Genus Cistus: a model for exploring labdane-type diterpenes' biosynthesis and a natural source of high value products with biological, aromatic, and pharmacological properties

Phytochemical Profile and In Vitro Cytotoxic, Genotoxic, and Antigenotoxic Evaluation of Cistus monspeliensis L. Leaf Extract

Cistus monspeliensis L. (C. monspeliensis) is used in Italian folk medicine. This study was performed to determine genotoxic and antigenotoxic effects of C. monspeliensis leaf extract against mitomycin C (MMC) using an in vitro cytokinesis-block micronucleus assay (CBMN) in the Chinese Hamster Ovarian K1 (CHO-K1) cell line. The phytochemical composition of C. monspeliensis extract was evaluated using an untargeted metabolomic approach by employing UPLC-PDA-ESI/MS. The automated in vitro CBMN assay was carried out using image analysis systems with a widefield fluorescence microscope and the ImageStreamX imaging flow cytometer. The phytochemical profile of C. monspeliensis extract showed, as the most abundant metabolites, punicalagin, myricetin, gallocathechin, and a labdane-type diterpene. C. monspeliensis, at the tested concentrations of 50, 100, and 200 μg/mL, did not induce significant micronuclei frequency, thus indicating the absence of a genotoxic potential. When testing the C. monspeliensis extract for antigenotoxicity in the presence of MMC, we observed a hormetic concentration-dependent effect, where low concentrations resulted in a significant protective effect against MMC-induced micronuclei frequency, and higher concentrations resulted in no effect. In conclusion, our findings demonstrate that C. monspeliensis extract is not genotoxic and, at low concentration, exhibits an antigenotoxic effect. In relation to this final point, C. monspeliensis may act as a potential chemo-preventive against genotoxic agents.

Characterising the Metabolomic Diversity and Biological Potentials of Extracts from Different Parts of Two Cistus Species Using UHPLC-MS/MS and In Vitro Techniques

This study investigates the biochemical composition and biological properties of different parts (leaves, roots, and twigs) of two Cistus species (Cistus monspeliasis and Cistus parviflorus). The extracts were analysed using UHPLC-MS/MS to determine their chemical profiling. A range of antioxidant assays were performed to evaluate the extract's antioxidant capabilities. The enzyme inhibition studies focused on acetylcholinesterase (AChE), butyrylcholinesterase (BChE), α-amylase, and α-glucosidase and tyrosinase. In addition, the study examined the antimicrobial effects on different bacteria and yeasts and evaluated the toxicity using the MTT assay. Quinic acid, citric acid, gallic acid, catechin, quercetin derivatives, kaempferol, myricetin, ellagic acid, prodelphinidins, procyanidins, scopoletin, and flavogallonic acid dilactone are the main bioactive compounds found in both species. In enzyme inhibition assays, C. monspeliasis roots exhibited significant activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), with the values of 2.58 ± 0.02 mg GALAE/g and 11.37 ± 1.93 mg GALAE/g, respectively. Cytotoxicity studies showed mostly weak toxicity, with some samples moderately reducing viability in RAW and HepG2 cells. These findings underscore the diverse biochemical profiles and bioactive potential of Cistus species, suggesting their utility as natural sources of antioxidants and enzyme inhibitors for pharmaceutical and nutraceutical development.

Variations of floral temperature in changing weather conditions

Floral temperature is a flower characteristic that has the potential to impact the fitness of flowering plants and their pollinators. Likewise, the presence of floral temperature patterns, areas of contrasting temperature across the flower, can have similar impacts on the fitness of both mutualists. It is currently poorly understood how floral temperature changes under the influence of different weather conditions, and how floral traits may moderate these changes. The way that floral temperature changes with weather conditions will impact how stable floral temperatures are over time and their utility to plants and pollinators. The stability of floral temperature cues is likely to facilitate effective plant-pollinator interactions and play a role in the plant's reproductive success. We use thermal imaging to monitor how floral temperatures and temperature patterns of four plant species (Cistus 'snow fire' and 'snow white', Coreopsis verticillata and Geranium psilostemon) change with several weather variables (illumination, temperature; windspeed; cloud cover; humidity and pressure) during times that pollinators are active. All weather variables influenced floral temperature in one or more species. The directionality of these relationships was similar across species. In all species, light conditions (illumination) had the greatest influence on floral temperatures overall. Floral temperature and the extent to which flowers showed contrasting temperature patterns were influenced predominantly by light conditions. However, several weather variables had additional, lesser, influences. Furthermore, differences in floral traits, pigmentation and structure, likely resulted in differences in temperature responses to given conditions between species and different parts of the same flower. However, floral temperatures and contrasting temperature patterns that are sufficiently elevated for detection by pollinators were maintained across most conditions if flowers received moderate illumination. This suggests the presence of elevated floral temperature and contrasting temperature patterns are fairly constant and may have potential to influence plant-pollinator interactions across weather conditions.

Exploring the Anti-Inflammatory and Antioxidant Potential, Metabolite Composition and Inorganic Profile of Cistus monspeliensis L. Aerial Parts and Roots

This work focuses on Cistus monspeliensis L. aerial parts (AP) and roots (R) extracts, investigating the anti-inflammatory and antioxidant potential of the two organs in comparison. At dosages between 1.56 and 6.25 µg/mL, both extracts showed a protective effect against LPS inflammatory stimulus on a macrophage cell line (RAW 264.7). Interestingly, only R was able to significantly reduce both IL-1β and IL-6 mRNA gene expression in the presence of LPS. Moreover, the treatment of a neuroblastoma cell line (SH-SY5Y) with AP and R at 6.25 µg/mL increased the cell survival rate by nearly 20% after H2O2 insult. However, only R promoted mitochondria survival, exhibited a significantly higher production of ATP and a higher activity of the enzyme catalase than the control. Both AP and R had similar primary metabolites; in particular, they both contained 1-O-methyl-epi-inositol. Labdane and methoxylated flavonoids were the most characteristic compounds of AP, while R contained mainly catechins, gallic acid, and pyrogallol derivatives. Considering the importance of elemental composition in plants, the inorganic profile of AP and R was also investigated and compared. No potentially toxic elements, such as Pb, were detected in any sample.

Chemical and transcriptomic analyses of leaf trichomes from Cistus creticus subsp. creticus reveal the biosynthetic pathways of certain labdane-type diterpenoids and their acetylated forms

Labdane-related diterpenoids (LRDs), a subgroup of terpenoids, exhibit structural diversity and significant commercial and pharmacological potential. LRDs share the characteristic decalin-labdanic core structure that derives from the cycloisomerization of geranylgeranyl diphosphate (GGPP). Labdanes derive their name from the oleoresin known as 'Labdanum', 'Ladano', or 'Aladano', used since ancient Greek times. Acetylated labdanes, rarely identified in plants, are associated with enhanced biological activities. Chemical analysis of Cistus creticus subsp. creticus revealed labda-7,13(E)-dien-15-yl acetate and labda-7,13(E)-dien-15-ol as major constituents. In addition, novel labdanes such as cis-abienol, neoabienol, ent-copalol, and one as yet unidentified labdane-type diterpenoid were detected for the first time. These compounds exhibit developmental regulation, with higher accumulation observed in young leaves. Using RNA-sequencing (RNA-seq) analysis of young leaf trichomes, it was possible to identify, clone, and eventually functionally characterize labdane-type diterpenoid synthase (diTPS) genes, encoding proteins responsible for the production of labda-7,13(E)-dien-15-yl diphosphate (endo-7,13-CPP), labda-7,13(E)-dien-15-yl acetate, and labda-13(E)-ene-8α-ol-15-yl acetate. Moreover, the reconstitution of labda-7,13(E)-dien-15-yl acetate and labda-13(E)-ene-8α-ol-15-yl acetate production in yeast is presented. Finally, the accumulation of LRDs in different plant tissues showed a correlation with the expression profiles of the corresponding genes.

Labdanum Resin from Cistus ladanifer L. as a Source of Compounds with Anti-Diabetic, Neuroprotective and Anti-Proliferative Activity

Labdanum resin or "gum" can be obtained from Cistus ladanifer L. by two different extraction methods: the Zamorean and the Andalusian processes. Although its main use is in the fragrance and perfumery sectors, ethnobotanical reports describe its use for medicinal purposes in managing hyperglycemia and mental illnesses. However, data concerning the bioactivities and pharmacological applications are scarce. In this work, it was found that the yield of labdanum resin extracted by the Andalusian process was 25-fold higher than the Zamorean one. Both resins were purified as absolutes, and the Andalusian absolute was purified into diterpenoid and flavonoid fractions. GC-EI-MS analysis confirmed the presence of phenylpropanoids, labdane-type diterpenoids, and methylated flavonoids, which are already described in the literature, but revealed other compounds, and showed that the different extracts presented distinct chemical profile. The potential antidiabetic activity, by inhibition of α-amylase and α-glucosidase, and the potential neuroprotective activity, by inhibition of acetylcholinesterase, were investigated. Diterpenoid fraction produced the higher α-amylase inhibitory effect (~30% and ~40% at 0.5 and 1 mg/mL, respectively). Zamorean absolute showed the highest α-glucosidase inhibitory effect (~14% and ~24%, at 0.5 and 1 mg/mL, respectively). Andalusian absolute showed the highest acetylcholinesterase inhibitory effect (~70% and ~75%, at 0.5 and 1 mg/mL, respectively). Using Caco-2 and HepG2 cell lines, Andalusian absolute and its purified fractions showed moderate cytotoxic/anti-proliferative activity at 24 h exposure (IC50 = 45-70 µg/mL, for Caco-2; IC50 = 60-80 µg/mL, for HepG2), whereas Zamorean absolute did not produce cytotoxicity (IC50 ≥ 200.00 µg/mL). Here we show, for the first time, that labdanum resin obtained by the Andalusian process, and its fractions, are composed of phytochemicals with anti-diabetic, neuroprotective and anti-proliferative potential, which are worth investigating for the pharmaceutical industry. However, toxic side-effects must also be addressed when using these products by ingestion, as done traditionally.

Polyphenol Fingerprint, Biological Activities, and In Silico Studies of the Medicinal Plant Cistus parviflorus L. Extract

Cistus parviflorus L. (Cistaceae) is a medicinal plant with several folkloric applications, including being used for urinary tract infections and as a food additive. In this study, the polyphenolic diversity and the antioxidant, antidiabetic, and antimicrobial activities of the C. parviflorus methanolic extract were evaluated. Spectrophotometric and HPLC-based analyses using standard polyphenolic compounds were conducted to measure the phenolics and flavonoids in the plant extract. The in vitro DPPH, ORAC, FRAP, and α-glucosidase assays were used to evaluate the plant's antioxidant and antidiabetic activities. Furthermore, disc diffusion and MIC-based microdilution tests were applied to evaluate the antimicrobial activity of the plant against broad-spectrum microorganisms. The analysis revealed the existence of high phenolic and flavonoid quantities that were measured at 302.59 ± 0.6 μg GAE and 134.3 ± 0.5 μg RE, respectively. The HPLC-based analysis revealed the existence of 18 phenolic acids and 8 flavonoids. The major phenolic acid was ellagic acid (169.03 ppm), while catechin was the major flavonoid (91.80 ppm). Remarkable antioxidant activity was measured using three different assays: DPPH, ORAC, and FRAP. Furthermore, strong inhibition of α-glucosidase compared to acarbose was recorded for the plant extract (IC50 0.924 ± 0.6). The results showed that C. parviflorus's extract had a strong anti-Escherichia coli effect with MIC value of 0.98 μg\mL and IZD value of 32.2 ± 0.58 mm compared to 25.3 ± 0.18 mm for gentamycin, the positive control. Moreover, Aspergillus niger, Aspergillus fumigatus, Staphylococcus aureus, Streptococcus pyogenes, and Salmonella typhimurium all showed significant growth inhibition in response to the extract, a result that may be related to the use of the plant in traditional medicine to treat urinary tract infections. The docking study indicated the higher binding affinity of the major identified compounds, i.e., ellagic acid, rutin, naringin, catechin, and punicalagin, to the S. aureus gyrase-DNA complex, which might suggest the possible mechanisms of the plant as antimicrobial agents.

Efficacy of Two Moroccan Cistus Species Extracts against Acne Vulgaris: Phytochemical Profile, Antioxidant, Anti-Inflammatory and Antimicrobial Activities

BACKGROUND

The genus Cistus L. (Cistaceae) includes several medicinal plants growing wild in the Moroccan area. Acne vulgaris (AV) is a chronic skin disorder treated with topical and systemic therapies that often lead to several side effects in addition to the development of antimicrobial resistance. Our study aimed to investigate the bioactivity of extracts of two Moroccan Cistus species, Cistus laurifolius L. and Cistus salviifolius L., in view of their use as potential coadjuvants in the treatment of mild acne vulgaris.

METHODS

Targeted phytochemical profiles obtained by HPLC-DAD and HPLC-ESI/MS analyses and biological activities ascertained by several antioxidants in vitro chemical and cell-based assays of the leaf extracts. Moreover, antimicrobial activity against Gram-positive and Gram-negative bacteria, and Candida albicans was evaluated.

RESULTS

Analyses revealed the presence of several polyphenols in the studied extracts, mainly flavonoids and tannins. Cistus laurifolius L. and Cistus salviifolius L. possessed good biological properties and all extracts showed antibacterial activity, particularly against Staphylococcus aureus, S. epidermidis, and Propionibacterium acnes, identified as the main acne-causing bacteria.

CONCLUSION

The results suggest that examined extracts are promising agents worthy of further studies to develop coadjuvants/natural remedies for mild acne treatment.

Artificial Intelligence Applied to Improve Scientific Reviews: The Antibacterial Activity of Cistus Plants as Proof of Concept

Reviews have traditionally been based on extensive searches of the available bibliography on the topic of interest. However, this approach is frequently influenced by the authors' background, leading to possible selection bias. Artificial intelligence applied to natural language processing (NLP) is a powerful tool that can be used for systematic reviews by speeding up the process and providing more objective results, but its use in scientific literature reviews is still scarce. This manuscript addresses this challenge by developing a reproducible tool that can be used to develop objective reviews on almost every topic. This tool has been used to review the antibacterial activity of Cistus genus plant extracts as proof of concept, providing a comprehensive and objective state of the art on this topic based on the analysis of 1601 research manuscripts and 136 patents. Data were processed using a publicly available Jupyter Notebook in Google Collaboratory here. NLP, when applied to the study of antibacterial activity of Cistus plants, is able to recover the main scientific manuscripts and patents related to the topic, avoiding any biases. The NLP-assisted literature review reveals that C. creticus and C. monspeliensis are the first and second most studied Cistus species respectively. Leaves and fruits are the most commonly used plant parts and methanol, followed by butanol and water, the most widely used solvents to prepare plant extracts. Furthermore, Staphylococcus. aureus followed by Bacillus. cereus are the most studied bacterial species, which are also the most susceptible bacteria in all studied assays. This new tool aims to change the actual paradigm of the review of scientific literature to make the process more efficient, reliable, and reproducible, according to Open Science standards.

Triterpenoid and Steroid Content of Lipophilic Extracts of Selected Medicinal Plants of the Mediterranean Region

The available phytochemical characteristics of the medicinal plants and derived herbal material often lack data concerning the content of steroids (including phytosterols) and triterpenoids, that can be responsible for various beneficial properties and therapeutic effects, either directly, or as a result of synergistic action with other bioactive constituents. The aim of the present work was the analysis of the content of these compounds in herbal material (leaves, aerial parts) derived from selected medicinal plants (Cistus ladanifer, Cistus monspeliensis, Erica arborea, Globularia alypum, Pistacia lentiscus, Rhamnus alaternus), widely used in folk medicine in the Mediterranean region. Results obtained by gas chromatography-mass spectrometry (GC-MS)-targeted profiling revealed the diversity in the profiles and contents of steroids and triterpenoids in the analyzed plant material, ranging from 5.7% d.w. in E. arborea to 0.1% in G. alypum. The obtained results supplement the existing phytochemical data of the investigated medicinal plants, pointing to the E. arborea aerial parts and P. lentiscus leaves as valuable resources of phytosterols and bioactive triterpenoids.

Comparative Evaluation of Polyphenol Contents and Biological Activities of Five Cistus L. Species Native to Turkey

In this study phytochemical compounds and antioxidant capacity, cytotoxic, antimicrobial and anti-biofilm activities of hydroethanolic extracts of five Cistus species (C. creticus L., C. laurifolius L., C. monspeliensis L., C. parviflorus Lam. and C. salviifolius L.) distributed in Turkey were investigated. (+)-catechin, epigallocatechin gallate, quercetin-3-O-rutinoside, quercetin-3-O-glucoside, kaempferol-3-O-glucoside, luteolin were detected in different amounts. Strongest antioxidant capacities were observed with C. creticus, and C. parvifolius (0.476 and 0.452, respectively). Minimum inhibitory concentrations (MIC) of the extracts were determined between 32 and 128 μg/mL against different bacteria and Candida strains. C. monspeliensis and C. laurifolius extracts were inhibited the biofilm production levels of three Gram-negative bacteria (E. coli, S. enterica, P. aeruginosa), two Gram-positive bacteria (S. aureus, B. subtilis) and three Candida strains (C. albicans, C. parapsilosis, C. krusei). C. creticus extract showed strongest cytotoxic activity against human breast adenocarcinoma (MCF-7) and prostate cell lines (PC-3) (IC₅₀ : 14.04±2.78 μg/mL and 34.04±2.74 μg/mL, respectively) among all plants tested.

Phytochemistry and Antihyperglycemic Potential of Cistus salviifolius L., Cistaceae

Cistus salviifolius has been previously reported as a traditional remedy for hyperglycemia. However, the plant has been scarcely investigated from scientific point of view. Thus, the aim was to examine the chemical composition and to evaluate its antioxidant and antihyperglycemic potential in vitro. Aqueous and ethanolic extracts were evaluated for total phenolic, tannin, and flavonoid content using spectrophotometric methods. Detailed chemical characterization was performed by high-performance liquid chromatography (HPLC-DAD). The volatile organic compounds (VOCs) profile was assessed by gas chromatography technique. The potential in diabetes treatment was evaluated through tests of free radicals neutralization, inhibition of lipid peroxidation process, and test of ferric ion reduction; activity in tests of inhibition of α-amylase, α-glucosidase and dipeptidyl peptidase-4 was also evaluated. High content of phenolics (majority being tannins) was detected; detailed HPLC analysis revealed high content of gallic acid, followed by rutin, chlorogenic and caffeic acids. The VOCs analysis determined sesquiterpene hydrocarbons and oxygenated sesquiterpenes as the main groups of compounds. The assays classified extracts as potent neutralizers of 2,2-diphenyl-1-picrylhydrazil and nitroso radicals formation and potent inhibitors of α-amylase and α-glucosidase. In conclusion, Cistus salviifolius represents a rich source of phenolics and essential oil with sesquiterpenes. The established results suggested its promising antioxidant and antihyperglycemic activities.

Antifungal Potential of Canarian Plant Extracts against High-Risk Phytopathogens

Phytopathogens are responsible for great losses in agriculture. In particular, Fusarium, Alternaria and Botrytis are fungal diseases that affect crops worldwide. In the search for eco-friendly solutions to pest control, plants and their chemo-biodiversity are promising sources of biopesticides for integrated pest management. The aim of the present study is to report the evaluation of sixteen plant species from the Canary Islands Archipelago against the phytopathogenic fungi Botrytis cinerea, Fusarium oxysporum, and Alternaria alternata. The plants were selected on the basis of their traditional uses in medicine and/or pest control, as well as on scientific studies reporting their uses in crop protection. Their growth inhibition (% I), in an in vitro test-assay on mycelium, was used to identify six ethanolic plant extracts displaying activity (% I > 30% at 1 mg/mL) against at least one of the assayed fungi. The most effective plant extracts were further fractionated by liquid−liquid partition, using solvents of increasing polarity. This procedure led to an improvement of the bioactivity against the phytopathogens, even affecting the hexane fraction from S. canariensis and achieving an 83.93% of growth inhibition at 0.5 mg/mL on B. cinerea. These findings identified five plant-derived extracts as potential candidates for the future development of new biofungicides, which could be applied in integrated pest management.

Insight into Cistus salviifolius extract for potential biostimulant effects in modulating cadmium-induced stress in sorghum plant

The main aim of the current study was to investigate the role of Cistus salviifolius leaves extract (CSE) in alleviating the toxic effect of cadmium (Cd) in sorghum (Sorghum bicolor) plants. The plants exposed to Cd (200 µM) exhibited limited growth, reduced biomass, and chlorophyll content compared to unstressed ones. Nevertheless, supplementation of CSE restored the negative effect of Cd and increased biomass and pigment content. CSE also increased the activities of antioxidant enzymes such as superoxide dismutase (SOD), isocitrate dehydrogenase (ICDH), glutathione peroxidase (GPx), glutathione reductase (GR), and Glutathione-S-Transferase (GST). Furthermore, supplementation of CSE decreased lipid peroxidation and further increased the content of soluble sugar and amino acid. We also found that CSE has a promising effect in modulating the perturbations of carbon and nitrogen metabolism in sorghum plants under Cd stress by examining several carbon-nitrogen enzyme activities: phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase (NAD-MDH), glutamine synthase (GS), glutamate dehydrogenase (GDH), and aspartate aminotransferase (AAT). Overall, our results confirm that the application of CSE can be a promising mechanism to overcome the negative effects of Cd stress in sorghum plants.

Effects of Thiamethoxam-Dressed Oilseed Rape Seeds and Nosema ceranae on Colonies of Apis mellifera iberiensis, L. under Field Conditions of Central Spain. Is Hormesis Playing a Role?

Simple Summary

The collapse of the honey bee colonies is a complex phenomenon in which different factors may participate in an interrelated manner (e.g., pathogen interactions, exposure to chemicals, beekeeping practices, climatology, etc.). In light of the current debate regarding the interpretation of field and monitoring studies in prospective risk assessments, here we studied how exposure to thiamethoxam affects honey bee colonies in Central Spain when applied as a seed treatment to winter oilseed rape, according to the good agricultural practice in place prior to the EU restrictions. Under the experimental conditions, exposure to thiamethoxam, alone or in combination with other stressors, did not generate and maintain sufficient chronic stress as to provoke honey bee colony collapse. The stress derived from exposure to thiamethoxam and honey bee pathogens was compensated by adjustments in the colony’s dynamics, and by an increase in the worker bee population, a behavior known as hormesis. An analysis of the factors underlying this phenomenon should be incorporated into the prospective risk assessment of plant protection products in order to improve the future interpretation of field studies and management practices.

Abstract

To study the influence of thiamethoxam exposure on colony strength and pathogen prevalence, an apiary (5 colonies) was placed in front of a plot sown with winter oilseed rape (wOSR), just before the flowering phase. Before sowing, the seeds were treated with an equivalent application of 18 g thiamethoxam/ha. For comparison, a second apiary (5 colonies) was located in front of a separate 750 m plot sown with untreated wOSR. Dead foragers at the entrance of hives were assessed every 2–3 days throughout the exposure period, while the colony strength (number of combs covered with adult honey bees and brood) and pathogens were monitored each month until the following spring. Foraging on the wOSR crop was confirmed by melissopalynology determination of the corbicular pollen collected periodically, while the chemical analysis showed that exposure to thiamethoxam was mainly through nectar. There was an increase in the accumulation of dead bees in the apiary exposed to thiamethoxam relating with the control, which was coped with an increment of bee brood surface and adult bee population. However, we did not find statistically significant differences between apiaries (α = 0.05) in terms of the evolution of pathogens. We discuss these results under hormesis perspective.

Antioxidant and Antiglycation Effects of Cistus × incanus Water Infusion, Its Phenolic Components, and Respective Metabolites

Reactive oxygen and carbonyl species promote oxidative and carbonyl stress, and the development of diabetes, metabolic syndrome, cardiovascular diseases, and others. The traditional herb Cistus × incanus is known for its antioxidant properties; therefore, the current study aimed to assess how the chemical composition of a C. incanus water infusion corresponds with its antioxidative and antiglycative effects in vitro. The composition of infusions prepared from commercial products was analyzed with UHPLC-ESI-qTOF-MS. Total phenolics, flavonoids, and non-flavonoid polyphenols were determined. Antioxidant activity of infusions and selected polyphenols was investigated using DPPH, ABTS, and FRAP. Fluorometric measurements and methylglyoxal capture were performed to investigate the antiglycation activity. PCA and PLS-DA models were applied to explore the correlation between chemical and antioxidant results. The principal flavonoids in C. incanus were flavonols. In vitro tests revealed that a stronger antioxidant effect was demonstrated by plant material from Turkey rich in flavonoids, followed by Albania and Greece. Flavonols and ellagic acid displayed stronger antiradical and reducing power than EA-derived urolithins. Hyperoside was the most potent inhibitor of glycation. The results indicate that flavonoids are primarily responsible for rock rose antioxidant and antiglycation properties. PLS-DA modeling can be used to identify the origin of plant material with sensitivity and specificity exceeding 86%.

Essential Oils Derived from Cistus Species Activate Mitochondria by Inducing SIRT1 Expression in Human Keratinocytes, Leading to Senescence Inhibition

Cistus L. is a genus of dicotyledonous perennial herbaceous plants. Cistus species have been commonly used in folk medicine in the Mediterranean region. In the present study, the biological activities of essential oils derived from Cistus species (Cistus laurifolius, C. monspeliensis, C. creticus, and C. salviifolius) were evaluated. Essential oils derived from C. laurifolius and C. monspeliensis were found to augment the expression of SIRT1, an anti-aging gene, in the normal culture of HaCaT cells. Furthermore, these essential oils increased the number and size of mitochondria and augmented their activity. These effects were thought to be caused by the up- and downregulated expression of MITOL and Drp1 in HaCaT cells, respectively, in response to the essential oil treatment. In addition, these essential oils were found to attenuate ultraviolet-B-induced mitochondrial damage and cellular senescence in HaCaT cells. These findings indicate that essential oils derived from C. laurifolius and C. monspeliensis may inhibit skin aging through mitochondrial regulation via SIRT1 activation.

Chemical Composition of Essential Oil, Phenolic Compounds Content, and Antioxidant Activity of Cistus monspeliensis from Northern Morocco

Currently, oxidative stress is one of the major problems that threatens human health. It is at the root of many diseases such as cancer. Despite the enormous efforts provided to combat this scourge, oxidative stress is still relevant and hence comes the need for research of new remedies especially from natural origin. For this purpose, the study of the antioxidant activity of extracts of Cistus monspeliensis from Morocco is a principal research objective. The phenolic extracts were obtained by maceration of the plant in a water/acetone mixture and then separated by liquid/liquid extraction with solvents of increasing polarity. The first phytochemical tests carried out on these extracts showed the existence of different families of phenolic compounds, such as flavonoids, tannins, and others. Assays for total polyphenols, flavonoids, hydrolysable, and condensed tannins were carried out by known colorimetric methods. The results of these assays have shown that the studied extracts are rich in phenolic compounds present in the plant in the form of flavonoids (69.81 ± 0.22 mg EQ/g DM), hydrolysable tannins (61.86 ± 0.89 mg ETA/g DM), and condensed tannins (70.05 ± 1.61 mg EC/g DM). The evaluation of the antioxidant activity is carried out by two different methods: the DPPH test (2,2-DiPhenyl-1-Picryl-Hydrazyl) and the FRAP test (Ferric Reducing Antioxidant Power). The results obtained show that the extracts of Cistus monspeliensis are active and have interesting antioxidant powers. In particular, the water/acetone (WAE) (IC₅₀ = 0.079 mg/mL) and butanolic (BUE) (IC_0.5 = 0.099 mg/mL) extracts are the most active with values comparable to that of ascorbic acid. The interesting results obtained in this study clearly show that Cistus monspeliensis originating from Morocco can be considered as a source of natural antioxidants. Therefore, the extracts of this plant deserve to be tested in the medicinal field, against cancer and cardiovascular diseases, and in food field as an additive and preservative.

Intraspecific Genetic Diversity of Cistus creticus L. and Evolutionary Relationships to Cistus albidus L. (Cistaceae): Meeting of the Generations?

Cistus (Cistaceae) comprises a number of white- and purple-flowering shrub species widely distributed in the Mediterranean basin. Within genus Cistus, many taxa are subject to various taxonomic uncertainties. Cistus creticus, a prominent member of the purple-flowered clade, is a prime case of the current taxonomic troubles. Floras and databases approve different species names and utilise different or additional/fewer synonyms. Various intraspecific classification systems based on subspecies or varieties are in use. The inconsistent determination of plant material makes it difficult to compare literature regarding the phytochemical diversity and biological activities of plant material and impedes a systematic utilization of the manifold medicinal properties of C. creticus. In the present investigation, we used DNA sequence data from one nuclear region (ITS) and two chloroplast regions (trnL-trnF, rpl32-trnL) to test the intraspecific genetic diversity of C. creticus and its evolutionary relationships to the closely related C. albidus. The combined DNA data confirmed C. creticus as a rather heterogeneous species that integrates two major evolutionary lineages with clearly different genetic characteristics. The ‘Eastern Mediterranean clade’ seems to represent old and ancestral characteristics. This lineage exhibits a close relationship to the geographically distant C. albidus, expressed by very closely related ribotypes and an interspecifically shared chlorotype. The ‘Western Mediterranean clade’ is characterized by a distinctive ITS polymorphism (co-occurring paralogous ribotypes) and more distantly related chlorotypes. The formation of the genetically complex ‘Western Mediterranean clade’ seems to have involved hybridization and recurrent formation or migration movements.

A Review on Cistus sp.: Phytochemical and Antimicrobial Activities

Resistance to drugs is reaching alarming levels and is placing human health at risk. With the lack of new antimicrobials drugs, infectious diseases are becoming harder to treat. Hence, there is an increasing awareness of active phytochemicals with therapeutic functions. The tremendous research interest on the Cistus L. genus includes numerous plants used in traditional medicine by people living around the Mediterranean Sea, also resulted in some interesting discoveries and written literature. This review aimed at gathering scientific literature about Cistus species, describing phytochemical profiles and the various pharmacological activities. We also extensively reviewed the antimicrobial activities, including antiviral, antiparasitic, antifungal, and antibacterial potentials of Essential Oils (EO), raw extracts as well as isolated compounds. Mechanisms of action along with methods used are also investigated in this review. Considering the findings of the Cistus species extracts, this genus offers an adequate reserve of active phytochemicals since many have been used to create drugs. Therefore, this review work can serve society by providing a global view on Cistus L. sp. regarding pharmacological potentials and their chemical profiles.

Traditional Foods and Sustainable Rural Development: Exploiting the Case of the Comoros Tea as a Potential Source of Bioactive Compounds

Although modern medicine is available in many developing countries, such as the Comoros Islands, the primary health-care needs of the local population are based on traditional foods and beverages derived from natural resources and medicinal plants for cultural and historical reasons. Aphloia theiformis (Vahl) Benn. (‘Mfandrabo’), Cinnamomum verum J.Presl (‘Mani yamdrara’), Ocimum gratissimum L. (‘Roulé’), Plectranthus amboinicus (Lour.) Spreng. (‘Ynadombwe’), Cymbopogon nardus (L.) Rendle (‘Sandze monach’) and Ocimum americanum L. (‘Kandza’) are six wild plants that are largely utilised to treat many diseases. The leaves of these plants are used in the traditional Comorian tea (aqueous infusion). This study aimed to identify and quantify the main health-promoting compounds in the traditional formulation of Comorian tea by HPLC profiling together with a preliminary assessment of antioxidant capacity to confirm the traditional use of these plants by the local population. The single plants were also studied. The Comoros tea presented a total polyphenolic content (TPC) of 4511.50 ± 74.41 mgGAE/100 g DW, a value higher than the TPCs of the different plants included in the Comorian tea. Moreover, the Comorian tea showed an antioxidant capacity (AOC) of 578.65 ± 6.48 mmol Fe2+/Kg DW, a value higher if compared to all the AOC values obtained in the single plants. The polyphenolic fraction (771.37 ± 35.76 mg/100 g DW) and organic acids (981.40 ± 38.38 mg/100 g DW) were the most important phytochemical classes in the Comorian tea (40.68% and 51.75% of the total phytocomplex, respectively), followed by the monoterpenes (5.88%) and vitamin C (1.67%), while carotenoids were detected in trace (0.02%). The Comorian tea could be important in meeting the high demand in the Comoros Islands and other developing countries for cost-effective and natural health-promoting foods and/or beverages to be produced by agri-food industries and used by the local population. This study may promote traditional foods in rural communities in the Comoros Islands and contribute to sustainable rural development and a commercial valorisation of these plants for health-promoting and food applications.

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.

Comparative Metabolite and Gene Expression Analyses in Combination With Gene Characterization Revealed the Patterns of Flavonoid Accumulation During Cistus creticus subsp. creticus Fruit Development

Cistus creticus L. subsp. creticus (rockrose) is a shrub widespread in Greece and the Mediterranean basin and has been used in traditional medicine as herb tea for colds, for healing and digestive hitches, for the treatment of maladies, as perfumes, and for other purposes. Compounds from its flavonoid fraction have recently drawn attention due to antiviral action against influenza virus and HIV. Although several bioactive metabolites belonging to this group have been chemically characterized in the leaves, the genes involved in their biosynthesis in Cistus remain largely unknown. Flavonoid metabolism during C. creticus fruit development was studied by adopting comparative metabolomic and transcriptomic approaches. The present study highlights the fruit of C. creticus subsp. creticus as a rich source of flavonols, flavan-3-ols, and proanthocyanidins, all of which displayed a decreasing trend during fruit development. The majority of proanthocyanidins recorded in Cistus fruit are B-type procyanidins and prodelphinidins, while gallocatechin and catechin are the dominant flavan-3-ols. The expression patterns of biosynthetic genes and transcription factors were analyzed in flowers and throughout three fruit development stages. Flavonoid biosynthetic genes were developmentally regulated, showing a decrease in transcript levels during fruit maturation. A high degree of positive correlations between the content of targeted metabolites and the expression of biosynthetic genes indicated the transcriptional regulation of flavonoid biosynthesis during C. creticus fruit development. This is further supported by the high degree of significant positive correlations between the expression of biosynthetic genes and transcription factors. The results suggest that leucoanthocyanidin reductase predominates the biosynthetic pathway in the control of flavan-3-ol formation, which results in catechin and gallocatechin as two of the major building blocks for Cistus proanthocyanidins. Additionally, there is a decline in ethylene production rates during non-climacteric Cistus fruit maturation, which coincides with the downregulation of the majority of flavonoid- and ethylene-related biosynthetic genes and corresponding transcription factors as well as with the decline in flavonoid content. Finally, functional characterization of a Cistus flavonoid hydroxylase (F3'5'H) was performed for the first time.

Delignification of Cistus ladanifer Biomass by Organosolv and Alkali Processes

Residues of Cistus ladanifer obtained after commercial steam distillation for essential oil production were evaluated to produce cellulose enriched solids and added-value lignin-derived compounds. The delignification of extracted (CLRext) and extracted and hydrothermally pretreated biomass (CLRtreat) was studied using two organosolv processes, ethanol/water mixtures (EO), and alkali-catalyzed glycerol (AGO), and by an alkali (sodium hydroxide) process (ASP) under different reaction conditions. The phenolic composition of soluble lignin was determined by capillary zone electrophoresis and by Py-GC/MS, which was also used to establish the monomeric composition of both the delignified solids and isolated lignin. The enzymatic saccharification of the delignified solids was also evaluated. The ASP (4% NaOH, 2 h) lead to both the highest delignification and enzymatic saccharification (87% and 79%, respectively). A delignification of 76% and enzymatic hydrolysis yields of 72% were obtained for AGO (4% NaOH) while EO processes led to lower delignification (maximum lignin removal 29%). The residual lignin in the delignified solids were enriched in G- and H-units, with S-units being preferentially removed. The main phenolics present in the ASP and AGO liquors were vanillic acid and epicatechin, while gallic acid was the main phenolic in the EO liquors. The results showed that C. ladanifer residues can be a biomass source for the production of lignin-derivatives and glucan-rich solids to be further used in bioconversion processes.

Evaluation of antidiabetic effect of Cistus salviifolius L. (Cistaceae) in streptozotocin-nicotinamide induced diabetic mice

Objectives Cistus salviifoluis L. is a shrub from Cistaceae family used in many traditional medicines for the treatment of various diseases including diabetes mellitus. The aim of this study was to evaluate the in vivo antidiabetic potential of the aerial parts aqueous extract of Cistus salviifolius L. (CSA). Methods Experimental diabetes was induced in adult male mice by intra-peritoneal injection of Streptozotocin-nicotinamide (STZ-NC). CSA at a dose of 500 mg/kg was administered daily to the diabetic mice for four weeks. The effect of the extract on hyperglycemia, body weight, serum total cholesterol, triglycerides, hepatic and renal functional markers were determined. Histopathological examination of the mice pancreas was also performed. The diabetic animals treated with CSA were compared with animals treated by the standard drug metformin. Results Treatment with CSA showed a significant reduction in blood glucose, total triglycerides and creatinine levels and prevented the reduction of body weight caused by diabetes. Furthermore, histopathological analysis of the mice pancreas showed that the group treated with CSA reduced damage induced by STZ-NC on islets of Langerhans cells when compared to the diabetic control. Conclusions The results suggest that the aqueous extract of Moroccan C. salviifolius L. possesses beneficial effect on treatment of diabetes.

In vitro and in vivo anti-salmonella properties of hydroethanolic extract of Detarium microcarpum Guill. & Perr. (Leguminosae) root bark and LC-MS-based phytochemical analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Typhoid fever treatment remains a challenge in endemic countries. Detarium microcarpum is traditionally used to manage typhoid.

AIM OF THE STUDY

The study aims to explore the efficacy of hydroethanolic extract of Detarium microcarpum root bark in rats infected with salmonella.

MATERIAL AND METHODS

The phytochemical profile of the extract was obtained by UHPLC-MS analysis in an attempt of standardization. The in vitro antimicrobial activity was determined using broth dilution method. Salmonella infection was induced by oral administration of S. thyphimurium to immunosuppressed rats. Infected rats were then treated 2 h later with the extract (75, 150 and 300 mg/kg), distilled water (normal and salmonella control) and ciprofloxacin (8 mg/kg) for control. Body weight was monitored and stools were cultured to determine the number of colony-forming units. At the end of treatment, animals were sacrificed, blood and organs were collected for hematological, biochemical and histopathological analyses.

RESULTS

Detarium microcarpum extract as well as the isolated compound (rhinocerotinoic acid) exhibited good antimicrobial activity in vitro with bacteriostatic effects. The plant extract significantly (p < 0.05) inhibited the bacterial development in infected animals with an effective dose (ED₅₀) of 75 mg/kg. In addition, the extract prevented body weight loss, hematological, biochemical and histopathological damages in treated rats.

CONCLUSION

Detarium microcarpum extract possesses antisalmonella properties justifying its traditional use for the typhoid fever management.

Differentiation between Cistus L. (Sub-) Species (Cistaceae) Using NMR Metabolic Fingerprinting

The genus Cistus is taxonomically complex, as taxonomic classification of individual species based on morphological criteria is often difficult and ambiguous. However, specific species contain valuable natural products, especially terpenoids and polyphenols, which exert various biological effects and might therefore be used for treatment of a broad array of disorders. Hence, a fast and reliable method for clear identification of different Cistus (sub-) species is required. Approaches for analysis of secondary metabolite profiles, e.g., with NMR, might remedy the challenging classification of Cistus (sub-) species and help to identify specific markers for differentiation between them. In the present study, 678 samples from wild-growing Cistus populations, including 7 species and 6 subspecies/varieties thereof, were collected in 3 years from populations in 11 countries all over the Mediterranean basin. Samples were extracted with buffered aqueous methanol and analysed with NMR. From the resulting 1D-¹H-NOESY and J-Res profile spectra, marker signals or spectral regions for the individual (sub-) species were identified with multivariate statistical tools. By examining the NMR profiles of these extracts, we were able to identify discriminators and specific markers for the investigated Cistus (sub-) species. Various influencing factors, like (sub-) species, wild harvestings of different populations from several countries, numerous collection sites, different years, and cultivation in greenhouses have been considered in this work. As the here identified markers are independent from these influencing factors, the results can be considered a robust model and might be used for future differentiation between Cistus (sub-) species.

Castanea spp. Agrobiodiversity Conservation: Genotype Influence on Chemical and Sensorial Traits of Cultivars Grown on the Same Clonal Rootstock

A large species diversity characterises the wide distribution of chestnuts in Asia, North America, and Europe, hence reflecting not only the adaptation of the genus Castanea to diverse environmental conditions, but also to different management strategies encompassing orchards. The characterisation and description of chestnut populations and cultivars are crucial to develop effective conservation strategies of one of the most important Italian and European fruit and wood species. Chestnut cultivars grown in the same pedoclimatic conditions and on the same clonal rootstock were characterised with sensory, spectrophotometric, and chromatographic analysis to determine the phytochemical composition and nutraceutical properties. A multivariate approach, including principal component analysis and conditional inference tree models, was also performed. The ease of peeling, seed colour, and intensity of sweetness were the sensory descriptors that allowed us to differentiate C. sativa cultivars. Antioxidant capacity ranged from 9.30 ± 0.39 mmol Fe+2 kg-1 DW ('Bouche de Bètizac') to 19.96 ± 1.89 mmol Fe+2 kg-1 DW ('Garrone Rosso'). Monoterpenes represented the main component, reaching 88% for hybrids, followed by polyphenols (10-25% for hybrids and chestnuts, respectively). A multivariate approach showed that phenolic acids and tannins were the bioactive classes with the highest discriminating power among different genotypes, and that genotype is a significant variable (p < 0.05). In addition, most of the analysed chestnut cultivars showed a content of bioactive compounds similar to or higher than the main hazelnut, walnut, and almond varieties. Chestnut agrobiodiversity could be intended as strictly associated to the genotype effect and underlines the large variability within the genus Castanea, and therefore, the importance of in farm and ex situ conservation of local germplasm is part of a global strategy aimed at increasing the levels of agrobiodiversity.

Metabolic variation in Cistus monspeliensis L. ecotypes correlated to their plant-fungal interactions

The effect of environmental factors on the chemical composition of plants eventually resulting in plant growth regulation is an age-old issue in plant biology. Nowadays, the acceleration in changes in environmental conditions (e.g. global warming) can act as an incentive to investigate their correlation with metabolic changes. In this study, Cistus monspeliensis plants grown on the island of Sardinia (Italy) were used to explore the geographical-mediated metabolic variation and its repercussion on plant-fungus interactions. Samples of different ecotypes of C. monspeliensis were collected and chemically profiled by ¹H NMR and HPTLC-based metabolomics and the relationship between the variations of biological activity was examined by multivariate data analysis. The ecotypes, collected from different geographical zones and altitudes, exhibited clearly distinguishable chemical profiles, particularly in their terpene and phenolic contents. In particular, multivariate data analysis revealed several diterpenes of the labdane and clerodane series among the terpenes and methoxyflavonoids to be responsible for the differentiation. The antifungal activity of the plants was used to explore the correlation between chemical variation and biological activity. Results showed that there was a strong correlation between the metabolic profiles and the antifungal activity, revealing terpenes and methoxylated flavonoids as the main involved metabolites. This demonstrated that environmental factors can influence the chemical variation of plant ecotypes, resulting in the generation of chemotypes that are potentially adapted to their niche conditions including the plant-fungal interactions.

UPLC-MS/MS Phytochemical Analysis of Two Croatian Cistus Species and Their Biological Activity

Aqueous extracts of two Cistus species wild growing in Croatia-Cistus creticus (CC) and Cistus salviifolius (CS)-have been assessed with UPLC-MS/MS, showing 43 different phytochemicals, with flavonol glycosides: myricetin-3-hexoside and myricetin-rhamnoside, predominate ones in CC and myricetin-3-hexoside in CS. Antioxidant potential tested with the FRAP method showed no difference between CS and CC aqueous extracts, while higher phenolic content of CC comparing to CS, determined with a Folin-Cicolateu reagent correlated to its higher antioxidant capacity observed by the DPPH method. Both extracts were assessed for antimicrobial activity, using disc-diffusion and broth microdilution assays, targeting the opportunistic pathogens, associated with food poisoning, urinary, respiratory tract, blood stream and wound infections in humans. Antimicrobial assays revealed that fungi were in general more sensitive to both Cistus aqueous extracts, comparing to the bacteria where two extracts showed very similar activity. The most potent activity was observed against A. baumannii for both extracts. The extracts were tested on human lung cancer (A549) cell line using the MTT assay, showing very similar antiproliferative activity. After 72 h treatment with CC and CS aqueous extracts in concentration of 0.5 g/L, the viability of the cells were 37% and 50% respectively, compared to non-treated cells.

Evaluation of Natural and Botanical Medicines for Activity Against Growing and Non-growing Forms of B. burgdorferi

Lyme disease is the most common vector-borne disease in the US and Europe. Although the current recommended Lyme antibiotic treatment is effective for the majority of Lyme disease patients, about 10-20% of patients continue to suffer from persisting symptoms. There have been various anecdotal reports on the use of herbal extracts for treating patients with persisting symptoms with varying degree of improvements. However, it is unclear whether the effect of the herb products is due to their direct antimicrobial activity or their effect on host immune system. In the present study, we investigated the antimicrobial effects of 12 commonly used botanical medicines and three other natural antimicrobial agents for potential anti-Borrelia burgdorferi activity in vitro. Among them, 7 natural product extracts at 1% were found to have good activity against the stationary phase B. burgdorferi culture compared to the control antibiotics doxycycline and cefuroxime. These active botanicals include Cryptolepis sanguinolenta, Juglans nigra (Black walnut), Polygonum cuspidatum (Japanese knotweed), Artemisia annua (Sweet wormwood), Uncaria tomentosa (Cat's claw), Cistus incanus, and Scutellaria baicalensis (Chinese skullcap). In contrast, Stevia rebaudiana, Andrographis paniculata, Grapefruit seed extract, colloidal silver, monolaurin, and antimicrobial peptide LL37 had little or no activity against stationary phase B. burgdorferi. The minimum inhibitory concentration (MIC) values of Artemisia annua, Juglans nigra, and Uncaria tomentosa were quite high for growing B. burgdorferi, despite their strong activity against the non-growing stationary phase B. burgdorferi. On the other hand, the top two active herbs, Cryptolepis sanguinolenta and Polygonum cuspidatum, showed strong activity against both growing B. burgdorferi (MIC = 0.03-0.06% and 0.25-0.5%, respectively) and non-growing stationary phase B. burgdorferi. In subculture studies, only 1% Cryptolepis sanguinolenta extract caused complete eradication, while doxycycline and cefuroxime and other active herbs could not eradicate B. burgdorferi stationary phase cells as many spirochetes were visible after 21-day subculture. Further studies are needed to identify the active constituents of the effective botanicals and evaluate their combinations for more effective eradication of B. burgdorferi in vitro and in vivo. The implications of these findings for improving treatment of persistent Lyme disease are discussed.

Quantification of the Antioxidant Activity of Plant Extracts: Analysis of Sensitivity and Hierarchization Based on the Method Used

Plants have a large number of bioactive compounds with high antioxidant activity. Studies for the determination of the antioxidant activity of different plant species could contribute to revealing the value of these species as a source of new antioxidant compounds. There is a large variety of in vitro methods to quantify antioxidant activity, and it is important to select the proper method to determine which species have the highest antioxidant activity. The aim of this work was to verify whether different methods show the same sensitivity and/or capacity to discriminate the antioxidant activity of the extract of different plant species. To that end, we selected 12 species with different content of phenolic compounds. Their extracts were analyzed using the following methods: 2,2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, ferric reducing (FRAP) assay, Trolox equivalent antioxidant capacity (ABTS) assay, and reducing power (RP) assay. The four methods selected could quantify the antioxidant capacity of the 12 study species, although there were differences between them. The antioxidant activity values quantified through DPPH and RP were higher than the ones obtained by ABTS and FRAP, and these values varied among species. Thus, the hierarchization or categorization of these species was different depending on the method used. Another difference established between these methods was the sensitivity obtained with each of them. A cluster revealed that RP established the largest number of groups at the shortest distance from the root. Therefore, as it showed the best discrimination of differences and/or similarities between species, RP is considered in this study as the one with the highest sensitivity among the four studied methods. On the other hand, ABTS showed the lowest sensitivity. These results show the importance of selecting the proper antioxidant activity quantification method for establishing a ranking of species based on this parameter.

Heat Waves Change Plant Carbon Allocation Among Primary and Secondary Metabolism Altering CO2 Assimilation, Respiration, and VOC Emissions

Processes controlling plant carbon allocation among primary and secondary metabolism, i.e., carbon assimilation, respiration, and VOC synthesis are still poorly constrained, particularly regarding their response to stress. To investigate these processes, we simulated a 10-day 38°C heat wave, analysing real-time carbon allocation into primary and secondary metabolism in the Mediterranean shrub Halimium halimifolium L. We traced position-specific ¹³C-labeled pyruvate into daytime VOC and CO₂ emissions and during light-dark transition. Net CO₂ assimilation strongly declined under heat, due to three-fold higher respiration rates. Interestingly, day respiration also increased two-fold. Decarboxylation of the C1-atom of pyruvate was the main process driving daytime CO₂ release, whereas the C2-moiety was not decarboxylated in the TCA cycle. Heat induced high emissions of methanol, methyl acetate, acetaldehyde as well as mono- and sesquiterpenes, particularly during the first two days. After 10-days of heat a substantial proportion of ¹³C-labeled pyruvate was allocated into de novo synthesis of VOCs. Thus, during extreme heat waves high respiratory losses and reduced assimilation can shift plants into a negative carbon balance. Still, plants enhanced their investment into de novo VOC synthesis despite associated metabolic CO₂ losses. We conclude that heat stress re-directed the proportional flux of key metabolites into pathways of VOC biosynthesis most likely at the expense of reactions of plant primary metabolism, which might highlight their importance for stress protection.

Heterologous production of labdane-type diterpenes in the green alga Chlamydomonas reinhardtii

Labdane diterpenes (LDs), and especially sclareol, are important feedstocks for the pharmaceutical and cosmetic industries, and therefore several lines of research have led to their heterologous production in non-photosynthetic microbes and higher plants. The potential of microalgae as bioreactors of natural products has been established for a variety of bioactive metabolites, including terpenes. In this work, a codon optimized sequence encoding a key plant labdane-type diterpene (LD) cyclase, copal-8-ol diphosphate synthase from Cistus creticus (CcCLS), was introduced into the chloroplast genome of Chlamydomonas reinhardtii. Of 49 transplastomic algal lines, 12 produced variable amounts of four LD compounds, namely ent-manoyl oxide, sclareol, labda-13-ene-8α,15-diol and ent-13-epi-manoyl oxide. The total LD concentrations measured in the transplastomic lines reached 1.172 ± 0.05 μg/mg cell DW for the highest overall producer, while the highest yield for sclareol was 0.038 ± 0.001 μg/mg cell DW. Thus, transplastomic expression of a key plant labdane diterpene cyclase in the C. reinhardtii chloroplast genome enabled the production of important plant-specific LD compounds.

The structure of (E)-biformene synthase provides insights into the biosynthesis of bacterial bicyclic labdane-related diterpenoids

The labdane-related diterpenoids (LRDs) are a large group of natural products with a broad range of biological activities. They are synthesized through two consecutive reactions catalyzed by class II and I diterpene synthases (DTSs). The structural complexity of LRDs mainly depends on the catalytic activity of class I DTSs, which catalyze the formation of bicyclic to pentacyclic LRDs, using as a substrate the catalytic product of class II DTSs. To date, the structural and mechanistic details for the biosynthesis of bicyclic LRDs skeletons catalyzed by class I DTSs remain unclear. This work presents the first X-ray crystal structure of an (E)-biformene synthase, LrdC, from the soil bacterium Streptomyces sp. strain K155. LrdC was identified as a part of an LRD cluster of five genes and was found to be a class I DTS that catalyzes the Mg²⁺-dependent synthesis of bicyclic LRD (E)-biformene by the dephosphorylation and rearrangement of normal copalyl pyrophosphate (CPP). Structural analysis of LrdC coupled with docking studies suggests that Phe189 prevents cyclization beyond the bicyclic LRD product through a strong stabilization of the allylic carbocation intermediate, while Tyr317 functions as a general base catalyst to deprotonate the CPP substrate. Structural comparisons of LrdC with homology models of bacterial bicyclic LRD-forming enzymes (CldD, RmnD and SclSS), as well as with the crystallographic structure of bacterial tetracyclic LRD ent-kaurene synthase (BjKS), provide further structural insights into the biosynthesis of bacterial LRD natural products.

Neglected Mediterranean plant species are valuable resources: the example of Cistus ladanifer

The combination of genotypic selection, targeted and improved cultivation, and processing techniques for specific applications gives C. ladanifer the potential to be used as a valuable resource in Mediterranean areas with poor agronomic advantages. Cistus ladanifer (rockrose) is a perennial shrub, well adapted to the Mediterranean climate and possibly to upcoming environmental changes. As a sequence to a thorough review on taxonomic, morphological, chemical and competitive aspects of C. ladanifer, the research team focuses here on the economic potential of C. ladanifer: from production to applications, highlighting also known biological activities of extracts and their compounds. The use of this natural resource may be a viable solution for poor and contaminated soils with no need for large agricultural techniques, because this species is highly resistant to pests, diseases and extreme environmental factors. In addition, this species reveals interesting aptitudes that can be applied to food, pharmaceutical, phytochemical and biofuel industries. The final synthesis highlights research lines toward the exploitation of this neglected resource, such as selection of plant lines for specific applications and development of agronomic and processing techniques.

Assessing Nutritional Traits and Phytochemical Composition of Artisan Jams Produced in Comoros Islands: Using Indigenous Fruits with High Health-Impact as an Example of Biodiversity Integration and Food Security in Rural Development

In the Comoros Islands, as in other developing countries, malnutrition and food insecurity affect a very large percentage of the population. Developing fruit-based products in order to make profit, reduce poverty and improve indigenous people diet could be very important for local population of countries as Comoros Islands. The aim of the present work was to study the chemical composition of jams and jellies produced from seven fruit species harvested in Grand Comore Island. The following parameters were studied sugars and organic acids, total phenolics, total anthocyanins and high-performance liquid chromatography (HPLC) fingerprint of the main phytochemicals. Antioxidant activity was also measured. A multivariate approach (Principal Component Analysis) was performed in order to better characterize the products and to set a potential analytical tool for jam characterisation. Results showed that the analysed products are a good source of polyphenolic constituents, as caffeic and gallic acids, catechin and quercetin and volatile compounds, as limonene and γ-terpinene: these molecules may be considered as suitable markers for these fruit-derived products as characterizing the chromatographic patterns. The characterisation of these products and their nutritional and nutraceutical traits is important as valorisation of local food production for poverty reduction and rural development. Further benefits of this approach include the maintenance of local agro-biodiversity as raw material for fruit-based products and the strengthening of food security practices.

Real-time carbon allocation into biogenic volatile organic compounds (BVOCs) and respiratory carbon dioxide (CO2) traced by PTR-TOF-MS, 13CO2 laser spectroscopy and 13C-pyruvate labelling

Our understanding of biogenic volatile organic compound (BVOC) emissions improved substantially during the last years. Nevertheless, there are still large uncertainties of processes controlling plant carbon investment into BVOCs, of some biosynthetic pathways and their linkage to CO2 decarboxylation at central metabolic branching points. To shed more light on carbon partitioning during BVOC biosynthesis, we used an innovative approach combining δ13CO2 laser spectroscopy, high-sensitivity proton-transfer-reaction time-of-flight mass spectrometry and a multiple branch enclosure system in combination with position-specific 13C-metabolite labelling. Feeding experiments with position-specific 13C-labelled pyruvate, a central metabolite of BVOC synthesis, enabled online detection of carbon partitioning into 13C-BVOCs and respiratory 13CO2. Measurements of trace gas emissions of the Mediterranean shrub Halimium halimifolium revealed a broad range of emitted BVOCs. In general, [2-13C]-PYR was rapidly incorporated into emitted acetic acid, methyl acetate, toluene, cresol, trimethylbenzene, ethylphenol, monoterpenes and sesquiterpenes, indicating de novo BVOC biosynthesis of these compounds. In contrast, [1-13C]-pyruvate labelling substantially increased 13CO2 emissions in the light indicating C1-decarboxylation. Similar labelling patterns of methyl acetate and acetic acid suggested tightly connected biosynthetic pathways and, furthermore, there were hints of possible biosynthesis of benzenoids via the MEP-pathway. Overall, substantial CO2 emission from metabolic branching points during de novo BVOC biosynthesis indicated that decarboxylation of [1-13C]-pyruvate, as a non-mitochondrial source of CO2, seems to contribute considerably to daytime CO2 release from leaves. Our approach, combining synchronised BVOC and CO2 measurements in combination with position-specific labelling opens the door for real-time analysis tracing metabolic pathways and carbon turnover under different environmental conditions, which may enhance our understanding of regulatory mechanisms in plant carbon metabolism and BVOC biosynthesis.

Volatile diterpene emission by two Mediterranean Cistaceae shrubs

Mediterranean vegetation emits a wide range of biogenic volatile organic compounds (BVOCs) among which isoprenoids present quantitatively the most important compound class. Here, we investigated the isoprenoid emission from two Mediterranean Cistaceae shrubs, Halimium halimifolium and Cistus ladanifer, under controlled and natural conditions, respectively. For the first time, diurnal emission patterns of the diterpene kaurene were detected in real-time by Proton-Transfer-Reaction-Time-of-Flight-Mass-Spectrometer. Kaurene emissions were strongly variable among H. halimifolium plants, ranging from 0.01 ± 0.003 to 0.06 ± 0.01 nmol m⁻² s⁻¹ in low and high emitting individuals, respectively. They were in the same order of magnitude as monoterpene (0.01 ± 0.01 to 0.11 ± 0.04 nmol m⁻² s⁻¹) and sesquiterpene (0.01 ± 0.01 to 0.52 nmol m⁻² s⁻¹) emission rates. Comparable range and variability was found for C. ladanifer under natural conditions. Labelling with ¹³C-pyruvate suggested that emitted kaurene was not derived from de novo biosynthesis. The high kaurene content in leaves, the weak relationship with ecophysiological parameters and the tendency of higher emissions with increasing temperatures in the field indicate an emission from storage pools. This study highlights significant emissions of kaurene from two Mediterranean shrub species, indicating that the release of diterpenes into the atmosphere should probably deserve more attention in the future.

New Findings in Prunus padus L. Fruits as a Source of Natural Compounds: Characterization of Metabolite Profiles and Preliminary Evaluation of Antioxidant Activity

European bird cherry (Prunus padus L.) has been known since the Middle Ages for its medical/food use and high health-promoting value. This study aimed to assess the potential of these fruits as a source of bioactive compounds through the characterization of its physicochemical traits, nutraceutical properties, phytochemical composition via HPLC fingerprint, and antioxidant capacity. Fully ripened fruits of Prunus padus L. (Colorata cv) were collected in mid-July 2017 in Chieri, north-western Italy. The TPC (194.22 ± 32.83 mgGAE/100 gFW) and TAC (147.42 ± 0.58 mgC3G/100 gFW) values were obtained from the analyzed extracts. The most important phytochemical class was organic acids (48.62 ± 2.31%), followed by polyphenols (35.34 ± 1.80%), monoterpenes (9.36 ± 0.64%), and vitamin C (6.68 ± 0.22%). In this research the most important flavonols selected as marker were quercitrin (16.37 ± 3.51 mg/100 gFW) and quercetin (11.86 ± 2.36 mg/100 gFW). Data were reported based on fresh weight. Moreover, fresh fruits showed a mean antioxidant activity value of 17.78 ± 0.84 mmol Fe2+·kg-1. Even though the seeds and leaves contain cyanogenic glycosides, this study showed that these fruits could be a natural source of bioactive compounds with high antioxidant properties, due to the contents of organic and phenolic acids, catechins, and a synergetic effect of vitamin C and flavonoids.

Cistus ladanifer (Cistaceae): a natural resource in Mediterranean-type ecosystems

Cistus ladanifer has a well-defined taxonomic identity. 2,2,6-trimethylcyclohexanone may be an authenticity and taxonomic marker. Its traits and applications make it a possible economic resource fitted for Mediterranean areas. Cistus ladanifer is a dominant shrub species endemic to the western Mediterranean region. Due to its dominant nature and its potential ecological, aromatic or pharmacological applications, C. ladanifer has been the object of numerous studies. In this review current knowledge on different aspects of this species is summarized, from its taxonomy to its chemical characterisation or its competitive traits. There are no doubts about the taxonomic entity of C. ladanifer, although the recognition of infraspecific taxa deserves more attention. Given that the fragrant exudate of C. ladanifer holds a very specific composition, one species specific carotenoid, 2,2,6-trimethylcyclohexanone, derivative is proposed as an authenticity marker for uses of C. ladanifer in pharmacological or aromatic industries. Evidence is also gathered on the extreme adaptation of C. ladanifer to stressful conditions in the Mediterranean region, such as the ability to survive in low hydric and high solar exposition conditions, presistence in poor and contaminated soils, and growth inhibition of several other plants through the release of allelochemicals. Thus, the finding of potential applications for this plant may contribute to enhance the economic dimension of derelict lands, such as mine tailings or poor agricultural Mediterranean areas.

Plant-based remedies for wolf bites and rituals against wolves in the Iberian Peninsula: Therapeutic opportunities and cultural values for the conservation of biocultural diversity

ETHNOPHARMACOLOGICAL RELEVANCE

Combined approaches to local knowledge and folk plant use improve awareness and promote effective strategies for the conservation of significant biocultural patrimony. Moreover, the information reported might be the basis for further appropriate phytochemical and pharmacological research. Therefore we provide an insight into traditional herbal remedies and practices for healing bite injuries in humans and domestic animals caused by the Iberian wolf. Wolf bites are associated with inflammatory processes and rabies is a potential complication AIMS: This paper describes and summarises the medicinal-veterinary empirical and ritual uses of the Iberian flora for wolf injuries and reviews the ethnopharmacological data of specific plants that are already published. The Iberian wolf is a critically endangered subspecies of the grey wolf. Livestock attacks attributed to wolves are increasingly frequent in the Iberian Peninsula, resulting in serious social problems. Interesting strategies for Iberian wolf conservation might be related to traditional grazing practices that are deeply linked with empirical knowledge and local practices passed on by oral tradition, which are also vulnerable now.

MATERIALS AND METHODS

Based on documentary sources from the beginning of the twentieth century to the present, we systematically searched old monographs, regional documents, technical papers, project reports, as well as the international and national databases and the available scientific literature, without restrictions regarding the language of the publications consulted.

RESULTS

A total of 39 remedies for healing wolf bite injuries in humans and domestic animals was reported, highlighting the medicinal use of 33 species of vascular plants, mostly wild herbs, belonging to 18 botanical families. The use of wood ashes was also reported. The number of use-reports found represents a very high number considering similar European studies. Leaves were the predominant plant part mentioned. Boiling plant materials in water for topical uses was the most frequent method of preparation found. Some traditional remedies combined two or more plant species in order to potentiate their effects. Moreover, some plant-based traditional practices and rituals to ward off wolves and to prevent wolf attacks were also documented. In these practices eleven other species (belonging to seven more families) were used.

CONCLUSIONS

Despite the decline of the Iberian wolf over the last few decades, wolves are still in the imaginary of rural communities that perceive this large carnivore as both a diabolic creature and a mythic and benign animal. Wolf-related cultural heritage is of great interest in terms of conservation strategies. This review emphasises the importance of local knowledge and provides useful information about several potential sources of phytochemicals and their claimed therapeutic effects, aiming at contributing to the conservation and appreciation of the Iberian biocultural heritage.

Proteomic Insights on the Metabolism of Penicillium janczewskii during the Biotransformation of the Plant Terpenoid Labdanolic Acid

Plant terpenoids compose a natural source of chemodiversity of exceptional value. Many of these compounds own biological/pharmacological activity, others are regarded as unique chemical skeletons for the synthesis of derivatives with improved properties. Functional chemical modification of terpenoids through biotransformation frequently relies on the use of Ascomycota strains, but information on major cellular responses is still largely lacking. Penicillium janczewskii mediates a stereo-selective hydroxylation of labdanolic acid (LA)-terpenoid found abundantly in Cistus ladanifer-producing 3β-hydroxy-labdanolic acid with yields >90%. Herein, combined analyses of mycelial and extracellular differential proteomes demonstrated that the plant terpenoid increased stress responses, especially against oxidative stress (e.g., accumulation of superoxide dismutase) and apparently altered mitochondria functioning. One putative cytochrome P450 monooxygenase differentially accumulated in the secretome and the terpenoid bioconversion was inhibited in vivo in the presence of a P450 inhibitor. The stereo-selective hydroxylation of the plant terpenoid is likely mediated by P450 enzymes, yet its unequivocal identity remains unclear. To the best of our knowledge, this is the first time that proteomics was used to investigate how a plant terpenoid impacts the metabolism of a filamentous fungus during its efficiently biotransformation. Our findings may encourage the development of new strategies for the valorization of plant natural resources through biotechnology.

Trichome patterning control involves TTG1 interaction with SPL transcription factors

Epidermal cell differentiation is a paramount and conserved process among plants. In Arabidopsis, a ternary complex formed by MYB, bHLH transcription factors and TTG1 modulates unicellular trichome morphogenesis. The formation of multicellular glandular trichomes of the xerophytic shrub Cistus creticus that accumulate labdane-type diterpenes, has attained much attention renowned for its medicinal properties. Here, we show that C. creticus TTG1 (CcTTG1) interacts with the SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPLA/B) proteins, putative homologs of AtSPL4/5 that in turn interact with AtTTG1. These interactions occur between proteins from evolutionarily distant species supporting the conserved function of TTG1-SPL complex. Overexpression of AtSPL4 and AtSPL5 decreased the expression of GLABRA2 (AtGL2), the major regulator of trichome morphogenesis, resulting in trichome reduction on the adaxial surface of cauline leaves, thereby illuminating the significance of TTG1-SPLs interactions in trichome formation control. AtGL2 and AtSPL4 have opposite expression patterns during early stages of leaf development. We postulate an antagonistic effect between SPLs and the heterogeneous MYB-bHLH factors binding to TTG1. Hence, the SPLs potentially rearrange the complex, attenuating its transcriptional activity to control trichome distribution.