Guillermo Schmeda-Hirschmann

Guillermo Schmeda-Hirschmann
Universidad de Talca · Instituto de Química de Recursos Naturales

Dr.rer.nat.

About

305
Publications
60,668
Reads
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8,675
Citations
Citations since 2016
76 Research Items
4393 Citations
20162017201820192020202120220200400600800
20162017201820192020202120220200400600800
20162017201820192020202120220200400600800
20162017201820192020202120220200400600800
Introduction
Chemistry and bioactivity of South American medicinal and food plants. Isolation and structural elucidation of plant and microbial compounds. Chemical profiling and bioactivity. Ethnopharmacology.
Additional affiliations
March 1989 - present
Universidad de Talca
Position
  • Professor (Full)
Description
  • Chemistry. bioactivity and traditional uses of natural products.
Education
April 1982 - June 1984
Technische Universität Berlin
Field of study
  • Organische Chemie
March 1973 - December 1978
Universidad Nacional de Asunción, Paraguay
Field of study
  • Biochemistry

Publications

Publications (305)
Article
Leaves from two Chilean Phaseolus vulgaris landraces cultivated in a growth chamber were assessed for total phenolic (TP), total flavonoid (TF) content and composition, as well as inhibition of α-glucosidase at three different development stages and three sampling times to determine the optimum production of bioactive constituents. The chemical pro...
Article
Full-text available
Fruit traits have historically been interpreted as plant adaptations to their seed dispersers. On the other hand, different environmental factors, which vary spatially and temporally, can shape fruit-trait variation. The mistletoe Tristerix corymbosus has a latitudinal distribution along the South American Pacific rim that encompasses two different...
Article
Phenolics can decrease the levels of advanced glycation end products (AGEs) from proteins, but their mechanisms in complex mixtures are poorly understood. Leaf extracts and the main phenolics from Chilean bean (Phaseolus vulgaris) landraces were assessed for their capacity to inhibit AGEs and oxidative modifications on bovine serum albumin incubate...
Article
Full-text available
Fresh blueberries are prone to softening and dehydration during postharvest, which limits their competitiveness when reaching the final markets. Commercial cultivars 'Duke' and 'Brigitta' exhibit contrasting softening patterns. Although 'Duke' berries usually show higher firmness levels at harvest as compared to 'Brigitta', they display higher soft...
Article
Ethnopharmacological relevance In Paraguay, healers from the Mbya culture treat cancer with a recipe prepared with the native toad Rhinella schneideri. However, the chemical composition and biological effects of the recipe remain unknown. Aim of the study: The aim is to determine the composition of the traditional preparation made using the toad R....
Article
Full-text available
Triadimefon (TDM) and cyproconazole (CPZ) are two triazoles widely used as fungicides. Several azoles were synthesised starting from commercial TDM and CPZ. The compounds were evaluated against phytopathogenic filamentous fungi, including Aspergillus fumigatus (AF), A. niger (AN), A. ustus (AU), A. japonicus (AJ), A. terreus (AT), Fusarium oxysporu...
Article
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The MeOH:H2O (7:3) extracts of leaves from Chilean bean landraces were assessed for total phenolic (TP), total flavonoid (TF), total proanthocyanidin (TPA) content, antioxidant capacity (ORAC, FRAP, TEAC, CUPRAC, DPPH) and the inhibition of enzymes associated with metabolic syndrome (α-glucosidase, α-amylase, pancreatic lipase). The chemical profil...
Article
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The ‘Khenizi’ date palm is one of the most recognized date palm cultivars. It is commonly consumed at the Bisr, Rutab, and Tamr stages of ripening; however, the fruit has a short shelf/storage life at this stage of maturity even with refrigeration. Preharvest application of a natural elicitor chitosan (Ch) has been reported to have positive influen...
Article
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Ethnopharmacological relevance: Information on the use of medicinal plants in the daily life by Paraguayan people is scarce in mainstream scientific literature. The study on the Paraguayan diaspora in the Provincia de Misiones, Argentina, gives an insight into Guaraní traditions, colonial legacy and current search for new medicinal plants to addre...
Article
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“Barhi” date fruit is highly appreciated and widely consumed at the Bisr stage (first edible stage) of maturity. However, maintaining its quality for long periods of time after harvest and throughout marketing is a substantial challenge. Therefore, the objective of this study was to investigate the effects of preharvest spray treatments of 1% chito...
Article
Berries are rich food sources of potentially health-beneficial (poly)phenols. However, they may undergo chemical modifications during gastrointestinal digestion. The effect of simulated gastrointestinal digestion on the content and composition of secondary metabolites from Gaultheria phillyreifolia and G. poeppigii berries was studied. The influenc...
Article
Full-text available
Despite the immense capabilities of the date palm, maintaining the fruit’s quality, marketability, and shelf life is still a challenge. This study aimed to assess the synergistic effect of a preharvest spray application of a natural elicitor chitosan, (Ch) 1% alone and in combination with salicylic acid (SA) 2 mM and calcium chloride (Ca) 3%; (Ch,S...
Chapter
Full-text available
This book provides a broad, well-structured review of strawberries and their cultivation under current environmental conditions. Methods of strawberry cultivation have undergone many improvements, and this book covers aspects from plant propagation, architecture, genetic resources, breeding, abiotic stresses and climate change to evolving diseases...
Article
Numerous dietary polyphenols possess antiglicating activity, but the effects of thermal treatment on this activity are mostly unknown. The effect of thermal treatment in the antiglycating activity of polyphenolic enriched extracts (PEEs) from Ribes cucullatum towards glyoxal-induced glycation of sarcoplasmic proteins was assessed. Sarcoplasmic prot...
Article
The Araucaria araucana kernels are a traditional food in southern Chile and Argentina. The aim of this work was to determine the composition of the phenolic-enriched extracts (PEEs) of the boiled kernels as well as their antioxidant capacity, inhibitory activity on metabolic syndrome-associated enzymes and effect on postprandial oxidative stress in...
Article
Full-text available
Since Rhinella sp. toads produce bioactive substances, some species have been used in traditional medicine and magical practices by ancient cultures in Peru. During several decades, the Rhinella horribilis toad was confused with the invasive toad Rhinella marina, a species documented with extensive toxinological studies. In contrast, the chemical c...
Article
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Gaultheria berries (Ericaceae) are consumed as food or used in folk medicine throughout the world. In the present study, Gaultheria tenuifolia berries were studied to describe their polyphenol and iridoid composition, aroma volatiles, and cytoprotective effects. In total, 14 metabolites were isolated using a combination of countercurrent chromatogr...
Article
A new library of twenty triazole-lapachol and nor-lapachol derivatives was synthesized. The compounds were evaluated against the epimastigotes form of Trypanosoma cruzi and promastigotes of Leishmania braziliensis and L. infantum. The cytotoxicity of the compounds was determined on murine fibroblasts and used to assess the selectivity index. The in...
Article
The Balanophoraceae Ombrophytum subterraneum is an endemic highland food plant occurring in Bolivia, northern Argentina and Chile. The upper part of this parasitic plant is eaten fresh. The aim of this work was to characterize the compounds occurring in the edible part and to assess any differences between the inflorescence and tuber. Ethanol extra...
Article
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The Chilean hazelnut (Gevuina avellana Mol., Proteaceae) is a southern South American nut consumed as a snack and included in different preparations of traditional Chilean cuisine. Recently we described the fatty acid profile, oxylipins, phenolic compounds, as well as the antioxidant capacity. The main compounds of the phenolic-enriched extract wer...
Article
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The "red chilto" (Solanum betaceum Cav) is a native fruit from the Yungas forest of Argentina. Red chilto is a neglected and underutilized native species (NUS). The objective of this work was to evaluate the potentiality of pulp, seed and skin from "red chilto" as a functional food ingredient to add value to a native resource of Argentine Yungas to...
Article
Background: The pods from several South American Prosopis species were a relevant food in arid and semi-arid South America since prehistoric times. The meal from the pods was processed to prepare different foods and beverages. Objective: To revise literature from the archeological evidence of use to the studies on the chemistry and (bio)activity o...
Article
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The crude drug ysypó hû (Adenocalymma marginatum DC., Bignoniaceae) is used traditionally by the Guarani of Eastern Paraguayan as a male sexual enhancer. The aim of the present study was to identify the main constituents of the crude drug and to evaluate the in vitro inhibitory activity towards the enzyme phosphodiesterase-5 (PDE-5). The main compo...
Article
Chilean currants (Ribes magellanicum and Ribes punctatum) are wild polyphenol-rich berries with interesting bioactivities in several in vitro models. The aim of this study was to investigate the effects of the pre-digested PEE (polyphenol-enriched extract) in a simulated colon model. Fruits were extracted, submitted to simulated gastrointestinal di...
Article
Full-text available
The fruits from the Chilean Podocarpaceae Prumnopitys andina have been consumed since pre-Hispanic times. Little is known about the composition and biological properties of this fruit. The aim of this work was to identify the secondary metabolites of the edible part of P. andina fruits and to assess their antioxidant activity by means of chemical a...
Article
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The Argentinean Patagonia berries Berberis microphylla, Berberis darwinii, and Fragaria chiloensis ssp. chiloensis f. patagonica were investigated for their polyphenol content and composition by means of liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry. The in vitro antioxidant activity and...
Article
The polyphenol-enriched extracts (PEEs) of Chilean currants Ribes magellanicum and R. punctatum were submitted to in vitro gastro-intestinal digestion and their anti-inflammatory activities were assessed using differentiated human Caco-2 (clone C2BBe1) cells stimulated with interleukin 1β (IL-1 β). The inhibitory effect of non-digested and digested...
Article
Roasted cotyledons of the Chilean hazelnut (Gevuina avellana) are appreciated as snacks. The aim of our work was to assess the fatty acid, oxylipin and phenolic composition using gas chromatography (GC) coupled to mass spectrometry (MS), ultra- high performance liquid chromatography (UHPLC) coupled to MS and HPLC coupled to diode array detector (HP...
Article
Ethnopharmacological relevance: Rhinella schneideri and Rhinella marina are toad venoms distributed in different parts of the world, including Brazil, Columbia and amazon. Venoms extracted from different species have many clinical applications such as antimicrobial cardiotonics and treatment of cancer. Aim of the study; In this study, we aim to in...
Article
Ethnopharmacological relevance: Patagonia is the southernmost part of the South American continent including Chile and Argentina. Berries and wild fruits have been gathered by the native Patagonians as food and medicine for over 14,000 years. The economic potential of the native berries as health promoting and relevant sources of bioactive substan...
Article
The berries from the native Chilean Gaultheria phillyreifolia and G. poeppigii are appreciated for their sweet taste and aroma. Fruits from both species were investigated for their secondary metabolite composition and antioxidant activity. The extracts were submitted to membrane chromatography to separate anthocyanins from copigments. Four anthocya...
Article
The native Chilean red strawberry (Fragaria chiloensis spp. chiloensis f. patagonica) is a wild strawberry with high polyphenol content and antioxidant activity originating in central-southern Chile. The aim of the present work was to compare the composition and bioactivity of polyphenol-concentrated extracts (PCE) of the fruit, before and after si...
Article
The aim of this work was to compare the anti-inflammatory activity of compounds prepared from terpenes and the synthetic drugs ibuprofen and naproxen. The anti-inflammatory activity of the hybrid compounds was compared with the activity of the parent compounds. This was accomplished using in vitro inhibition of lipoxygenases (LOX) and COX-2, and in...
Article
Ethnopharmacological relevance: Selected Peruvian Amazon plants are macerated into sugar cane distillates to prepare alcoholic beverages used to improve male sexual performance. The tree bark from Campsiandra angustifolia Spruce ex Benth (Fabaceae), Swartzia polyphylla DC (Fabaceae), Minquartia guianensis Aubl. (Olacaceae) and Thynantus panurensis...
Article
Ethnopharmacological relevance: Fabiana imbricata (Solanaceae) is a Patagonian medicinal plant with a long tradition of use. The aim of this review is to provide an integrative overview of the traditional uses, chemistry, bioactivity and chemical profiling of the crude drug. Materials and methods: The information was collected from scientific da...
Article
The design of novel delivery systems to treat vaginal fungal infections is a topic of high interest. Chitosan, being itself antimicrobial and having good mucoadhesive properties, is an excellent candidate as a delivery matrix for active compounds. In this work, chitosan microcapsules containing dry extracts of Argentinean medicinal plants with prov...
Article
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Amaryllidaceae plants are the commercial source of galanthamine, an alkaloid approved for the clinical treatment of Alzheimer’s disease. The chemistry and bioactivity of Chilean representatives of Rhodophiala genus from the family of Amaryllidaceae have not been widely studied so far. Ten collections of five different Chilean Rhodophiala were analy...
Article
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Naturally occurring terpenes were combined by click reactions to generate sixteen hybrid molecules. The diterpene imbricatolic acid (IA) containing an azide group was used as starting compound for the synthesis of all the derivatives. The alkyne group in the terpenes cyperenoic acid, dehydroabietinol, carnosic acid γ-lactone, ferruginol, oleanolic...
Article
Soluble amyloid-β (Aβ) oligomers have been recognized as early neurotoxic intermediates with a key role in the synaptic dysfunction observed in Alzheimer's disease (AD). Aβ oligomers block hippocampal long-term potentiation (LTP) and impair rodent spatial memory. Additionally, the presence of Aβ oligomers is associated with imbalanced intracellular...
Article
The Chilean white strawberry (Fragaria chiloensis spp. chiloensis f. chiloensis) is a semi-domesticated strawberry with high polyphenol content and antioxidant activity occurring in southern Chile. The aim of this work was to compare the composition and bioactivity of the polyphenol-enriched fruit extract (PEE) before and after simulated gastrointe...
Article
Larrea divaricata (Ld), Larrea cuneifolia (Lc) and Larrea nitida (Ln) are shrubs occurring in Northwestern Argentina used in traditional medicine to treat fungal and bacterial infections and as anti-inflammatory. Antibacterial and antifungal activity of several Larrea species has been reported. However, their potential use in vaginal infections has...
Article
Ethnopharmacological relevance: The Argentinean medicinal plant Tetraglochin cristatum (Britton) Rothm is used in traditional medicine by inhabitants from Argentinean northwestern highlands (Puna) to treat candidiasis and as anti-inflammatory. Aim of the study: To assess the potential of the crude drug as an anti-Candida agent with anti-inflamma...
Article
Full-text available
A straightforward one-pot vs. stepwise esterification of lapachol was performed to obtain highly diversified heterocycles. Whereas the one-pot esterification leads to mono esterified lapachol, the stepwise approach generated benzo[h]chromene. Furthermore, benzo[h]chromene architectures with embedded triazole moieties were synthesized through late-s...
Article
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Glucose autoxidation has been proposed as a key reaction associated with deleterious effects induced by hyperglycemia in the eye lens. Little is known about chromophores generated during glucose autoxidation. In this study, we analyzed the effect of oxidative and dicarbonyl stress in the generation of a major chromophore arising from glucose degrad...
Article
Full-text available
The native tree Geoffroea decorticans (cha ar) grows in the arid lands of northern Chile. It has been used as a food plant since prehistoric times. Phenolic-enriched extracts (PEEs) of Chilean cha ar fruits were assessed for their chemical composition, antioxidant properties and inhibition of pro-inflammatory and metabolic syndrome-associated enzym...
Article
Full-text available
Abstract Echinodorus scaber is popularly used to relieve inflammatory complaints and as diuretic. A comparative study on the antinociceptive effect and selected marker compounds in 11 extracts from different locations was undertaken and their antinociceptive effect was assessed. The fingerprints were compared by HPLC-DAD and the content of vitexin,...
Article
The mistol (Ziziphus mistol) is a native food tree occurring in dry areas of Northwestern and Central Argentina. Studies on its functional properties and bioactive compounds are scarce so far. In this work we assess the nutritional and functional components of lyophilized powder of mistol skin, pulp and seed. The powder from the different fruit par...
Conference Paper
The South American Ribes species are very appreciated for their sweet taste. Continuing our research on Ribes species, we decided to investigate the cytoprotective activity of this fruits against oxidative stress. Phenolic-enriched extracts (PEE), the anthocyanin fraction (AF) and copigments fraction (CF) were prepared in the lab. The cytoprotectiv...
Article
The wild Chilean currants Ribes magellanicum and R. punctatum are a good source of polyphenolic compounds. The effect of simulated gastrointestinal digestion (GID) on phenolic content, composition and antioxidant capacity was determined. The inhibitory activity of the non-digested and digested samples towards metabolic syndrome-associated enzymes (...
Article
Full-text available
The prevalence of cytoprotective mechanisms induced by polyphenols such as activation of intracellular antioxidant responses (ICM) and direct free radical scavenging was investigated in native Chilean species of strawberries, raspberries, and currants. Human gastric epithelial cells were co- and preincubated with polyphenolic-enriched extracts (PEE...
Article
Ethnopharmacological relevance: Human groups in the Argentinean Andes highlands (Puna) selected native plants as anti-inflammatory agents. The indications of use are mainly to relieve pain, as infusions, ethanolic extracts or plasters. Aim of the study: The objective of the study was to assess the effect of hydroalcoholic extracts from native hi...
Article
Full-text available
Tropical parasitic diseases such as Chagas disease and leishmaniasis are considered a major public health problem affecting hundreds of millions of people worldwide. As the drugs currently used to treat these diseases have several disadvantages and side effects, there is an urgent need for new drugs with better selectivity and less toxicity. Struct...
Article
Ethnopharmacological relevance: Toads belonging to genus Rhinella are used in Paraguayan traditional medicine to treat cancer and skin infections. Aim of the study: The objective of the study was to determine the composition of venoms obtained from three different Paraguayan Rhinella species, to establish the constituents of a preparation sold i...
Data
Figure S1. Chilean native berries used in this study: Rubus geoides (A), Ribes magellanicum (B) and Fragaria chiloensis ssp. chiloensis f. chiloensis (white fruits) (C). Figure S2. Effect of the Fenton type reaction on cell viability in AGS cells. The black line represents the cell viability of AGS cells exposed to different concentrations of Cu+2....
Article
Full-text available
The roots of the South American vine Herreria montevidensis Klotzsch ex Griseb. (Herreriaceae) are used in traditional medicine by several Amerindian groups of the Paraguayan Chaco. Little is known on the chemistry of the plant, despite its widespread use across the South American Chaco. From the ethyl acetate/methanol 1:1 extract of the roots, fou...
Article
Little is known on the composition of Peruvian Amazon toad venoms. The large toad Rhinella marina is common in the cleared tropical forests of the Iquitos region and is regarded as poisonous. The venom from two different populations of R. marina was collected in the Departamento de Loreto, Perú. The samples were assessed for antiproliferative effec...
Article
Mass spectrometry has become the preferred analytical technique to characterize organic compounds in biological samples because of its sensitivity and selectivity. Hybrid UHPLC coupled to Orbitrap mass analyzer is an innovative state of the art technology that allows fast and accurate metabolomic analyses. In this work, Several flavanones, flavonol...
Article
The phenolic composition of Chilean edible fruits including the native Cactaceae “copao” (Euychnia acida), the Chilean currants (Ribes spp., Grossulariaceae) and the Patagonian raspberry Rubus geoides (Rosaceae) was established by spectroscopic and spectrometric methods. The antioxidant activity of the extracts, phenolic-enriched fractions, main co...