The Effect of Nitrogen Fertigation and Harvesting Time on Plant Growth and Chemical Composition of Centaurea raphanina subsp. mixta (DC.) Runemark

Abstract

The aim of the present study was to evaluate the effect of nitrogen fertigation (0, 200, 400, and 600 ppm of total nitrogen) and harvesting time (9 March 2018 and 19 April 2018) on the plant growth, chemical composition, and bioactive properties of Centaurea raphanina subsp. mixta plants. The highest yield of fresh leaves was observed for the treatment of 200 ppm of N without compromising nutritional value. The increasing nitrogen levels resulted in an increase of α- and total tocopherols and sugars content, especially in the second harvest for tocopherols and in the first harvest for sugars. Similarly, total organic acids and oxalic acid content increased with increasing nitrogen levels in both harvests, while fatty acids composition had a varied response to the tested factors. Pinocembrin neohesperidoside and pinocembrin acetyl neohesperidoside isomer II were the most abundant phenolic compounds with the highest content being observed in the control treatment of the first and second harvest, respectively. The highest antioxidant activity was observed for the control and the 600 ppm treatments of the second harvest for the OxHLIA and TBARS assays, respectively, probably due to the high content of pinocembrin acetyl neohesperidoside isomer II and α-tocopherol, respectively. Finally, cytotoxic effects and antimicrobial properties showed a varied response depending on the treatment. In conclusion, C. raphanina subsp. mixta has low requirements of nitrogen to achieve the highest yield, while a varied response to the tested fertigation treatments and harvesting time was observed in terms of the chemical composition and the bioactive properties.

Bioactive Properties and Phenolic Compound Profiles of Turnip-Rooted, Plain-Leafed and Curly-Leafed Parsley Cultivars

“…A list with the names and the types of cultivars is presented in Table 6. After emergence, young seedlings were thinned to three plants per container with equal distances, using 15 containers for each cultivar [49]. Cultivation was initially performed in an unheated glasshouse at the experimental farm of the University of Thessaly in Velestino, Greece, while the containers were moved outdoors in March 2019, given the rising temperatures within the greenhouse.…”

A Systematic Review on the Antimicrobial Properties of Mediterranean Wild Edible Plants: We Still Know Too Little about Them, but What We Do Know Makes Persistent Investigation Worthwhile

“…For Centaurea raphanina , four studies compared the plant grown in situ, or wild, with the ex situ, or cultivated [ 17 ], through a further analysis of the soil enrichment effects on the plant antimicrobial properties [ 16 , 20 , 37 ]. The wild C. raphanina displayed the highest capacity to inhibit bacterial growth.…”

“…Nonetheless, in many studies MWEPs and antibiotics are used at the very same concentration (mg/mL) to compare their antimicrobial activities. In several cases, MWEPs extracts do work like conventional antibiotics (e.g., ampicillin), if not at lower concentrations [8,12,16,17,21,26,30,[36][37][38][39]44], especially for bacterial species known for displaying ABR. In future studies, it will be advisable to analyze the effectiveness of the extracts formulated with different nanocarriers.…”

“…For example, Bacillus cereus is an opportunistic bacterium that became a serious cause of nosocomial infections [4]. Nine studies (see Table S3) reported in this review provide experimental data of MWEPs effective against this bacterium that could become pathogenic in immunocompromised hosts [8,11,12,16,17,30,32,33,39].…”

Bioactive and Nutritional Potential of Medicinal and Aromatic Plant (MAP) Seasoning Mixtures

“…The lipid fraction in MAPs is generally low and data on the composition of fatty acids is essential, especially with respect to the content of polyunsaturated fatty acids (PUFA) and saturated fatty acids (SFA) [ 34 ]. The fatty acid composition of the mixtures under study is shown in Table 5 .…”