Paolo Manitto

Stereospecific reduction of geraniol to (R)-(+)-citronellol bySaccharomyces cerevisiae

(R)-(+)-citronellol, a useful C10 chiral synthon for natural terpenoid products, can be obtained in enantiomerically pure form and satisfactory yield by yeast reduction of geraniol.

Acid-catalyzed addition of alcohols and thiols to bilirubin.

In mezzo fortemente acido la bilirubina reagisce con gli alcooli e con i tioli fornendo con alte rese prodotti di addizione identici a quelli ottenibili per via fotochimica in assenza di acidità.

A C-glucosylated 5-methylchromone from Kenya aloe

Abstract A new bitter C -glucoside, aloeresin D, was isolated from a commercial sample of Kenya aloe. Its structure was assigned as 8- C -β- d -[2- O -( E )- p -coumaroyl]glucopyranosyl-2-[(R)-2-hydroxy]propyl-7-methoxy-5-methyl-chromone by spectral data and chemical transformations.

In silico design of tubulin-targeted antimitotic peptides

Microtubules are polymeric structures formed by the self-assembly of tubulin dimers. The growth and shrinkage of these dynamic arrays have a key role during the cell-proliferation process. This makes tubulin the molecular target of many anticancer drugs currently in use or under clinical trial. Their impressive success is limited by the onset of resistant tumour cells during the treatment, so new resistance-proof molecules need to be developed. Here we use molecular dynamics and free-energy calculations to study the network of interactions that allow microtubule formation. Modelling the protein-protein interface allows us to identify the amino acids responsible for tubulin-tubulin binding and thus to design peptides, which correspond to tubulin subsequences, that interfere with microtubule formation. We show that the application of molecular modelling techniques leads to the identification of peptides that exhibit antitubulin activity both in vitro and in cultured cells.

Feralolide, a dihydroisocoumarin from cape aloe

Abstract Feralolide, a new dihydroisocoumarin, was isolated from a commercial sample of Cape aloe. Its structure and absolute stereochemistry [(3 R )-3,4-dihydro-6,8-dihydroxy-3-(2′-acetyl-3′,5′ -dihydroxyphenyl)methyl-1 H -[2] benzopyran- 1-one)] were determined by spectroscopic methods and chemical evidence.

Aloeresin c, a bitter c,o-diglucoside from cape aloe

Abstract A new bitter C , O -diglucoside, aloeresin C, was isolated from commercial Cape aloe. Its structure, 2-acetonyl-7- O -β- D -glucopyranosyl-8- C -β- D -[2′- O -(E)- p -coumaroyl]glucopyranosyl-5-methylchromone, was established by spectral and chemical methods.

Aloe revisited the structure of aloeresin A

Abstract Aloeresin A, a major constituent of Cape Aloe, is shown to be 2′-O-(E)-p-coumaroyl aloesin ( 3 ) instead of 6′-O-(E)-p-coumaroyl aloesin ( 2 ) as accepted so far.

Stereoselective total synthesis of natural phytol via double bond reductions by baker's yeast

Abstract Natural ( E )-(7 R , 11 R )-Phytol ( 1 ), a component of the chlorophyll molecule, vitamin K1 ( 2 ) and other natural compounds, was synthesized in enantiomerically and diastereomerically pure form by Li2CuCl4-induced coupling of two C10-units ( 8 , 12 ). Both these units were prepared from geraniol ( 3 ) via enzymatic enantioselective hydrogenation of activated double bonds.

Decarboxylation of cinnamic acids by Saccharomyces cerevisiae

Abstract The stereochemistry of the decarboxylation of 3,4-dimethoxycinnamic acids by Saccharomyces cerevisiae and the enzymatic specificity with respect to the substrate structure were studied. This reaction proceeds with retention of configuration at the side-chain double bond as well as enzymatic specificity for the (E) configuration. The influence of substituents in the α and β positions was also studied. Hypotheses on the reaction mechanism were proposed.

Singlet oxygen reactions in aqueous solution. Physical and chemical quenching rate constants of crocin and related carotenoids

Thermal decomposition of 3-(1,4-epidioxy-4-methyl-1,4-dihydro-1-naphthyl)propionic acid (2) has been used to measure both the physical and chemical quenching rate constants of 1O2 (kQ and kR, respectively) by water-soluble 8,8′-diapocarotenoids such as crocin (1a) and its derivatives (1b,c). The value of kQ was found to be slightly lower than the diffusion controlled rate constant in all the solvents examined, whereas kR showed strong dependence on the medium, going from ca. 108 in H2O to 106 M−1s−1 in DMF and DMSO. These findings suggest that both energy- and electron-transfer mechanisms are involved in the quenching of O2 (1Δg) by crocinoids.