealed that the numbers of digestive and proliferating cells were lower in lectin-treated individuals than in the control, and caspase-3 staining confirmed the occurrence of cell apoptosis. Enteroendocrine cells were not seen in the treated individuals. The midguts from treated insects showed greater staining for peroxidase than the control, suggesting that the lectins caused oxidative stress. Staining with wheat germ agglutinin conjugated to FITC revealed that the lectins interfered with the integrity of the peritrophic matrix. This study showed that termiticidal lectins from M. urundeuva cause severe injuries, oxidative stress and cell death in the midgut of N. corniger workers

A trypsin inhibitor from <i>Moringa oleifera</i> flower extract is cytotoxic to <i>Trypanosoma cruzi</i> with high selectivity over mammalian cells

<p>In this study, <i>Moringa oleifera</i> flower extract and a trypsin inhibitor (MoFTI) isolated from it were evaluated for anti-protozoal activity against <i>Trypanosoma cruzi</i> and cytotoxicity to mammalian cells. The presence of flavonoids was remarkable in the HPLC fingerprints of the extract at 254 and 360 nm. Amino acid sequences of peptides derived from in-gel digestion of MoFTI were determined. Both the extract and MoFTI caused lysis of <i>T. cruzi</i> trypomastigotes with LC_{50/24 h} of 54.18 ± 6.62 and 41.20 ± 4.28 μg/mL, respectively. High selectivity indices (7.9 to >12) for <i>T. cruzi</i> cells over murine peritoneal macrophages and Vero cells were found for the extract and MoFTI. The results show that MoFTI is a trypanocidal principle of the flower extract.</p