Sustainable use of plants adapted to the Mediterranean climate as sources of bioactive compounds with health and environmental applications

This PhD project was focused on the identification of some species of Mediterranean climate to be used according to eco-sustainability criteria for the obtainment of bioactive compounds with health properties or with applications in the environmental field. Himantoglossum robertianum flowers and Carpobrotus edulis leaves were micromorphologically characterized and used to obtain an hydroalcoholic and an aqueous extract, respectively. These extracts were then analysed from the phytochemical point of view. In addition, antioxidant and anti-inflammatory properties, inhibitory activities against enzymes involved in the extracellular matrix degradation and in inflammations, and their cicatrizing abilities were evaluated. Tests were performed both by cell-free enzymatic techniques and using in vitro cell cultures. H. robertianum is a terrestrial epiphytic orchid that can reach up to 80 cm in height, commonly known as Giant orchid due to its showy inflorescence and its considerable dimensions. According to previous data, this species resulted rich orchicyanin I and II and serapianin, anthocyanins already used in cosmetic formulations. With this in mind and considering that the species is in progressive expansion along Mediterranean coasts, we used its flowers to obtain a hydro-alcoholic extract to be tested for biological properties. Since H. robertianum is a protected species, we also planned and optimized techniques for in vitro micropropagation of the plant. Concerning C. edulis, the Hottentot fig, it is highly cited in ethnobotanical surveys for the treatment of various ailments and skin affections. This plant is an alien invasive species now naturalized in the Mediterranean area to the detriment of indigenous flora, thus representing a serious environmental problem. The species is therefore subject to several and repeated eradication campaigns. In a perspective of circular economy and sustainable use of natural resources we decided to use the leaves material with the aim to evaluate the biological activity of an aqueous extract obtained from the leaves. Data collected support the use of C. edulis as a natural resource for skin care and confirm the advisability of using material removed from the natural environment for this purpose. Finally, again concerning the sustainable use of resources, peels from three different species of Citrus spp, widely cultivated in Southern Italy, were employed for the obtainment of their essential oils. Peels nowadays represent a consistent by-product of the citrus industry. Sites of production of bioactive compounds were morphologically characterised and essential oils obtained were evaluated from the phytochemical point of view. Essential oils were then tested for their phytotoxic activity against weeds and for their potential use as bioherbicides