Evaluating the exploitability of several essential oils constituents as a novel biological treatment against cultural heritage biocolonization

This work aimed at evaluating the possible use of several organic compounds as novel conservation products against the biocolonization of cultural heritage materials. In a first step, the antifungal activity of 10 selected essential oil (EOs) constituents was tested against a strain of Aspergillus niger collected from a Roman mural painting (Pompeii, Italy). According to antifungal assays, thymol, eugenol and cinnamaldehyde provided a strong and enduring inhibition effect. These properties open the way to the possible exploitability of EOs constituents for middle and long-term protection applications. In this perspective, the three compounds were exposed to different light conditions with the purpose of assessing their stability under photo-oxidation conditions. After ageing, Fourier transform infrared spectroscopy (FTIR) analysis and in vitro antifungal assays were performed. The collected results proved that light exposure had a critical negative effect on the antifungal capability of cinnamaldehyde samples. On the contrary, composition and properties of eugenol and thymol were not affected by ageing, confirming their possible use in the future development of long-lasting conservation products.