Sardinian Plant Research Articles

Antitumor Potential and Phytochemical Profile of Plants from Sardinia (Italy), a Hotspot for Biodiversity in the Mediterranean Basin.

Sardinia (Italy), with its wide range of habitats and high degree of endemism, is an important area for plant-based drug discovery studies. In this work, the antitumor activity of 35 samples from Sardinian plants was evaluated on human osteosarcoma cells U2OS. The results showed that five plants were strongly antiproliferative: Arbutus unedo (AuL), Cynara cardunculus (CyaA), Centaurea calcitrapa (CcA), Smilax aspera (SaA), and Tanacetum audibertii (TaA), the latter endemic to Sardinia and Corsica. Thus, their ability to induce cell cycle arrest and apoptosis was tested. All extracts determined cell cycle block in G2/M phase. Nevertheless, the p53 expression levels were increased only by TaA. The effector caspases were activated mainly by CycA, TaA, and CcA, while AuL and SaA did not induce apoptosis. The antiproliferative effects were also tested on human umbilical vein endothelial cells (HUVEC). Except for AuL, all the extracts were able to reduce significantly cell population, suggesting a potential antiangiogenic activity. The phytochemical composition was first explored by 1H NMR profiling, followed by further purifications to confirm the structure of the most abundant metabolites, such as phenolic compounds and sesquiterpene lactones, which might play a role in the measured bioactivity.

Sardinian plants with antimicrobial potential. Biological screening with multivariate data treatment of thirty-six extracts

In this paper, thirty-six extracts from Sardinian plants were evaluated in vitro for their antimicrobial activity towards a panel of reference strains, Staphylococcus aureus, S. epidermidis, Klebsiella pneumoniae and Escherichia coli, and for their cytotoxicity on mammalian cells. The biological data, together with total phenolic and flavonoid content of the extracts, were treated by PCA (Principal Components Analysis), which highlighted the positive correlation among total phenolic content and increasing antibacterial activities, and a possible involvement of flavonoids in mitigate the cytotoxicity. Thirteen extracts displayed relevant IC50 values (half maximal inhibitory concentration) on S. aureus (IC50 from 1.4 to 153.6 μg/mL), ten out of them were active also against S. epidermidis (IC50 from 3.9 to 150 μg/mL), seven against K. pneumoniae (IC50 from 28.5 to 97.5 μg/mL), and two against E. coli (IC50 74.9 and 156.3 μg/mL). In particular, three extracts obtained from Pistacia terebinthus ssp. terebinthus, Cytinus hypocistis and Limonium morisianum emerged as promising antibacterial candidates. They exhibited remarkable inhibitory activity towards bacterial strains from clinical specimens and presenting different antibiotic-resistance profiles.

Falcarinol is a covalent cannabinoid CB 1 receptor antagonist and induces pro-allergic effects in skin

The skin irritant polyyne falcarinol (panaxynol, carotatoxin) is found in carrots, parsley, celery, and in the medicinal plant Panax ginseng. In our ongoing search for new cannabinoid (CB) receptor ligands we have isolated falcarinol from the endemic Sardinian plant Seseli praecox. We show that falcarinol exhibits binding affinity to both human CB receptors but selectively alkylates the anandamide binding site in the CB 1 receptor ( K i = 594 nM), acting as covalent inverse agonist in CB 1 receptor-transfected CHO cells. Given the inherent instability of purified falcarinol we repeatedly isolated this compound for biological characterization and one new polyyne was characterized. In human HaCaT keratinocytes falcarinol increased the expression of the pro-allergic chemokines IL-8 and CCL2/MCP-1 in a CB 1 receptor-dependent manner. Moreover, falcarinol inhibited the effects of anandamide on TNF-alpha stimulated keratinocytes. In vivo, falcarinol strongly aggravated histamine-induced oedema reactions in skin prick tests. Both effects were also obtained with the CB 1 receptor inverse agonist rimonabant, thus indicating the potential role of the CB 1 receptor in skin immunopharmacology. Our data suggest anti-allergic effects of anandamide and that falcarinol-associated dermatitis is due to antagonism of the CB 1 receptor in keratinocytes, leading to increased chemokine expression and aggravation of histamine action.

Chemical and biological comparisons on supercritical extracts of Tanacetum cinerariifolium (Trevir) Sch. Bip. with three related species of chrysanthemums of Sardinia (Italy)

In this manuscript, the authors compare the chemical composition and the biological effects of extracts of some Sardinian plant species: Glebionis coronaria (L.) Spach [=Chrysanthemum coronarium L.], locally known as ‘caragantzu’, Glebionis segetum (L.) Fourr. [=Chrysanthemum segetum L.], known as ‘caragantzu masedu’, and Sardinian endemic species Plagius flosculosus (L.) Alavi and Heywood [=Chrysanthemum flosculosus L.], known as ‘caragantzu burdu’. In addition, the authors compare the pyrethrins contained in these species with an extract of Tanacetum cinerariifolium (Trevir.) Sch. Bip. [=Chrysanthemum cinerariifolium (Trevir.) Vis.], a commercial species rich in pyrethrins. The volatile fractions from chrysanthemum flowers were obtained by supercritical fluid extraction (SFE) with CO2 at 90 bar and 50°C and by hydrodistillation. Pyrethrins were extracted, together with other high molecular mass compounds, by SFE at high pressure, 300 bar and 40°C. The composition of the volatile oils is determined by GC–MS analysis and the amount of pyrethrins by HPLC analysis. Moreover, the antibacterial and antimycotic activities of volatile fractions were investigated in order to compare to their traditional uses.

Iridoidic pattern in endemic Sardinian plants: the case of Galium species

The monoterpenoid fractions of three endemic Galium ssp. (Rubiaceae) from Sardinia Island were examined and compared with the iridoidic pattern yet known in Galium species. This comparison evidenced theirs endemic characters. In particular, in G.corsicum and in G. glaucophyllum loganic acid was isolated and identified for the first time in Galium genus. In G. schmidii a rare iridoid is present, 10-hydroxy-loganin, whose presence in this genus was evidenced only in G. mollugo and loganin isolated for the first time.

Genetic and phytochemical difference between some Indian and Italian plants of Withania somnifera (L.) Dunal

The geographical distribution of Withania somnifera (L.) Dunal is quite wide. However, in Italy, this species is very rare and grows spontaneously only in Sicily and in Sardinia. The PCR–RAPD technique has been utilized in this work to determine the genetic relationship among Sicilian, Sardinian and Indian samples and the HPLC analysis of whitaferin A was used as a marker to evaluate the phytochemical differences. The genetic difference between Indian and Sicilian plants of W. somnifera turned out to be smaller than that between Indian and Sardinian plants of this species. The phytochemical analysis as well showed that the Sardinian specimen strongly differed from the Indian and Sicilian ones in its contents of withaferin A. Our results seem to confirm the hypothesis that the Italian populations of this species may not be indigenous but naturalised. Due to the high withaferin A content of the Sardinian samples, these plants could be used as a source for pharmaceutical purposes.

Antioxidant properties of extracts and compounds from Psoralea morisiana

AbstractThe antioxidant activity of various extracts (MeOH, petroleum ether, EtOAc) from the aerial parts of Psoralea morisiana, an endemic Sardinian plant, was evaluated during autoxidation and iron‐mediated oxidation of linoleic acid at 37 °C and during cholesterol oxidation at 140 °C, in the absence of solvent. The activity of erybraedin C, bitucarpin A and plicatin B, isolated from the extracts, was investigated under the same experimental conditions and compared to that of BHT and α‐tocopherol. All the extracts, erybraedin C (major constituent of the extracts) and plicatin B showed powerful antioxidant properties. None of the extracts and pure compounds showed any prooxidant activity. The cytotoxicity of the extracts, erybraedin C, and plicatin B was further evaluated in VERO cells, a line of fibroblasts derived from monkey kidney. Erybraedin C, at non‐cytotoxic concentrations, showed a strong inhibition of FeCl3‐induced oxidation in VERO cells.

Antiproliferative effects of daucane esters from Ferula communis and F. arrigonii on human colon cancer cell lines

Certain jaesekanadiol p-hydroxy- and p-methoxybenzoates - typical of Ferula communis and Ferula arrigonii sardinian plants - show antiproliferative activity on human colon cancer less. The inhibitory doses 50%, calculated after 72 h of treatment, revealed that the antiproliferative capacity of the compounds was in the following descending order: ferutinin > 2alpha-OH-ferutidin > ferutidin > siol anisate > lapiferin > jaeskeanadiol. Evidence is presented that interaction with type II estrogen-binding sites (EBS) underlies this activity.

The genus «Allium» L. in Italy. XIII. Morphological, caryological and leaf anatomical study in some C-W Mediterranean triploid populations of «Allium trifoliatum» Cyr

Abstract Triploid (2n = 3x = 21) sterile populations of A. trifoliatum from Calabria, Sicily, Sardinia, were analysed. Morphological differences were seen but idiograms look very similar in chromosome shape and arm ratio, although the Sardinian plants show a shorter karyotype than the others. Giemsa C-banding reveals a consistent similarity of the C-banding patterns within the tested populations. Neither a highly improbable long-distance dispersal nor the spreading in remote times of the triploid A. trifoliatum can be invoked in explanation of the presence of sterile biotypes in different populations and widely scattered distributions. In the authors' opinion, the polytopic origin may be explained in terms of a casual hybridization phenomenon involving di- and tetraploid Alliums of the «subvillosum-subhirsutum» complex. Flower anomalies and sterility also suggest the hybrid nature of A. trifoliatum in the Italian flora.

Appunti citotassonomici sul genere Biarum Schott (Araceae) in Italia

Abstract Cytotaxonomic notes on the genus Biarum Schott (Araceae) in Italy. Morphological and caryological observations on sicilian and italian specimens of Biarum tenuifolium (L.) Schott could not prove its taxonomic separability from B. cupanianum Paglia. In our opinion the latter is to be considered as a synonym of the former. The chromosome number of B. tenuifolium is very variable (2n = 16, 20, 26); the chromosomes show eu- and heterochromatic regions. A sardinian plant usually assigned to Biarum bovei Blume needs further studies in order to verify its taxonomic identity.