Edible flowers are becoming an essential component of people's nutrition in the Mediterranean basin. In the last decades, many researchers also have focused their attention on the nutritional composition of the edible flowers, as well as their antioxidant and antimicrobial properties, including studies on their safety issues. Despite the growing interest in the use of flowers in human nutrition, the ethnobotanical literature is lacking coverage of some important issues, particularly those which concern the use of flowers in the folk tradition. Only recently, a review regarding the contribution of 32 edible flowers to the Mediterranean diet was published. The aim of the present review is to document the plant lore regarding the wild and cultivated edible flowers consumed in the Mediterranean basin. Based on the 112 studies reviewed, we documented 251 taxa as being used in the Mediterranean basin as edible flowers. The plant species belong to 45 families and 141 genera. Asteraceae (54 taxa) is the most frequently cited family. Sambucus nigra L. is the most cited species. This study can be the basis for future research on the supposed bioactivity and toxicity of wild and cultivated flowers.

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The antimicrobial properties of essential oil from various Santolina species have not been investigated enough in the previous studies dealing with the biological activities of medicinal plants. In Tunisia, Santolina chamaecyparissus L. (Asteraceae) is the only Santolina species recorded and is used as vermifuge and emmenagogue. The chemical composition, antibacterial and antifungal properties of essential oils from the flowerheads and roots of spontaneous S. chamaecyparissus growing in Tunisia and the chemical composition which leads to the Tunisian chemotype are investigated here for the first time. Essential oils isolated by hydro distillation from flowerheads and roots of S. chamaecyparissus were analyzed by GC and GC/MS. Two methods served for antimicrobial assays of the essential oils: diffusion in a solid medium and micro-well dilution assay. Antifungal tests were carried out by the agar incorporation method. Sixty-seven constituents were identified from the essential oil of the flowerhead. The major constituents were: 1,8-cineole and β -eudesmol. Two non identified compounds were present at the highest concentration in root oil. Flowerhead oil was characterized by high contents in monoterpenes and sesquiterpenes oxygenated compounds. The flowerhead essential oil demonstrated potent of antibacterial properties against Pseudomonas aeruginosa ATCC and Enterococcus faecalis ATCC, with MIC of 0.625 μg/ml. These findings demonstrate that the flowerhead essential oils of S. chamaecyparissus have excellent antibacterial properties and for this reason they could contribute to decrease the problem of microbial resistance to antibiotics.

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Essential oils of aromatic plants have numerous applications in fields like medicine, cosmetic and food industry. Nevertheless, the average yield of essential oil distilled from aromatic plants is below 5% (w/w) and consequently a considerable amount of solid residues is generated. These residues are especially rich in polyphenols that can be exploited as health-promoting compounds in food and feed or as anti-aging ingredients in cosmetic products, and thus to enhance the overall profitability of the aromatic plants. In this work, we have tentatively identified the polyphenols present in solid residues from the steam distillation of Cistus ladanifer, Lavandula×intermedia, Santolina rosmarinifolia and Thymus mastichina, and evaluated their antioxidant and chelating activities by means of several in vitro methods, such as the β-carotene/linoleate model system, reducing power, DPPH radical scavenging, and iron and copper ion chelation. A Soxhlet extraction and an ultrasound-assisted extraction have been used in terms of comparison. Most of the extracts whether they were obtained by Soxhlet system or by ultrasonic method showed good antioxidant activities. Soxhlet ethanolic extract of T. mastichina showed an antioxidant activity comparable to the standard red grape pomace. The influence of the total polyphenol content on the chelating activities was not as important as on the antioxidant activities and the predominant role of certain polyphenols and/or the presence in the extracts of other compounds with a favourable chemical structure to metal complexation can be assumed. This was the case of the ultrasound ethanolic extract of C. ladanifer, which was the most effective in iron chelating activity despite its medium-to-low content of total polyphenols. All these data point to profit from these aromatic plant solid residues as a valuable source of bioactive compounds.

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The seasonal variation of the essential oil extracts from the aerial parts of a Santolina rosmarinifolia population has been studied. Oil yields increased in the months of March, April, May and June. Oil concentration showed significant correlations with both precipitation (positive) and temperature (negative). Essential oil main components were sabinene, beta-pinene, myrcene, beta-phellandrene, limonene, 1,8-cineole, artemisia ketone, terpinen-4-ol, capillene, ar-curcumene and beta-eudesmol. Monoterpenes like beta-phellandrene, limonene and 1,8-cineole showed a significant negative correlation with temperature, while capillene presented a strong positive correlation with precipitation. The rest of the essential oil components did not show any noticeable trend.

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The hexane extract of aerial parts of Santolina rosmarinifolia subsp. canescens afforded eight new sesquiterpenes in addition to known compounds. Their structures were determined by spectroscopic methods and chemical transformations. The conformational analysis of the germacrane constituents was carried out by spectroscopic methods, including NMR at varying temperature and by molecular mechanics calculations. The antifeedant, antibacterial and antitumoral activity of selected compounds has been tested.

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