The beneficial effects of plant essential oils (EOs) have been known for a long time and now they are used in various fields such as medicine and aromatherapy as well as in food and pharmaceutical industries. In the last few years, the use of plant EOs has been noticed against biodeterioration of cultural heritage, which represents a powerful resource of green conservation strategies. This research aims to evaluate the antimicrobial effect of 3 essential oils of rosemary, eucalyptus and thyme on 5 fungal strains, including Aspergillus niger, Penicillium polonicum, Cladosporium limoniform, Penicillium chrysogenom, Parengyodontium album, and 3 bacterial strains including Bacillus cereus, Bacillus licheniformis, Kocuria rosea isolated from deteriorative areas of Jamé Mosque of Isfahan. The results showed that among the used EOs, thyme EO had the greatest antimicrobial effect on the selected microorganisms. This EO in 50% dilution prevented the growth of the tested microorganisms. Eucalyptus EO showed the lowest antimicrobial effect. This EO did not show any antimicrobial effect on Penicillium chrysogenum. However, eucalyptus EO was effective on the tested bacterial strains with the diameter of non-growth zone of 25, 28 and 15 mm on Bacillus cereus, Bacillus licheniformis and Kocuriarosea, respectively. According to these results, thyme EO can be potentially used to control the biodeterioration of cultural heritage.
Biological contamination of paper artifacts is a significant threat, causing not only damage to the paper itself but also posing health risks to conservators and restorers who are in close contact with them. Therefore, identifying the type of contamination is crucial for effective preservation and restoration. This article focuses on identifying biological contamination in a collection of paper artifacts from the Imamzadeh Mohammad in Tafresh, Iran. Preliminary examinations revealed evidence of biological contamination, including stains resulting from biological activity. These stains are a consequence of biodeterioration, leading to a reduction in the structural and artistic quality of the artifacts. To investigate the biological contamination, samples were taken from areas suspected of contamination and cultured on Sabouraud dextrose agar (for fungal contamination) and nutrient agar (for bacterial contamination). After incubation, the grown colonies were examined and identified. The results of the identification of isolated fungal and bacterial showed contamination with various fungi, including Penicillium, Aspergillus, Cladosporium, and yeasts, as well as bacteria belonging to the Actinomycetes and Bacillus genus.
The biological degradation of paper-based historical artifacts is a major concern in cultural heritage preservation, particularly due to fungal contamination. Fungi thrive in environments with high humidity and poor ventilation, rapidly breaking down cellulose fibers and causing irreversible damage. Although chemical antifungal agents have traditionally been used for prevention and control, their adverse effects on human health, the environment, and sometimes the artifact itself have prompted a search for safer alternatives. This review explores the current literature on the antifungal effects of medicinal plants relevant to the conservation of paper-based artifacts. It presents a synthesis of studies on the active compounds in plant-based treatments, evaluates their effectiveness against common paper-degrading fungal species, and highlights practical applications involving direct use on paper substrates. While the results are promising, further research is needed to standardize treatment protocols, determine optimal concentrations, and assess long-term stability and safety of these natural compounds for heritage conservation.
