Heterotheca Inuloides Research Articles

Synthesis, Characterization, and Antibacterial Activity of Silver Nanoparticles Supported on Bovine Bone Powder Using Heterotheca inuloides: An In Vitro Study

This paper reports on the biosynthesis, characterization, as well as the bactericide and cytotoxic properties of silver nanoparticles supported on bovine bone powder (Ag-NPs/BBP). The silver nanoparticles were obtained through the bioreduction of AgNO3, using an infusion of Heterotheca inuloides leaves and flowers as a reducing agent and bovine bone powder as a support. The ratio of Ag-NPs/bovine bone powder was set as 1:10. The characterization was performed with SEM–EDS, XRD, UV–Vis, and TEM, which showed the formation of nanoparticles with an average size of 22.6 ± 10.8 nm and a quasi-spherical Ag-NPs morphology supported on the BBP surface. The nanocomposite exhibited a band gap of 2.19 eV. The minimal inhibitory concentration and the minimal bactericidal concentration against S. aureus, E. coli, and S. epidermidis were determined for each strain. In addition, the cytotoxic evaluation of the Ag-NPs/BBP on J774.2 mouse macrophage cells was performed. The Ag-NPs/BBP exhibited a bactericide effect on the strains studied, and the cytotoxicity had a dose-dependent behavior on the cells studied. Therefore, it was found that the ecofriendly synthesized Ag-NPs supported on bovine bone powder resulted in an effective bactericidal system against the strains studied, without significant cytotoxicity.

Evaluation of the Insecticidal Potential of Heterotheca inuloides Acetonic and Methanolic Extracts against Spodoptera frugiperda and Their Ecotoxicological Effect on Poecilia reticulata.

For the management of Spodoptera frugiperda, botanical extracts have been used to reduce the environmental impacts of synthetic chemical pesticides. In the present investigation, the insecticidal activity of the acetonic and methanolic extracts of Heterotheca inuloides (Asteraceae) and of the main compound 7-hydroxy-3,4-dihydrocadalene on this pest as well as its ecotoxicological effect on Poecilia reticulata were evaluated. A greater insecticidal response was obtained from the acetonic extracts than from the methanolic extracts, with LC50 values of 730.4 ppm and 711.7 ppm for samples 1 and 2, respectively. Similarly, there was a lethal effect on 50% of the P. reticulata population at low concentrations in the acetonic extract compared to the methanolic extract. The sesquiterpene 7-hydroxy-3,4-dihydrocadalene has greater insecticidal activity by presenting an LC50 of 44.36 ppm; however, it is classified as moderately toxic for guppy fish.

The cytotoxicity effect of 7-hydroxy-3,4-dihydrocadalene from Heterotheca inuloides and semisynthetic cadalenes derivates towards breast cancer cells: involvement of oxidative stress-mediated apoptosis.

Heterotheca inuloides, traditionally employed in Mexico, has demonstrated anticancer activities. Although it has been proven that the cytotoxic effect is attributed to cadinane-type sesquiterpenes such as 7-hydroxy-3,4-dihydrocadalene, the mechanism of action by which these agents act in tumor lines and their regulation remain unknown. This study was undertaken to investigate for first time the cytotoxic activity and mechanism of action of 7-hydroxy-3,4-dihydrocadalene and two semi-synthetic cadinanes derivatives towards breast cancer cells. Cell viability and proliferation were assayed by thiazolyl blue tetrazolium bromide (MTT) assay and Trypan blue dye exclusion assay. Cell migration measure was tested by wound-healing assay. Moreover, the reactive oxygen species (ROS) and lipid peroxidation generation were measured by 2',7'-dichlorofluorescein diacetate (DCFH-DA) assay and thiobarbituric acid reactive substance (TBARS) assay, respectively. Furthermore, expression of caspase-3, Bcl-2 and GAPDH were analyzed by western blot. The results showed that 7-hydroxy-3,4-dihydrocadalene inhibited MCF7 cell viability in a concentration and time dependent manner. The cytotoxic potency of semisynthetic derivatives 7-(phenylcarbamate)-3,4-dihydrocadalene and 7-(phenylcarbamate)-cadalene was remarkably lower. Moreover, in silico studies showed that 7-hydroxy-3,4-dihydrocadalene, and not so the semi-synthetic derivatives, has optimal physical-chemical properties to lead a promising cytotoxic agent. Further examination on the action mechanism of 7-hydroxy-3,4-dihydrocadalene suggested that this natural product exerted cytotoxicity via oxidative stress as evidenced in a significantly increase of intracellular ROS levels and in an induction of lipid peroxidation. Furthermore, the compound increased caspase-3 and caspase-9 activities and slightly inhibited Bcl-2 levels. Interestingly, it also reduced mitochondrial ATP synthesis and induced mitochondrial uncoupling. Taken together, 7-hydroxy-3,4-dihydrocadalene is a promising cytotoxic compound against breast cancer via oxidative stress-induction.

In Vitro Cytotoxic Activity of Methanol Extracts of Selected Medicinal Plants Traditionally Used in Mexico against Human Hepatocellular Carcinoma.

Medicinal plants are traditionally used in Mexico to treat diseases such as cancer. The present study aimed to evaluate the cytotoxic, antioxidant, and anti-hemolytic activity of 15 plants of ethnopharmacological use in Mexico. For this, plant methanol extracts were prepared by the Soxhlet method, after which their cytotoxic activity was evaluated against human hepatocellular carcinoma (HEP-G2) and monkey kidney epithelial (Vero) cells by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction colorimetric assay. The selectivity index (SI) of each extract was then determined by the IC50 ratio of normal to tumor cells. We showed that Ruta chalepensis extract possessed an IC50 of 1.79 µg/mL and 522.08 µg/mL against HEP-G2 and Vero cells, respectively, resulting in an SI of 291.50. Furthermore, antioxidant activity was evaluated by the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging technique, where the best antioxidant potential was shown by the Heterotheca inuloides extract (IC50 = 19.24 µg/mL). Furthermore, the hemolytic potential was determined against human erythrocytes, which showed that the extracts with the highest anti-hemolytic activity were Smilax aspera (IC50 = 4.41 µg/mL) and Amphipterygium adstringens (IC50 = 5.35 µg/mL). In conclusion, we observed that R. chalepensis methanol extract possesses cytotoxic activity against HEP-G2 cells, without affecting non-tumorigenic Vero cells. Our results indicated the antitumor potential of medicinal plants used in Mexico.

In vitro screening of Mexican arnica (Heterotheca inuloides Cass.) inhibitory activity of the angiotensin converting enzyme as a hypotensive mechanism

The high incidence of cardiovascular diseases has become a major public health problem worldwide, and hypertension highly first. The renin-angiotensin-aldosterone system is one of the main routes of blood pressure regulation, and for this reason, inhibition of the angiotensin-converting enzyme has become a fundamental target for regulation and control of hypertension. Today, the search for treatment has turned to natural products. Heterotheca inuloides Cass., Mexican arnica, has high concentrations of phenolic compounds such as flavonoids, which have been correlated with free radical scavenging capacity (FRSC) and angiotensin converting enzyme inhibitory capacity (ACEI) as a hypotension mechanism. This study aimed to determine FRSC, ACEI and flavonoids of extracts of the H. inuloides shoot. Leaves had the highest concentration of total phenolic compounds (3177.85 mg gallic acid equivalents/100 g dry plant) and the highest concentration of total flavonoids (3896.47 mg total/100 g dp); outstanding were high concentrations of quercetin (706.68 mg/100 g dp) and kaempferol (39.22 mg/100 g dp). Regarding the FRSC of tested radicals, the behavior of the extracts was proportional to the content of phenolic compounds. Regarding ACEI capacity, compared with 90% inhibition by Captopril (2.5 mg/mL), the extracts inhibited 50–70%, with no significant statistical difference. The high FRSC and ACEI capacities of the shoot make this plant an alternative in preventing cardiovascular problems associated with oxidative stress and hypertension.

Ethnopharmacology of the Asteraceae family in Mexico

Background: In Mexico, the Asteraceae are part of traditional knowledge where its members have several uses, but they are particularly remarkable in traditional medicine and are used for different purposes.
 Questions: What pharmacologically studies have been carried out with Asteraceae species used in Mexican traditional medicine? What pharmacological activities have been tested? What compounds are responsible for the tested activities?
 Species studied: Asteraceae species used in Mexican traditional medicine pharmacologically tested.
 Methods: A database including scientific studies on Asteraceae species which studies on pharmacological activity or phytochemical characterization was compiled and analyzed.
 Results: From 249 reviewed studies only 202 fulfilled the criteria for our analysis. A total of 101 species distributed in 65 genera and 16 tribes were registered. The tribes Heliantheae and Senecioneae were the most studied. Ageratina pichinchensis , Artemisia ludoviciana , Heliopsis longipes , and Heterotheca inuloides were the most studied species. In Mexico, the Asteraceae family is mainly used in the treatment of diseases or symptoms related to the digestive and respiratory systems. In 48 % of the studies some biocidal activity was evaluated but only 21.8 % included phytochemical characterizations.
 Conclusions: The antimicrobial activity and phytochemical characterizations are the main kind of ethnopharmacological studies for Asteraceae in Mexico. Most of the compounds responsible for the activities have not been identified yet. The uses of Asteraceae in Mexico are similar to other countries emphasizing its cultural importance in the world. Mexican Asteraceae should be prioritized in conservation and bioscreening schemes.

Ultra-Small Platinum Nanoparticles with High Catalytic Selectivity Synthesized by an Eco-friendly Method Supported on Natural Hydroxyapatite

The biosynthesis of Pt-nanoparticles (Pt NPs) supported on bovine bone powder was conducted by an environmentally friendly method that consists on immersing bovine bone powder into a Pt4+ metal ion solution at room temperature, atmospheric pressure and subsequent reduction by Heterotheca inuloides. It is worth pointing out that a calcination process is not required for the synthesis of this catalyst by the method reported herein. The nanocomposite was characterized by transmission electron microscopy (TEM), which revealed uniformly dispersed platinum nanoparticles with quasi-spherical form and average particle size of 7.1 nm. The XPS studies exhibited the presence of 47.62% Pt° and 51.84% PtO. The catalyst activity was tested in the selective hydrogenation of 2-butyne-1,4-diol towards 2-butene-1,4-diol. The nanocomposite exhibits a reasonable catalytic performance with nearly 100% conversion of the alkyne and 96% selectivity towards 2-butene-1,4-diol.

Chemo-sensitizing activity of natural cadinanes from Heterotheca inuloides in human uterine sarcoma cells and their in silico interaction with ABC transporters

Sensitizing activities exerted by 3,4-dihydro-7-hydroxycadalene (1), rac-3,7-dihydroxy-3(4H)-isocadalen-4-one (4) and (1R,4R)-4H-1,2,3,4-tetrahydro-1-hydroxycadalen-15-oic acid (9), the major cadinanes isolated from Heterotheca inuloides, towards multidrug-resistant MES-SA/MX2 and parental MES-SA epithelial human uterine sarcoma cell lines were evaluated. We also evaluated the in silico interactions (expressed as ΔGbinding in kcal/mol) of cadinanes 1, 4 and 9 in an in vitro assay, and also tested several structurally related natural compounds with the multidrug resistance protein (MDR1, P-glycoprotein), human multidrug resistance protein 1 (MRP1), and breast cancer resistance protein (BCRP) structures as pharmacological targets using AutoDock and AutoDock Vina. Compound 1 potentiated the cytotoxicity of doxorubicin and mitoxantrone drugs in resistant MES-SA/MX2 cells, compared to cells treated with each drug alone. Compound 1 could reverse the resistance to doxorubicin 12.44 fold at a concentration of 5 μM. It also re-sensitized cells to mitoxantrone 3.94 fold. Hence, compound 1 may be considered as a potential chemosensitizing agent to overcome multidrug resistance in cancer. The docking analysis suggested that there are interactions between cadinanes from H. inuloides and MDR1, MRP1, and BCRP proteins mainly through π-π interactions and hydrogen bonds.

In vitro nematicidal activity of natural and semisynthetic cadinenes from Heterotheca inuloides against the plant-parasitic nematode Nacobbus aberrans (Tylenchida: Pratylenchidae).

Nacobbus aberrans (Tylenchida: Pratylenchidae) is one of the main plant-parasitic nematodes species that affects crops in Mexico, generating substantial economic losses. Traditionally, the control of the nematodes is carried out using chemical products; however, research efforts are presently focused on the search for new methods for the control of this pest. Natural products derived from plants are an alternative for the control of populations of plant-parasitic nematodes. The genus Heterotheca (Asteraceae) is characterized by containing sesquiterpenes with cadinane skeleton, and some species of this genus exert nematicidal activity. We determined the effects of selected Heterotheca inuloides plant metabolites and some semisynthetic derivatives on the hatching of eggs isolated from the gelatinous matrix and infective second-stage juveniles (J2) of the false root-knot nematode N. aberrans using an in vitro experimental model. Among the evaluated compounds, nematodes were more susceptible to hydroxylated and quinone compounds, whereas the remaining compounds showed moderate or no activity. The presence of the hydroxyl group is essential for nematicidal potential, with changes at the hydroxyl group modifying the nematicidal activity. Flowers of Heterotheca inuloides contain bioactive compounds that showed nematicidal activity against N. aberrans. Here we report the nematicidal activities of cadinenes isolated from the flowers of H. inuloides and their semisynthetic derivatives against the false root-knot nematode N. aberrans. © 2018 Society of Chemical Industry.

Ethnomedicinal plants used for the treatment of dermatological affections on the Purépecha Plateau, Michoacán, Mexico

Background and Aims: Inhabitants of the Purépecha Plateau preserve an excellent ancestral knowledge on medicinal plants used for dermatological affections, which has not been documented. An ethnopharmacological survey was carried out in this region to gather information on the use of medicinal plants and herbal preparations for treating dermatological affections, to disseminate the Purépecha indigenous knowledge and identifying promising plants for developing new formulations for cutaneous conditions.Methods: The study was conducted in the 21 municipalities that compose the Purépecha Plateau. A total of 86 local inhabitants (62 women and 24 men) were interviewed. The data were quantitatively analyzed through the determination of the use value, fidelity level and informant consensus factor.Key results: A total of 97 plant species belonging to 47 families were documented for treating 19 dermatological conditions on the Purépecha Plateau. Asteraceae was the leading family among the collected medicinal plants (20.61%), followed by Lamiaceae (13.40%) and Solanaceae (5.15%). The largest number of plants was used for the treatment of cuts (40.20%), skin inflammation (37.11%) and rash (37.11%). The aerial parts were the most commonly used (34.75%). The medicinal plant species with larger use values were Heterotheca inuloides (0.53), Aloe vera (0.37) and Oenothera rosea (0.21). The comparison of results with ethnomedicinal literature worldwide revealed that 8.25% of plants used on the Purépecha Plateau were recorded for the first time for the treatment of dermatological affections.Conclusions: This study provides new information on medicinal plants used on the Purépecha Plateau to treat cutaneous diseases. Future pharmacological and toxicological investigations are required to demonstrate the efficacy and safety of these species for treating dermatological affections.

Efecto de las condiciones de cultivo en la producción de fenoles, flavonoides totales y su capacidad antioxidante en el árnica (Heterotheca inuloides)

En la actualidad, Heterotheca inuloides o árnica para su nombre común, ha sido utilizada por su actividad anti inflamatoria, además, esta planta tiene otras aplicaciones como tratamiento contra el reumatismo, desordenes gastrointestinales, entre otros. Estas propiedades terapéuticas, son debido a metabolitos secundarios como los fenoles y flavonoides. La concentración de estos compuestos puede ser influenciada por estrés biótico o abiótico, en donde las condiciones de cultivo como la humedad relativa, la temperatura del ambiente e incluso el tipo de riego, representan un estrés abiótico. Es por esto que el objetivo de este trabajo es comparar diferentes condiciones de cultivo sobre la producción de fenoles, flavonoides totales y su capacidad antioxidante en el árnica (Heterotheca inuloides). Para cumplir con este objetivo se obtuvieron las plantas del árnica de manera comercial, colocándose 14 plantas dentro de un invernadero y 14 plantas en cultivo a cielo abierto. Además, cada uno de estos sistemas de cultivo tuvo dos tipos de sistemas de riego, el primero de agua con solución nutritiva y el segundo con agua residual acuícola. También, se elicitó con ácido salicílico a las concentraciones 0.0 mM, 0.5 mM y 1 mM, en dos ocasiones cada 14 días. Se determinó la concentración de fenoles, flavonoides totales y la capacidad antioxidante antes de cada elicitación. Los compuestos fenólicos máximos se presentaron en las plantas cultivadas en campo, regadas con solución nutritiva y elicitadas a 0.5 mM. Los flavonoides totales y la actividad antioxidante se presentaron en las plantas en invernadero, regadas con solución nutritiva, sin efecto sobre la elicitación. De acuerdo con algunos de los resultados obtenidos sé que concluye en que las condiciones de cultivo para la producción de fenoles no son diferentes para la producción de flavonoides y la capacidad antioxidante de dichos compuestos.

Anti-Helicobacter pylori metabolites from Heterotheca inuloides (Mexican arnica)

Preparations of the plant known as “Mexican arnica” (Heterotheca inuloides) have been traditionally used for the treatment of several ailments including stomach ulcers and for relief of colic. To find possible biologically active components against these ailments, we tested the acetone extract as well as different metabolites biosynthesized by this species, including cadinane-type sesquiterpenoids, triterpenes, phytosterols and flavonoids, against Helicobacter pylori. Among these compounds, sesquiterpenes 7-hydroxy-3,4-dihydrocadalene (3) and 7-hydroxy-cadalene (4) exhibited strong anti-H. pylori activity with MICs values of 1.95 and 3.91 μg/mL, respectively. HPLC-UV/DAD analyses revealed that both substances together with related compounds 7, 8 and 9 were the major constituents of the acetone extract. Enzymatic assays and docking studies showed that unlike quercetin (10), a secondary metabolite also isolated from this species, compounds 3 and 4 did not inhibit the activity of urease, a potent virulence factor of H. pylori. Additionally, two new C1-C9 secocadinanes (1 and 2) were isolated from the aerial parts of this species. Their structures were determined by extensive NMR and HRESIMS spectroscopic data analyses.

Effect of natural and semi-synthetic cadinanes from Heterotheca inuloides on NF-κB, Nrf2 and STAT3 signaling pathways and evaluation of their in vitro cytotoxicity in human cancer cell lines

The effects of ten natural cadinane sesquiterpenoids isolated from Heterotheca inuloides on the pathways of the NF-κB, Nrf2 and STAT3 transcription factors were studied for the first time. The main constituent in this species, 7-hydroxy-3,4-dihydrocadalene (1), showed anti-NF-κB activity and activated the antioxidant Nrf2 pathway, which may explain the properties reported for the traditional use of the plant. In addition to the main metabolite, a structurally similar compound, 7-hydroxy-cadalene (2), also displayed anti-NF-κB activity. Thus, both natural compounds were used as templates for the preparation of a novel semi-synthetic derivative set, including esters and carbamates, which were evaluated for their potential in vitro antiproliferative activities against six human cancer cell lines. Carbamate derivatives 32 and 33 were found to exhibit potent activity against human colorectal adenocarcinoma and showed important selectivity in cancer cells. Among ester derivatives, compound 13 was determined to be a more potent NF-κB inhibitor and Nrf2 activator than its parent, 7-hydroxy-3,4-dihydrocadalene (1). Furthermore, this compound decreases levels of phospho-IκBα, a protein complex involved in the NF-κB activation pathway. Molecular simulations suggest that all active compounds interact with the activation loop of the IKKβ subunit in the IKK complex, which is the responsible of IκBα phosphorylation. Thus, we identified two natural, and one semi-synthetic, NF-κB and Nrf2 modulators and two new promising cytotoxic compounds.

Assessment of Mexican Arnica (Heterotheca inuloides Cass) and Rosemary (Rosmarinus officinalis) Extracts on Dopamine and Selected Biomarkers of Oxidative Stress in Stomach and Brain of Salmonella typhimurium Infected rats.

Background:The effects of some natural products on dopamine (DA) and 5-hydroxyindole acetic acid (5-HIAA) in brain of infected models are still unclear.Objective:The purpose of this study was to measure the effect of Mexican arnica/rosemary (MAR) water extract and oseltamivir on both biogenic amines and some oxidative biomarkers in the brain and stomach of young rats under infection condition.Methods:Female Wistar rats (weight 80 g) in the presence of MAR or absence (no-MAR) were treated as follows: group 1, buffer solution (controls); oseltamivir (100 mg/kg), group 2; culture of Salmonella typhimurium (S.Typh) (1 × 106 colony-forming units/rat) group 3; oseltamivir (100 mg/kg) + S.Typh (same dose) group 4. Drug and extracts were administered intraperitoneally every 24 h for 5 days, and S.Typh was given orally on days 1 and 3. On the fifth day, blood was collected to measure glucose and hemoglobin. The brains and stomachs were obtained to measure levels of DA, 5-HIAA, glutathione (GSH), TBARS, H2O2, and total ATPase activity using validated methods.Results:DA levels increased in MAR group treated with oseltamivir alone but decreased in no-MAR group treated with oseltamivir plus S.Typh. 5-HIAA, GSH, and H2O2 decreased in this last group, and ATPase activity increased in MAR group treated with oseltamivir plus S.Typh. TBARS (lipid peroxidation) increased in MAR group that received oseltamivir alone. Most of the biomarkers were not altered significantly in the stomach.Conclusion:MAR extract alters DA and metabolism of 5-HIAA in the brain of young animals infected. Antioxidant capacity may be involved in these effects.SUMMARY The purpose of this study was to measure the effect of Mexican arnica/rosemary water extract and oseltamivir on both biogenic amines and some oxidative biomarkers in the brain and stomach of young rats under infection condition. Results: Mexican arnica and rosemary extract alter dopamine and metabolism of 5-HIAA in the brain of young animals infected. Antioxidant capacity may be involved in these effects. Abbreviations used: AS: Automated system, ATP: Adenosine triphosphate, CNS: Central nervous system, CFU: Colony-forming unit, DA: Dopamine EDTA: Ethylenediaminetetraacetic acid, 5-HIAA: Äcido 5-hidroxindolacético (serotonina), GABA: γ-aminobutyric acid, GSH: Glutathione, H2O2: Hidrogen peroxide, HCLO4: Perchloric acid, iNOS: Inducible nitric oxide synthase, LPS: Lipopolysaccharides, MAR: Arnica/Rosemary, NaCl: Sodium Chloride, NOGSH: nitrosoglutathione, NOS: Nitric oxide, OPT: Ortho-phtaldialdehyde, Pbs: Phosphate buffered saline, pH: potential of Hydrogen, Pi: Inorganic phosphate, ROS: Reactive oxygen species, RNSs: Reactive nitrogen species Tba: Thiobarbaturic acid, TBARS: Thiobarbituric aid reactive, Tca: Trichloroacetic, Tris-HCL: Tris hydrochloride, TSA: Trypticasein Soya Agar

Biological activities of natural and semisynthetic cadinanes from Heterotheca inuloides (Asteraceae). Characterization by HPLC of different populations and structure of additional compounds

Biological activities of natural and semisynthetic cadinanes from Heterotheca inuloides (Asteraceae). Characterization by HPLC of different populations and structure of additional compounds

Thermodynamics and statistical correlation between supercritical-CO2 fluid extraction and bioactivity profile of locally available Mexican plants extracts

Supercritical-CO2 fluid extraction (SFE) is a green technology which is being used for the extraction of bioactive compounds such as pigments and fatty acids, in recent years. Naturally occurring plants or plant-based extracts are considered potential candidates with antioxidant and antimicrobial activities. Therefore, in this work, a range of locally available natural plants i.e. oregano, Mexican arnica also known as Heterotheca inuloides, lemon peel, and blackberry marc was analyzed for the extraction of high-value compounds. A multivariable linear regression model was used to analyze the output variables in relation with the inputs i.e. pressure (P), temperature (T), and co-solvent (CoS). Based on Arrhenius equation, the linear correlativity of the data with an activation energy Ea=6064.14kJ/mol and a pre-exponential factor of k0=0.388s−1 were recorded. The thermodynamic parameters of enthalpy, entropy, and Gibbs free energy were also evaluated, correlating the thermodynamics with the extraction yield of the process.

Identification of Bioactivity, Volatile and Fatty Acid Profile in Supercritical Fluid Extracts of Mexican arnica.

Supercritical fluid extraction (SFE) is a sustainable technique used for the extraction of lipophilic metabolites such as pigments and fatty acids. Arnica plant is considered a potential candidate material with high antioxidant and antimicrobial activities. Therefore, in this study, a locally available Heterotheca inuloides, also known as Mexican arnica, was analyzed for the extraction of high-value compounds. Based on different pressure (P), temperature (T), and co-solvent (CoS), four treatments (T) were prepared. A maximum 7.13% yield was recovered from T2 (T = 60 °C, P = 10 MPa, CoS = 8 g/min), followed by 6.69% from T4 (T = 60 °C, P = 30 MPa, CoS = 4 g/min). Some bioactive sesquiterpenoids such as 7-hydroxycadalene, caryophyllene and δ-cadinene were identified in the extracts by GC/MS. The fatty acid profile revealed that the main components were palmitic acid (C16:0), followed by linoleic acid (C18:2ω6c), α-linolenic acid (C18:3ω3) and stearic acid (C18:0) differing in percent yield per treatment. Antibacterial activities were determined by the agar diffusion method, indicating that all the treatments exerted strong antibacterial activity against S. aureus, C. albicans, and E. coli strains. The antioxidant capacity of the extracts was also measured by three in vitro assays, DPPH, TEAC and FRAP, using Trolox as a standard. Results showed high antioxidant capacity enabling pharmaceutical applications of Mexican arnica.

Synthesis of silver nanoparticles using aqueous extracts of Heterotheca inuloides as reducing agent and natural fibers as templates: Agave lechuguilla and silk

Silver nanoparticles (Ag NPs) were synthesized using a one-pot green methodology with aqueous extract of Heterotheca inuloides as a reducing agent, and the support of natural fibers: Agave lechuguilla and silk. UV–Vis spectroscopy, X-Ray photoelectron spectroscopy XPS and transmission electron microscopy TEM were used to characterize the resulting bionanocomposite fibers. The average size of the Ag NPs was 16nm and they exhibited low polydispersity. XPS studies revealed the presence of only metallic Ag in the nanoparticles embedded in Agave. lechuguilla fibers. Significant antibacterial activities against gram-negative Escherichia coli and gram-positive Staphylococcus aureus were determined. AgO as well as metallic Ag phases were detected when silk threads were used as a substrates hinting at the active role of substrate during the nucleation and growth of Ag NPs. These bionanocomposites have excellent mechanical properties in tension which in addition to the antibacterial properties indicate the potential use of these modified natural fibers in surgical and biomedical applications.

Heterotheca inuloides (Mexican arnica) metabolites protect Caenorhabditis elegans from oxidative damage and inhibit nitric oxide production

We tested a series of compounds derived fromHeterotheca inuloidesfor their ability to protectCaenorhabditis elegansunder stressful conditions.

Additional constituents from Heterotheca inuloides. Absolute configuration of some cadinanes

H. inuloides is one of the plants most used in the Mexican folk medicine and its applications are mainly related with the treatment of inflammatory processes [1]. Cadinane type sesquiterpenes are considered representative constituents of this species, however, the absolute configuration of some of them has not been defined. In the present investigation triterpenes, flavonoids, sterols and eight cadinanes (1 – 8) were isolated from the aerial parts of H. inuloides. Among these, 1 – 4 have not yet been described in the literature. The structures of these metabolites were elucidated on the basis of 1D and 2D NMR spectroscopic data analysis and confirmed by X-ray crystallographic analyses of the majority of them. The absolute configurations of compounds 2 – 5 were determined by comparing their experimental CD spectra with those calculated by the SCF-CI-DV MO method, and further checked via refinement of the Flack parameter using anomalous X-ray scattering from the oxygen atoms and chemical correlation methods. The 4R,10S configuration for compound 2 is the opposite to that of (+)-δ-cadinene isolated from Gossypium hirsutum. These findings are in agreement with previous investigations [2] and allowed to conclude that G. hirsutum and H. inuloides biosynthesize cadinanes of opposite enantiomeric series. All sesquiterpene compounds were evaluated for their anti-inflammatory potential applying the TPA-induced mouse ear edema model. The results revealed that some of these compounds display moderated activity.