Margarita Gutiérrez

Proximate composition and biological activity of food plants gathered by chilean Amerindians

The proximate composition and biological activity of food plants and mushrooms gathered by Chilean Amerindians were assessed. The gathered plants served primarily as sources of carbohydrates with highest values for Dioscorea tubers, Prosopis alba pods meal and Bromus catharticus seeds. The mushrooms Clavaria coralloides and Boletus loyus proved to be the best protein sources in our survey, but deficient in the amino acids methionine and cysteine. Some extracts of the plants and mushrooms under study showed biological activity as free radical scavengers, enzyme inhibitors, hypotensive or DNA binding effect. Free radical scavenging activity was detected in Cryptocarya alba fruit extract, while Typha angustifolia showed a strong DNA binding effect at 0.50 mg/ml. Methanolic extracts of the Apiaceae species Sanicula graveolens and Apium australe were moderately active as β-glucuronidase inhibitors at 50 fig/ml.ResumenCompositión proximal y actividad biológica de plantas alimenticias recolectadas por Amerindios chilenos. Se determine la composition proximal y la actividad biológica de plantas y hongos alimenticios recolectados por amerindios de Chile. Las plantas colectadas fueron en conjunto una fuente de carbohidratos, con valores mayores en los tubérculos de Dioscorea, la harina de frutos de Prosopis alba y los frutos de Bromus catharticus. Los hongos Clavaria coralloides y Boletus loyus resultaron ser las mejores fuentes proteicas de este estudio, siendo ambos, sin embargo, deficitarios en los aminodcidos esenciales metionina y cisteina. Algunos extrados de las plantas y hongos en estudio mostraron actividad biológica como atrapadores de radicales libres, inhibidores enzimáticos, efecto hipotensor o union al ADN. Se detecta actividad atrapadora de radicales libres en el extracto de frutos de Cryptocarya alba, asi como un fuerte efecto de union al ADN del extracto de Typha angustifolia a 0.50 mg/ml. Extractos metanólicos de las Apiaceae Sanicula graveolens y Apium australe fueron moderadamente activos como inhibidores de la enzima β-glucuronidasa a 50 ug/ml.

Antiplatelet, anticoagulant, and fibrinolytic activity in vitro of extracts from selected fruits and vegetables

A diet rich in fruits and vegetables is known to decrease the risk of cardiovascular disease. However, the information regarding the antithrombotic activity (antiplatelet, anticoagulant, and fibrinolytic) of fruits and vegetables is scarce. The aim of this study was to assess the antithrombotic activity of extracts from fruits and vegetables widely consumed in central Chile. The study included samples of 19 fruits and 26 vegetables, representative of the local diet. The extracts prepared from each sample included an aqueous (juice or pressed solubles) and/or methanol-soluble fraction. The extracts were evaluated for antiplatelet, anticoagulant, and fibrinolytic activity in vitro at a final concentration of 1 mg/ml. The antiplatelet activity was assessed by platelet aggregation inhibition; anticoagulant activity was measured by the prothrombin time (PT), diluted prothrombin time (dPT), activated partial thromboplastin time (APTT), kaolin clotting time (KCT), and thrombin time. The fibrinolytic effect was determined with the euglobin clot lysis time and fibrin plate methods. Extracts of green beans and tomatoes inhibited platelet aggregation induced by ADP and arachidonic acid, in a concentration-dependent manner. The methanolic extracts of grapes prolonged the PT and dPT. Finally, extracts of raspberry prolonged the APTT and also presented fibrinolytic activity. In conclusion, from a screening that included a variety of fruits and vegetables, we found antiplatelet activity in green beans and tomatoes, anticoagulant activities in grapes and raspberries, whereas fibrinolytic activity was observed only in raspberries. Further investigations are necessary to advance in knowledge of the active compounds of these fruits and vegetables and their mechanisms of action.

Fractions of aqueous and methanolic extracts from tomato (Solanum lycopersicum L.) present platelet antiaggregant activity.

Cardiovascular disease (CVD) is the leading cause of death worldwide. Its prevention emphasizes three aspects: not smoking, physical activity and a healthy diet. Recently, we screened the antithrombotic activity of a selected group of fruits and vegetables. Among them, tomato showed an important effect. The aim of this study was to evaluate and characterize the platelet antiaggregatory activity of tomato (Solanum lycopersicum L.). For this, we obtained aqueous and methanolic tomato extracts and evaluated the effect of pH (2 and 10) and temperature (22, 60 and 100°C) on this activity. Furthermore, in order to isolate the antiaggregant principle, we separated tomato extracts into several fractions (A–D) by size exclusion chromatography. In addition, we evaluated the platelet antiaggregating activity ex vivo in Wistar rats. Aqueous and methanolic extracts of tomato treated at 22, 60 and 100°C and pH 2 and 10 still inhibited platelet aggregation (in vitro). Moreover, it was noted that one of the fractions (fraction C), from both aqueous and methanolic extracts, presented the highest activity (∼70% inhibition of platelet aggregation) and concentration dependently inhibited platelet aggregation significantly compared with control (P < 0.05). These fractions did not contain lycopene but presented two peaks of absorption, at 210 and 261 nm, compatible with the presence of nucleosides. In rats treated with tomato macerates, a mild platelet antiaggregating effect ex vivo was observed. Further studies are required to identify the molecules with platelet antiaggregating activity and antiplatelet mechanisms of action.

Bioassay-Guided Isolation and HPLC Determination of Bioactive Compound That Relate to the Antiplatelet Activity (Adhesion, Secretion, and Aggregation) from Solanum lycopersicum

In seeking the functionality of foodstuff applicable to medicine, ripe tomato fruits were found to show an antiplatelet activity. Therefore, the bioactive compound was isolated, structurally identified, and studied for an inhibitory effects on platelet adhesion, secretion, and aggregation. The concentration of adenosine in ripe tomato fruits (pulp and skin extracts) and its processing by-products (paste and pomace) was determined by reversed-phase high-performance liquid chromatography (HPLC). According to platelet aggregation inhibition induced by ADP, the total extract residual was fractionated by liquid-liquid separation, obtaining aqueous, ethyl acetate and petroleum ether extracts. The aqueous extract was subjected to repeated permeation over sephadex LH-20 and semipreparative TLC. The isolate finally obtained was identified as adenosine on the basis of ESI-MS, 1H NMR, HPLC, and UV spectra. Adenosine concentration dependently (2.3–457 μM) platelet aggregation inhibited induced by ADP. Also, adenosine present inhibition of platelet secretion and thrombus formation under flow conditions. The quantitative HPLC analysis revealed significant amounts of adenosine in ripe tomato fruits and its processing by-products. From these results, extracts/fractions of ripe tomato fruits and their processing by-products may be referred to as functional food and functional ingredients containing a compound that inhibits platelet function with a potent preventive effect on thrombus formation, as those that occur in stroke.

Antioxidant and Antiplatelet Activities in Extracts from Green and Fully Ripe Tomato Fruits (Solanum lycopersicum) and Pomace from Industrial Tomato Processing

The consumption of fruits and vegetables is accepted to be one of the strategies to reduce risk factors for these diseases. The aim of this study was to examine potential relationships between the antioxidant and the antiplatelet activities in green mature and fully ripe (red) tomatoes and of lycopene-rich byproducts of tomato paste processing such as pomace. The total phenol content of tomato components was the highest in peels, pulp, and in the mucilaginous myxotesta covering the tomato seeds with values 36.9 ± 0.8, 33.3 ± 00.5, and 17.6 ± 0.9 mg GAE/100 g, respectively (P < 0.05). Tomato peels had the highest antioxidant activity, both, as measured by the FRAP (46.9 ± 0.9 μmol Fe+2/g, P < 0.05) and the DPPH assays (97.4 ± 0.2%, 1000 μg/mL, P < 0.05). Pomace extracts showed the highest antiplatelet activity induced by ADP, collagen, TRAP-6, and arachidonic acid. While the maturation stage of the tomato fruit affected the antioxidant effect, antiplatelet activity was independent of fruit ripeness. Finally, based on the present results, tomato and its byproducts may be considered as a valuable source of antioxidant and antiplatelet activities.

The submarine volcanic succession of the basal complex of Fuerteventura, Canary Islands: A model of submarine growth and emergence of tectonic volcanic islands

Three lithostratigraphic units have been distinguished in the volcanic succession of the basal complex of Fuerteventura Island. These units are, from bottom to top: the submarine volcanic group, the transitional volcanic group, and the subaerial volcanic group. These three groups record the submarine growth and emergence of the island. The volcanism is represented by ultra-alkaline and strongly alkaline igneous series. The igneous activity was due to the presence of an anomalous zone in the sublithospheric mantle, the low density of which also caused uplift of the Mesozoic oceanic crust. Two extensional phases and an intervening contractional phase developed coeval to the generation of the volcanic succession. The submarine volcanic group was deposited in the hanging wall basin of a large listric extensional detachment directed toward the SSW. The transitional volcanic group was syntectonic with respect to a late inversion of the listric detachment. Finally, the subaerial volcanic group resulted from a second episode of WNW extension. This study of the evolution of the basal complex of Fuerteventura serves as the basis for a tectonic model of submarine growth and emergence of volcanic islands.

Protective Mechanisms of Guanosine from Solanum lycopersicum on Agonist-Induced Platelet Activation: Role of sCD40L

In the past 30 years, only three natural products have been sources of new drugs with antiplatelet activity. In this study, we have demonstrated for the first time that guanosine from Solanum lycopersicum possesses antiplatelet (secretion, spreading, adhesion and aggregation) activity in vitro and inhibition of platelet inflammatory mediator of atherosclerosis (sCD40L). According to ADP-induced platelet aggregation inhibiting, the total extract residue was fractionated by liquid chromatography/phase separation, affording an aqueous fraction. This fraction was subjected to repeated permeation over Sephadex LH-20 and semi-preparative TLC. The isolated compound finally obtained was identified as guanosine on the basis of its UV-spectra, HPLC and 1H-NMR data. Guanosine concentration dose-dependently (1 to 4 mmol/L) inhibited platelet secretion and aggregation induced by ADP and collagen. Spread of human platelets on collagen in the presence of guanosine was fully inhibited. After incubation of whole blood with guanosine, the platelet adhesion and aggregation under flow conditions was inhibited concentration dependently (0.2 to 2 mmol/L). At the same concentrations that guanosine inhibits platelet aggregation, levels of sCD40L were significantly decreased. Guanosine is thus likely to exert significant protective effects in thromboembolic-related disorders by inhibiting platelet aggregation.

Isoxazoles: synthesis, evaluation and bioinformatic design as acetylcholinesterase inhibitors

Inhibition of acetylcholinesterase (AChE) is a common treatment for early stages of Alzheimers disease. In this study, nine isoxazoles derivatives were tested for their in‐vitro AChE activity. The molecular docking showed the interaction of the compounds with the active site.

Triterpenoids from Azorella trifurcata (Gaertn.) Pers and their effect against the enzyme acetylcholinesterase

The inhibition of the enzyme acetylcholinesterase is considered as a strategy for the treatment of Alzheimer’s disease, senile dementia, ataxia, and myasthenia gravis. Three lanostane- and two cycloartane-type triterpenes, together with two mulinane-type diterpenes were isolated from petroleum ether extract of the whole shrub of Azorella trifurcata (Gaertn.) Pers. Their effect on the enzyme acetylcholinesterase was assessed as well. In addition, this is the first report of these triterpenes in the genus Azorella .

Biological activity and food analysis of Cyttaria spp. (Discomycetes)

The biological activity and nutritional composition of Chilean collections ofCyttaria berteroi C. darwinii, C. espinosae, C. harioti andC. johowii have been determined. The crude protein, lipid, ash, and carbohydrate content of the samples examined were similar to that of other edible fungi. Amino acid analysis of ChileanCyttaria showed that proteins of all species are deficient in methionine and cysteine and excepting oneC. espinosae collection, all samples proved to be below the WHO values for the essential amino acids valine, isoleucine, leucine, and lysine. The acute oral toxicity test ofC. espinosae in rats showed that doses up to 2.5 g extract/kg body weight (corresponding to 25.7–38.7 g fresh weight/kg) did not produce mortality or macroscopic damage in the organs examined of the test animals. Cyttaria extracts assayed at 50 fig/ml were inactive or moderately active as inhibitors towards the enzymes xanthine oxidase (0-31%) and β-glucuronidase (0-65%), and lacked antifungal and antibacterial effects in a battery of antimicrobial assays. When administered intravenously at 2.5 mg/kg, the water-soluble extract ofCyttaria produced a hypotensive response in rats (-16 to -21%). Furthermore, most of the aqueous extracts ofC. espinosae andC. harioti showed DNA binding activity. The main sterols fromCyttaria espinosae andC. berteroi were identified as dihydrobrassicasterol derivatives. Our study suggests that edibleCyttaria species do not represent an acute toxicity risk for consumers and that their nutritional value is similar to that of other edible, cultivated mushrooms. The preservation ofCyttaria spp. as a food resource is linked to the protection of the temperateNothofagus forests.ResumenSe determinó la composieión proximal y actividad biológica de colecciones chilenas deCyttaria berteroi, C. espinosae, C. harioti, C. johowii yC. darwinii. El contenido de proteína cruda, lípidos, cenizas y carbohidratos fué similar al de otros hongos comestibles. El análisis de aminoácidos de las muestras chilenas demostró que las proteínas de todas las especies deCyttaria investigadas son deficitarias en metionina y cisteína. Exceptuando una colección deC. espinosae, los valores de los aminoácidos esenciales valina, isoleucina, leucina y Usina de todas las muestras fueron inferiores a los valores recomendados por la OMS. Ensayos de toxicidad aguda de extrados deC. espinosae en ratas demostraron que dosis orales de hasta 2.5 g extracto por kg de peso (correspondientes a 25.7–38.7 g peso fresco/kg) no producian mortalidad ni daño macroscópico observable en los órganos examinados en las necropsias. Los extrados deCyttaria fueron inactivos o moderadamente activos al ensayarse como inhibidores de las enzimas xantina oxidasa y ß-glucuronidasa a 50 μg/ml. En una batería de ensayos antimicrobianos, los extrados fueron inactivos. Al administrarse en forma intravenosa a 2.5 mg/kg, los extrados hidrosolubles produjeron una respuesta hipotensora importante en ratas. Los esteroides mayoritarios deCyttaria espinosae yC. berteroi se identificaron como derivados del dihidrobrasicasterol. Este estudio sugiere que las especies comestibles deCyttaria no representan un riesgo de toxicidad aguda para sus consumidores y que su valor nutritivo es similar al de otros hongos comestibles cultivados. La preservación deCyttaria spp. como una fuente de alimentos y posiblemente compuestos bioactivos está ligada a la protección de los bosques templados deNothofagus.