Cynara cardunculus L. (cardoon) has several health benefits mainly attributed to its abundance in polyphenols. In this study, cardoon heads (capitula) were harvested in Greece during the flowering stage, and the hydroethanolic extracts were assessed in terms of phenolic compounds composition and antioxidant, cytotoxic, anti-inflammatory, and antimicrobial activities. The phenolic profile was evaluated by HPLC-DAD-ESI/MS to better understand the seasonal changes in the individual compound levels and how these changes correlate with bioactive properties. The main phenolic compounds identified were caffeoylquinic and dicaffeoylquinic acid derivatives. Immature heads (Car A: principal growth stage (PGS) 5) had the highest phenolic content (34.3 mg/ g) and cytotoxic (GI 50 of 69-268 µg/mL) and anti-inflammatory (IC 50 of 183 µg/mL) activities. Sample Car D (PGS 6/7) revealed the highest antioxidant (IC 50 of 23-227 µg/mL) and antifungal (MIC of 0.26-0.51 mg/mL) potential. Regarding the antibacterial activity, Car E (PGS 7) revealed the best results (MIC of 0.59-1.18 mg/ mL). This study suggests that the maturity stage of the plant influences the phenolic composition and bioactivity.

Solid biomass fuels are useful and cost effective renewable energy source. The energy content of biomass is determined by its calorific value. The objective of this study was to determine experimentally the gross calorific value (GCV) of different agroforestry species and bio-based industry residues that could be used by: a) companies specialized in processing raw biomass solid biofuel production, b) small-scale consumers (households, medium-sized residential buildings, etc.). The fuel samples used were from agricultural residues and wastes (rice husks, apricot kernels, olive pits, sunflower husks, cotton stems, etc.), energy crops and wetland herbs (cardoon, switchgrass, common reed, narrow-leaf cattail), and forest residues (populus, fagus, pinus). The GCV of the biomass samples was experimentally determined based on CEN/TS 14918:2005, and an oxygen bomb calorimeter was used (Model C5000 Adiabatic Calorimeter, IKA ®-Werke, Staufen, Germany). The GCV of different agroforestry species and residues ranges from 14.3-25.4 MJ•kg −1. The highest GCV was obtained by seeds and kernels due to higher unit mass and higher lipid content. Pinus sylvestris with moisture content 24.59% obtained the lowest GCV (13.973 MJ•kg −1).

Chemical composition and biological activity of cardoon (Cynara cardunculus L. var. altilis) seeds harvested at different maturity stages

The present study evaluated the effect of maturity stage on the chemical composition of cardoon bracts. Plant material was collected in Greece at eight different maturation stages (C1–C8) and the chemical composition was analyzed in regard to lipidic fraction and the content in fatty acids, tocopherols, organic acids, and free sugars. Samples of late maturity (C6–C8) revealed the lowest lipidic content, while a total of 29 fatty acids was identified in all the samples, with palmitic, stearic, oleic, and eicosatrienoic acids present in the highest levels depending on harvesting time. Immature (C1) and mature (C8) bracts were more abundant in saturated fatty acids (SFA) than bracts of medium-to-late maturity (C5, C6), where the monounsaturated fatty acids (MUFA) were the prevalent class. The α- and γ-tocopherols were the only identified isoforms of vitamin E, while the highest content was observed in sample C8 (199 µg/100 g dry weight (dw). The detected organic acids were oxalic, quinic, malic, citric, and fumaric acids, while fructose, glucose, sucrose, trehalose, and raffinose were the main detected sugars. The results of the present study allowed us to reveal the effect of maturity stage on cardoon bracts chemical composition and further valorize this byproduct by improving its bioactive compounds content.

a b s t r a c tBiomass dry matter partitioning and growth characteristics are important selection criteria for energy crops. The objective of the study was to examine the response of switchgrass (cv. Alamo) to irrigation (2 levels: rainfed and irrigated with 250 mm) and N-fertilization (4 levels: 0, 80, 160 and 240 kg N ha −1 ) under two different soil-climatic conditions for two growing seasons 2011 and 2012. The results demonstrated a significant effect (P < 0.05) of irrigation, fertilization and their interaction on crop growth and biomass productivity. Biomass yield ranged from 14 to 27 Mg ha −1 for the calcareous, clay loam to clay, fertile soil (Velestino; Greece) and for the deep, calcareous sandy loam to loam, semi-fertile soil (Palamas; Greece), respectively. In both sites, switchgrass accumulated a high amount of biomass in stems. Dry stem/total biomass ratio was stabilized in the 3rd growing year and it was rather constant throughout the growing period (range 68-71%). The maximum growth rates were similar for both sites with value of 390 kg ha −1 day −1 , whereas the highest leaf area index observed was 7.59, indicating that switchgrass has high growth rate independently of the site and its microclimate. Therefore switchgrass should be included in future cropping systems as an important energy crop for solid bio-fuel production.

Matricaria chamomilla is one of the most important medicinal herbs. The aim of this study was to investigate irrigation and N-fertilization effect on German chamomile yield and essential oil production. For the purposes of this study, field experiments were established at the Experimental Farm of the University of Thessaly, Larissa, Greece, in 2016 and 2017. The experimental design was a factorial split-plot design with main factor irrigation (I1: rainfed, I2: 100% ETo) and sub factor N-fertilization (F1: 0, F2: 80, and F3: 160 kg ha-1) with four replications. Flower yield measured by samplings at the ideal collection stage (2/3 of the rounds of tubes have been opened on the elevated flowering plant). Essential oil content was determined, using a Clevenger-type distillation apparatus and essential oil analysis by a GC-MS on a fused silica DB-5 column. Irrigation had a significant effect on yield, with irrigated treatments producing higher yield in comparison with rainfed treatments (5,250 and 2,200 kg ha-1, fresh and dry flowers, respectively). Furthermore, N-application had also a significant effect on yield, with the higher N-supply producing higher yield. The highest yield and essential oil production were found for the irrigated and fertilized treatment with the higher N-dressing (I2F3, 3,800 and 25 kg ha-1 dry flowers and essential oil yield, respectively). Moreover, it was found that the irrigated treatments produced lower amount of essential oil, while N-fertilization had a positive effect on α-bisabolol and chamazulene and a negative effect on bisabolol oxide A. Although irrigation had a negative impact on the content of essential oils, the high increase in yield led to a maximization of the essential oil production for the irrigated cultivation with maximum nitrogen fertilization. Therefore, chamomile seems to be a promising annual cultivation in Greece which can be established in areas of similar environmental conditions producing satisfactory yields.

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