Manuel Cortés

SYNTHESIS AND ANTITUMOR ACTIVITY OF PUUPEHEDIONE AND RELATED COMPOUNDS

Abstract The first enantiospecific synthesis of bioactive marine puupehedione ( 2 ) and related compounds from (−)-sclareol ( 11 ) is reported. The antitumor activity of these compounds was assayed and compared with that of the natural products.

Synthesis and antiprotozoal activity of naphthofuranquinones and naphthothiophenequinones containing a fused thiazole ring

The synthesis of tetracyclic quinones 10a,b, 14a,b, 19a,b and 20a,b is described. The preparations involve regioselective Diels-Alder reactions via trapping the thiazole o-quinodimethane 9 with several benzofuranquinones and benzothiophenequinones. The structure of the regioisomers was assigned through 2D NMR 1H-13C HMBC experiments performed on 10a and 14a. Compounds 10a,b, 14a as well as phenol 1 and the starting quinones 2, 5, 7 and 15 are evaluated against Leishmania sp., Toxoplasma gondii and THP-1 cells. Almost all the tested compounds exhibit significant antiprotozoal activities with lower cytotoxicities than the reference compounds. Among them, quinones 2 and 14a possess the best activities towards L. donovani and T. gondii with the lowest toxicities.

Microbial hydroxylation of natural drimenic lactones

Incubation of confertifolin and isodrimenin with Mucor plumbeus, Aspergillus niger or Rhizopus arrhizus gave in good yields the corresponding 3 beta-hydroxy derivatives. From isodrimenin, the known natural 7 alpha-hydroxy derivative (futronolide) was also obtained and its structure was definitely established by X-ray crystallographic study of its acetate derivative.

Studies on quinones. Part 35: Access to antiprotozoal active euryfurylquinones and hydroquinones

(+)-Euryfuran adds regiospecifically to activated monosubstituted 1,4-benzoquinones under mild conditions to give the corresponding Michael adducts which, depending on the quinone substituent, undergo in situ redox reactions to the respective euryfurylbenzoquinones. One of these Michael adducts undergoes a facile stereoselective cyclisation under oxidant conditions to afford a naphthofuro[4,3-c]benzopyran derivative. The in vitro activities of the obtained euryfurylquinones and hydroquinones against Leishmania amazonensis are described.

Microbiological hydroxylation in the drimane series

Abstract The Products of the microbiological hydroxylation of drimenol and related compounds by Mucor plumbeus and Rhizopus arrhizus were investigated Complementary results (hydroxylation at 3β- and/or 6α-positions) were obtained with both microorganism.

(−)-3β-Acetoxydrimenin from the leaves of Drimys winteri

Abstract A new natural product, 3β-acetoxydrimenin was isolated from the petrol extract of the leaves of Drimys winteri which also contains the known compounds safrol, drimenol and polygodial. The structure of the new compound was determined by chemical and spectroscopic methods.

Labdane diterpenes from Cistus symphytifolius

Abstract The investigation of the aerial part of Cistus symphytifolius afforded, in addition to sitosterol, trimethoxykaempferol, cativic acid, labdenic acid, labdanolic acid and labdan-8α,15-diol, three new bicyclic diterpenes: cistadienic acid, cistenolic acid and labd-13( E )- ene-8α,15-diol. The structures of these were determined by spectral studies and correlations. CD spectral studies showed that cistenolic acid and salvic acid are enantiomeric compounds, so the stereochemistry of salvic acid (7α-hydroxy-labd-8(17)-ene-15-oic acid) should be changed to 7β-hydroxy-eperu-8(17)-ene-15-oic acid (7β-hydroxy- ent -labd-8(17)-ene-15-oic acid).

Proximate composition and biological activity of chilean Prosopis species

The proximate and amino acid compositions of the leaves and pods of Prosopis chilensis and P tamarugo and the leaves of P alba have been assessed. The biological activity of the leaves and pods of the first two species as well as the leaves and exudate of P alba has been determined for free radical scavenging activity, xanthine oxidase inhibition and DNA binding. The best protein source among the forage trees was the leaves of P chilensis; P alba and P tamarugo leaves showed higher crude protein, fat and nitrogen-free extract values than reported in previous studies. According to their amino acid profiles, all species surveyed are deficient in essential amino acids. The alkaloids β-phenethylamine and tryptamine were isolated from P chilensis, and phenethylamine was detected in P tamarugo. At 0.50 mg ml−1, both compounds showed DNA binding activity, with values of 18.5 and 11% respectively. The exudate of P alba showed a strong free radical scavenging effect. The activity was related with the total phenolics content, consisting mainly of catechin. © 2000 Society of Chemical Industry

A new example of 1α-hydroxylation of drimanic terpenes through combined microbial and chemical processes

Abstract Among various filamentous fungi, Aspergillus niger ATCC 9142 was the most efficient strain to convert confertifolin in high yield into its 3β-hydroxy derivative, which was then chemically converted to 1α-hydroxy-, 1α,11α-dihydroxy- and 1α-acetoxy-11α-hydroxyconfertifolin, new compounds structurally related to bioactive natural products isolated from plants or marine sponges.

Chemical Composition of the Essential Oil from Drimys winteri Forst. Wood

Abstract GC/MS analysis of the essential oil from the wood of Drimys winteri Forst. allowed the identification of 56 components and showed a high content of α-pinene (14.9%) and α-cubebene (10.9%).