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A comprehensive analysis of the responses of Nigella sativa L. to elevated zinc concentrations was assessed in pot experiments. Zn excess supply did not affect the germination but drastically reduced radicle elongation. A concentration-dependent reduction in all growth parameters, yield, and yield components was observed. With the increasing Zn concentrations, total lipid contents decreased and changes in fatty composition toward the production of saturated ones were underscored. Despite the reduction in the seeds essential oil yield, a redirection of the terpene metabolism toward the synthesis of oxygenated compounds has been evidenced. A significant increase in the total phenols and flavonoids contents concomitant with improved antioxidant activities has also been found. Collectively, these results highlight the possible use of N. sativa L. in phytoremediation applications, on the one hand, and that Zn excess could represent an excellent alternative to improve the nutritional attributes of this important species, on the other hand.

Introduction Rosa species are known by their richness in bioactive compounds useful in cosmetic, perfumery, food and phytotherapy. These metabolites are influenced by several factors accordingly affecting the plant properties in different environments. Objective Exploration of polyphenolic composition and antioxidant activity of stem extracts from Rosa moschata Herrm., R. canina L. and R. sempervirens L. growing in different northern areas in Tunisia. Methods Phytochemical composition was carried out by means of high‐performance liquid chromatography diode‐array detector (HPLC‐DAD) and HPLC‐DAD‐ESI‐MS (electrospray ionisation mass spectrometry). Antioxidant activity was measured using the DPPH (1,1‐diphenyl‐2‐picrylhydrazyl) radical scavenging assay, the FRAP (ferric reducing antioxidant power) test, the TEAC (Trolox equivalent antioxidant capacity) and the ORAC (oxygen radical absorbance capacity) assays. Results Rosa stem profiles were dominated by flavonols but qualitative variation was recorded between sections (Caninae and Synstylae). Aromadendrin‐O‐hexoside‐deoxyhexoside, quercitrin and quercetin 3‐O‐glucoside were identified as the major compounds of R. sempervirens, R. moschata and R. canina, respectively. Quantitative differences were found between species, provenances and extracts either for the individual compounds or for the total phenolic contents. This variability was also highlighted in Rosa scavenger ability results. The highest mean values were recorded by methanolic extracts of R. moschata from Bizerte (TEAC and FRAP) and R. canina for DPPH. However, for ORAC assay, the most active extract was obtained by ethyl acetate from stems of R. canina. Conclusion Results allow concluding that stems of R. sempervirens, R. moschata and R. canina could present a new natural residual source of bioactive phytochemicals, to be employed as additives in pharmaceutical products or in cosmetic and food preparations.

This study aims to evaluate the nutritive value of Ajuga iva (A. iva) harvested from three distinct altitude regions in Tunisia (Dougga, Mograne, and Nabeul). The chemical composition, phenolic concentration, gas production, and in vitro dry matter (DM) digestibility were determined. The highest concentrations of neutral detergent fiber (NDF) and acid detergent fiber (ADF) were for A. iva cultivated in Nabeul. In contrast, the highest crude protein (CP) concentration was observed in that cultivated in Mograne, and the lowest (p < 0.01) CP concentration was noted in that cultivated in Dougga. Additionally, the cultivation regions affected the concentrations of free-radical scavenging activity, total flavonoids, and total polyphenols (p < 0.01). The highest free-radical scavenging activity was observed with A. iva cultivated in Dougga and Mograne. The highest (p < 0.05) gas production rate and lag time were observed in A. iva cultivated in Mograne and Nabeul regions. DM digestibility differed between regions and methods of determination. The highest (p < 0.01) DM degradability, determined by the method of Tilley and Terry and the method of Van Soest et al., was for A. iva cultivated in Mograne and Dougga, while the lowest (p < 0.01) value was recorded for that cultivated in the Nabeul region. Likewise, metabolizable energy (ME) and protein digestibility values were higher for A. iva collected from Mograne region than that collected from the other sampling areas. In conclusion, the nutritive value of A. iva differed between regions. Therefore, care should be taken when developing recommendations for using A. iva in an entire region. Season- and region-specific feeding strategies for feeding A. iva are recommended.

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