As is the case for all forms of cultural heritage, museum collections are under a serious threat of biodeterioration, with fungi playing a significant role in this phenomenon, compromising the preservation and dissemination of past knowledge, artifacts and traditions. As part of the ongoing efforts to study the fungal contaminations observed in the artifacts that compose the collection of the Science Museum of the University of Coimbra, non-invasive sampling of four objects present in the archive was conducted and 43 fungal isolates were retrieved. These isolates were subjected to a comprehensive analysis based on molecular and morphological characteristics and were identified as belonging to 15 different species. Of the 15 isolated species, 5 were selected for in vitro antifungal essential oil assays, based on their relative abundance and biodeteriorative potential. For these, essential oils of Cymbopogon citratus, Lavandula angustifolia, Thapsia gummifera, Mentha pulegium, Mentha suaveolens, Thapsia villosa, Thymus mastichina and Agastache foeniculum were obtained via hydrodistillation, in accordance with the European Pharmacopeia. Of the tested oils, most impacted fungal growth, with Cymbopogon citratus and Lavandula angustifolia being able to fully inhibit the growth of most fungi even at the lowest tested concentrations.

Background/Objectives: Plants inhabiting mediterranean-influenced climatic zones, like Helichrysum stoechas (L.) Moench subsp. stoechas, Lavandula pedunculata (Mill.) Cav., and Thymus mastichina (L.) L. subsp. mastichina, have been scarcely investigated regarding their richness in phenolic compounds, herein explored as sources of skin anti-aging compounds. Methods: In this investigation, Fourier transform infrared spectroscopy (FTIR) in attenuated total reflectance (ATR) mode and high-performance liquid chromatography coupled with diode-array detection and electrospray ionization tandem mass spectrometry (HPLC-DAD-ESI/MSⁿ) were employed to chemically characterize the hydroethanolic extracts (HEs), and their cell-free antioxidant potential was screened. Thereafter, non-toxic concentrations of HEs were determined in human skin cells using Alamar blue^® and Sulforhodamine B assays. The cytoprotective and antioxidant effects of HEs were assessed in tert-butyl hydroperoxide-stimulated fibroblasts, their anti-inflammatory potential was studied in lipopolysaccharide-injured macrophages, and enzymatic inhibition assays were performed. Notably, the irritant effects of HEs were tested according to Test Guideline No. 439 of the Organization for Economic Co-operation and Development (OECD). Results: The major compounds identified in the T. mastichina and L. pedunculata HEs were rosmarinic and salvianolic acid derivatives, while H. stoechas HE was mainly composed of caffeoyl and feruloyl derivatives, and O-glycosylated flavonoids. T. mastichina (≤0.4 mg/mL) exhibited significant cytoprotective, anti-inflammatory, and antioxidant effects, as well as remarkable anti-hyaluronidase activity. Conclusions: Shedding light on the quantitative and qualitative chemical picture of these HEs highlighted T. mastichina as a promising candidate to target skin aging effects, which correlates with its phenolic content. Further investigation is warranted regarding its anti-aging pharmacological activity, which could lead to the development of plant-based skin anti-aging products.

Plant-based extracts are rich sources of phenolic compounds, which may act as skin antiaging mediators. Herein, Cistus albidus L. (Ca), Cistus ladanifer L. subsp. ladanifer (Cl) and Cistus salviifolius L. (Cs) were selected to test whether their phytochemical profile and bioactive potential align to target human skin aging. Hydroethanolic extracts (HEs) were prepared and characterized using infrared vibrational spectroscopy (FTIR-ATR) and liquid chromatography–mass spectrometry (LC-MS). Non-toxic concentrations were screened, and cytoprotective and antioxidant effects were studied in tert-butyl hydroperoxide-stimulated normal human dermal fibroblasts (NHDFs). Lipopolysaccharide-stimulated RAW 264.7 macrophages were used to assess anti-inflammatory activity, the Organization for Economic Co-operation and Development (OECD) Test Guideline No. 439 was used to assess irritant effects, and the anti-senescence potential was assessed in etoposide-stimulated NHDFs. A series of enzymatic inhibition assays was performed. All extracts comprised ellagic acid derivatives, as well as myricetin and quercetin derivatives in Cs and Ca. The HE of Cs was also markedly composed of ligstroside. At non-toxic concentrations, cytoprotective effects were observed in NHDFs. However, only Cs and Cl exhibited significant antioxidant activity in these cells (p < 0.001 and p < 0.0001, respectively). In addition to that, Cl demonstrated highly significant anti-inflammatory (p < 0.0001) and anti-senescence (p < 0.0001) effects. Cs and Cl showed a remarkable potential to inhibit elastase; in addition, Cs also showed anti-hyaluronidase and anti-tyrosinase activities. Meaningfully, Cs and Cl extracts did not exhibit skin irritant effects. The unveiled potential of Cl in skin aging offset highlights the need to elucidate the detailed mechanisms of action, paving the way for the development of skin anti-aging formulations.