J. B. Fernandes

Structure of Trypanosoma cruzi glycosomal glyceraldehyde-3-phosphate dehydrogenase complexed with chalepin, a natural product inhibitor, at 1.95 Å resolution

The structure of the glycosomal glyceraldehyde‐3‐phosphate dehydrogenase (gGAPDH) from Trypanosoma cruzi complexed with chalepin, a natural product from Pilocarpus spicatus, has been determined by X‐ray crystallography to 1.95 Å resolution. The structure is in the apo form without cofactors in the subunits of the tetrameric gGAPDH in the asymmetric unit. Unequivocal density corresponding to the inhibitor was clearly identified in one monomer. The final refined model of the complex shows extensive conformational changes when compared with the native structure. The mode of binding of chalepin to gGAPDH and its implications for inhibitor design are discussed.

Limonoids from Toona ciliata and speculations on their chemosystematic and ecological significance

Abstract Evolution of limonoids in the Meliaceae appears to be consistent with the resistance of Melioideae against the shoot borer Hypsipyla . The limonoid chemistry of Toona , which has shown absence of attacks of H. grandella , is reminiscent of Melioidease. An investigation of T. ciliata , has led to the identification of two novel meliacin butenolides, 21-hydroxycedrelonelide and 23-hydroxycedrelonelide, two known limonoids, cedrelone and 23-hydroxytoonacilide, and sitosterol, α-amyrin and β-amyrin acylated with fatty acids. Three known coumarins, siderin, scopoletin and isofraxidin were also isolated. All structures were established from spectral data. Some 13 C NMR signals for cedrelone are reassigned.

In vitro cytotoxicity activity on several cancer cell lines of acridone alkaloids and N -phenylethyl-benzamide derivatives from Swinglea glutinosa (Bl.) Merr.

The methanol extract from the stems and fruits of Swinglea glutinosa (Rutaceae) afforded 11 known acridone alkaloids and three N-phenylethyl-benzamide derivatives, glycocitrine-IV, 1,3,5-trihydroxy-4-methoxy-10-methyl-2,8-bis(3-methylbut-2-enyl)acridin-9(10H)-one, 1,3,5- trihydroxy-2,8-bis(3-methylbut-2-enyl)-10-methyl-9-acridone, citbrasine, citrusinine-II, citrusinine-I, 5-dihydroxyacronycine, pyranofoline, 3,4-dihydro-3,5,8-trihydroxy-6-methoxy-2,2,7-trimethyl-2H-pyrano[2,3-a]acridin-12(7H)-one, 2,3-dihydro-4,9-dihydroxy-2-(2-hydroxy-propan-2-yl)-11-methoxy-10-methylfuro[3,2-b]acridin-5(10H)-one, bis-5-hydroxyacronycine, N-(2-{4-[(3,7-dimethylocta-2,6-dien-1-yl)oxy]phenyl}ethyl)benzamide, N-(2-{4-[(3,7-dimethyl-4-acethyl-octa-2,6-dien-1-yl)oxy]phenyl}ethyl)benzamide, and severine acetate. All compounds isolated were examined for their activity against three cancer cell lines: human lung carcinoma (COR-L23), human breast adenocarcinoma (MCF7), human melanoma (C32), and normal human fetal lung cell line, MRC-5. The acridones tested exhibited weak cytotoxicity but the amides showed moderate nonselective cytotoxic activity.

Synthetic amides toxic to the leaf‐cutting ant Atta sexdens rubropilosa L. and its symbiotic fungus

1 Nine synthetic amides similar to natural N‐piperidine‐3‐(4,5‐methylenedioxyphenyl)‐2‐(E)‐propenamide and N‐pyrrolidine‐3‐(4,5‐methylenedyoxiphenyl)‐2‐(E)‐propenamide were synthesized and identified by their spectroscopic data. 2 The toxicity of these synthetic amides to the Atta sexdens rubropilosa workers and the antifungal activity against Leucoagaricus gongylophorus, the symbiotic fungus of the leaf‐cutting ants, were determined. 3 Workers ants that were fed daily on an artificial diet to which these compounds were added had a higher mortality rate than the controls for N‐pyrrolidine‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide and N‐benzyl‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide at a concentration of 100 µg/mL. 4 The completely inhibition (100%) of the fungal growth was observed with N‐piperidine‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide and N,N‐diethyl‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide at concentrations of 50 and 100 µg/mL and N‐pirrolidine‐3‐(3′,4′‐methylenedioxyphenyl)‐2‐(E)‐propenamide at a concentration of 100 µg/mL. 5 The possibility of controlling these insects in the future using synthetic piperamides that can simultaneously target both organisms is discussed.

The chemosystematics of Dictyoloma

The fruit and stem of Dictyoloma vandellianum have yielded the limonoids and a mixture of two alkaloids. The limonoids were identified as deacetylspathelin and the corresponding 21- and 23γ-hydroxybutenolide derivatives. The limonoids were isolated from the fruits and stem, while the alkaloids were found only in the stem. These results provide firm support for including the genus Dictyoloma in the Rutaceae.

Complete 1H and 13C chemical shift assignments of a new C22-quassinoid isolated from Picrolemma sprucei Hook by NMR spectroscopy

The 1H and 13C NMR spectra of a new C22‐quassinoid from Picrolemma sprucei were completely assigned. In addition to conventional 1D NMR, a variety of 2D shift‐correlated NMR experiments [1H × 1H‐COSY, 1H × 13C‐HMQC‐1J(C,H), 1H × 13C‐HMBC‐nJ(C,H) (n = 2 and 3) and 2D 1H × 1H‐NOESY] was used. Copyright

Effects of limonoids from Cipadessa fruticosa on fall armyworm.

Six mexicanolide limonoids isolated from the dichloromethane extract of the fruits of Cipadessa fruticosa Blume (Meliaceae) were evaluated against Spodoptera frugiperda (J. E. Smith). Gedunin was used as a positive control. When incorporated into an artificial diet of neonates at 50.0 mg kg-1, febrifugin A showed 73.3% mortality. All the compounds showed moderate insecticidal activity, except for ruageanin A, when compared with the control. Febrifugin also showed growth inhibition and antifeedant activities (at 100.0 mg kg-1). The correlation between the insecticidal activity of the isolated compounds and their chemical structure was discussed.