Limonoids and insecticidal activity on Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) of Trichilia catigua A. Juss. (Meliaceae).

The aim of the study was to evaluate the effects of the seeds, exocarp and aril extracts from Trichilia catigua A. Juss. (Meliaceae) against Spodoptera frugiperda and present the phytochemical study carried out with the aril extract of T. catigua. Limonoids were isolated from the aril of T. catigua through chromatographic techniques and their structures were proposed by spectroscopic analysis and comparison with literature data. The effects of the seeds, exocarp and aril extracts from T. catigua against S. frugiperda were evaluated considering as parameters the duration and mortality of the larval phase, in addition to the pupal weight. Phytochemical investigation of the aril extracts of T. catigua has led to the identification of the limonoids 6α-O-acetyl-7-deacetyl-14,15-dihydro-15-oxo-nimocinol (1), cedrelone (2) and 6α-O-acetyl-7-deacetylnimocinol (3). The hexane and CH2Cl2 extracts of the aril showed a high rate of larval mortality (100 and 90%, respectively). In addition, a prolongation of larval phase and a reduction in the pupal weight were observed for insects treated with hexane, CH2Cl2 and methanol extracts of seeds and with CH2Cl2 extract of exocarp of T. catigua.

Acetylation of cedrelone increases its cytotoxic activity and reverts the malignant phenotype of breast cancer cells in 3D culture.

Cedrelone is a limonoid isolated from the plant Trichilia catigua (Meliaceae). Previous studies have demonstrated that cedrelone (1) has several damaging effects on triple negative breast tumor (TNBC) cell line MDA-MB-231. In this work we investigated two new derivatives of cedrelone, the acetate (1a) and the mesylate (1b), to examine whether their effects are improved in comparison to the lead molecule. Cedrelone acetate (1a) was the most cytotoxic compound on TNBC cells and was chosen for additional analyses in traditional two-dimensional (2D) monolayer cultures and three-dimensional (3D) assays. In 2D, 1a induced cell cycle arrest, apoptosis and inhibited essential steps of the metastasis process of the MDA-MB-231 cells, in vitro. Moreover, 1a was able to revert the malignant phenotype of the T4-2 cells in 3D. These effects were concomitant with the downregulation of EGFR, ß1-integrin and phospho-Akt, which could have resulted in a decrease of NFκB levels and MMP9 activity. These results suggest that 1a could be used as an important model for the design of a new drug to be applied in cancer treatment and be further studied in vivo for its antitumor and antimetastatic effects.

Cathepsin D immobilized capillary reactors for on-flow screening assays.

The treatment of diseases using enzymes as targets has called for the development of new and reliable methods for screening. The protease cathepsin D is one such target involved in several diseases such as tumors, degenerative processes, and vital processes of parasites causing schistosomiasis. Herein, we describe the preparation of a fused silica capillary, cathepsin D (CatD)-immobilized enzyme reactor (IMER) using in a multidimensional High Performance Liquid Chromatography-based method (2D-HPLC) and zonal affinity chromatography as an alternative in the search for new ligands. The activity and kinetic parameters of CatD-IMER were evaluated by monitoring the product MOCAc-Gly-Lys-Pro-Ile-Leu-Phe (P-MOCAc) (KM = 81.9 ±â€¯7.49 µmol/L) generated by cleavage of the fluorogenic substrate MOCAc-Gly-Lys-Pro-Ile-Leu-Phe-Phe-Arg-Leu-Lys(DNP)-d-Arg-NH2 (S-MOCAc). Stability studies have indicated that CatD-IMER retained 20% of activity after 5 months, a relevant result, because proteases are susceptible to autoproteolysis in solution assays with free enzyme. In the search for inhibitors, 12 crude natural product extracts were analyzed using CatD-IMER as the target, resulting in the isolation of different classes of natural products. In addition, 26 compounds obtained from different species of plants were also screened, demonstrating the efficiency and reproducibility of the herein reported assay even in the case of complex matrices such as plant crude extracts.

Isolation of xanthyletin, an inhibitor of ants' symbiotic fungus, by high-speed counter-current chromatography.

Xanthyletin, an inhibitor of symbiotic fungus (Leucoagaricus gongylophorus) of leaf-cutting ant (Atta sexdens rubropilosa), as well as suberosin, seselin and xanthoxyletin were isolated from Citrus sinensis grafted on Citrus limonia. A two-phase solvent system composed of hexane/ethanol/acetonitrile/water (10:8:1:1, v/v) was used for the high-speed counter-current chromatographic isolation of xanthyletin with high yield and over 99% purity as determined by liquid and gas chromatography with mass spectrometry detection. Identifications were performed by UV spectra, IR spectra, (1)H NMR and (13)C NMR.

High-speed counter-current chromatographic isolation of ricinine, an insecticide from Ricinus communis.

The alkaloid ricinine, an insecticide for leaf-cutting ant (Atta sexdens rubropilosa), was obtained from Ricinus communis. A two-phase solvent system composed of CH(2)Cl(2)/EtOH/H(2)O (93:35:72, v/v/v) was used for high-speed counter-current chromatographic (HSCCC) isolation of ricinine in high yield and with over 96% purity, as determined by liquid and gas chromatography-mass spectrometry (LC-MS and GC-MS). Identification of ricinine was performed by comparison of (1)H NMR, (13)C NMR and LC-MS/MS data.