Cistus Ladanifer Research Articles

Plant invasion modifies isohydricity in Mediterranean tree species

Abstract Understanding of plant hydraulic strategies (i.e. the degree of iso‐/anisohydricity) is crucial to predict the response of plants to changing environmental conditions such as climate‐change induced extreme drought. Several abiotic factors, including evaporative demand, have been shown to seasonally modify the isohydricity of plants. However, the impact of biotic factors such as plant–plant interactions on hydraulic strategies has seldom been explored. Here, we investigated adaptations and changes in hydraulic strategies of two woody species in response to seasonal abiotic conditions, experimental drought and plant invasion in a Mediterranean cork oak (Quercus suber) ecosystem with a combined shrub invasion (Cistus ladanifer) and rain exclusion experiment. From the dry to wet season, Q. suber shifted from a partial isohydric to an anisohydric behaviour while C. ladanifer shifted from strict anisohydric to partial isohydric. During drought, water competition by plant invasion significantly modified the hydraulic strategy of invaded Q. suber, which was accompanied by lower pre‐dawn leaf water potentials, sap flow density, leaf area index and trunk increment rates. This altered isohydricity of invaded Q. suber trees was most likely caused by interspecific competition for water resources by water spending C. ladanifer shrubs. Both species do have the highest proportion of fine roots in the topsoil and thus, an additional water consumer, such as C. ladanifer can lead to more stressful conditions for Q. suber during times of water scarcity. Further underlying mechanisms of the altered isohydricity of Q. suber, such as potential allelopathic effects of C. ladanifer exudates on root growth of Q. suber, have to be investigated in the future. In conclusion, we demonstrate that the degree of isohydricity of two woody Mediterranean plant species is dynamically determined by the interplay of species‐specific hydraulic traits and their abiotic and biotic environment. Read the free Plain Language Summary for this article on the Journal blog.

Soil VOC emissions of a Mediterranean woodland are sensitive to shrub invasion.

Many belowground processes, such as soil respiration and soil-atmosphere VOC (volatile organic compounds) exchange, are closely linked to soil microbiological processes. However, little is known about how changes in plant species cover, i.e. after plant invasion, alter these soil processes. In particular, the response of soil VOC emissions to plant invasion is not well understood. We analysed soil VOC emissions and soil respiration of a Mediterranean cork oak (Quercus suber) ecosystem, comparing soil VOC emissions from a non-invaded Q. suber woodland to one invaded by the shrub Cistus ladanifer. Soil VOC emissions were determined under controlled conditions using online proton-transfer time-of-flight mass spectrometry. Net soil VOC emissions were measured by exposing soils with or without litter to different temperature and soil moisture conditions. Soil VOC emissions were sensitive to C. ladanifer invasion. Highest net emission rates were determined for oxygenated VOC (acetaldehyde, acetone, methanol, acetic acid), and high temperatures enhanced total VOC emissions. Invasion affected the relative contribution of various VOC. Methanol and acetaldehyde were emitted exclusively from litter and were associated with the non-invaded sites. In contrast, acetone emissions increased in response to shrub presence. Interestingly, low soil moisture enhanced the effect of shrub invasion on VOC emissions. Our results indicate that shrub invasion substantially influences important belowground processes in cork oak ecosystems, in particular soil VOC emissions. High soil moisture is suggested to diminish the invasion effect through a moisture-induced increase in microbial decomposition rates of soil VOC.

Labdanum Resin from Cistus ladanifer L.: A Natural and Sustainable Ingredient for Skin Care Cosmetics with Relevant Cosmeceutical Bioactivities.

Labdanum resin from Cistus ladanifer L. (Cistaceae) is an abundant natural resource in the Iberian Peninsula worth being explored in a sustainable manner. It is already used in the cosmetic industry; mainly by the fragrances/perfumery sector. However, given the highest market share and traditional uses, labdanum resin also has the potential to be used and valued as a cosmetic ingredient for skincare. Aiming to evaluate this potential, labdanum methanolic absolute and fractions purified by column chromatography were characterized by UPLC-DAD-ESI-MS and then evaluated for UV-protection, antioxidant, anti-elastase, anti-inflammatory, and antimicrobial activities. Labdanum absolute represented ~70% of the resin; diterpenoid and flavonoid fractions represented ~75% and 15% of the absolute, respectively. Labdane-type diterpenoids and methylated flavonoids were the main compounds in labdanum absolute and in diterpenoid and flavonoid fractions, respectively. Labdanum absolute showed a spectrophotometric sun protection factor (SPF) near 5, which is mainly due to flavonoids, as the flavonoids’ SPF was 13. Low antioxidant activity was observed, with ABTS radical scavenging being the most significant (0.142 ± 0.017, 0.379 ± 0.039 and 0.010 ± 0.003 mgTE/mgExt, for the absolute and flavonoid and terpene fractions, respectively). Anti-aging and anti-inflammatory activity are reported here for the first time, by the inhibition of elastase activity (22% and 13%, by absolute and flavonoid extract at 1 mg/mL), and by the inhibition of nitric oxide production in LPS-induced RAW 264.7 cells (84% to 98%, at 15 µg/mL extracts, flavonoid fraction the most active), respectively. Antimicrobial activity, against relevant skin and cosmetic product microorganisms, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Escherichia coli, revealed that only S. aureus was susceptible to labdanum absolute (MIC: 1.2 mg/mL) and its fractions (MIC: <0.3 mg/mL). In conclusion, labdanum resin showed potential to be used in sunscreen cosmetics, anti-inflammatory skincare cosmeceuticals or medicines but has low potential as a cosmetic product preservative given the low antioxidant and low-spectrum antimicrobial activities.

Evaluation of the Activity of Estragole and 2-Isopropylphenol, Phenolic Compounds Present in Cistus ladanifer

A large number of studies of Cistus ladanifer highlight this Mediterranean shrub as a source of the phenolic compounds responsible for the allelopathic potential of this species. There are few phenolic compounds present in C. ladanifer that have not yet been studied. The objective of this work was to evaluate the activity of estragole and 2-isopropylphenol on filter paper and soil on monocotyledons (Allium cepa) and dicotyledons (Lactuca sativa). The results showed that when the test was carried out on paper, the germination and the growth of the L. sativa was strongly inhibited by 2 isopropylphenol and estragole. 2 isopropylphenol showed an IC50 on the germination of 0.7 mM and 0.1 mM on the germination rate, 0.4 mM on the size of radicle and 0.3 mM on the size of hypocotyl. Estragole showed an IC50 on the germination rate of 1.5 mM and 1.1 mM on the size of hypocotyl. The effects of these pure compounds on A. cepa were lower, and when the assays were performed on the soil, they were dissipated. The mixture of these compounds on A. cepa had 0.6 mM IC50 for the length hypocotyl on paper and 1.1 mM for the length of the radicle on soil. The mixture on L. sativa also inhibited the length of the radicle with an IC50 of 0.6 mM. On the other hand, it was also observed that estragole stimulated the growth of the A. cepa radicle length on soil, showing a hormetic effect with an EC50 of 0.1 mM. In conclusion, it can be said that for a species to be allelopathic in nature, it is essential to verify the effect of its possible allelochemicals on the target species, on the soil in which they will exert their action and at the concentrations found in their usual environment, in addition to taking into account the interaction with other compounds present in the medium.

Cistus ladanifer seeds: From ancient snack to novel and sustainable food ingredient

Cistus ladanifer is a persistent, abundant and widespread underexplored resource in the Iberian Peninsula. The seeds have been used as food for centuries, although their nutritional value and potential as food ingredients have not been exploited until now. In this study seeds from natural shrubland were collected three times during summer for two consecutive years. Analytical evaluation of the macronutrient content, fatty acids, and mineral composition was performed. Regarding the macronutrients, seeds showed a carbohydrate content of 46.1 ± 1.6%, a fibre content of 20.9 ± 1.4%, a protein content of 16.2 ± 0.4%, a lipid content of 13.0 ± 1.1%, and an ash content of 3.87 ± 0.16%. The fatty acids were found to be mostly unsaturated (74.05 ± 0.59%). Potassium was the most abundant mineral (975 ± 53 mg/100 g) followed by phosphorous, magnesium and calcium. In conclusion, several nutrient-related label claims may be used for C. ladanifer seeds as food ingredient. Compared to common cereals, nuts and seeds, C. ladanifer seeds are close to flax and chia seeds in relation to nutritional composition, and to pine nuts in relation to mineral composition.

D-Lactic acid production from Cistus ladanifer residues: Co-fermentation of pentoses and hexoses by Escherichia coli JU15

In this study, glucan-rich solids, and xylose-rich hydrolysates obtained from Cistus ladanifer distillery residues (CLR) were used for d-lactic acid (d-LA) production by the d-lactogenic Escherichia coli strain JU15. Firstly, hemicellulosic hydrolysates obtained by the autohydrolysis process were submitted to dilute sulfuric acid-catalysed post-hydrolysis. The influence of operational conditions on oligosaccharides hydrolysis was assessed by the combined severity parameter (CS) in the range of 1.1–2.3. The optimum post-hydrolysis conditions were found for CS of 1.6 (300 mM H2SO4, 15 min, 121 °C). Subsequent detoxification procedures on post hydrolysed liquors were carried out, where 9.1% (w/v) powdered activated charcoal enabled a full removal of furfural, 5-hydroxymethylfurfural (HMF), and phenolic compounds together with a reduction of acetic acid (37%), and formic acid (27%). Diverse fermentation modes using detoxified and non-detoxified hydrolysates, as well as using previously NaOH delignified glucan-rich solids alone (SHF or SSF) or together with pentoses liquors (SSCF) (5% loading) were performed. For all the tested conditions, both hemicellulose- and cellulose-derived sugars can be efficiently used as the carbon source to produce d-lactic acid by E. coli JU15 with a d-LA yield always surpassing 92 gd-LA/100 g sugars.

Rockrose Land Management: Contribution of Periodic Harvesting to Increase Value and Control Cistus Ladanifer L. Shrublands

Rockrose Land Management: Contribution of Periodic Harvesting to Increase Value and Control Cistus Ladanifer L. Shrublands

Chemical and Bioactive Characterization of the Essential Oils Obtained from Three Mediterranean Plants.

Cupressus sempervirens L., Juniperus communis L. and Cistus ladanifer L. are Mediterranean arboreal and shrub species that possess essential oils (EO) in their leaves and branches. This study aimed at characterizing the EOs obtained by steam distillation from the three species collected in different locations from Spain (Almazán, Andévalo, Barriomartín, Cerezal, Ermitas and Huéscar). For this purpose, volatiles composition was determined by GC-MS, and different bioactivities were evaluated. The highest content in terpenes was observed in C. sempervirens (Huéscar origin) followed by J. communis (Almazán origin), corresponding to 92% and 91.9% of total compounds, respectively. With exception of C. ladanifer from Cerezal that presented viridiflorol as the most abundant compound, all the three species presented in common the α-pinene as the major compound. The EOs from C. ladanifer showed high antibacterial potential, presenting MIC values from 0.3 to 1.25 mg/mL. Concerning other bioactivities, C. ladanifer EO revealed an oxidation inhibition of 83%, while J. communis showed cytotoxicity in the MCF-7 cell line, and C. sempervirens and C. ladanifer EOs exhibited the highest potential on NCI-H460 cell lines. Nevertheless, some EOs revealed toxicity against non-tumoral cells but generally presented a GI50 value higher than that of the tumor cell lines.

Effect of fire on viability and germination behaviour of Cistus ladanifer and Cistus salvifolius seeds

Fire is a natural phenomenon that is very frequent in ecosystems of the Mediterranean basin. Cistus ladanifer and C. salvifolius (Cistaceae family) are evergreen shrubs and components of plant communities found in this region. The objective of this study was to evaluate the effect of fire on the germination of C. ladanifer and C. salvifolius seeds. For this purpose, seeds of both species were subjected to different heat-shock treatments simulating natural fire conditions (50–175°C for 1 and 5 min). To elucidate the ecological significance of the effects of fire, viability and different traits informative about the dynamics of the germination process, such as final germination percentage (FGP), first day of germination (FDG), last day of germination (LDG), time spread of germination (TSG) and coefficient of velocity of germination (CVG), were determined. Seeds of both species exhibited fire-related behaviour, as they showed seed heat resistance and heat-stimulated germination. Germination in control, untreated seeds was very low, with 10 and 0% FGP for C. ladanifer and C. salvifolius, respectively. Thermal treatments significantly increased germination in both cases, with optimal results achieved at 100–125°C for 1 min and 75–100°C for 5 min. Under these conditions, greater germination percentages were obtained in C. salvifolius (92–95%) than in C. ladanifer (64–68%). Temperature proved to have a greater influence on seed viability and germination than the accumulated heat dose. The pattern of seed germination varied depending on the species and the heat shock treatments. In general, C. ladanifer exhibited earlier and faster germination. These characteristics, along with the high number of seeds produced per plant, make C. ladanifer a more competitive species for colonizing empty spaces after fire.

Chemical profile and eco-safety evaluation of essential oils and hydrolates from Cistus ladanifer, Helichrysum italicum, Ocimum basilicum and Thymbra capitata

The demand for natural-based products for industrial applications is increasing sharply and therefore the search for new alternatives to the plants traditionally used is growing. These alternative plants can be an important source of bioactive compounds under a circular economy approach. Considering the potential future use of new plant products by the industry, it is necessary to assess the risk associated with their introduction into the ecosystem. This work aims to provide an insight into the volatile profiles and evaluate the potential (eco)toxic effects of essential oils (EO’s) and hydrolates of four plant species, namely rockrose (Cistus ladanifer), curry plant (Helichrysum italicum), conehead thyme (Thymbra capitata) and basil (Ocimum basilicum). Chemical analysis were performed by GC-MS and acute toxicity tests were performed using the model organism Daphnia magna. The essential oil and the hydrolate from H. italicum, as well as all the other hydrolates caused no immobilization up to the highest concentrations tested, suggesting that all hydrolates present low to no risk towards D. magna. Similarly, the essential oil of H. italicum, presented negligible risk towards D. magna. For C. ladanifer and T. capitata essential oils, the EC50 (the concentration estimated to immobilize 50 per cent of the Daphnia) at 48 h varied between 199.7 mg/L and 12.1 mg/L, respectively. The essential oil from C. ladanifer was mainly characterised by monoterpene hydrocarbons, while the H. italicum was richer in sesquiterpene hydrocarbons. Both essential oil and hydrolate from T. capitata contained exclusively monoterpene hydrocarbons with a particularly high content of carvacrol. The higher acute toxicity of T. capitata essential oil can be attributed to the high amount of carvacrol present in the distillate. Overall, of the essential oils and hydrolates tested, all can be classified as practically non-toxic, except for T. capitata essential oil that, according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations, can be classified as moderately toxic.

Effects of fuel reduction treatments on the sporocarp production and richness of a Quercus/Cistus mixed system

Wildfire is a recurrent factor that shapes and influences Mediterranean ecosystems where mixed oak (Quercus) forests with a rockrose (Cistus) understory are broadly represented. These ecosystems are also associated with large and diverse fungal communities. These fungal communities play essential ecological roles for the survival of vascular plant, such as the mineral and water uptaking or resistance against pathogens carried out by mycorrhizal fungi, as the saprotrophic fungi are a key factor for the recycling of the dead matter. In addition, edible fungi, such as Boletus edulis, provide a source of income for the nearby rural population. Fuel reduction treatments are applied to reduce the risk of wildfire; however, their potential impact on fungal communities is unclear. Thus, the aim of this work was to investigate the effect of different fuel reduction treatments on fungi associated with Quercus and Cistus. This aim is accompanied by the management-driven objective to obtain data from fuel reduction treatments that will enable managers to find solutions with a balanced approach to maintaining productive areas of edible mushroom production while reducing fire risks across the landscape. Sporocarps were sampled over a five-year period in stands dominated by mature or coppiced Quercus pyrenaica and accompanied by Cistus ladanifer understory. These stands had been subjected to different fuel reduction treatment levels involving moderate- or high-intensity thinning, for Q. pyrenaica, or clearing, for C. ladanifer. The goal was to determine sporocarp production, species richness, and taxonomic composition. Sporocarp production and fungal richness were drastically affected by the fuel reduction treatments but only when C. ladanifer is included in the treatment. Taxa composition was strongly correlated with the treatments applied to the rockrose understory. This was probably due to the large range of associated ectomycorrhizal fungi of C. ladanifer and their high capacity to recolonize an area after disturbances. Based on our results, we conclude that the implementation of moderate-/high-intensity fuel reduction treatments is compatible with the conservation of the fungal community present in these systems. In addition, the creation of a multi-stage mosaic of stands through mechanical management could enable fire prevention to be managed in an effective way while maintaining fungal diversity and sporocarp production, favoring the use of non-wood resources in rural areas and conserving a healthier forest ecosystem.

The role of littoral cliffs in the niche delimitation on a microendemic plant facing climate change.

Obligate coastline taxa generally occupy very limited areas, especially when there is a close affinity with a specific coast type. Climate change can be a meaningful threat for them, reducing suitable habitat or forcing migration events. Cistus ladanifer subsp. sulcatus is an endemic plant of Portugal, known to occur only in the top of its south-western coast’s prominent cliffs. In spite of being included in the annexes II and IV of the European Habitats Directive of Natura 2000 Network, this taxon is still understudied, especially regarding the effects of climate change on its distribution. To overcome such gap, Maxent was used to model the current distribution of C. ladanifer subsp. sulcatus and project its future distribution considering different General Circulation Models, periods (2050 and 2070) and Representation Concentration Pathways (4.5 and 8.5). The results suggested an extensive range contraction in the future, and extinction is a possible scenario. The proximity to littoral cliffs is crucial for this plant’s occurrence, but these formations are irregularly distributed along the coast, hindering range expansions, further inhibited by a small dispersal capacity. Cistus ladanifer subsp. sulcatus will probably remain confined to south-western Portugal in the future, where it will continue to face relevant threats like human activity, reinforcing the need for its conservation.

Chemical Composition, Antibacterial and Antifungal Activity of the Essential Oil from Cistus ladanifer L.

Cistus ladanifer L. is a plant widely used in folk medicine to treat various illnesses. This study aims to evaluate the effect of the plant flourishing time harvest on the chemical composition and the antimicrobial effect of its essential oil. Chemical analysis of the essential oil was carried out using gas chromatography-mass spectrometry (GC-MS). The antibacterial and antifungal proprieties were tested against four selected bacteria (Staphylococcus aureus, Salmonella Typhi, Escherichia coli, and Acinetobacter baumannii) and nine fungi (Yeasts (Candida tropicalis, Candida glabrata, Candida dubliniensis, Candida sp., Rhodotorula rubra, Cryptococcus neoformans) and molds (Penicillium sp. (P), Fusarium sp. (F), Aspergillus niger (A. niger)), respectively. The essential oil of C. ladanifer demonstrated a powerful antibacterial activity with an inhibition zone of 55 ± 0.22 mm for Staphylococcus aureus, 42 ± 0.11 mm for Escherichia coli, 35 ± 0.27 mm for Acinetobacter baumannii (Full resistant to antibiotics) and 30 ± 0.25 mm for Salmonella Typhi. It also inhibited all tested bacteria at 10 µL/mL. For the antifungal activity test, C. tropicalis and C. neoformans appeared to be the most sensitive strains to the essential oil with an inhibition zone of 13 mm, followed by R. rubra and Penicillium sp. (12 mm), then C. dubliniensis and C. glabrata (11 mm). The chemical analysis of the essential oil by GC-MS revealed that the major components of the essential oil were viridiflorol (17.64%), pinocarveol (11.02%), bornylacetate (9.38%), and ledol (8.85%). C. ladanifer exhibited a remarkable antimicrobial activity that could be more exploited to develop targeted natural remedies against specific diseases.

Nonlinear plant-plant interactions modulate impact of extreme drought and recovery on a Mediterranean ecosystem.

Interaction effects of different stressors, such as extreme drought and plant invasion, can have detrimental effects on ecosystem functioning and recovery after drought. With ongoing climate change and increasing plant invasion, there is an urgent need to predict the short- and long-term interaction impacts of these stressors on ecosystems. We established a combined precipitation exclusion and shrub invasion (Cistus ladanifer) experiment in a Mediterranean cork oak (Quercus suber) ecosystem with four treatments: (1) Q.suber control; (2) Q.suber with rain exclusion; (3) Q.suber invaded by shrubs; and (4) Q.suber with rain exclusion and shrub invasion. As key parameter, we continuously measured ecosystem water fluxes. In an average precipitation year, the interaction effects of both stressors were neutral. However, the combination of imposed drought and shrub invasion led to amplifying interaction effects during an extreme drought by strongly reducing tree transpiration. Contrarily, the imposed drought reduced the competitiveness of the shrubs in the following recovery period, which buffered the negative effects of shrub invasion on Q.suber. Our results demonstrate the highly dynamic and nonlinear effects of interacting stressors on ecosystems and urges for further investigations on biotic interactions in a context of climate change pressures.

Evaluating the post-fire natural regeneration of Mediterranean-type scrublands in Central Spain

We performed a five-year assessment of the natural vegetation restoration capacity following the 2012 fires in Valdemaqueda (Madrid, Spain) via the characterization of the post-fire and residual vegetation and the analysis of soil physico-chemical characteristics. Six pilot-plots were established in the affected site. Forest species, representative of the potential natural vegetation of the area (Juniperus oxycedrus subsp. lagunae and Quercus rotundifolia woodlands) and broom shrubs (Cytisus scoparius, Retama sphaerocarpa) were planted to assess the relationship among the stages of ecological succession, competition, and soil restoration processes following devastating fire events.&#x0D; The fire-driven alteration of the soil’s physico-chemical properties was evident, given the increased pH and reduced C/N ratio in the first years of the study. However, we observed an increased soil enrichment in the last years of study, accompanied by the propagation of herbaceous species, su[1]pporting our seed bank findings, showing a clear difference in the sprouting rate between burnt and control plots (80% vs. 20%, respectively). The establishment of robust, pyrophyte shrub species (Cistus ladanifer, C. laurifolius, Rosmarinus officinalis) rather than natural succession evidenced the clear conversion of the vegetation in burnt areas. These findings in the pilot-plots allowed evidencing the high vulnerability of the natural vegetation to the settling of pyrophytes, given their low survival rate under the strong competitive pressure of these pyrophytic species. The proliferation of these pyrophytes could translate into changes in soil macro- and microbiota, nutrient dynamics, species diversity, and interaction, added to the alteration of fire regimes in the area. Overall, these results highlight the risk for soil impoverishment and possible erosion of the fire-affected sites. Moreover, they underline the importance of the establishment and regeneration of Genisteae species to outcompete pioneer pyrophytic species, favoring the restoration of the area’s potential natural vegetation

Phytotoxic Activity of p-Cresol, 2-Phenylethanol and 3-Phenyl-1-Propanol, Phenolic Compounds Present in Cistus ladanifer L.

Numerous studies about the leaf exudate of Cistus ladanifer highlight this Mediterranean shrub as an allelopathic species. Despite the very high diversity of secondary metabolites identified in its labdanum, only a few components have been evaluated. p-Cresol, 2-phenylethanol and 3-phenyl-1-propanol are three phenolic components present in the labdanum of C. ladanifer whose role has not been specified to date. The present study, through a static acute toxicity test, analyzed their activity, with respect to Allium cepa and Lactuca sativa. These three separate compounds and the mixture of all of them have a more or less phytotoxic activity depending on the medium, species and concentration tested. When the test is carried out on paper, the three pure allelochemicals and their mixture at 1 mM significantly inhibited the total germination, the germination rate and the development of the Allium cepa and Lactuca sativa seedlings to a lesser extent, but when the test performed in soil, the effects on the size of roots and cotyledons are attenuated. Furthermore, in the two species tested on paper, the joint action of the three compounds at 1 mM shows a significantly greater inhibition of the measured indices than each of the compounds separately.

Influence of the Storage of Cistus ladanifer L. Bales from Mechanised Harvesting on the Essential Oil Yield and Qualitative Composition.

Cistus ladanifer is a Mediterranean native plant from which valuable products, such as essential oil, are obtained. Manual harvesting of the plants in wild shrublands is usual during short periods of time. Their mechanised harvesting could increase the volume of harvested plants and prevent fires, further storage of the plants collected being necessary. The objective of this work is to study the influence of the storage period of mechanically harvested bales on the essential oil yield and qualitative composition. The harvesting trials were carried out with an adapted commercial harvester baler and the storage of the bales was performed indoors during 1–7 days, 15–30 days and 100–120 days. Afterwards, the bales were crushed (30 mm) and distilled in a 30 litre stainless steel still with saturated steam (0.5 bar). The essential oil components were identified by GC-MS and quantified by GC-FID. The storage of mechanically harvested Cistus ladanifer does not decrease the oil yield of steam distillation on a pilot scale. However, it leads to differences in the quantitative composition of the essential oils, decreasing the total monoterpene compounds content and increasing that of oxygenated sesquiterpenes, especially when the biomass is stored for 100–120 days, without affecting its qualitative composition.

Identification of the chemical composition of six essential oils with mass spectroscopy and evaluation of their antibacterial and antioxidant potential

AbstractThis study determined the chemical composition of Cinnamomum verum J.Presl, Cistus ladaniferus L., Laurus nobilis L., Senecio anteuphorbuim, Boswellia serrata Roxb. ex Colebr. and Schinus molle L. essential oils (EOs) by gas chromatography‐mass spectrometry. Moreover, the six EOs were screened in order to reveal their antibacterial and antioxidant activities. They were initially tested against six pathogenic bacteria: Staphylococcus aureus (MRSA: methicillin‐resistant Staphylococcus aureus), Escherichia coli (ESBL: extended‐spectrum β‐lactamases), Enterococcus faecalis (VRE: vancomycin‐resistant enterococcus), Klebsiella pneumoniae (CRK: carbapenem‐resistant klebsiella), clinical isolate Staphylococcus aureus and Escherichia coli ATCC 25922. Then, the antioxidant effect was assessed by β‐carotene‐linoleic acid. Cinnamomum verum J.Presl, Cistus ladaniferus L. and Laurus nobilis L. exhibited the greatest antibacterial activity except Boswellia serrata Roxb. ex Colebr. oil. But this last one showed the highest antioxidant activity (85.75%) comparable to that of BHT (98.25%). The principal component analysis between the antibacterial activity and the twenty major components of six EOs revealed that α‐pinene, β‐pinene, 4‐carene, α‐phellandrene, 1,8‐cineole, linalool, 1,3,8‐p‐menthatriene, α‐terpineol, cinnamyl alcohol and cinnamaldehyde are responsible for their antibacterial activity against multi‐resistant strains. From this study, the results obtained show that the EOs may constitute an alternative to the emergence of multidrug‐resistant bacteria.

Effects of Increasing Doses of Condensed Tannins Extract from Cistus ladanifer L. on In Vitro Ruminal Fermentation and Biohydrogenation.

Simple SummaryRuminant edible products have been associated with adverse health effects, due to their high saturated fatty acids and low polyunsaturated fatty acids content, resulting from the extensive biohydrogenation conducted by rumen microbiota. Cistus ladanifer condensed tannins were able to change the lamb ruminal biohydrogenation, increasing the beneficial fatty acids production. The aim of this study was to test the effect of increasing doses of C. ladanifer condensed tannins extract (0, 25, 50, 75 and 100 g/kg dry matter) on in vitro rumen fermentation and biohydrogenation. The increasing doses of condensed tannins led to a moderate decrease of volatile fatty acids production, a pronounced depression in microbial odd and branched fatty acids and of dimethyl acetals production, and a minor effect on the biohydrogenation, which indicates that microbial growth was more inhibited than fermentative and biohydrogenation activities. The ability of C. ladanifer condensed tannins extract to modulate the biohydrogenation (BH) was not observed in the present study. However, the results obtained suggest a possible adaptative response of the microbial population to stress stimuli of condensed tannins and lipid supplementation.Cistus ladanifer (rockrose) is a perennial shrub quite abundant in the Mediterranean region, and it is a rich source in secondary compounds such as condensed tannins (CTs). Condensed tannins from C. ladanifer were able to change the ruminal biohydrogenation (BH), increasing the t11–18:1 and c9,t11–18:2 production. However, the adequate conditions of the C. ladanifer CTs used to optimize the production of t11–18:1 and c9,t11–18:2 is not yet known. Thus, we tested the effect of increasing the doses of C. ladanifer CT extract (0, 25, 50, 75 and 100 g/kg dry matter (DM)) on in vitro rumen BH. Five in vitro batch incubations replicates were conducted using an oil supplemented high-concentrate substrate, incubated for 24 h with 6 mL of buffered ruminal fluid. Volatile fatty acids (VFAs) and long chain fatty acids (FA) were analyzed at 0 h and 24 h, and BH of c9–18:1, c9, c12–18:2 and c9, c12, c15–18:3, and BH products yield were computed. Increasing doses of C. ladanifer CTs led to a moderate linear decrease (p < 0.001) of the VFA production (a reduction of 27% with the highest dose compared to control). The disappearance of c9–18:1 and c9,c12–18:2 as well as the production of t11–18:1 and c9, t11:18:2 was not affected by increasing doses of C. ladanifer CTs, and only the disappearance of c9, c12, c15–18:3 suffered a mild linear decrease (a reduction of 24% with the highest dose compared to control). Nevertheless, increasing the C. ladanifer CT dose led to a strong depression of microbial odd and branched fatty acids and of dimethyl acetals production (less than 65% with the highest dose compared to control), which indicates that microbial growth was more inhibited than fermentative and biohydrogenation activities, in a possible adaptative response of microbial population to stress induced to CTs and polyunsaturated fatty acids. The ability of C. ladanifer to modulate the ruminal BH was not verified in the current in vitro experimental conditions, emphasizing the inconsistent BH response to CTs and highlighting the need to continue seeking the optimal conditions for using CTs to improve the fatty acid profile of ruminant fat.

Antioxidant, Antihypertensive and Antimicrobial Properties of Phenolic Compounds Obtained from Native Plants by Different Extraction Methods.

This study aims to evaluate the efficacy of two methods (agitation and ultra-sound) for extracting phenolic compounds from 15 native plants. Plant species collected in the Dehesa of Extremadura were used. The antioxidant, antihypertensive and antimicrobial activity of the phenolic extracts was investigated. Significantly different results were obtained when comparing the two extraction methods, with the highest concentrations of phenolic compounds found for ultrasound extraction. In addition, the extracts obtained for Cistus albidus, Cistus salviifolius, Rubus ulmifolius and Quercus ilex showed the highest concentrations of phenolic compounds. The antioxidant activity was higher in the extracts of Cistus and Q. ilex obtained by ultrasound, as was the antihypertensive activity. Antimicrobial activity was also higher in the extracts obtained by ultrasound from C. salviifolius and Q. ilex plants against bacteria and from Cistus ladanifer against yeasts. Therefore, it can be concluded that, with the ultrasound extraction of phenolic compounds from C. ladanifer, C. albidus and Q. ilex plants, it is possible to obtain extracts with important functional properties, so they could be studied for their use in food with the aim of obtaining healthy and safe products, favouring the sustainability of the environment of the Dehesa Extremeña.