C. Pizza

Inhibition of HIV infection by caffeoylquinic acid derivatives

The caffeoylquinic acids 3,4,5-tri-O-caffeoylquinic acid (1) and 4,5-di-O-caffeoylquinic acid (2), as well as caffeic acid (4) and synapoic acid (5) were isolated from the plant Securidaka longipedunculata (polygalaceae). 1 exhibited a greater selective inhibition of HIV replication than 2 which had an anti-HIV activity similar to that of 3,4,5-tri-O-galloylquinic acid (3), isolated from Guiera senegalensis (combretaceae); 4 and 5 were ineffective and the structurally related compound rosmarinic acid (6) had only slight anti-HIV activity. Studies of the actions of these compounds suggest that inhibition of the viral reverse transcriptase in vitro is non-specific and that they act by specific binding to gp120 which prevents its interaction with CD4 on T-lymphocytes and thus inactivates virus infectivity.

Triterpenes and quinovic acid glycosides from Uncaria tomentosa

Abstract Three new polyoxygenated triterpenes and six new quinovic acid glycosides have been isolated from Uncaria tomentosa . The triterpenes are based on ursolic or quinovic acid structures; the glycosides have a C-3, a C-3,27 or a C-27 glycosylation pattern, and the sugar moietics are made up of one to three hexopyranoses (rhamnose, glucose, quinovose, galactose). Their structures were determined by spectral methods. Copyright

A triterpenoid pigment with the isomalabaricane skeleton from the marine sponge .

The constitution and stereochemistry of , a yellow triterpenoid pigment isolated from a Somalian collection of the sponge ., has bben unequivocally established by spectral and x-ray crystallographic methods. The assignment of -- stereochemistry to the tricyclic nucleus of 1 suggests that the structures of several recently described tritepenoids from be reassigned.

Steroidal glycosides from starfishes

This paper covers recent work much of it from the authors laboratory dealing with novel steroidal oligoglycosides from starfishes. The steroidal glycosides until now encountered in this class of marine animals can be grouped into three structure types. Compounds of the first type, recognized for long time, include the sulphated saponins (asterosaponins) , characterized by steroidal aglycones possessing a 3,6ct-diol pattern and a 9,11-double bond; the oligosaccharide moiety (four up to six sugar units) is attached at C-6 and the sulphate residue is at C-3. Compounds of the second type, recently discovered in two species of the genus Echinaster, have a number of unusual features: a L7,3,613-dihydroxy steroidal moiety, there is no sulphate group and, most remarkably, the carbohydrate chain (three sugar units) is cyclized between C-3 and C-6 of the aglycone. Compounds of the third type include glycosides having highly hydroxylated steroidal aglycones; the carbohydrate moiety (one or two sugar units) is attached at C-24 of the side chain and there is no sulphate residue. During the course of our investigation on the steroidal glycosides from starfishes we have also encountered several polyhydroxylated sterols and their structures are presented.

Antiviral Activity of Constituents of Tamus communis

The antiviral activity of the phenanthrene derivatives 1-6, of the spyrostane triglycosides dioscin (7) and gracillin (8), of the furostanol tetraglycosides methylprotodioscin (9), its (25S) epimer methylprotoneodioscin (10), and methylprotogracillin 11, have been tested towards two RNA viruses: vesicular stomatitis virus and human rhinovirus type 1B. All these products were extracted from the rizomes of Tamus communis L; compound 11 was isolated also from Asparagus cochinchinesis, together with pseudoprotodioscin (12), a 20 (22)-unsaturated furostanoside, which was also investigated for antiviral activity. The results were of some interest mainly for the phenanthrene derivatives.

Phytochemical investigation on Mercurialis annua

Abstract A new natural flavonol glycoside, isorhamnetin-3-rutinoside-4′-glucoside, together with rutin, narcissin, quercetin-3-(2 G -glucosyl)-rutinoside and isorhamnetin-3-rutinoside-7-glucoside, was identified from the MeOH extract of Mercurialis annua L. The structures were established on the basis of chemical and spectral ( 1 H and 13 C NMR, FAB MS) data.

Triterpene saponins from Alternanthera repens

Abstract Four new triterpene saponins were isolated from the methanol extract of the aerial parts of Alternanthera repens . Their structures have been elucidated using a combination of 1D and 2D NMR techniques as 2α,3β-dihydroxyurs-12,20(30)-dien-28 oic acid 3- O -{ O -β- d -glucopyranosyl-(1→2)- O -α- l -arabinopyranosyl-(1→2)- O -[β- d -xylopyranosyl-(1→3)]β- d -glucopyranoside}; 2α,3β-dihydroxyurs-12,20(30)-dien-28 oic acid 3- O -{ O -β- d -quinovopyranosyl-(1→2)- O -α- l -arabinopyranosyl-(1→2)- O -[β- d -xylopyranosyl-(1→3)]β- d -glucopyranoside}; 2α,3β-dihydroxyurs-12,20(30)-dien-28 oic acid 3- O -{ O -α- l -arabinopyranosyl-(1→2)- O -[β- d -xylopyranosyl-(1→3)]β- d -glucopyranoside}; 2α,3β-dihydroxyurs-12,20(30)-dien-28 oic acid 3- O -{ O -β- d -xylopyranosyl-(1→3)-β- d -glucopyranoside}.

5α-cholestane-3β,6β,15α,16β,26-pentol: a polyhydroxylated sterol from the starfish Hacelia attenuata

Abstract A pentahydroxylated sterol isolated from a starfish, Hacelia attenuata, has been shown by spectral data and chemical transformation to be 5α-cholestane-3β,6β,15α,16β,26-pentol.

Starfish saponins VI - unique 22,23-epoxysteroidal cyclic glycosides, minor constituents from Echinaster sepoeitus

Abstract On the basis of comparative 1H− and 13C-n.m.r. data, the structures of the minor saponins from the starfish Echinaster sepositus have been elucidated to be 2-4. They closely resemble 1, the major saponin from the same starfish, and, in addition to the cyolic trisaccharide moiety bridging C-3 and C-6 of the steroid, include epoxide functionalities in the steroidal side-chains.

Three flavonoids from Licania heteromorpha

Abstract Three new flavonoids were isolated from the methanolic extract of the aerial parts of Licania heteromorpha var. heteromorpha . Their structures were elucidated as myricetin 3,4′-di- O -α- l -rhamnopyranoside, myricetin 7-methyl ether 3,4′-di- O -α- l -rhamnopyranoside and myricetin 4′-methyl ether 3- O -β- d -galactopyranoside by means of spectral data.