A new diterpene and other compounds from the unripe female cones of Wollemia nobilis.

In this work, the first phytochemical analysis ever performed on the unripe female cones of Wollemia nobilis W. G. Jones, K. D. Hill & J. M. Allen was described. The analysis evidenced the presence of a new derivative of sandaracopimaric acid together with rare diterpenoid derivatives and known compounds of chemosystematic and bioactivity relevance. Some of these were evidenced in the species or in the family for the first time during this study. The further implications of the isolated compounds in the field of chemosystematics, pharmacology and nutraceutics were discussed.

Bioactive Constituents of Juniperus turbinata Guss. from La Maddalena Archipelago.

A comprehensive phytochemical study of Juniperus turbinata (Cupressaceae) collected from La Maddalena Archipelago (Sardinia, Italy) is reported. Both the essential oil and the ethanolic extract obtained from the aerial parts were analyzed. The essential oil appears to belong to a new chemotype compared to other Mediterranean juniper accessions, as it was favored by geographic isolation of the isles. It showed a low content of monoterpene hydrocarbons and α-terpineol, ent-manoyl oxide, 1,10-di-epi-cubenol as the major constituents. The ethanolic fraction contained mainly diterpenoids. Among these, 15-formyloxyimbricatolic acid (7) is a new natural product since it has hitherto been obtained only by synthetic route. The phenolic fraction contained biflavonoids: cupressuflavone (9), followed by minor amounts of amentoflavone (10) and hinokiflavone (11). The essential oil and six purified compounds (1 - 4, 8 and 9) were assessed for biological activities, namely antioxidant (assessed by DPPH· , ABTS·+ and FRAP methods) and cytotoxic effects towards selected human tumor cell lines (MDA-MB 231, A375 and HCT116 cells). Compound 3 exhibited higher radical scavenging activity against ABTS·+ radical than the reference Trolox. Noteworthy, compound 8 showed powerful effects towards tumor cell lines, with IC50 values in the range of 0.060 - 0.201 µm, which make it a promising anticancer drug candidate.

New N,N-dimethylcarbamate inhibitors of acetylcholinesterase: design synthesis and biological evaluation.

A series of N,N-dimethylcarbamates containing a N,N-dibenzylamino moiety was synthesized and tested to evaluate their ability to inhibit Acetylcholinesterase (AChE). The most active compounds 4 and 8, showed 85 and 69% of inhibition at 50 µM, respectively. Furthermore, some basic SAR rules were outlined: an alkyl linker of six methylene units is the best spacer between the carbamoyl and dibenzylamino moieties; electron-withdrawal substituents on aromatics rings of the dibenzylamino group reduce the inhibitory power. Compound 4 produces a slow onset inhibition of AChE and this is not due to the carbamoylation of the enzyme, as demonstrated by the time-dependent inhibition assay of AChE with compound 4 and by MALDI-TOF MS analysis of trypsinized AChE inhibited by compound 4. Instead, compound 4 could act as a slow-binding inhibitor of AChE, probably because of its high conformational freedom due to the linear alkyl chain.

Synthesis of LoganVir, a new carbocyclic nucleoside analogue.

Starting from a natural cyclopentanoid monoterpene belonging to the class of iridoid glucosides called loganin, we performed the synthesis of a new carbocyclic nucleoside, allowing the preparation of a new lead compound, with a potential HIV antiviral activity as an reverse transcriptase competitive inhibitor that we named LoganVir. The stereocontrol of the coupling reaction was completed utilizing the procedure described by Mitsunobu with a purinic base.

Phytochemical analysis of non-volatile fraction of Artemisia caerulescens subsp. densiflora (Viv.) (Asteraceae), an endemic species of La Maddalena Archipelago (Sardinia--Italy).

Artemisia caerulescens subsp. densiflora Viv. is a rare endemic species from Corsica and Sardinia. We studied a sample collected from Razzoli, an island of the La Maddalena Archipelago. The polar secondary metabolites content of this species was investigated for the first time in this study showing the presence of sesquiterpenoids, flavonoids, caffeoylquinic acids and a coumarin, with the presence of several compounds already recognised in this genus. The metabolites composition was analysed in two different phenological stages, post blooming and flowering. During the blooming stage, the plant showed a molecular pattern mainly represented by sesquiterpenes and sterols with a minor amount of phenolics, while in flowering stage the molecular pattern was more rich in flavonoids and phenylpropanoids.

Essential oil composition and biological activity from Artemisia caerulescens subsp. densiflora (Viv.) Gamisans ex Kerguélen & Lambinon (Asteraceae), an endemic species in the habitat of La Maddalena Archipelago.

The purpose of this study was to investigate the composition of the essential oil obtained from a population of Artemisia caerulescens subsp. densiflora growing in Razzoli, an island in the La Maddalena Archipelago (Sardinia, Italy). A. caerulescens sups. densiflora Viv. (Asteraceae), a wild herb, seldom studied in the Mediterranean, represents one of the many rare endemic species growing in North Sardinia. The essential oil composition was analysed by means of GC/MS analysis, which showed davana ethers as the major volatile components, accounting together for 17.5%, followed by (E)-nerolidol (4.5%), ß-oplopenone (3.3%), cis-sabinene hydrate (5.2%) and terpinen-4-ol (4.7%). The oil was tested for antioxidant activity by means of DPPH test, inhibition of lipid oxidation test and hypochlorous acid test, which showed a quite interesting scavenger capacity. For the first time, we reported the cytotoxic activity of the essential oil of A. caerulescens subsp. densiflora, against three human tumour cell lines (A375, MDA-MB231 and HCT116), with IC50 values in the range 5.20-7.61 µg/mL, which deserved further studies to support its use as chemopreventive agent. Finally, the antimicrobial activity of the essential oil, displayed on a panel of human pathogens, was very low.

A new glucosidic phthalide from Helichrysum microphyllum subsp. tyrrhenicum from La Maddalena Island (Sardinia, Italy).

In this study, we reported the analysis of the medium polarity fraction obtained from an accession of Helichrysum microphyllum subsp. tyrrhenicum from La Maddalena Island. Besides several compounds already evidenced in this species and related genera, i.e. micropyrone (1), arzanol (2), helipyrone (3), acetyl-bitalin derivatives (4, 5), gnaphaliol (6), caffeic acid (7), ursolic acid (8), 7-O-ß-(D-glucopyranosyl)-5-methoxy-1(3H)-isobenzofuranone (9), gnaphaliol-9-O-ß-D-glucopyranoside (11) and gnaphaliol-3-O-ß-D-glucopyranoside (12), the presence of a new glycosidic phthalide, 6-O-ß-(D-glucopyranosyl)-4-methoxy-1(3H)-benzofuranone (10), was evidenced for the first time, which resulted in a structural isomer of compound (9). The occurrence of this new benzofuranone derivative is an additional evidence of the deep intraspecific variability expressed by this species, which was also stated for the non-volatile components, and may be a distinctive trait of the population growing on La Maddalena Island.

Chemical composition and biological activity of the essential oil from Helichrysum microphyllum Cambess. ssp. tyrrhenicum Bacch., Brullo e Giusso growing in La Maddalena Archipelago, Sardinia.

Helichrysum microphyllum Cambess. subsp. tyrrhenicum Bacch., Brullo e Giusso (Asteraceae), previously known as Helichrysum italicum ssp. microphyllum (Willd.) Nyman, is one of the many endemic species growing in Sardinia, Corsica and Balearic Islands. In the present work the composition of the essential oil obtained from a population of H. microphyllum ssp. thyrrenicum growing in a littoral location of La Maddalena Archipelago was investigated by GC-FID and CG-MS. The major compounds of the oil were the monoterpene ester neryl acetate (18.2%), the oxygenated sesquiterpene 5-eudesmen-11-ol (rosifoliol, 11.3%), the sequiterpene hydrocarbons δ-cadinene (8.4%) and γ-cadinene (6.7%), showing a peculiar composition in comparison with other Sardinian populations. The oil was tested for cytotoxicity on three human tumor cell lines (MDA-MB 231, HCT116 and A375) by MTT assay showing a strong inhibitory activity on human malignant melanoma cells A375 (IC50 of 16 µg/ml). In addition the oil was assessed for antioxidant activity by DPPH and ABTS assay.

Phytochemical study of Caulerpa racemosa (Forsk.) J. Agarth, an invading alga in the habitat of La Maddalena Archipelago.

Caulerpa racemosa is a marine Chlorophyta widely distributed in tropical areas, introduced into the Mediterranean Sea since 1990. It has been invading the Mediterranean Sea causing ecological problems. This invasive event can be considered as one of the most serious in the history of species introduced into the Mediterranean Sea, even if C. racemosa has not triggered as much attention as the famous 'killer alga' Caulerpa taxifolia. The aim of this work is to analyse phytochemically C. racemosa in the northern Sardinia area for secondary metabolites. Marine algae shows the molecular pattern of bis-indole alkaloids, sesquiterpenes, diterpenes and sterols. The intention is to expand phytochemical analysis in order to understand just how significant the anti-tumour, anti-inflammatory and antinociceptive actions can be.

Chemopreventive and antioxidant activity of the chamazulene-rich essential oil obtained from Artemisia arborescens L. growing on the Isle of La Maddalena, Sardinia, Italy.

The essential oils of Artemisia arborescens growing in Sardinia (Italy), collected during three plant growth stages, i.e., from the vegetative stage to post-blooming time, were characterized. Moreover, the in vitro antiproliferative and antioxidant activities of the oil isolated from aerial parts collected in February were evaluated. The essential oils belonged to the ß-thujone/chamazulene chemotype, notably with the highest amount of chamazulene (ca. 52%) ever detected up to now in the genus Artemisia and, in general, in essential oils. Quantitative variations in the oil composition were observed as the plant passes from the vegetative to the blooming stage. The oil was tested for its potential tumor cell growth-inhibitory effect on T98G, MDA-MB 435S, A375, and HCT116 human cell lines, using the MTT (=3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) assay. The highest activity was observed on A375 and HCT116 cell lines, with IC50 values of 14 µg/ml. Moreover, the in vitro antioxidant and free radical-scavenging assays revealed the oil to be an effective scavenger of the ABTS radical cation, with an activity comparable to that of Trolox(®) . These results support the use of A. arborescens oil for the treatment of inflamed skin conditions. Finally, the composition of the polar fraction of the A. arborescens aerial parts was also examined, and the main component detected was 5-O-caffeoylquinic acid, which was identified for the first time in this plant.