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Archival documents and artworks stored in libraries frequently undergo degradative processes promoted by the so-called "biodeteriogens" that inhabit these places. A renewed interest in plant-derived products has arisen in those research groups focusing on cultural heritage preservation and looking for new and safe disinfection techniques. In this view, essential oils (EOs) and their volatile organic constituents are very appealing thanks to their versatility of action. A literature survey of the scientific publications involving EOs and/or their major constituents related to the conservation of paper items of cultural heritage interest is presented here, aiming to reveal benefits and limitations of such peculiar plant-derived compounds. [ABSTRACT FROM AUTHOR]

Paper items from historical archives and libraries are frequently colonized by biodeteriogens, the management of which is a major concern. Essential oil Volatile Organic Compounds (VOCs) of thymol, carvacrol and eugenol, with high levels of antimicrobial and insect repellent activity, were stabilized within crystalline networks of β-cyclodextrins and phenazine-based cocrystals, as a new tool for the control of paper-degrading agents. These formulations were obtained via solvent-free methodologies and resulted as easy handling powders, suitable for the treatment of paper items by indirect contact. Their antimicrobial activity was evaluated on the following species isolated from a book depository at Forte Belvedere (Florence, IT): Alternaria alternata , Aspergillus sp., Cladosporium sp., Trichoderma orientale , Metschnikowia sp., and Bacillus sp. Both formulates displayed a significant antimicrobial activity in vitro , with cocrystals showing higher efficacy than β-cyclodextrins. The formulates were also tested against the pest Lasioderma serricorne , towards which the cocrystals entrapping carvacrol and thymol exhibited repellent activity. Overall, the phenazine-carvacrol cocrystal was the best-performing formulate, also giving favourable outcomes in terms of antifungal activity in an on-paper in vitro experiment designed to reproduce on a small-scale the critical conditions of an infested archive. These promising results pave the way towards further experimentations of VOC-based solid formulates, to shed light on such products applicability for the preservation of paper items. [Display omitted] • Volatile organic compounds (VOCs) trapped into β-cyclodextrins and cocrystals. • Solid formulates of thymol, carvacrol and eugenol to combat paper biodeteriogens. • Powdery formulates releasing VOCs with high antimicrobial activity. • VOC-based formulates showing insect repellent activity. [ABSTRACT FROM AUTHOR]

Plants produce considerable amounts of volatile organic compounds (VOCs) with several biological functions, including protection against biotic agents such as viruses and their vectors. In citrus species, these metabolites can be related with their different susceptibility/tolerance toward the Tristeza virus (CTV), one of the main biotic constraints for the citrus industry. The objective of this study was to compare the VOCs pattern from the leaves of a CTV-susceptible citrus variety such as Citrus aurantium and from three CTV-tolerant varieties: Citrus volkameriana, Carrizo citrange, and Forner-Alcaide no. 5. The VOCs emitted were analyzed via the headspace SPME method, while plant metabolites sequestered in the leaves were analyzed by heptane extraction followed by GC-MS. The results indicated that the majority of the VOCs emitted and sequestered in the leaves of the varieties tolerant and susceptible to CTV are constituted mainly by volatile terpenes (VTs) that exhibit strong qualitative/quantitative differences among the profiles of the four citrus species. In detail, the VOC emission indicated different patterns between C. aurantium and C. volkameriana and from both of them in comparison with Forner-Alcaide no. 5 and Carrizo citrange that exhibited more similarities, with the last two characterized by a higher presence of sesquiterpenes. The data obtained from the analysis of the VOCs sequestered in leaf tissues of the CTV-tolerant varieties indicated a higher presence of monoterpenes such as limonene, α-pinene, and p-cymene, known to be the main components of several plant extracts showing deterrent properties toward viruses and insect vectors. As VOC evaluation is a fast and noninvasive measure of phenotypic dynamics, allowing the association of plant phenotypes in accordance to plant disease resistance and/or stress tolerance, the possible implications of such differences in terms of tolerance grade to CTV and/or its related vectors are discussed. [ABSTRACT FROM AUTHOR]