Plant Essential Oils as Biocides in Sustainable Strategies for the Conservation of Cultural Heritage

Biodeterioration is a complex network of interactions between macro/micro-biological systems and organic/inorganic substrates involving physical and chemical alterations, strictly related to their metabolic activities. Concerning microbial deterioration, finding a correct approach to counteract this process is often difficult, requiring an understanding of the kind of alterations and the use of methods that respect artwork and human and environmental health. Specific conservative and remedial methods are used for this aim. They comprise physical, mechanical, and chemical methods, as well as, frequently, synthetic chemical biocides, which have obvious limitations because of their toxicity to operators or because they contain polluting substances that persist in the natural environment. New and alternative research has strongly focused on strategies to replace the use of toxic methods with natural products that do not have undesired effects, as well as implementing safe, novel compounds. Several plants contain natural chemical compounds such as oils, phenols, flavonoids, alkaloids, coumarins, tannins, etc., commonly used as drugs, bioactive molecules, and nutrients. Essential oils extracted from plants can be the correct way to prevent the biodeterioration of cultural heritage in a safe manner. This review aims to summarize the latest research on the use of natural essential oils in restoration procedures for cultural heritage, considering them sustainable means with respect to the environment and human health.