Eco-friendly control of biodeteriogenic black fungi on cultural heritage stones using Lamiaceae essential oils

This study evaluates the antifungal efficacy of essential oils from selected Lamiaceae species against black fungi associated with the biodeterioration of historical monuments. The research was conducted in the Ancient City of Side (Turkey), focusing on black fungi of the genus Capnobotryella, which are recognized as major contributors to the deterioration of cultural heritage structures. Essential oils were extracted from Origanum majorana L., Origanum minutiflorum O. Schwarz & P.H. Davis, and Mentha longifolia L. subsp. typhoides (Brig.), and their antifungal activities were evaluated in vitro against isolates of the target fungal genus. Three concentrations of essential oils (0.1%, 1%, and 3%) were tested, and microfungal cell counts were performed before and after treatment. Statistical analyses confirmed that essential oils, particularly at higher concentrations, significantly reduced fungal growth. Crucially, no visible color change was observed on the stone surface following applications, underscoring their potential as eco-friendly agents for cultural heritage preservation.