N. De Tommasi

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.

Glycolipids from Byrsonima crassifolia

Abstract From the leaves of Byrsonima crassifolia four new glycolipids, 1,2-di- O -miristoyl-3- O -(6-sulpho-α- d -quinovopyranosyl)-glycerol, 1,2-di- O -(8-hexadecenoyl)-3- O -(6-sulpho-α- d -quinovopyranosyl)-glycerol, 1,2-di- O -palmitoyl-3- O -(β- d -glucopyranosyl)- glycerol and 1,2-di- O -(8-hexadecenoyl)-3- O -(β- d -glucopyranosyl)-glycerol, have been isolated. Nine known compounds were also found. The structures of new compounds were elucidated on the basis of chemical and spectral data.

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

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}.

Ectopic expression of the Osmyb4 rice gene enhances synthesis of hydroxycinnamic acid derivatives in tobacco and clary sage

In this work, we report the ectopic expression of the Osmyb4 rice gene, encoding the Myb4 transcription factor, in Nicotiana tabacum and Salvia sclarea. Transcriptional analysis of T2 homozygous tobacco plants overexpressing Osmyb4 revealed that Myb4 activated the transcription of several genes of the phenylpropanoid pathway such as PAL, C4H, 4CL1, 4CL2 (encoding phenylalanine ammonia-lyase, cinnamic acid 4-hydroxylase, 4-coumarate: Co A ligase1, 4-coumarate: Co A ligase2). Moreover, the Myb4 increased expression of HQT encoding hydroxycinnamoyl-CoA: quinate transferase, which specifically triggers the accumulation of chlorogenic acid (CGA). In addition, increased acccumulation of rosmarinic acid (RA) was found in transgenic plants of both species. These results open the possibility of using the Osmyb4 gene to increase the production of specific bioactive hydroxycinnamates.

Effect of sesquiterpene lactone coronopilin on leukaemia cell population growth, cell type-specific induction of apoptosis and mitotic catastrophe

Objectives:  The aim of this study was to investigate anti‐leukaemic potential of coronopilin, a sesquiterpene lactone from Ambrosia arborescens, and to characterize mechanism(s) underlying its activity.

Antioxidant activities and quali-quantitative analysis of different Smallanthus sonchifolius [(Poepp. and Endl.) H. Robinson] landrace extracts

Five landraces of Smallanthus sonchifolius [(Poepp. and Endl.) H. Robinson], known as yacon, were investigated in total phenolic content, antioxidant activity and chemical composition of ethanol extracts (EEs) and decoction extracts (DEs). The results demonstrated that DEs are rich in phenolic acids as caffeic acid, while the EEs show an higher amount of flavonoids, as luteolin 3′,7-O-diglucoside and luteolin 7-O-glucoside. These flavonoid glycosides were identified for the first time in yacon extracts, together with apigenin and luteolin. The phytochemical profile explains the different antioxidant activities shown in our study. The landraces PER6-DE and PER4-DE showed the highest radical-scavenging activity and reducing power related to their polyphenolic contents. Results also show that yacon can be considered an important source of bioactive compounds with significant differences among the analysed landraces.

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.

Polyhydroxylated triterpenes from Senecio pseudotites

Three new polyhydroxylated triterpenes were isolated from the chloroform-methanol extract of the leaves of Senecio pseudotites. Their structures were elucidated as 2α,3β,23-trihydroxy-urs-12,19(29)-dien-28-oic-acid; 2α,3β,23-trihydroxy-urs-12,19(29)-dien-28-oic-acid-23-acetyl ester; 23-(trans-p-coumaroyloxy)-2α,3β-dihydroxy-urs-12,19(29)-dien-28-oic-acid by NMR spectroscopy.

Data collection and advanced statistical analysis in phytotoxic activity of aerial parts exudates of Salvia spp

In order to define the phytotoxic potential of Salvia species a database was developed for fast and efficient data collection in screening studies of the inhibitory activity of Salvia exudates on the germination of Papaver rhoeas L. and Avena sativa L.. The structure of the database is associated with the use of algorithms for calculating the usual germination indices reported in the literature, plus the newly defined indices (Weighted Average Damage, Differential Weighted Average Damage, Germination Weighted Average Velocity) and other variables usually recorded in experiments of phytotoxicity (LC50, LC90). Furthermore, other algorithms were designed to calculate the one-way ANOVA followed by Duncans multiple range test to highlight automatically significant differences between the species. The database model was designed in order to be suitable also for the development of further analysis based on the artificial neural network approach, using Self-Organising Maps (SOM).