Antiproliferative Effects of Cynara Cardunculus in Colorectal Cancer Cells Are Modulated by the Circadian Clock.

The circadian clock generates 24 h rhythms in behavioural, cellular and molecular processes. Malfunctions of the clock are associated with enhanced susceptibility to cancer, worse treatment response and poor prognosis. Clock-controlled genes are involved in cellular processes associated with tumour development and progression including metabolism of drugs and the cell cycle. Cynara cardunculus, a plant of the Asteraceae family, has been reported to have antiproliferative effects on breast cancer cells. Here, we used the human colorectal cancer (CRC) cell line HCT116 and its knockout variants for different core-clock genes (BMAL1, PER2, NR1D1), to investigate the treatment effect of C. cardunculus lipophilic leaf extract under different clock scenarios. Our results show a direct effect of C. cardunculus on the circadian phenotype of the cells, as indicated by alterations in the phase, amplitude, and period length of core-clock gene oscillations. Furthermore, our data indicate a role for the circadian clock in sensitivity to C. cardunculus treatment. In particular, the treatment inhibited proliferation and induced cytotoxicity and apoptosis in a clock knockout-specific manner, in CRC cells. These results point to a potential effect of C. cardunculus lipophilic leaf extracts as a modulator of the circadian clock, in addition to its anti-proliferative properties.

Anti-Inflammatory and Immunoregulatory Action of Sesquiterpene Lactones.

Sesquiterpene lactones (SL), characterized by their high prevalence in the Asteraceae family, are one of the major groups of secondary metabolites found in plants. Researchers from distinct research fields, including pharmacology, medicine, and agriculture, are interested in their biological potential. With new SL discovered in the last years, new biological activities have been tested, different action mechanisms (synergistic and/or antagonistic effects), as well as molecular structure-activity relationships described. The review identifies the main sesquiterpene lactones with interconnections between immune responses and anti-inflammatory actions, within different cellular models as well in in vivo studies. Bioaccessibility and bioavailability, as well as molecular structure-activity relationships are addressed. Additionally, plant metabolic engineering, and the impact of sesquiterpene lactone extraction methodologies are presented, with the perspective of biological activity enhancement. Sesquiterpene lactones derivatives are also addressed. This review summarizes the current knowledge regarding the therapeutic potential of sesquiterpene lactones within immune and inflammatory activities, highlighting trends and opportunities for their pharmaceutical/clinical use.

Genetic diversity and population structure of Cynara cardunculus L. in southern Portugal.

Cynara cardunculus L. is a cardoon species native to the Mediterranean region, which is composed of three botanical taxa, each having distinct biological characteristics. The aim of this study was to examine wild populations of C. cardunculus established in Portugal, in order to determine their genetic diversity, geographic distribution, and population structure. Based on SSR markers, 121 individuals of C. cardunculus from 17 wild populations of the Portuguese Alentejo region were identified and analysed. Ten SSRs were found to be efficient markers in the genetic diversity analysis. The total number of alleles ranged from 9 to 17 per locus. The expected and observed means in heterozygosity, by population analysed, were 0.591 and 0.577, respectively. The wild population exhibited a high level of genetic diversity at the species level. The highest proportion of genetic variation was identified within a geographic group, while variation was lower among groups. Geographic areas having highest genetic diversity were identified in Alvito, Herdade da Abóboda, Herdade da Revilheira and Herdade de São Romão populations. Moreover, significant genetic differentiation existed between wild populations from North-Alentejo geographic locations (Arraiolos, Évora, Monte da Chaminé) and Centro Hortofrutícola, compared with other populations. This study reports genetic diversity among a representative number of wild populations and genotypes of C. cardunculus from Portugal. These results will provide valuable information towards future management of C. cardunculus germplasm.

Development of bioactive films based on chitosan and Cynara cardunculus leaves extracts for wound dressings.

The development of natural based, effective and protective wound dressings associated to local treatment applied on chronic wounds, represents a major challenge nowadays. In this work chitosan-based films were prepared with different concentrations of ethanolic ultrasound assisted extracts from Cynara cardunculus leaves (EtPUAE). The physico-chemical film properties revealed that extract incorporation influences the volumetric swelling capacity and mechanical properties of the films, leading to materials with a lower fluid absorption capacity and more fragile. However, no impact was detected on the thermal properties of the films, as well as on their dense structure characterized by Scanning Electronic Microscopy (SEM) analysis. Biological screening of chitosan-based films show that chitosan with a 1% (w/w) and a 5% (w/w) EtPUAE loading did not induce cytotoxicity on normal human skin fibroblasts (Bj5-ta cell line), mainly attributed to cynaropicrin (extract key active compound) present in the film below its IC50 value. Nevertheless, chitosan-based films with 5% (w/w) EtPUAE presented an interesting anti-inflammatory activity. Bj5-ta cells stimulated with liposaccharides (LPS), presented a reduction of 86% on IL-6 cytokine levels, after exposure to chitosan with 5% EtPUAE film extract. The results obtained in this study open up the possibility of successfully using chitosan films doped with EtPUAE for development of chronic wound dressings, with the advantage of using naturally-sourced materials with anti-inflammatory activity.

Haplotype analysis of the germacrene A synthase gene and association with cynaropicrin content and biological activities in Cynara cardunculus.

Cynara cardunculus: L. represents a natural source of terpenic compounds, with the predominant molecule being cynaropicrin. Cynaropicrin is gaining interest since it has been correlated to anti-hyperlipidaemia, antispasmodic and cytotoxicity activity against leukocyte cancer cells. The objective of this work was to screen a collection of C. cardunculus, from different origins, for new allelic variants in germacrene A synthase (GAS) gene involved in the cynaropicrin biosynthesis and correlate them with improved cynaropicrin content and biological activities. Using high-resolution melting, nine haplotypes were identified. The putative impact of the identified allelic variants in GAS protein was evaluated by bioinformatic tools and polymorphisms that putatively lead to protein conformational changes were described. Additionally, cynaropicrin and main pentacyclic triterpenes contents, and antithrombin, antimicrobial and antiproliferative activities were also determined in C. cardunculus leaf lipophilic-derived extracts. In this work we identified allelic variants with putative impact on GAS protein, which are significantly associated with cynaropicrin content and antiproliferative activity. The results obtained suggest that the identified polymorphisms should be explored as putative genetic markers correlated with biological properties in Cynara cardunculus.