Search

A investigacao fitoquimica dos frutos maduros de Solanum caavurana Vell. (Solanaceae) forneceu um novo alcaloide esteroidal do tipo espirosolano, caavuranamida, juntamente com os alcaloides 4-tomatiden-3-ona e 5α-tomatidan-3-ona. Suas estruturas foram elucidadas atraves de metodos espectroscopicos. As atividades antiproliferativa e antimicrobiana para o extrato etanolico e subfracoes provenientes de particao e de extracao acido-base foram investigadas. A caavuranamida apresentou atividade antibacteriana similar ao controle positivo cloranfenicol contra Rhodococcus equi. Phytochemical investigation of the ripe fruits of Solanum caavurana Vell. (Solanaceae) afforded a novel steroidal alkaloid with spirosolane-type skeleton, named as caavuranamide, together with the alkaloids 4-tomatiden-3-one and 5α-tomatidan-3-one. Their structures were elucidated on the basis of spectroscopic methods. The antiproliferative and antimicrobial activities for the ethanolic extract, sub-fractions obtained from partition and acid-base treatment were also evaluated. Caavuranamide showed antibacterial activity similar to the chloramphenicol positive control against Rhodococcus equi.

Phytochemical study of the bark of Guatteria blepharophylla (Mart.) Mart. afforded twelve compounds, namely two sesquiterpenes, caryophyllene oxide (1) and spathulenol (3), one xanthone, lichexanthone (2), a mixture of steroids, β-sitosterol (4), and stigmasterol (5), and seven isoquinoline alkaloids, O-methylmoschatoline (6), lysicamine (7), nornuciferine (8), liriodenine (9), isocoreximine (10), subsessiline (11), and isomoschatoline (12). Their structures were established on the basis of spectroscopic methods. Compounds 1-6, 11 and 12 were reported for the first time in this species. The 13C NMR (nuclear magnetic resonance) data for the compounds 11 and 12 are described for the first time in the literature. The antiproliferative activity against human tumour cell lines and antimicrobial activities were investigated for the major compounds. Compound 9 showed significant activity against cell lines of breast (MCF-7, Michigan Cancer Foundation-7), superior to the positive control doxorubicin. Compound 12 presented antifungal activity similar to the positive control nystatin against Candida albicans.

This report deals with the formal synthesis of deoxynojirimycin using D-glucitol as an inexpensive starting material. Through a sequence of several selective protection/deprotection and nucleophilic substitution reactions, many isopropylidene derivatives were obtained. Formation of an epoxide intermediate and its subsequent ring opening, via intramolecular nucleophilic substitution, leads to the synthesis of heterocyclic 1,5-dideoxy-1,5-diamine-2,3-O-isopropylidene-6-silyl-D-glucitol, which is a precursor of deoxynojirimycin (DNJ). Descrevemos a síntese formal da desoxinojirimicina usando D-glucitol como material de partida economicamente atraente. Através de uma seqüência de reações de proteção e desproteção seletivas e reações de substituição nucleofílica obtivemos diversos intermediários isopropilidênicos. A formação de um epóxido intermediário e sua subseqüente abertura, através de uma reação nucleofílica intramolecular, levou à obtenção do heterociclo 1,5-didesoxi-1,5-diamino-2,3-O-isopropilideno-6 -silila-D-glucitol, que é um precursor da desoxinojirimicina (DNJ).

A series of acetonides was obtained during the formal synthesis of deoxynojirimycin. The 1H NMR spectra of these derivatives contain strongly coupled multiplets covering a chemical shift range of about 1 ppm. The spectra are severely complicated by second-order effects and were assigned by 2D NMR and 13C NMR experiments. Copyright © 1999 John Wiley & Sons, Ltd.