Lavandula angustifolia mill. for a suitable non-invasive treatment against fungal colonization on organic-media cultural heritage

Abstract

In the context of bio-deterioration of cultural heritage, the Lavandula angustifolia Mill. plant proves to be of interest for a green approach to the preservation of art manufacts on organic media. Supercritical CO2 fluid extraction (SFE) was utilized to obtain both lavender essential oil (E2LS3) and hydrolate (E2LS3A), while ultrasound assisted maceration in n-hexane:ethanol (99:1, v:v) provided LA2/1 extract. The extracts, all chemically characterized by UHPLC-HRMS and GC–MS analyses, were screened for their antifungal capability towards six fungi isolated from the plywood support of Haim Steinbach's contemporary artwork "Un-color becomes alter ego #2" (1984). To this purpose, disk diffusion method was applied on both mycelium and conidial suspensions to unravel whether the inhibitory activity affects the growth of fungi at different life cycle stages. The micro-atmosphere method was also explored to assess the response of fungal growth in a saturated atmosphere. Data acquired highlighted that SFE-obtained lavender essential oil, whose oxygenated monoterpene part mostly accounting for terpinene-4-ol, borneol, linalool, camphor, and 1,8-cineole, proves to be a dose- and time-dependent inhibitor of fungal growth. It has also been shown that exposure to the oil vapor phase is more effective at very low dose levels. The promising results allow us to hypothesize the use of the essential oil for treating fungal colonization by exposure to its volatile components in a modified atmosphere environment, with no direct contact with the artwork.Graphical abstract