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Lemon (Citrus limon L. Burm. f.) is used for fresh consumption because it is rich in several nutraceutical products especially vitamin C. The physicochemical properties and the bioactive compounds of the peel, such as the essential oil, are strictly depended on the genotype. In this context, peel and juice qualitative traits of 24 lemon cultivars were described: 20 varieties of the Italian germplasm, mostly belonging to Femminello (F.) lines, and 4 international varieties were studied. This study which may be considered one of the few examples carried out on a large number of varieties of a single Citrus species, was conducted over two years and the oils collected by hydro-distillation of the flavedo were analyzed by GC-FID and GC-MS. Differences were observed in the oil yields. For an easier comparison the essential oils' component were subdivided in five classes: monoterpene hydrocarbons, oxygenated monoterpenes, sesquiterpene hydrocarbons, oxygenated sesquiterpenes and others (not terpenoidic compounds). Among the monoterpene hydrocarbons, in all the cultivars the most abundant compounds were limonene, followed by β-pinene and γ-terpinene. In particular, Monachello showed the highest content of monoterpene hydrocarbons, while the lowest value was observed in F. Carrubaro, Fino and Akragas. Femminello lines are interesting cultivars for qualitative traits of the juice (organic acids and vitamin C) and for the highest content of volatile compounds in the peel, such as limonene, myrcene, β-pinene, α-pinene, γ-terpinene and sabinene. Significant differences in morphological and physicochemical traits were observed: fruits of Lemox, F. Adamo and F. Scandurra showed to be seedless, while high acidity content was observed in F. 2Kr, which also showed the highest vitamin C content. [Display omitted] • Lemox, F. Adamo, F. Scandurra and F. Cerza cultivars resulted seedless. • The juice of F. 2Kr showed the highest content of vitamin C. • PCA analysis indicated geranial, neral, neryl and geranyl acetate as main descriptors. • LDA analysis discriminated Femminello genotypes by identifying biological markers. [ABSTRACT FROM AUTHOR]

[Display omitted] • Extracts of Hypericum perforatum are rich in active metabolites. • Content in active metabolites is highly variable between years and biotypes. • The stability over years of several metabolites was evaluated in seven genotypes. • Only one biotype showed constantly higher-than-average amounts of most identified metabolites. St John's Wort (Hypericum perforatum L.; Hypericaceae) is a perennial medicinal herb widespread and largely used in folk medicine inside the Mediterranean basin. Many bioactive compounds have been identified within its extracts. Under a pharmacological point of view, the most important of them belong to the chemical classes of naphthodianthrones, phloroglucinols and polyphenols. Many factors have been claimed responsible for the phytochemical variability in Hypericum perforatum , such as genotype, geographical origin, harvesting stage and age of the plants. Yet, when harvested plant material is addressed to the industry, the standardization of the active ingredients over cultivation years is a crucial issue. With the aim to detect the stability over years and genotypes of several bioactive Hypericum compounds, seven Hypericum biotypes retrieved from different Italian geographical areas were cultivated in 2015 and 2016, and their aerial flowering parts were analyzed. Naphthodianthrones (hypericin and its biosynthetic precursors), phloroglucinols (hyperforin and adhyperforin), and main polyphenols were determined by HPLC-DAD analysis. The results were statistically evaluated through ANOVA, and the stability over cultivation years of the tested genotypes was assessed. In rather all the examined metabolites, the ANOVA revealed a remarkable effect of both factors "year" (Y) and "provenance" (P), but the occurrence of significant "Y x P" interactions evidenced that the effect of climatic variability was often different according to the genotype. The evaluation of the stability level between years evidenced that only one biotype out of seven exhibited constantly higher-than-average amounts of rather all identified metabolites. [ABSTRACT FROM AUTHOR]

Hypericum is one out of the nine genera belonging to the botanical family Clusiaceae Lindl (syn. Hypericaceae Juss.; APG III, 2009). The genus contains 484 species spread worldwide, one of which, Hypericum perforatum , is largely used in folk medicine. The aim of this study was to evaluate the chemical composition, along with the antioxidant and phototoxic activity, of 11 Hypericum species grown in Sicily ( H. perforatum L., H. aegypticum L., H. androsaemum L., H. calycinum L., H. hircinum L., H. hirsutum L., H. montanum L., H. patulum Thunb., H. perfoliatum L., H. pubescens Boiss., H. tetrapterum Fr.). Samples of flowering tops collected from these Hypericum species were extracted and analysed by high performance liquid chromatography with diode-array detection and mass spectrometry (HPLC-DAD-MS) to determine their content of main polyphenols, acylphloroglucinols, and naphthodianthrones. The extracts were also subjected to a photocytotoxic assay using murine fibroblast (NIH/3T3), and their antioxidant activity evaluated by means of Folin-Ciocalteau, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, and oxygen radical antioxidant capacity assays. Phytochemical analysis allowed us to identify and quantify 20 metabolites, each of them possessing a well-known biological activity. Furthermore, all examined species showed a good cytotoxic and antioxidant/radical scavenging activity. These results indicate that in addition to the well-known H. perforatum , at least other three species ( H. tetrapterum , H. pubescens , and H. montanum ) represent potential sources of biologically active compounds, and at least other two species ( H. perfoliatum and H. tetrapterum ), due to their phototoxicity are candidates for application in photodynamic therapy. [ABSTRACT FROM AUTHOR]

Pistacia vera oleoresin is one of the natural products used traditionally for the management of wounds. However, there were no scientific reports documented so far on the wound healing activities to substantiate the claim. This study assesses the potential of the oleoresin of P. vera collected in Italy and Algeria for wound healing efficacy via in vivo circular wound excision model. Italian and Algerian oleoresins were subjected to purification and successive fractionation to obtain three matrices. The fractions have been characterized using GC-FID and GC–MS analyses. Oleoresins mixed with vaseline (5% w /w) were topically applied on wound excision induced on the dorsum of rabbits. Wound healing effects were evaluated by percent of wound contraction. Biopsies performed after healing were histologically assessed. Phytochemical results showed a high content of terpenoids components inducing an efficient wound healing effect determined by an in vivo study. Italian and Algerian oleoresins ointments showed significant wound contraction from day 8 to day 16 as compared to the negative control. The two ointments have not showed statistically difference as compared to Cicatryl, reference drug. These results have also been confirmed by the histological evaluation of the tissues involved. The absence of signs of toxicity on the skin of rabbits indicated the safety of the ointments. The study showed that both oleoresins have a very high effectiveness as wound healing agents and appear to justify their traditional use in wound healing in several countries and offer a scientific support to the treatment of traditional healers. [Display omitted] • First report on wound healing activity of Pistacia vera L. oleoresin. • The chemical complexity of the total Pistacia oleoresins has been established. • Terpenoids are the main components of P. vera oleoresins. • P. vera oleoresin ointment is a wound healing agent in traditional medicine. [ABSTRACT FROM AUTHOR]

Abstract: Mathematical operators whose transformation rules constitute the building blocks of a multi-linear algebra are widely used in physics and engineering applications where they are very often represented as tensors. In the last century, thanks to the advances in tensor calculus, it was possible to uncover new research fields and make remarkable progress in the existing ones, from electromagnetism to the dynamics of fluids and from the mechanics of rigid bodies to quantum mechanics of many atoms. By now, the formal mathematical and geometrical properties of tensors are well defined and understood; conversely, in the context of scientific and high-performance computing, many tensor-related problems are still open. In this paper, we address the problem of efficiently computing contractions among two tensors of arbitrary dimension by using kernels from the highly optimized BLAS library. In particular, we establish precise conditions to determine if and when GEMM, the kernel for matrix products, can be used. Such conditions take into consideration both the nature of the operation and the storage scheme of the tensors, and induce a classification of the contractions into three groups. For each group, we provide a recipe to guide the users towards the most effective use of BLAS. [Copyright &y& Elsevier]

Essential oils from six different populations of Origanum vulgare subsp. hirtum were compared for their antibiofilm properties. The six essential oils (A to F) were characterized by a combination of gas chromatography with flame ionization detector and gas chromatography with mass spectrometer detector analyses. All oils showed weak activity against the planktonic form of a group of Staphylococcus aureus strains and against a Pseudomonas aeruginosa ATCC 15442 reference strain. The ability to inhibit biofilm formation was investigated at sub-MIC levels of 200, 100, and 50 µg/ml by staining sessile cells with safranin. Sample E showed the highest average effectiveness against all tested strains at 50 µg/ml and had inhibition percentages ranging from 30 to 52%. In the screening that used preformed biofilm from the reference strain P. aeruginosa, essential oils A through E were inactive at 200 µg/ml; F was active with a percentage of inhibition equal to 53.2%. Oregano essential oil can inhibit the formation of biofilms of various food pathogens and food spoilage organisms. [ABSTRACT FROM AUTHOR]

Abstract: Thirty samples of wild thyme collected from as many Sicilian locations have been analysed for their qualitative and quantitative essential oil profiles. The oils, obtained by hydrodistillation, have been analysed by a combination of GC-FID-MS; in all, 46 components, representing more than 98% of the oils, were fully characterized. Monoterpenes, both hydrocarbons and oxygenated, were the most highly represented components: the former with a range of 8–61% and the latter with a range of 31–86%. Carvacrol was the main compound in 29 samples, ranging between 49 and 83%, suggesting that Thymus capitatus Hoff. et Link. [syn. Coridothymus capitatus (L.) Rchb.f., Satureja capitata L., Thymbra capitata (L.) Cav.] is the most widespread wild species in the Sicilian area. Only one sample, identified as Thymus longicaulis C. Presl., collected from the North-East of Sicily showed a different composition, p-cymene and thymol being the main compounds with 40 and 16%, respectively. Statistical analyses allowed establishing a single broad group, confirming the substantial compositional uniformity of the essential oil profiles of the wild Sicilian thyme. [ABSTRACT FROM AUTHOR]

Abstract: The qualitative and quantitative composition of the essential oils obtained from wild Sicilian rosemary plants (Rosmarinus officinalis L.) has been investigated. Samples were collected in Sicily after an ideal division of the island into three large areas, namely Val Mazara (M), Val di Noto (N) and Val Demona (D), according to an ancient and historical territorial subdivision of the island. The essential oils were obtained by hydrodistillation and analyzed by GC-FID-MS, identifying 100 compounds representing more than 96% of the oils. Monoterpenes, both hydrocarbons and oxygenated, were the most highly represented components: the former with a range of 21–68% and the latter with a range of 29–79%. On the basis of the results of this study, comprising a cluster analysis, and on the commonly accepted subdivision of rosemary essential oils, namely cineoliferum, verbenoniferum and camphoriferum chemotypes, most of the wild Sicilian rosemary samples must be classified as cineoliferum chemotype. [ABSTRACT FROM AUTHOR]

Abstract: Fifty-six samples of wild fennel (Foeniculum vulgare Mill.) have been collected in different localities of Sicily and analysed for their content in seed essential oils. The GC-FID-MS analyses allowed identifying 78 compounds, representing more than 98% of the oils. Phenylpropanoids are the most highly represented components – 55 samples show estragole as the main compound ranging between 34 and 89%, while (E)-anethole is the other phenylpropanoid ranging between 0.1 and 36%, although it only reaches appreciable values in a few samples, largely being present below 1%. The oxygenated monoterpene, fenchone, a typical fennel oil component, has been found in all samples, in the 2–27% range; α-pinene (1–21%), limonene (1–17%) and γ-terpinene (<1–4%) were the monoterpene hydrocarbons found in all samples. Only one sample showed piperitenone oxide and limonene as main components, with 42 and 34%, respectively, and with the lack of any phenylpropanoid. Sesquiterpenes and others compounds class had only negligible values or were not detected in all samples. Statistical analyses allowed to single out five groups, reflecting the compositional differences of the essential oil profiles of the wild Sicilian fennel. [Copyright &y& Elsevier]

Abstract: The qualitative and quantitative composition of the essential oils obtained from wild Sicilian oregano plants has been investigated. Samples were collected from three areas of Sicily namely Val Mazara (M), Val di Noto (N) and Val Demona (D). These areas are based on historical territorial subdivision. The essential oils were obtained by hydrodistillation and analyzed by GC-FID-MS. Seventy eight compounds were identified representing more than 98% of the compounds in the oils. All samples are thymol-chemotype with variable percentage of γ-terpinene, p-cymene, trans-sabinene hydrate, terpinen-4-ol and carvacrol. Statistical analyses were performed in order to evaluate the variability of the essential oils. Six groups were formed reflecting the compositional differences of the essential oil profiles of the wild Sicilian oregano samples. [Copyright &y& Elsevier]

• Arborescens was cultivated at three increasing shading levels. • Plants height, leaves/plant, stem diameter increased with shading. • Percentages of aloenin A and aloin B were higher in full sunlight. • Content per plant of all studied metabolites was lower in full sunlight. Leaves of Aloe arborescens Mill. are a relevant source of secondary metabolites of pharmaceutical relevance. Notwithstanding, specialized cultivations of A. arborescens are still rather limited, and a straightforward agronomical research addressed to the obtainment of high-quality material is lacking. With the purpose to fill this gap, from 2016 to 2018, a trial was arranged to evaluate the growth and development of A. arborescens , along with the production of four active metabolites (aloin A and B, aloenin A, and isoaloeresin D) with varying some growth conditions. Two growth substrates ("A"- a commercial substrate, and "B"- the same substrate + 20 % perlite), two durations of pre-transplant open-air storage ("stress", 7 and 14 days), and 3 illumination levels obtained by means of shadow nets with different mesh dimensions (SL: full sunlight; T50: 50 % shading; T70: 70 % shading) were tested, combined in a factorial experimental layout with 3 repetitions. In general, light intensity was the most crucial experimental factor, whereas the effects of growth substrate and pre-transplant stress were scarce and limited in time. The addition of perlite to the growth substrate gave the best results in terms of leaf size and root growth, without any significant effect on the yield of active metabolites. The increasing shading level caused a parallel increase of several biometrical characters of plants (height, number of leaves per plant and mean diameter of the stem), whereas the number of suckers per plant was positively affected by the increase of illumination level. The illumination level was also responsible for significant variations in the content of all secondary metabolites, except for aloin A, that resulted statistically not different among the illumination treatments (from 0.80 to 0.98 % in dry matter). The content of aloenin A and aloin B was higher in the plants exposed in full sun, statistically well differentiated from those exposed to 70 % shadow (2.0 vs. 1.4 % d.m. aloenin A, and 1.12 vs 0.86 % d.m. aloin B, in full sun and 70 % shadow, respectively). Contrastingly, the highest levels of isoaloeresin D were reached in the two shaded treatments (4.98 % in 50 % shadow and 4.89 % in 70 % shadow), whereas the full sun treatment reached the lowest value. The higher number of leaves in plants exposed at reduced illumination, however, brought to increased total amounts per plant of aloin (A and B) and aloenin A with increasing shadow levels. [ABSTRACT FROM AUTHOR]

The aim of this work is the encapsulation of essential oils (EOs) in polymeric nanocapsules (NCs), in order to enhance their antimicrobial activity against food-borne pathogens. Thymus capitatus and Origanum vulgare EOs were selected for their different chemical composition, carvacrol (73%) and thymol (44%) being the major constituent, respectively. Polymeric poly(ɛ-caprolactone) (PCL) nanocapsules loaded with EOs were prepared by a nanoprecipitation method. The EO-NCs showed monomodal distribution with diameter size 171 and 175 nm, high efficiency of encapsulation and stability with high retention of EOs at both 4 °C and 40 °C, for a period of at least 30 days. The antimicrobial activity of EO-NCs against food-borne pathogens was higher than that of the corresponding pure essential oils and the NCs loaded with Thymus capitatus EO were the most active . Interestingly EO-NCs showed a bactericidal activity even at the minimum inhibitory concentrations (MICs). It makes them appealing as natural food preservatives. [ABSTRACT FROM AUTHOR]

Highlights • First chemical characterization of the oleoresin of P. vera L. • First study on antimicrobial properties of P. vera L. oleoresin. • P. vera L. oleoresin shows strong anti-virulence properties against S. mutans. • P. vera L. oleoresin reducing S. mutans's ability to form biofilm. • Potential use for the P. vera L. oleoresin in oral hygiene. Abstract Objective The aim of this study was to characterize the chemical composition of oleoresin of Pistacia vera L. and to determine its antimicrobial and anti-virulence activity versus selected oral streptococci. Design A gaschromatografic analysis of the oleoresin was performed. The antimicrobial and anti-virulence activity of the oleoresin and its fractions was evaluated by the Minimum Inhibitory Concentration (MIC) and/or Minimum Bactericidal Concentration (MBC), biofilm production and haemolytic activity inhibition experiments. Results The oleoresin MBCs were ≥1024 μg/mL for all tested strains; the neutral and acidic fraction MBCs ranged from 128 to 2048 μg/mL. Essential oil's MBCs (from 256 to 2048 μg/mL) were almost identical to MICs, suggesting a bactericidal effect. P. vera oleoresin at sub-lethal concentrations significantly reduced biofilm production by Streptococcus mutans (up to 49.4%) and by Streptococcus sanguinis (up to 71.2%). In addition, the acidic fraction showed a specific anti-biofilm activity against S. mutans (up to 41.3% reduction). A significant dose-dependent reduction in the haemolytic activity of S. mutans (up to 65.9%) and of S. anginosus (up to 78.3%) was observed after growth in the presence of oleoresin at sub-lethal concentrations. The acidic fraction reduced haemolytic activity (up to 54.3% at 64 μg/mL) of S. mutans only. Conclusions Given the anti-virulence activity of the P. vera oleoresin and its acidic fraction against S. mutans , our findings suggest their potential use in oral hygiene. These data represent the first step in the exploitation of P. vera L. oleoresin. [ABSTRACT FROM AUTHOR]

Abstract: We compare two approaches to compute a fraction of the spectrum of dense symmetric definite generalized eigenproblems: one is based on the reduction to tridiagonal form, and the other on the Krylov-subspace iteration. Two large-scale applications, arising in molecular dynamics and material science, are employed to investigate the contributions of the application, architecture, and parallelism of the method to the performance of the solvers. The experimental results on a state-of-the-art 8-core platform, equipped with a graphics processing unit (GPU), reveal that in realistic applications, iterative Krylov-subspace methods can be a competitive approach also for the solution of dense problems. [Copyright &y& Elsevier]

Abstract: The characterization of the essential oil profile together with the sensory analysis of five samples of oregano, four of which cultivated in different areas of Sicily and one of commercial origin, have been carried out. The Sicilian cultivated samples belong to Origanum vulgare ssp. hirtum (Link) Béguinot (syn. O. heracleoticum L.), the most typical Sicilian oregano species. The essential oils, obtained by hydrodistillation, have been analysed by GC–FID–MS. On the whole, 53 compounds representing more than 98% of the oils have been fully characterized. The four cultivated samples showed a very similar chemical profile, thymol and γ-terpinene being the main compounds followed by p-cymene, α-terpinene, carvacrol and thymol methyl ethers, myrcene and carvacrol. The commercial sample, instead, showed a different profile, with carvacrol largely being the main component (>77%), followed by p-cymene, γ-terpinene and thymol, in that order. According to the chemical composition, the sensory profile of the Sicilian oregano samples proved fairly homogenous, whereas different results were obtained for the commercial sample. Indeed, the intensity of sensory attributes “typical oregano flavour” and off-flavour are similar for the four cultivated samples; instead the commercial sample has less freshness and a lower typical oregano flavour, associated with a higher level of off-flavour. [Copyright &y& Elsevier]

[Display omitted] Essential oils (EOs) of Thymus capitatus (Th) carvacrol chemotype and Origanum vulgare (Or) thymol and carvacrol chemotype were encapsulated in biocompatible poly(ε-caprolactone) nanocapsules (NCs). These nanosystems exhibited antibacterial, antifungal, and antibiofilm activities against Staphylococcus aureus, Escherichia coli, and Candida albicans. Th-NCs and Or-NCs were more effective against all tested strains than pure EOs and at the same time were not cytotoxic on HaCaT (T0020001) human keratinocyte cell line. The genotoxic effects of EO-NCs and EOs on HaCaT were evaluated using an alkaline comet assay for the first time, revealing that Th-NCs and Or-NCs did not induce DNA damage compared with untreated control HaCaT cells in vitro after 24 h. The cells morphological changes were assessed by label-free live cell Raman imaging. This study demonstrate the ability of poly(ε-caprolactone) nanocapsules loaded with thyme and oregano EOs to reduce microbial and biofilm growth and could be an ecological alternative in the development of new antimicrobial strategies. [ABSTRACT FROM AUTHOR]

• Lavender plants were grown in different peat-conifer wood biochar substrates. • Biochar amendment of growing substrates did not affect plant growth and ornamental value. • Biochar amendment did not influence essential oil quality and chemical profile. • Antioxidant activity of essential oils and hydro-distilled wastewaters was also determined. • Conifer wood biochar may be used as peat substitute for lavender cultivation. The dramatic increase of peat use for agricultural purposes and the consequent depletion of peatlands has resulted in an increasing environmental concern about peat extraction and in a continuous search for sustainable substitutes. In order to find an efficient alternative to peat as substrate component for horticultural industry, a study was accomplished to assess the influence on Lavandula angustifolia Miller potted plants grown in a peat-based substrate amended with increasing amount of conifer wood biochar: 0, 25, 50, 75 and 100 % (by volume). Higher values of plant height, leaf area, leaves and flowers production were recorded in potted lavenders grown in substrates with a biochar content ranging from 25 % to 75 %; at a visual-quality evaluation no significant differences were observed among substrates on the general aesthetic effect of the plants. The aforesaid five different substrates tested did not significantly affect the leaf dry weight and the root-to-shoot ratio. The biochar amendment of peat-based substrates, even at high rates (75 % or 100 %), did not influence lavender essential oil (EO) quality, its chemical profile and antioxidant activity. The radical scavenging activities of EO and hydro-distilled wastewaters were also detected. Main results from our study seem to suggest that a conifers wood biochar may be efficiently used as substrate alternative to peat to grow Lavandula angustifolia plants for EO production. [ABSTRACT FROM AUTHOR]

Skin acts as a protective barrier between the body and the external environment. Skin wounds are a common inflammatory disorder for the solution of which plants and essential oils have been applied as a medical option for centuries. Origanum vulgare essential oil (OEO) is largely used in folk medicine, but its molecular mechanisms of action are not fully known. In this study, we evaluated the anti-inflammatory/antioxidant activity as well as wound healing capacity of a well-characterized OEO on human keratinocytes NCTC 2544 treated with interferon-gamma (IFN-γ) and histamine (H) or subjected to a scratch test. The expression of pro-inflammatory mediators such as reactive oxygen species (ROS), inter-cellular adhesion molecule (ICAM)-1, inducible nitric oxide synthase (iNOS), and cyclooxygenase (COX)-2 were verified. The DNA damage was shown by the formation of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-OHdG) and activation of proliferating cell nuclear antigen (PCNA). Moreover, the abnormal modification of extracellular matrix components (ECM) was examined by determining matrix metalloproteinase (MMP)-1, and −12. Compared to untreated control, OEO showed efficacy in supporting and enhancing the cell motility. In IFN-γ and H treated cells, OEO displayed a significant reduction of ROS, ICAM-1, iNOS, COX-2, 8-OHdG, MMP-1, and MMP-12. OEO proved useful to treat inflammation and support cell motility during wound healing. Image 1 • Interferon-γ and histamine stimulation produces inflammation in in vitro keratinocytes. • Interferon-γ and histamine stimulation produces high levels of ROS, ICAM-1, iNOS, and COX-2. • Origanum vulgare essential oil provides anti-inflammatory and wound healing activity. • Origanum vulgare essential oil reduces and/or modulates ROS, ICAM-1, iNOS, COX-2, 8-OHdG, MMP-1, and MMP-12. • This study highlights the potential use of Origanum vulgare essential oil to treat skin inflammation and wound healing. [ABSTRACT FROM AUTHOR]

Controlling of cultural heritage biodeterioration is a serious problem in the world. Chemical biocides, used to kill unwanted microorganism, can represent a risk for human health and environment, and interfere with the restoration material. Natural biocides could represent a valid alternative to conventional ones. In this study we report the use of nanocapsules suspensions (NCs) loaded with Origanum vulgare and Thymus capitatus essential oils (EOs) to contrast the development of bacterial growth of two microrganisms (Escherichia coli and Kokuria rhizophila) on the marble stone from 18th century church altar. No structural change was observed on the stone after treatment with the aqueous suspension containing nanoparticles as evidenced by SEM-EDX analysis. The nanostructurate systems (EO-NCs) were able to inhibit the bacterial grow on the stone pretreated with bacterial inoculum as showed by agar discs contact test. Nanocapsules, based on biodegradable and biocompatible polymer (poly(ε-caprolactone)), loaded with thyme EO are more efficient than nanocapsules loaded with oregano EO. The obtained results evidenced the potential of these natural biocides in the treatment of biodeteriorated cultural heritage. Image 1 • Natural biocides a valid alternative to conventional ones. • Nanocapsules loaded with essential oils inhibit the growth of Gram+ and Gram-bacterial strains. • Nanocapsules loaded with thyme essential oil are more active. • 18th century marble stone as model material to test antimicrobial activity of essential oil nanocapsules. [ABSTRACT FROM AUTHOR]