The chemical profile of the Thymus vulgaris (Lamiaceae) essential oil (EO) was investigated in order to evaluate its biological properties against microorganisms affecting two Tholu Bommalu, typical Indian leather puppets stored at the International Puppets Museum “Antonio Pasqualino” of Palermo, Italy. A GC–MS analysis, using both polar and apolar columns, was used to determine the chemical composition of the essential oil. The aim of this study was to evaluate the antimicrobial effectiveness of the Thymus vulgaris and Crithmum maritimum essential oils in vapor phase to disinfect heritage leather puppets. Pieces of leather artifacts that were affected by different bacterial colonies were exposed to EO under vacuum and static evaporation conditions. The results presented showed that the vaporization of essential oil was an efficient method in the disinfection of natural skins, eradicating microorganism in short times. T. vulgaris EO in the 50% solution showed excellent inhibitory activity against isolated bacteria with both methods, but the obtained results suggest that the vacuum method allowed for faster exposition of the artifacts to the biocide. Furthermore, the biocidal properties of the essential oil of a Sicilian accession of Crithmum maritimum (Apiaceae) aerial parts were compared and investigated. The results of the latter essential oil showed a poor activity against the isolated micro-organisms.

Tholu Bommalu are typical leather puppets of the traditional Indian shadow theatre. Two of these objects are part of a collection in the International Puppets Museum “Antonio Pasqualino” (Palermo, Sicily, Italy), which can count on one hundred-seventy-three of artifacts. These Indian puppets were investigated to obtain information related to the use of dyes for their manufacturing through a multi-technical approach exploiting the combination of highly sensitive spectroscopic techniques. Wet cotton stubbons were used to entrap small particles of dyes on the fibers from the art objects for the consequent analyses. Visible Light Micro-Reflectance spectroscopy was employed for the preliminary identification of the molecular class of dyes directly on the swabs, while Surface Enhanced Raman Scattering allowed the identification of the specific dye. Several synthetic dyes belonging to different typologies of coloring compounds were identified. The study resulted in an interesting overview of dyes used in recent Tholu Bommalata manufacturing through the combination of micro-invasive techniques directly on the sampling substrate.

The possibility of using materials from the waste of agricultural products for the conservation of cultural and artistic heritage has led to important technological developments on mortars, plasters, colors, and other applications. In this experimental work, we investigated the binding properties of mucilage obtained from two different species of the genus Opuntia, both collected in Sicily, Italy: Opuntia ficus-indica (L.) Mill. and Opuntia stricta (Haw.) Haw. Through chemical acid hydrolysis, and subsequent spectroscopic analysis conducted at ¹³C-NMR, the main monosaccharide composition of both mucilage was studied, identifying considerable compositional differences. In fact, the mucilage of O. ficus indica had similar total amounts of arabinose (23.65%), galactose (20.87%), and glucose isomers (23.89%), while that of O. stricta was characterized by significant amounts of arabinose (36.48%) and galactose (32.31%) units. The samples were obtained by dispersing pigments on the mucilage and applying the obtained tempera by a brush onto both paper and chalk supports, in order to observe if the colors changed with different substrates. Colorimetric analysis, measuring ΔE, showed how the same pigment modifies its aspect depending on the binder used. After a two-week UV ageing process, pigments that had dispersed in O. stricta changed their aspect more than those dispersed in O. ficus-indica. Overall, it is also evident how ΔE data for organic pigments are higher than those for inorganic ones.

Over the years in the field of conservation of cultural heritage, a wide use of traditional products for the plastic reintegration of wooden artifacts has been seen. However, they are usually not designed for this purpose. The present study also shows, in terms of material compatibility, the material most suited for wood restoration, cellulose pulp, from the perspective of a new green approach of reusing waste. Indeed, microcellulose was obtained by simple alkaline treatment from softwood almond shells. In particular, Prunus dulcis Miller (D.A.) Webb. was considered an agro-industrial waste largely available in southern Italy. To value the possibility of using this material in a circular economy framework, a microcellulosic material was used, by adding different binders, to manufacture several stuccos to utilize as wood consolidants. Successively, in order to obtain stuccos with biocidal properties against fungal colonization or insect infestation, to which wooden artifacts are often exposed, cellulose pulp was combined with the essential oil of Thymus capitaus (L.) Hoffmanns. & Link., whose biological properties have been largely reported. The physical flexion properties of all new materials were tested.

Achillea cretica (L.) (Asteraceae) is a suffruticosa camefite plant, mainly distributed in Crete, Aegean Islands, and eastern Mediterranean area. In the present study, the chemical composition of the essential oil from aerial parts of a not previously investigated accession of Achillea cretica, collected in Crete, was analysed by GC-MS. The results showed the presence of large quantity of α-bisabolol (53.88%) followed by the related compound α-bisabolol-oxide (2.76%), and spathulenol (5.94%). Based on the composition of the essential oils of all the other Achillea taxa, several consideration have been carried out. Graphical Abstract