Chemical Composition Analysis, Antioxidant, and Antibacterial Activities of Eggplant Leaves.

Agricultural by-products represent one of the biggest pollutants for the environment, therefore, investigating new sources for the extraction of bioactive compounds is a topic of great interest for the entire scientific community. This work is aimed at studying the chemical composition (pigments, phenolics, volatile compounds) and biological activities (antioxidant and antimicrobial properties) of young and mature leaves of five eggplant cultivars (Solanum melongena L.) grown in Tunisia (Tizona, A1014, Nawel, A336, and Mirval). Pigment analysis showed no statistical variations between the two types of leaves, whereas higher levels of anthocyanins were recorded in young leaves of three out of five cultivars (24.7-52.8 mg 100 g-1 ). Total phenolic compounds (966.5-2072.6 mg 100 g-1 ) and o-diphenols (343.9-741.2 mg 100 g-1 ) contents varied significantly according to leaf age and cultivar. However, no statistically significant variation between young and mature leaves was found in flavonols and tannins content. As for volatile profiles, 62 constituents were characterized with non-terpene derivatives (52.0-61.6 %) and apocarotenes (19.9-35.6 %) as major chemical classes. Regarding the antioxidant activity, methanol extracts of Tizona cultivar mature leaves displayed important antiradical properties using DPPH, ABTS, and phosphomolybdenum assays (IC50 0.1, 0.2 and 0.01 mg mL-1 , respectively). With regards to reducing power determination, the most active extract was obtained from mature A1014 leaves. Further, young Mirval leaves proved to be significantly active from a bactericidal point of view against Candida albicans and Staphylococcus aureus of 3.1 mg mL-1 and 0.2 mg mL-1 MBC, respectively. In conclusion, eggplant leaves are a noteworthy source of antioxidant and antimicrobial compounds with potential use in the pharmaceutical, the cosmetics and the food industries.

Effect of Vicia faba L. var. minor and Sulla coronaria (L.) Medik associated with plant growth-promoting bacteria on lettuce cropping system and heavy metal phytoremediation under field conditions.

Researches involving the use of association between legumes and PGPBs (plant growth-promoting bacteria) in heavy metal phytoremediation process were mainly performed for soils highly contaminated. However, even in agriculture soils, with moderate or low contamination levels, plants can accumulate high rates of heavy metals. So, food chain contamination by these metals presents a real threat to animal and human health. This work aimed to evaluate the use of two legumes/PGPB symbioses; Vicia faba var. minor and Sulla coronaria have been inoculated with specific heavy metal-resistant inocula in a crop rotation system with Lactuca sativa as a following crop, in order to assess their effects on soil fertility, lettuce yield, and heavy metal content. Our results showed that legume inoculation significantly enhanced their biomass production, nitrogen and phosphorus content. The use of our symbioses as green manure before lettuce cultivation, as a rotation cropping system, affected positively soil fertility. In fact, we recorded a higher organic matter content, with rapid decomposition in the soil of inoculated plots. Besides, results demonstrated a greater nitrogen and phosphorus content in this soil, especially in the plot cultivated with inoculated V. faba var. minor. The improvement of soil fertility enhanced lettuce yield and its nitrogen and phosphorus content. Moreover, inoculated legumes extracted and accumulated more heavy metals than non-inoculated legumes. Our symbioses play the role of organic trap for heavy metals, making them unavailable for following crops. These facts were supported by lettuce heavy metal content, showing a significant decrease in metal accumulation, mainly zinc and cadmium, in edible parts. Results showed the usefulness of the studied symbioses, as a main part of a rotation system with lettuce. Our symbioses can be suggested for agriculture soil phytoremediation, aiming to enhance non-legume crop yield and limit heavy metal translocation to food chain.