The study explores the application of natural biocides (oregano essential oil and eugenol, directly applied in solutions or encapsulated within silica nanocapsules) for safeguarding stone cultural heritage from biodeterioration, using green algae (Chlorococcum sp.) and cyanobacteria (Leptolyngbya sp.) as common pioneer biodeteriogens. Core-shell nanocontainers were built for a controlled release of microbicidal agents, a safe application of chemicals and a prolonged efficacy. The qualitative and quantitative evaluations of biocide efficiency at different doses were periodically performed in vitro, after six scheduled intervals of time (until 100 days). The release kinetics of composite biocide-embedding silica nanocapsules were characterized by the UV-Vis spectroscopy technique. Data showed both promising potential and some limitations. The comparative tests of different biocidal systems shed light on their variable efficacy against microorganisms, highlighting how encapsulation influences the release dynamics and the overall effectiveness. Both the essential oils showed a potential efficacy in protective antifouling coatings for stone artifacts. Ensuring compatibility with materials, understanding their differences in biocidal activity and their release rates becomes essential in tailoring gel, microemulsion or coating products for direct on-site application.

Plant motifs had a significant role in ancient cultures, with decorative, artistic, and communicative values. However, little knowledge exists of the botanical composition of festoons, widely used in Greek-Roman art. We analysed 81 festoons, exclusively from sculpture artworks, collected from 13 museums and archaeological sites in Rome (1st century BC–3rd century AD). Using iconographic sources and previous data, we identified the represented species and analysed their abundance and composition using statistical methods (Cluster Analysis, Principal Components Analysis) and diversity indexes (Shannon and Evenness). We documented 3081 botanical elements, identifying 30 taxa, in which fruits with leaves (45%) or alone (10%) represented the most common ones. Laurus nobilis and Quercus cfr. robur were the most frequently depicted species, followed by “pomes” (Pyrus, Malus, Cydonia), Vitis vinifera, Punica granatum, and Ficus carica. Festoons with one or two species can be easily distinguished from those with multiple species, often arranged with figs or vine branches at the ends, with symbolic aims related to fertility, rebirth, and abundance values. A balanced botanical composition also exists, with flowers typically in the middle and a species distribution that is not casual. The results enriched our comprehension of ancient Roman society, considering funerary and celebrative events.