Georgia Ntatsi

Salinity effect on nutritional value, chemical composition and bioactive compounds content of Cichorium spinosum L.

Soil salinization is an increasing problem for many areas throughout the world that renders prohibitive vegetables and crop production in general. In the present study, Cichorium spinosum L. plants were grown under saline conditions in order to evaluate chemical composition and bioactive compounds content of their leaves. Salinity increase resulted in significant changes of macro and micro-nutrients content (nutritional value, sugars, fatty acids, minerals, ascorbic acid and tocopherols), whereas the concentration of phenolic compounds was not significantly affected. Chicoric and 5-O-caffeoylquinic acid were the most abundant phenolic acids. In contrast, antioxidant activity and mineral composition were beneficially affected by mid-to-high and high salinity levels. In conclusion, C. spinosum can be cultivated under saline conditions without compromising the quality of the final product, especially in semi-arid areas where irrigation water is scarce and/or of low quality due to high content of NaCl (coastal areas or areas where underground water is saline).

Nutritional value and chemical composition of Greek artichoke genotypes

The nutritional value and chemical composition of various artichoke genotypes cultivated in Greece were evaluated. Significant differences were detected in water content, as well as in fat, ash, protein and carbohydrate content. Proteins and carbohydrates were detected in high amounts in all the genotypes. Antioxidant activity was also varied between the studied samples. Palmitic and linoleic acids were the most abundant fatty acids in artichoke heads, while stearic, oleic, alpha-linolenic, arachidic, behenic and lignoceric acids were detected in lesser amounts. 3,5-O-Dicaffeoylquinic acid and 5-O-caffeoylquinic acid were the main phenolic compounds. In conclusion, heads of artichoke genotypes cultivated in Greece showed a high nutritional value and antioxidant activity which signifies the importance of this vegetable for the Mediterranean diet, while the diversity in chemical composition between the studied samples should be further exploited for the selection of elite cultivars with specific end-uses of the final product.

Vegetable Organosulfur Compounds and their Health Promoting Effects

BACKGROUND Trends in modern pharmaceutical science show an increase in demand for new drugs and diet supplements derived from natural products, while during the last decades, great research is conducted regarding the natural compounds and their medicinal and bioactive properties. Organosulfur compounds are present in many plants and their bioactive properties have been used in folk and traditional medicine throughout the centuries. Not until recently, modern science confirmed and revealed the chemical compounds that are responsible for these properties, the chemistry involved in their biosynthesis and the main mechanisms of action. OBJECTIVE In the present review, the organosulfur compounds of vegetable origin and their health effects are presented, focusing on the chemical composition of their main compounds, their biosynthesis and the mechanisms involved in their health effects. Sulfur compound sources presented include mainly vegetable species belonging to Allium genus and Brassicaceae family. CONCLUSION Organosulfur compounds of vegetable sources are very important in human diet, and their regular consumption has a beneficial contribution to health and well-being. Moreover, their medicinal properties and therapeutic effects have been described thousands of years ago, while they constitute an important ingredient in traditional medicines and preparations. However, not until recently, the mechanisms of action of organosulfur compounds have started to unravel, with promising results for further exploitation of these significant bioactive compounds in drug development and novel nutraceutical products. This review reveals the numerous biological activities of organosulfur compounds of vegetable origin, while it also presents the results of recent clinical studies and trials.

Chemical Composition and Yield of Six Genotypes of Common Purslane (Portulaca oleracea L.): An Alternative Source of Omega-3 Fatty Acids

Common purslane (Portulaca oleracea L.) is an annual weed rich in omega-3 fatty acids which is consumed for its edible leaves and stems. In the present study six different genotypes of common purslane (A-F) were evaluated for their nutritional value and chemical composition. Nutritional value and chemical composition depended on genotype. Oxalic acid content was the lowest for genotype D, whereas genotypes E and F are more promising for commercial cultivation, since they have low oxalic acid content. Genotype E had a very good antioxidant profile and a balanced composition of omega-3 and omega-6 fatty acids. Regarding yield, genotype A had the highest yield comparing to the other genotypes, whereas commercial varieties (E and F) did not differ from genotypes B and C. This study provides new information regarding common purslane bioactive compounds as affected by genotype and could be further implemented in food industry for products of high quality and increased added value.

Phylogenetic multilocus sequence analysis of indigenous slow-growing rhizobia nodulating cowpea (Vigna unguiculata L.) in Greece

Cowpea (Vigna unguiculata) is a promiscuous grain legume, capable of establishing efficient symbiosis with diverse symbiotic bacteria, mainly slow-growing rhizobial species belonging to the genus Bradyrhizobium. Although much research has been done on cowpea-nodulating bacteria in various countries around the world, little is known about the genetic and symbiotic diversity of indigenous cowpea rhizobia in European soils. In the present study, the genetic and symbiotic diversity of indigenous rhizobia isolated from field-grown cowpea nodules in three geographically different Greek regions were studied. Forty-five authenticated strains were subjected to a polyphasic approach. ERIC-PCR based fingerprinting analysis grouped the isolates into seven groups and representative strains of each group were further analyzed. The analysis of the rrs gene showed that the strains belong to different species of the genus Bradyrhizobium. The analysis of the 16S-23S IGS region showed that the strains from each geographic region were characterized by distinct IGS types which may represent novel phylogenetic lineages, closely related to the type species of Bradyrhizobium pachyrhizi, Bradyrhizobium ferriligni and Bradyrhizobium liaoningense. MLSA analysis of three housekeeping genes (recA, glnII, and gyrB) showed the close relatedness of our strains with B. pachyrhizi PAC48T and B. liaoningense USDA 3622T and confirmed that the B. liaoningense-related isolate VUEP21 may constitute a novel species within Bradyrhizobium. Moreover, symbiotic gene phylogenies, based on nodC and nifH genes, showed that the B. pachyrhizi-related isolates belonged to symbiovar vignae, whereas the B. liaoningense-related isolates may represent a novel symbiovar.

Application and further characterization of the snap bean S156/R123 ozone biomonitoring system in relation to ambient air temperature

Increased mixing ratios of ground-level ozone (O3) threaten individual plants, plant communities and ecosystems. In this sense, O3 biomonitoring is of great interest. The O3-sensitive S156 and the O3-tolerant R123 genotypes of snap bean (Phaseolus vulgaris L.) have been proposed as a potential tool for active biomonitoring of ambient O3. In the present study, an O3 biomonitoring was conducted, with the S156/R123 tool, along with a monitoring of O3 and other environmental conditions in an urban area in Athens, Greece, during the growing seasons of 2012 and 2013. Plant yield was evaluated to assess the effectiveness of AOT40 in interpreting O3-induced phytotoxicity. Across the two genotypes, an approximately two times lower total number of pods - and consequently lower bulk mass of seeds - was found in 2012 than in 2013, although there was no significant difference in the final AOT40 between the two years. No significant differences were observed in the stomatal density or conductance between the two genotypes, whereas it was estimated that, in both genotypes, the abaxial leaf surface contributes 2.7 fold to O3 intake in comparison to the adaxial one. By testing the role of ambient air temperature in outdoor plant environment chambers (OPECs), it was found that increased temperature limits mature pod formation and complicates interpretation of O3 impacts in terms of S156/R123 yields ratios. This is the first study providing evidence for a hormetic response of plants to ambient air temperature. This study also points out the complexity of using yield as a measure of O3 impact across different environments with the snap bean system, whereas visible foliar injury is more consistently related to O3 effects.

Cowpea fresh pods – a new legume for the market: assessment of their quality and dietary characteristics of 37 cowpea accessions grown in southern Europe

BACKGROUND Cowpea is traditionally cultivated in some regions of southern Europe for its dried seeds; however, there is a scarcity of information on the quality and dietary characteristics of fresh pods, which are occasionally used in folk diets. This paper aims at covering this gap in knowledge, thereby contributing to the dissemination of fresh cowpea pods as a novel product for the market. The quality and dietary characteristics of pods from 37 accessions (Vigna unguiculata ssp. unguiculata and ssp. sesquipedalis) grown in southern Europe were assessed in an attempt to provide information on pod quality and nutritional properties and to identify relationships between quality traits and accession origin. RESULTS Pods from the sesquipedalis accessions were heavier and larger, and reached commercial maturity 2 days later, than those from the unguiculata accessions. There were also large differences in the quality and dietary characteristics of the accessions. The pods of most accessions were rich in proteins, chlorophylls, carotenoids and phenolics, and showed high antioxidant activity and low concentrations of nitrates and raffinose-family oligosaccharides. Cluster analysis based on quality, dietary or antinutritional traits did not reveal any apparent grouping among the accessions. All the quality characteristics were independent of accession origin and subspecies. CONCLUSION Most of the accessions produced fresh pods of good quality and high dietary value, suitable for introduction in the market and/or for use as valuable genetic material for the development of new improved varieties.

Phenotypic diversity and evaluation of fresh pods of cowpea landraces from Southern Europe: Fresh pod variability of cowpea landraces

BACKGROUND Cowpea fresh pods are consumed as green vegetables in many countries in Southern Europe. Among cowpea cultivated material, a relatively large number of landraces can be found, maintaining species genetic diversity. To assess the value of these landraces in breeding programs, the characterization and estimation of diversity levels is therefore required. In the present study, an estimation of the diversity and evaluation of cowpea landraces originating from Portugal, Spain and Greece, in terms of their fresh pod traits, was performed, aiming to assist with the problem of low cowpea production in Southern Europe. RESULTS A notable mean total phenotypic diversity (HT = 0.57) was observed in the whole collection. The Spanish cv. - gr. unguiculata collection exhibited the highest value of total phenotypic diversity (0.56). Landraces did not differ significantly from each other regarding the three countries of origin. Landraces such as Cp4906, Vg60 and BGE038478 presenting higher values of some traits studied could contribute to the breeding of new cowpea varieties for fresh pod production. Positive correlations were observed, indicating the feasibility of breeding for preferable traits regarding fresh pod consumption. CONCLUSION The present study has revealed a wide diversity among and within cowpea landraces that could enhance fresh pod production in South European countries.

Impact of grafting and rootstock on nutrient-to-water uptake ratios during the first month after planting of hydroponically grown tomato

ABSTRACT Tomato plants (cv. Primadonna F1), non-grafted, self-grafted, or grafted onto the commercial rootstocks ‘He-man’ and ‘Maxifort’, were grown in recirculating nutrient solution. The uptake concentrations (UCs), i.e. mean nutrient-to-water uptake ratios of N, P, K, Ca, Mg, Fe, Mn, Zn, Cu, and B, were estimated based either on depletion from the nutrient solution or on accumulation in the plant biomass. Grafting onto both commercial rootstocks increased the total plant biomass. Hetero-grafting also increased the leaf N, Ca, and Cu concentrations but decreased those of Mg and Fe in comparison with self- and non-grafted plants. The mean UCs of N, Ca, and Cu were higher in plants grafted onto both commercial rootstocks in comparison with self- and non-grafted plants. However, hetero-grafting also raised the UCs of P, Fe, Mn, and B, because of an increased deposition of these nutrients to the roots in comparison with self-rooted plants. The method used to estimate the UCs, i.e. nutrient removal from the recirculating nutrient solution vs. nutrient recovery from plant biomass per volume unit of transpired water, resulted in similar values for N, Ca, Zn, and Cu, but had a significant impact on those of P, K, Mg, Fe, Mn, and B.

Chemical composition and antioxidant activity of Cichorium spinosum L. leaves in relation to developmental stage

In the present study, chemical composition and bioactivity of Cichorium spinosum leaves were examined at different growth stages for optimum harvest stage and end-use assessment. Total fresh weight and number of leaves were higher at 4th growth stage; however, at this stage the end-use is not indicated for raw consumption but mostly for pickled or dried products. Regarding chemical composition, the highest content of tocopherols and minerals was observed in the 1st growth stage, whereas sugars content was the highest in 3rd and 4th growth stage. Polyunsaturated fatty acids content was the highest during the first two growth stages, whereas antioxidant activity, phenolic acids and total phenolic compounds content in the 3rd stage. In conclusion, the results of this study indicate that chemical composition of C. spinosum is highly depended on development stage, and harvest stage should be considered for alternative uses of end-products with high bioactivity.