Ceanothanes Derivatives as Peripheric Anionic Site and Catalytic Active Site Inhibitors of Acetylcholinesterase: Insights for Future Drug Design.

Alzheimer's disease (AD) is a multifactorial and fatal neurodegenerative disorder. Acetylcholinesterase (AChE) plays a key role in the regulation of the cholinergic system and particularly in the formation of amyloid plaques; therefore, the inhibition of AChE has become one of the most promising strategies for the treatment of AD, particularly concerning AChE inhibitors that interact with the peripheral anionic site (PAS). Ceanothic acid isolated from the Chilean Rhamnaceae plants is an inhibitor of AChE through its interaction with PAS. In this study, six ceanothic acid derivatives were prepared, and all showed inhibitory activity against AChE. The structural modifications were performed starting from ceanothic acid by application of simple synthetic routes: esterification, reduction, and oxidation. AChE activity was determined by the Ellmann method for all compounds. Kinetic studies indicated that its inhibition was competitive and reversible. According to the molecular coupling and displacement studies of the propidium iodide test, the inhibitory effect of compounds would be produced by interaction with the PAS of AChE. In silico predictions of physicochemical properties, pharmacokinetics, drug-likeness, and medicinal chemistry friendliness of the ceanothane derivatives were performed using the Swiss ADME tool.

Synthesis and Isolation of Phenol- and Thiol-Derived Epicatechin Adducts Prepared from Avocado Peel Procyanidins Using Centrifugal Partition Chromatography and the Evaluation of Their Antimicrobial and Antioxidant Activity.

Polyphenols from agro-food waste represent a valuable source of bioactive molecules that can be recovered to be used for their functional properties. Another option is to use them as starting material to generate molecules with new and better properties through semi-synthesis. A proanthocyanidin-rich (PACs) extract from avocado peels was used to prepare several semi-synthetic derivatives of epicatechin by acid cleavage in the presence of phenol and thiol nucleophiles. The adducts formed by this reaction were successfully purified using one-step centrifugal partition chromatography (CPC) and identified by chromatographic and spectroscopic methods. The nine derivatives showed a concentration-dependent free radical scavenging activity in the DPPH assay. All compounds were also tested against a panel of pathogenic bacterial strains formed by Listeria monocytogenes (ATCC 7644 and 19115), Staphylococcus aureus (ATCC 9144), Escherichia coli (ATCC 11775 and 25922), and Salmonella enterica (ATCC 13076). In addition, adducts were tested against two no-pathogenic strains, Limosilactobacillus fermentum UCO-979C and Lacticaseibacillus rhamnosus UCO-25A. Overall, thiol-derived adducts displayed antimicrobial properties and, in some specific cases, inhibited biofilm formation, particularly in Listeria monocytogenes (ATCC 7644). Interestingly, phenolic adducts were inactive against all the strains and could not inhibit its biofilm formation. Moreover, depending on the structure, in specific cases, biofilm formation was strongly promoted. These findings contribute to demonstrating that CPC is a powerful tool to isolate new semi-synthetic molecules using avocado peels as starting material for PACc extraction. These compounds represent new lead molecules with antioxidant and antimicrobial activity.

Cyclopeptide Alkaloids from Discaria chacaye (Rhamnaceae) as Result of Symbiosis with Frankia (Actinomycetales).

Cyclopeptide alkaloids with different biological activities are present in plants of the family Rhamnaceae. Plants of this family grow in a symbiotic relationship with aerobic Gram-positive actinomycetes belonging to the genus Frankia. This goal of this research was a study of the comparative profile of alkaloids present in Discaria chacaye and to establish a connection between the presence or absence of Frankia sp. and the alkaloids. In addition, insecticidal activities of the alkaloidal extract were examined. A total of 24 alkaloids were identified, of which 12 have a benzylisoquinoline skeleton, 9 were cyclopeptides, 2 isoquinolines, and 1 aporphine. The presence of cyclopeptide alkaloids is associated with Frankia nodules in the plant root. The alkaloid extracts showed insecticidal activity with mortality dose-dependence and LD50 values between 44 to 71 µg/mL.

Dyhidro-ß-agarofurans natural and synthetic as acetylcholinesterase and COX inhibitors: interaction with the peripheral anionic site (AChE-PAS), and anti-inflammatory potentials.

In order to find molecules of natural origin with potential biological activities, we isolate and synthesise compounds with agarofuran skeletons (epoxyeudesmanes). From the seeds of Maytenus disticha and Maytenus magellanica we obtained six dihydro-ß-agarofurans, and by means of the Robinson annulation reaction we synthesised five compounds with the same skeleton. The structures were established on the basis of NMR, IR, and MS. The evaluated compounds showed inhibitory activity on the acetylcholinesterase enzyme and on the COX enzymes. Compound 4 emerged as the most potent in the acetylcholinesterase inhibition assay with IC50 17.0 ± 0.016 µM on acetylcholinesterase (AChE). The compounds evaluated were shown to be selective for AChE. The molecular docking, and the propidium displacement assay suggested that the compounds do not bind to the active site of the enzyme AChE, but rather bind to the peripheral anionic site (PAS) of the enzyme, on the other hand, the natural compound 8, showed the best inhibitory activity on the COX-2 enzyme with an IC50 value of 0.04 ± 0.007 µM. The pharmacokinetic profile calculated in silico using the SWISSADME platform shows that these molecules could be considered as potential drugs for the treatment of neurodegenerative diseases such as AD.

Assessments of Ceanothanes Triterpenes as Cholinesterase Inhibitors: An Investigation of Potential Agents with Novel Inspiration for Drug Treatment of Neurodegenerative Diseases.

The purpose of this study was to determine the inhibitory capacity of ceanothanes triterpenes isolate from Chilean Rhamnaceae on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. Seven ceanothanes triterpenes were isolated from aerial parts of plant material by classical phytochemical methods or prepared by the hemisynthetic method. Structures were determined by the spectroscopic method (1H-NMR and 13C NMR) and mass spectrometry (MS). AChE and BChE activity were determined by the Ellmann method for all compounds. All tested compounds exerted a greater affinity to AChE than to BChE, where compound 3 has an IC50 of 0.126 uM for AChE and of >500 uM to BChE. Kinetic studies indicated that its inhibition was competitive and reversible. According to the molecular coupling and displacement studies of the propidium iodide test, the inhibitory effect of compound 3 would be produced by interaction with the peripheral anionic site (PAS) of AChE. The compounds tested (1−7) showed an important inhibitory activity of AChE, binding to PAS. Therefore, inhibitors that bind to PAS would prevent the formation of the AChE-Aß complex, constituting a new alternative in the treatment of Alzheimer's disease (AD).

Electrospun Fibers Loaded with Natural Bioactive Compounds as a Biomedical System for Skin Burn Treatment. A Review.

Burns are a major threat to public health and the economy due to their costly and laborious treatment and high susceptibility to infection. Efforts have been made recently to investigate natural bioactive compounds with potential use in wound healing. The importance lies in the capacities that these compounds could possess both in infection control by common and resistant microorganisms, as well as in the regeneration of the affected tissues, having in both cases low adverse effects. However, some bioactive molecules are chemically unstable, poorly soluble, and susceptible to oxidative degradation or have low bioavailability. Therefore, developing new technologies for an efficient treatment of wound healing poses a real challenge. In this context, electrospun nanofibers have gained increasing research interest because bioactive molecules can be easily loaded within the nanofiber, resulting in optimal burst control and enhanced drug stability. Additionally, the nanofibers can mimic the extracellular collagen matrix, providing a suitable highly porous structural support for growing cells that facilitate and accelerate skin burns healing. This review gives an overview of the current state of electrospun fibers loaded with natural bioactive compounds as a biomedical system for skin burn treatment.

Anthocyanins from Aristotelia chilensis Prevent Olanzapine-Induced Hepatic-Lipid Accumulation but Not Insulin Resistance in Skeletal Muscle Cells.

Type 2 diabetes and obesity are major problems worldwide and dietary polyphenols have shown efficacy to ameliorate signs of these diseases. Anthocyanins from berries display potent antioxidants and protect against weight gain and insulin resistance in different models of diet-induced metabolic syndrome. Olanzapine is known to induce an accelerated form of metabolic syndrome. Due to the aforementioned, we evaluated whether delphinidin-3,5-O-diglucoside (DG) and delphinidin-3-O-sambubioside-5-O-glucoside (DS), two potent antidiabetic anthocyanins isolated from Aristotelia chilensis fruit, could prevent olanzapine-induced steatosis and insulin resistance in liver and skeletal muscle cells, respectively. HepG2 liver cells and L6 skeletal muscle cells were co-incubated with DG 50 µg/mL or DS 50 µg/mL plus olanzapine 50 µg/mL. Lipid accumulation was determined in HepG2 cells while the expression of p-Akt as a key regulator of the insulin-activated signaling pathways, mitochondrial function, and glucose uptake was assessed in L6 cells. DS and DG prevented olanzapine-induced lipid accumulation in liver cells. However, insulin signaling impairment induced by olanzapine in L6 cells was not rescued by DS and DG. Thus, anthocyanins modulate lipid metabolism, which is a relevant factor in hepatic tissue, but do not significantly influence skeletal muscle, where a potent antioxidant effect of olanzapine was found.

Polyphenolic Compounds Extracted and Purified from Buddleja Globosa Hope (Buddlejaceae) Leaves Using Natural Deep Eutectic Solvents and Centrifugal Partition Chromatography.

Chemical profiling of Buddleja globosa was performed by high-performance liquid chromatography coupled to electrospray ionization (HPLC-DAD-ESI-IT/MS) and quadrupole time-of-flight high-resolution mass spectrometry (HPLC-ESI-QTOF/MS). The identification of 17 main phenolic compounds in B. globosa leaf extracts was achieved. Along with caffeoyl glucoside isomers, caffeoylshikimic acid and several verbascoside derivatives (ß-hydroxyverbascoside and ß-hydroxyisoverbascoside) were identified. Among flavonoid compounds, the presence of 6-hydroxyluteolin-7-O-glucoside, quercetin-3-O-glucoside, luteolin 7-O-glucoside, apigenin 7-O-glucoside was confirmed. Campneoside I, forsythoside B, lipedoside A and forsythoside A were identified along with verbascoside, isoverbascoside, eukovoside and martynoside. The isolation of two bioactive phenolic compounds verbascoside and forsythoside B from Buddleja globosa (Buddlejaceae) was successfully achieved by centrifugal partition chromatography (CPC). Both compounds were obtained in one-step using optimized CPC methodology with the two-phase solvent system comprising ethyl acetate-n-butanol-ethanol-water (0.25:0.75:0.1:1, v/v). Additionally, eight Natural Deep Eutectic Solvents (NADESs) were tested for the extraction of polyphenols and compared with 80% methanol. The contents of verbascoside and luteolin 7-O-glucoside after extraction with 80% methanol were 26.165 and 3.206 mg/g, respectively. Among the NADESs tested in this study, proline- citric acid (1:1) and choline chloride-1, 2- propanediol (1:2) were the most promising solvents. With these NADES, extraction yields for verbascoside and luteolin 7-O-glucoside were 51.045 and 4.387 mg/g, respectively. Taken together, the results of this study confirm that CPC enabled the fast isolation of bioactive polyphenols from B. globosa. NADESs displayed higher extraction efficiency of phenolic and therefore could be used as an ecofriendly alternative to classic organic solvents.

Assessment of Insecticidal Activity of Benzylisoquinoline Alkaloids from Chilean Rhamnaceae Plants against Fruit-Fly Drosophila melanogaster and the Lepidopteran Crop Pest Cydia pomonella.

The Chilean plants Discaria chacaye, Talguenea quinquenervia (Rhamnaceae), Peumus boldus (Monimiaceae), and Cryptocarya alba (Lauraceae) were evaluated against Codling moth: Cydia pomonella L. (Lepidoptera: Tortricidae) and fruit fly Drosophila melanogaster (Diptera: Drosophilidae), which is one of the most widespread and destructive primary pests of Prunus (plums, cherries, peaches, nectarines, apricots, almonds), pear, walnuts, and chestnuts, among other. Four benzylisoquinoline alkaloids (coclaurine, laurolitsine, boldine, and pukateine) were isolated from the above mentioned plant species and evaluated regarding their insecticidal activity against the codling moth and fruit fly. The results showed that these alkaloids possess acute and chronic insecticidal effects. The most relevant effect was observed at 10 µg/mL against D. melanogaster and at 50 µg/mL against C. pomonella, being the alteration of the feeding, deformations, failure in the displacement of the larvae in the feeding medium of D. melanogaster, and mortality visible effects. In addition, the docking results show that these type of alkaloids present a good interaction with octopamine and ecdysone receptor showing a possible action mechanism.

Isolation of Three Lycorine Type Alkaloids from Rhodolirium speciosum (Herb.) Ravenna Using pH-Zone-Refinement Centrifugal Partition Chromatography and Their Acetylcholinesterase Inhibitory Activities.

Preparative separation of three lycorine type alkaloids from Rhodolirum speciosum (Amaryllidaceae) was successfully carried out using pH-zone-refinement centrifugal partition chromatography (CPC) using the solvent system methyl-tert-butyl ether/acetonitrile/water (4:1:5, v/v/v) in descending mode. Using this system, Alkaloid 1 (165.7 mg, 88.2%, purity), 2 (60.1 mg, 97.7% purity) and 3 (12.3 mg, 84.4% purity) were obtained in one step. For structure elucidation, the pure alkaloids were subjected to spectroscopy analysis using nuclear magnetic resonance experiments (1H-NMR, 13C-NMR) and gas chromatography coupled with mass spectrometry (GC-MS). Alkaloids 1, 2, and 3 were identified as 1-O-acetyl-5,6-dehydrolycorine, 1-O-acetyl-lycorine, and 1,2-O-diacetyl-5,6-dehydrolycorine, respectively. The acetylcholinesterase inhibitory activity of these alkaloids was IC50 151.1 µg/mL, IC50 203.5 µg/mL, IC50 470.0 µg/mL, and IC50 17.1 µg/mL, respectively.

Green Extraction of Alkaloids and Polyphenols from Peumus boldus Leaves with Natural Deep Eutectic Solvents and Profiling by HPLC-PDA-IT-MS/MS and HPLC-QTOF-MS/MS.

Peumus boldus Mol., is a Chilean medicinal tree used for gastrointestinal and liver diseases. Such medicinal properties are associated with the presence of bioactive flavonoids and aporphine alkaloids. In this study, a new green and efficient extraction method used seven natural deep eutectic solvents (NADES) as extraction media. The extraction efficiency of these NADES was assessed, determining the contents of boldine and total phenolic compounds (TPC). Chemical profiling of P. boldus was done by high-performance liquid chromatography coupled to photo diode array detector and electrospray ion-trap mass spectrometry (HPLC-PDA-ESI-IT/MS) and electrospray ionization quadrupole time-of-flight high-resolution mass spectrometry (HPLC-ESI-QTOF-MS). Among the NADES tested, NADES4 (choline chloride-lactic acid) and NADES6 (proline-oxalic acid) enable better extraction of boldine with 0.427 ± 0.018 and 2.362 ± 0.055 mg of boldine g-1 of plant, respectively. Extraction of boldine with NADES4 and NADES6 was more efficient than extractions performed with methanol and water. On the other hand, the highest TPC were obtained using NADES6, 179.442 ± 3.79 mg of gallic acid equivalents (GAE g-1). Moreover, TPC in extracts obtained with methanol does not show significant differences with NADES6. The HPLC-PAD-MS/MS analysis enable the tentative identification of 9 alkaloids and 22 phenolic compounds. The results of this study demonstrate that NADES are a promising green extraction media to extract P. boldus bioactive compounds and could be a valuable alternative to classic organic solvents.

In vitro micropropagation and alkaloids analysis by GC-MS of Chilean Amaryllidaceae plants: Rhodophiala pratensis.

INTRODUCTION: Plants from Amaryllidaceae family are of interest since they produce a particular type of alkaloid useful for the treatment of neurodegenerative diseases of the central nervous system, such as Galanthamine. Given the low content of these secondary metabolites in the plant, it is necessary to study mechanisms to increase the productivity of them. OBJECTIVE: To obtain fast qualitative and quantitative analysis of the alkaloids and extend the understanding of biosynthesis and metabolism in these kinds of plants. Furthermore, establish a reliable, simple and fast analytical method for the in vitro callus culture of vegetative organs for Rhodophiala pratensis species. METHODS: The alkaloids composition of the callus culture of R. pratensis were analysed by gas chromatography coupled with mass spectrometry (GC-MS). RESULTS: A methodology for the qualitative and quantitative analysis of the alkaloids present in fresh callus culture of this wild plant species was established. The analysis showed alternation in the alkaloids type ratio and number of compounds between wild bulbs, in vitro bulbs and callus. It was possible to identify 24 alkaloids from a pool of 60 signals whose fragmentation pattern corresponds to the alkaloids of Amaryllidaceae plants. Together with the aforementioned, the amount and type of alkaloid present in the plant material obtained by in vitro culture of R. pratensis was determined in the same way. The results show the high biosynthetic potential of in vitro grown bulbs and callus tissue that are able to produce significant amounts of pharmacologically relevant alkaloids from R. pratensis in various proportions that depend on the culture conditions such as supplementation with growth substances. The in vitro grown bulbs produce an alkaloidal extract that contain a 52.6% w/w of alkaloids. CONCLUSION: This study allowed the alkaloid content in callus culture of R. pratensis to be found by means of GC-MS. These results allowed a relationship between the type of growth regulator and the type of alkaloids found to be established. Finally, we can say that the results achieved to state that the production of alkaloids using different combinations of growth regulators could be directed during in vitro micropropagation from provided plant material.

Fractionation and Hydrolyzation of Avocado Peel Extract: Improvement of Antibacterial Activity.

Avocado Hass (Persea americana Mill) peel extract (APE) has the potential as a natural ingredient to substitute for chemical preservatives. The objectives of this study were to assess the phytochemical composition by high-performance liquid chromatography-quadrupole time-of-flight mass/mass spectrometry (HPLC-qTOF-MS/MS), total phenolic content (TPC), proanthocyanidin (PAC) content, and antioxidant activity of the APE, the organic fraction (OF), the aqueous fraction (AF), and the acid-microwave hydrolyzed APE (HAPE), on the antibacterial activity (ABA). The results indicated that APE and OF contained (p ˂ 0.05) a higher phenolic composition and antioxidant activity than AF and HAPE. The ABA specified that Pseudomonas aeruginosa and Bacillus cereus were inhibited by all the extracts (minimal inhibitory concentration-MIC ≥ 500 µg/mL), Staphylococcus aureus was only significantly inhibited by APE (≥750 µg/mL), the same MIC was observed for the OF on Salmonella spp. and Listeria monocytogenes. The HAPE increased the inhibitory efficiency up to 25% on Escherichia coli and Salmonella spp. (MIC ≥ 750 µg/mL), and 83.34% on L. monocytogenes (MIC ≥ 125 µg/mL) compared to APE (MIC ≥ 750 µg/mL). Also, HAPE inhibited the biofilm formation at the lowest concentration (125 µg/mL); meanwhile, the biofilm disruption showed to be concentration-time-dependent (p ˃ 0.05) compared to amoxicillin. In conclusion, the fractionation and hydrolyzation of APE improved the ABA; thus, those strategies are useful to design new antimicrobial compounds.

Chilean Rhubarb, Gunnera tinctoria (Molina) Mirb. (Gunneraceae): UHPLC-ESI-Orbitrap-MS Profiling of Aqueous Extract and its Anti-Helicobacter pylori Activity.

The full UHPLC-MS metabolome fingerprinting and anti-Helicobacter pylori effect of Gunnera tinctoria (Molina) Mirb. (Nalca) total extract (GTE) and fractions prepared from its edible fresh petioles were evaluated. The activity of G. tinctoria against H. pylori strains ATCC 45504 and J99 was assessed in vitro by means of agar diffusion assay, Minimum Inhibition Concentration (MIC), and Minimum Bactericidal Concentration (MBC), while killing curve and transmission electronic microscopy (TEM) were conducted in order to determine the effect of the plant extract on bacterial growth and ultrastructure. Additionally, the inhibitory effect upon urease was evaluated using both the Jack Bean and H. pylori enzymes. To determine which molecules could be responsible for the antibacterial effects, tentative identification was done by ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-Q-Orbitrap®-HR-MS). Furthermore, the total G. tinctoria extract was fractionated using centrifugal partition chromatography (CPC), giving four active fractions (1-4). It was determined that the crude extract and centrifugal partition chromatography fractions of G. tinctoria have a bactericidal effect being the lowest MIC and MBC = 32 µg/ml. In the killing curves, fraction one acts faster than control amoxicillin. In the urease assay, F3 exhibited the lowest IC50 value of 13.5 µg/ml. Transmission electronic microscopy showed that crude G. tinctoria extract promotes disruption and separation of the cellular wall and outer membrane detachment on H. pylori causing bacterial cell death.

Neuroprotective activity of isoquinoline alkaloids from of Chilean Amaryllidaceae plants against oxidative stress-induced cytotoxicity on human neuroblastoma SH-SY5Y cells and mouse hippocampal slice culture.

In this study we evaluate the chemical composition and neuroprotective effects of alkaloid fractions of the Amaryllidaceae species Rhodophiala pratensis, Rhodolirium speciosum, Phycella australis and Phaedranassa lehmannii. Gas chromatography-mass spectrometry (GC/MS) enable the identification of 41 known alkaloids. Rhodolirium speciosum and Rhodophiala pratensis were the most active extracts against acetylcholinesterase (AChE), with IC50 values of 35.22 and 38.13 µg/mL, respectively. The protective effect of these extracts on human neuroblastoma cells (SH-SY5Y) subjected to mitochondrial oxidative stress with rotenone/oligomycin A (R/O) and toxicity promoted by okadaic acid (OA) was evaluated. Only Phycella australis and Rhodophiala pratensis at 0.75 and 1.5 µg/mL, tend to reverse the cell death induced by R/O by around 12%. In OA assay, alkaloid fractions of Phycella Australis and Phaedranassa lehmannii displayed a concentration-dependent (0.375-3.0 µg/mL) effect with a maximum neuroprotective response of 78% and 84%, respectively. Afterwards, neuroprotective effects of Phycella australis (3 and 6 µg/mL) in mouse hippocampal slices stressed with oxygen glucose deprivation/reoxygenation (OGD/R), shown a protection greater than 14%. Finally, Phycella Australis (6 µg/mL) reverted the cell viability from 65% to 90% in slices treated with OA, representing a protection of 25% attributable to the alkaloids of this species.

Effects of Bauhinia forficata Link Tea on Lipid Profile in Diabetic Patients.

Twenty-five type 2 diabetic volunteer patients (mean age 62 years) were recruited in a quasi-experimental study without a control group to evaluate the effects of Bauhinia forficata Link tea on lipid profiles. Participants drank the tea of 0.4% B. forficata in 200 mL of water twice a day for 3 months. The clinical parameters evaluated were cholesterol and triglycerides (mg/dL), total cholesterol (mg/dL), weight (kg), postprandial glycemia (mg/dL), and glycosylated hemoglobin (HbA1c). For the study period, statistically significant decreases in triglycerides and total cholesterol levels of 48 and 17 mg/dL, respectively, were observed. B. forficata tea as a complementary therapy in type 2 diabetic patients may help to reduce the levels of some lipid profile parameters. Further studies are suggested to evaluate the effect of the tea.

Chemical properties and assessment of the antioxidant capacity of native species from the genus Ugni / Características químicas y evaluación de la capacidad antioxidante de especies del género Ugni

Introduction: Ugni molinae Turcz., Ugni candollei Barn. (Berg) and Ugni selkirkii (Hook. et Arn.) Berg are Chilean species that share morphological characteristics and they are distributed in geographic locations with very diverse habitats. Its is considered important for the characterization of the Chilean flora to determine if there are similarities in the sort of chemical compounds among species with close morphological relations, growing in different habitats and their consequent biological activity. Objective: to assess the chemical composition and the antioxidant capacity of leaf extracts from the Chilean species of the genus Ugni, and to compare with the U. molinae characteristics. Methods: composition of chemical compounds was determined by chromatographic methods (HPLC-ESI-MS). The antioxidant capacity was assessed by DPPH, ABTS and by stabilization of the hydroxyl radical. Results: as expected, given the great morphological similarity existing among the three species of Ugni that grow in Chile, similarities were found in their chemical composition. Nevertheless, it was also expectable to find variations among them. Thus, U. candollei and U. selkirkii are the species that present greater content and variety of phenolic and terpenic compounds. These species exert greater antioxidant capacity in comparison toU. molinae. U. candollei hightlights for its flavonoid content such as glycosides and quercetin derivatives, and the species U. selkirkii, is important in galotannins. U. molinae is characterized in ellagic acids derivatives. Conclusion: these data and the morphological characteristics could become a useful toll in order to determine the closeness degree among these species(AU

Introducción: Ugni molinae Turcz., Ugni candollei (Barn.) Berg y Ugni selkirkii (Hook. et Arn.) Berg son especies chilenas que comparten características morfológicas y se distribuyen en lugares geográficos con muy diversos hábitats. Se considera importante para la caracterización de la flora chilena determinar si hay similitudes en el tipo de compuestos químicos entre especies con relaciones morfológicas cercanas, que crecen en diferentes hábitats y su actividad biológica consecuente. Objetivo: evaluar la composición química y la capacidad antioxidante de extractos de hojas de las especies chilenas del género Ugni, y compararlas con las características de la especie U. molinae. Métodos: la composición química se determinó por métodos cromatográficos (HPLC-ESI-MS). La capacidad antioxidante se evaluó por los métodos DPPH, ABTS, y la estabilización del radical hidroxilo. Resultados: como era de esperar, dada la gran similitud morfológica existente entre las tres especies de Ugni que crecen en Chile, se encontraron similitudes en su composición química. Sin embargo, también era esperable encontrar variaciones entre ellas. Por lo tanto, U. candollei y U. selkirkii son las especies que presentan mayor contenido y variedad de compuestos fenólicos y terpénicos. Estas especies ejercen una mayor capacidad antioxidante en comparación con U. molinae. U. candollei se caracteriza por su contenido en flavonoides como quercetina glucósidos y sus derivados, y la especie U. selkirkii, por la presencia de galotaninos. U. molinae se caracteriza por contener derivados del ácido elágico. Conclusión: estos datos y las características morfológicas podrían convertirse en una herramienta útil para determinar el grado cercanía entre estas especies(AU)

In vitro determination of the antioxidant capacity of extracts and phenolic compounds from Ugni molinae Turcz. leaves / Determinación in vitro de la capacidad antioxidante de extractos y compuestos fenólicos de hojas de Ugni molinae Turcz.

Introduction: Ugni molinae Turcz., (Myrtaceae) is a plant that is distributed in central-southern of Chile, including Juan Fernández Islands. The leaves have been used in folk medicine for diarrhea and oral infections due to their astringent and antiseptic properties. Objective: antioxidant activity of two extracts (ethyl acetate and methanol) from U. molinae leaves was assessed in several assays. Methods: HPLC (high performance liquid chromatography) for chemical analysis and in vitro antioxidant methods. Results: HPLC profiling of both extracts showed the presence of flavan-3-ols (catechin) and gallic acid, flavonoids and caffeic acid derivates as main constituents. These extracts showed significant activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH), cupric ion reducing antioxidant capacity (CUPRAC) and hydroxyl radical assays. It is noteworthy that bleaching of b-carotene-linoleate liposomes and copper-induced oxidation of human LDL were prevented by both extracts. Conclusions: results suggest that polyphenol-rich extracts of U. molinae could slow down lipid peroxidation and limit free radical damage.

Introducción: Ugni molinae Turcz. (Myrtaceae) es una planta que se distribuye en el centro-sur de Chile, incluido el archipiélago de Juan Fernández. Las hojas se han utilizado en medicina popular para diarreas e infecciones bucales, por sus propiedades astringentes y antisépticas. Objetivo: la actividad antioxidante de los dos extractos (acetato de etilo y metanólicol) de las hojas de Ugni molinae se evaluó mediante diferentes ensayos. Métodos: HPLC (high performance liquid chromatography) para el análisis químico y los métodos antioxidantes in vitro. Resultados: los perfiles HPLC de ambos extractos mostraron la presencia de flavan-3-oles (catequinas) y ácido gálico, flavonoides y derivados del ácido cafeico como constituyentes principales. Estos extractos mostraron actividad significativa frente a 2,2-difenil-1-picrilhidrazilo (DPPH), capacidad reductora del ión cobre (CUPRAC) y ensayos frente al radical hidroxilo. Es importante destacar que el blanqueamiento de liposomas de b-caroteno-linoleato y la oxidación producida por cobre de LDL (low density lipoprotein) humana fueron evitados por ambos extractos. Conclusiones: los resultados sugieren que los extractos de Ugni molinae ricos en polifenoles podrían evitar la peroxidación lipídica y el daño de radicales libres.

Efectos antimicrobianos de extractos de plantas chilenas de las familias Lauraceae y Atherospermataceae / Antimicrobial effects of extracts from Chilean plants of Lauraceae and Atherospermataceae families

Introducción: las familias Lauraceae y Atherospermataceae son fuentes importantes de aceites esenciales, en los que se ha observado actividad frente a microorganismos. Este estudio se realizó en las especies chilenas: Cryptocarya alba Looser (Peumo), Persea lingue (Ruiz & Pav.) Nees (Lingue) de la familia Lauraceae y Laurelia sempervirens (Ruiz & Pav.) Tul. (laurel chileno) de la familia Atherospermataceae. De estas solo se conocen antecedentes morfológicos y usos populares, sin presentar estudios acabados sobre la composición química ni la actividad biológica. Objetivo: evaluar la actividad de sus aceites esenciales frente a microorganismos y aportar antecedentes de su composición química. Métodos: las muestras se recolectaron en la región del Bío-Bío. Se obtuvieron aceites esenciales por hidrodestilación. La caracterización química se realizó por CG-MS. La actividad antimicrobiana se evaluó a través de ensayos antifúngicos por el método de dilución en agar y difusión de vapor frente a Penicillium sp. y Fusarium oxysporum; los ensayos antibacterianos a través del método del pocillo y papel frente a Escherichia coli, Bacillus subtillis, Pseudomonas aeruginosa y Staphyloccoccus aureus. Resultados: estos indican que los aceites esenciales de las 3 especies poseen un efecto selectivo frente a hongos y bacterias, lo cual sugiere que su naturaleza química diferente tendría un papel en el mecanismo de acción. Conclusiones: se sugiere la continuación de estudios concentrando esfuerzos en el desarrollo de productos para el control de microorganismos que provocan pérdidas económicas y en la salud humana.

Introduction: the antimicrobial activity has been reported for the essential oils of some species in the families Lauraceae and Atherospermataceae. The present study was conducted with three Chilean species: Cryptocarya alba Looser (Peumo) and Persea lingue (Ruiz & Pav.) Nees (Lingue) from the family Lauraceae, and Laurelia sempervirens (Ruiz & Pav.) Tul. (Chilean laurel) from the family Atherospermataceae. The morphological aspects and the popular uses of these species are the only known aspects. Thorough studies of their chemical composition and biological activity are lacking. Objective: to evaluate the activity of the essential oils against microorganisms and to provide information on the chemical composition of these species. Methods: samples were collected in the Bío-Bío Region and essential oils were obtained by steam distillation. Chemical characterization was done using GC-MS. Antimicrobial activity was evaluated against Penicillium sp. and Fusarium oxysporum through antifungal agar dilution and vapor diffusion assays. Antibacterial tests against Escherichia coli, Bacillus subtilis, Pseudomonas aeruginosa, and Staphylococcus aureus, were carried out using agar disk and well diffusion assays. Results: the results for the essential oils from the three species indicated selective activity against fungi and bacteria, suggesting that the different chemical features of these oils may play a role in their mechanisms of action. Conclusions: further studies focusing efforts on developing products to control microorganisms that cause economic losses and affect human health.

Actividad de extractos ricos en polifenoles de cáscara de manzana sobre Helicobacter pylori: estudios in vitro e in vivo / Activity of extracts rich in polyphenols of apple peel on Helicobacter pylori: in vitro and in vivo studies

Helicobacter pylori (H. pylori) infecta la mucosa gástrica de la mitad de la población mundial, y es el único microorganismo conocido capaz de sobrevivir exitosamente en el estómago humano. Muchos estudios han establecido a H. pylori como agente etiológico del cáncer gástrico, linfoma del tejido linfoide asociado a la mucosa (MALT), y la úlcera péptica. En efecto, en 1994, la Agencia Internacional para la Investigación sobre el Cáncer (IARC) de la Organización Mundial de la Salud (OMS), definió a H. pylori como un agente carcinógeno definitivo (tipo I) en el cáncer gástrico. Es importante destacar que en Chile la prevalencia de la infección por H. pylori normalizada para la población mundial de entre 20 y 60 años es aproximadamente de un 80%. Este alto nivel de infección por H. pylori explicaría por qué Chile tiene la mayor tasa de mortalidad por cáncer gástrico en América, y se ubica entre los cinco primeros países del mundo con respecto a la mortalidad por cáncer gástr