SAR ANALYSIS OF SYNTHETIC NEOLIGNANS AND RELATED-COMPOUNDS WHICH ARE ANTI-LEISHMANIASIS ACTIVE COMPOUNDS USING PATTERN-RECOGNITION METHODS

Potentially active new neolignan and analogues against leishmaniasis are proposed. Structure-activity relationship (SAR) techniques were employed. Physicochemical properties such as log P, molecular volume, atomic charge and quantum chemical parameters were calculated for a group of synthetic substances for which the biological activities against leishmaniasis are known. Only about half a dozen out of more than twenty parameters were found to be efficient for the classification of the compounds into active and inactive groups.34018519

J. E. M. Walls: Equatorial Weather, with particular reference to Southeast Asia, University of London Press Ltd. 1955, 225 s., 25 sh.

CYTOTOXIC DERIVATIVES OF WITHANOLIDES ISOLATED FROM THE LEAVES OF Acnistus arborescens.. In view of anticancer activity of 7 beta-acetoxywithanolide D (2) and 7 beta-16 alpha-diacetoxywithonide D (3), isolated from the leaves of Acnistus arborescens (Solanaceae), five withanolide derivatives were obtained and their structures were determined by NMR, MS and IV data analysis. The in vitro anticancer activity of these derivatives was evaluated in a panel of cancer cell lines: human breast (BC-1), human lung (Lu1), human colon (Col2) and human oral epidermoid carcinoma (KB). Compounds 2a (acetylation of 2), 3b (oxidation of 3) and 2c (hydrogenation of 2) exhibited the highest anticancer activity against human lung cancer cells, with ED(50) values of 0.19, 0.25 and 0.63 mu g/mL, respectively

Pyrrolizidine alkaloids in three Senecio species from southern Brazil

32121219122

LIGNANS AND A NEOLIGNAN FROM VIROLA-OLEIFERA LEAVES

The chlorophyll-free dichloromethane fraction of the ethanolic extract from leaves of Virola oleifera yielded four new natural lignans, including a known lignan-7-ol, and galbacin, eupomatenoid-8 and (+)-aristolignin. Structural elucidations were made by spectroscopic methods.3261567157

STEREOCHEMICAL INVERSION OF PYRROLIZIDINE ALKALOIDS BY MECHANITIS-POLYMNIA (LEPIDOPTERA, NYMPHALIDAE, ITHOMIINAE) - SPECIFICITY AND EVOLUTIONARY SIGNIFICANCE

Pyrrolizidine alkaloids (PAs), acquired by adults or larvae of Danainae and Ithomiinae butterflies and Arctiidae moths from plants, protect these lepidopterans against predators and are biosynthetic precursors of male sex pheromones. The investigation of PAs in many species of wild-caught adults of Ithomiinae showed lycopsamine (I) [(7R)-OH, (2'S)-OH, (3'S)-OH] as the main alkaloid. In incorporation experiments, PA-free (freshly emerged) adults of the ithomiine Mechanitis polymnia were fed seven PAs: lycopsamine and four of its known natural stereoisomers-indicine (2) [(7R)-OH, (2'R)-OH, (3'S)-OH], intermedine (3) [(7R)-OH, (2'S)-OH, (3'R)-OH], rinderine (4) [(7S)-OH, (2'S)-OH, (3'R)-OH], and echinatine (5) [(7S)-OH, (2'S)-OH, (3'S)-OH], and two PAs without the 7-OH: supinine (6) [(2'S)-OH, (3'R)-OH] and amabiline (7) [(2'S)-OH, (3'S)-OH]. Males epimerized PAs 3, 4, and 5 mainly to lycopsamine (1). Females fed these same three PAs changed a smaller proportion to lycopsamine; their lesser capacity to modify PAs corresponds to their normal acquisition of already transformed PAs from males during mating rather than through visits of adults to plant sources of PAs. The alkaloids 1 and 2, both 7R and 3'S, were incorporated without or with minimum change by males and females. Feeding experiments with 6 and 7 (males only) showed an inversion at the 3' center of 6 and no change in 7. The inversion from 7S to 7R (probably via oxyreduction) may be closely related to the evolution of acquisition of PAs by butterflies and moths. Two hypotheses are discussed: (1) The ancestral butterflies are probably adapted to tolerate, assimilate, and use (7R)-PAs (most common in plants; all widespread 1,2-unsaturated macrocyclic PA diesters show this configuration). The development of (7R)-PA receptors in the butterflies could lead to a specialization on this configuration in two ways: to help find PA plants and to utilize these components in sexual chemical communication. A later appearance of (7S)-PAs in plants could have selected an enzymatic system for the inversion of this chiral center in order to continue producing (7R)-PA-derived pheromones. (2) The inversion would be due to the evolution of a enzyme system specialized in the transport of (7R)-PAs to the integument; the failure of this system to carry (7S)-PAs led to an enzymatic system to invert them to transportable (7R)-PAs. In this case, the 7R configuration is an effect and not a cause of (7R)-PA-derived pheromones. In both hypotheses, the partial inversion of the 3'-asymmetric center, when the butterfly was fed intermedine (3), rinderine (4), and supinine (6), could be fortuitous due to the conformation of the molecule and/or the enzymatic system.20112883289

C-13 NMR SPECTRAL ANALYSIS OF LIGNANS FROM ARAUCARIA-ANGUSTIFOLIA

17349950

Fragrant lactones in the steam distillation residue of Aeollanthus suaveolens Mart. ex Spreng and analysis by HS-SPME

The volatiles found in the headspace of Aeollanthus suaveolens were analyzed by solid phase microextraction coupled with GC/MS. This led to the identification of the 23 compounds. During steam distillation of the oil of A. Suaveolens, the very fragrant lactones, massoia lactone and delta- decalactone, were concentrated in the residue from which they can easily be extracted for perfumery purposes.19327127