Natural product chemistry and metabolomics: a roadmap through circular economy, sustainable agriculture, and biodiversity valorization

Inspired by the Sustainable Developmental Goals of the Agenda 2030, this work addressed three topics of pivotal importance in the sustainability era, namely: circular economy, sustainable agriculture, and biodiversity valorization. Natural products chemistry and metabolomics were keys to achieve the following aims: 1) the valorization of waste plant material for circular economy, 2) the achievement of deep knowledge of plant-environment interactions in view of sustainable agriculture, 3) the biodiversity valorization through the investigation of local flora. The first aim was accomplished by analyzing the phytochemical profile and the bioactivity of neglected plants matrices. Residues of aromatic plants after distillation resulted active against a plant pathogen suggesting a potential reuse of these matrices in agriculture. In addition, by-products of chestnut cultivation proved endowed with in vitro neuroprotective properties. The second aim was achieved by the development of two case studies. In particular, a work was carried out in field to study Sorghum bicolor subjected to several environmental and anthropic factors, and the other one in greenhouse exploring Taxus baccata responses to different LED lighting. Metabolomics proved successful to identify sorghum biomarkers for crop quality and development and allowed to monitor taxus growth providing useful insights for sustainable agriculture. To achieve the third aim, spontaneous plants collected in Sardinia were investigated for their antiproliferative activities. Five plants resulted endowed with promising bioactivity thus their phytochemical composition was investigated through NMR spectroscopy. Finally, a focus on chemodiversity was placed by studying Solanum dulcamara chemotypes through MS metabolomics which revealed that the chemotypes differed for the leaf steroidal glycoalkaloids. The overall thesis work underlined the importance of plant specialized metabolites in multiple fields and demonstrated that the study of these molecules aids the sustainable development, enhancing circular economy, sustainable agriculture, and biodiversity valorization. In this context, metabolomics approach resulted particularly interesting.