Examinando por Autor "Sepúlveda, Beatriz"
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- PublicaciónSólo datosErythrinoid and indol alkaloids isolated from the seeds of Erythrina rubrinervia Kunth: Chemotaxonomic significance(Biochemical Systematics and Ecology, 2021-06-16) Urrea Florián, Simón; Sepúlveda, Beatriz; Torres-Benítez, Alfredo; Simirgiotis, Mario J.; Fuentes-Estrada, Marcial; Areche, Carlos; García Beltrán, OlimpoIn the present work, we report the isolation of five alkaloids from the seeds of Erythrina rubrinervia. Four of the isolated alkaloids are erythrinoid type alkaloids which were identified as erysodine (1), erysovine (2), erythraline (3) and erysotrine (4), plus an indolic alkaloid which was identified as hypaphorine (5). The analysis of spectroscopic data for the alkaloid l-hypaphorine shows that the published structure (5a) must be revised, and the correct structure is that depicted as the structure 5c. The chemical structures were elucidated by full spectroscopic analysis. The chemotaxonomic significance of those findings in the genus Erythrina is also discussed.
- PublicaciónSólo datosGastroprotective activity of synthetic coumarins: Role of endogenous prostaglandins, nitric oxide, non-protein sulfhydryls and vanilloid receptors(Bioorganic & Medicinal Chemistry Letters, 2016-11-21) Sepúlveda, Beatriz; Quispe, Cristina; Simirgiotis, Mario; Torres-Benítez, Alfredo; Reyes-Ortíz, Johanna; Areche, Carlos; García-Beltrán, OlimpoNatural or synthetic coumarins showed gastroprotective and antiulcer activity in animal models. In this study, we have synthetized twenty coumarins using classic methods to evaluate their gastroprotective effects on the ethanol/HCl-induced gastric lesion model in mice at 20 mg/kg. Among the coumarins synthetized, compounds 6 and 10 showed the greatest gastroprotective activity being as active as lansoprazole at 20 mg/kg and reducing gastric lesions by 75 and 76%, respectively. Then, in a second experiment, compounds 6 and 10 were re-evaluated in order to understand the possible mode of gastroprotective activity. Regarding coumarin 6, the protective effect was reduced by pre-treatment of the mice with N-ethylmaleimide and l-NAME suggesting that sulfhydryl compounds and endogenous nitric oxide are involved in its gastroprotective activity. While for coumarin 10 the effect was reduced by pre-treatment with indomethacin suggesting that prostaglandins are positively involved in its gastroprotective activity.
- PublicaciónSólo datosGastroprotective effects of new diterpenoid derivatives from Azorella cuatrecasasii Mathias & Constance obtained using a β-cyclodextrin complex with microbial and chemical transformations(Bioorganic And Medicinal Chemistry Letters, 2016-07-15) Sepúlveda, Beatriz; Quispe, Cristina; Simirgiotis, Mario; García-Beltrán, Olimpo; Areche, CarlosMulinane diterpenoids isolated from Azorella species have displayed gastroprotective effects in animal models. In this study we have transformed the main constituent, mulin-11,13-dien-20 oic acid from this plant using the filamentous fungus Mucor plumbeus and a β-cyclodextrin inclusion complex and we have obtained two main products with good yields (33% and 15% for compound 4 and 5, respectively) for further preparation of semisynthetic derivatives to evaluate their gastroprotective effects. In addition, one of the compounds isolated from Azorella cuatrecasasii was new (9-epi-13α-hydroxymulinene 1). Six new derivatives 4a–4c and 5a–5c were then prepared by simple chemical transformations. The structures of all compounds were elucidated by spectroscopic means based on 1D and 2D-NMR techniques. Some 8 diterpenes were evaluated for their gastroprotective effects in the ethanol/HCl-induced ulcer model in mice at 20 mg/kg. The highest gastroprotective activity was shown by 7α,16-dihydroxymulin-11,13-dien-20-oic acid 5, which was higher than the reference drug lansoprazole, while 16-hydroxymulin-11,13-dien-20-oic acid 4 was as active as lansoprazole.
- PublicaciónSólo datosMetabolomic Analysis of Two Parmotrema Lichens: P. robustum (Degel.) Hale and P. andinum (Mull. Arg.) Hale Using UHPLC-ESI-OT-MS-MS(Molecules, 2017-10-30) Torres-Benítez, Alfredo; Rivera Montalvo, María; Sepúlveda, Beatriz; Castro, Olivio N.; Nagles, Edgar; Simirgiotis, Mario; García-Beltrán, Olimpo; Areche, CarlosLichens are symbiotic associations of fungi with microalgae and/or cyanobacteria. Lichens belonging to the Parmeliaceae family comprise 2700 species of lichens, including the Parmotrema genus which is composed of 300 species. The metabolites of this genus include depsides, depsidones, phenolics, polysaccharides, lipids, diphenylethers and dibenzofurans, which are responsible for the biological activities reported including antidiabetic, antihelmintic, anticancer, antioxidant, antibacterial, anti-inflammatory, antimitotic, antitumoral, antifungal, and antioxidant enzyme inhibitory. Due to scarce knowledge of metabolomic profiles of Parmotrema species (P. andinum and P. robustum), a full metabolome study based on ultra-high performance liquid chromatography- diode array detector-electrospray ionization-quadrupole-orbitrap-mass-spectrometry (UHPLC-DAD-ESI-Q-orbitrap MS) was performed for a comprehensive characterization of their substances. From the methanolic extracts of these species, a total of 54 metabolites were identified for the first time using this hyphenated technique, including thirty compounds in P. andinum, and thirty-seven in P. robustum. Moreover, two compounds were not identified as known compounds, and could be new structures, according to our data. This report shows that this technique is effective and accurate for rapid chemical identification of lichen substances and the compounds identified could serve as chemotaxonomic markers to differentiate these ruffle lichens.
- PublicaciónSólo datosMulinum crassifolium Phil; Two New Mulinanes, Gastroprotective Activity and Metabolomic Analysis by UHPLC-Orbitrap Mass Spectrometry(Molecules, 2019-04-28) Areche, Carlos; Fernandez-Burgos, Ronald; Cano de Terrones, Teresa; Simirgiotis, Mario; García-Beltrán, Olimpo; Borquez, Jorge; Sepúlveda, BeatrizMulinum crassifolium Phil. (Apiaceae) is an endemic shrub from Chile commonly used as infusion in traditional medicine to treat diabetes, bronchial and intestinal disorders and stomach ailments, including ulcers. From the EtOAc extract of this plant, the new mulinane-type diterpenoids 3 and 5 were isolated along with three known diterpenoids. The gastroprotective effect of the infusion of the plant was assayed to support the traditional use and a fast HPLC analysis using high resolution techniques was performed to identify the bioactive constituents. The EtOAc extract and the edible infusion showed gastroprotective effect at 100 mg/kg in the HCl/EtOH induced gastric ulcer model in mice, reducing lesions by 33% and 74%, respectively. Finally, a metabolomic profiling based on UHPLC-ESI-MS/HRMS of the edible infusion was performed and thirty-five compounds were tentatively identified including quercetin, caffeic acid, apigenine glucoside, p-coumaric acid, chlorogenic acids, and caffeoylquinic acids, which have been associated previously with gastroprotective and antiulcer properties. This scientific evidence can support the contribution of polyphenols in the gastroprotective activity of the edible infusion of this plant, and can validate at least in part, its ethnopharmacological use.
- PublicaciónSólo datosUHPLC-ESI-ORBITRAP-MS analysis of the native Mapuche medicinal plant palo negro (Leptocarpha rivularis DC. – Asteraceae) and evaluation of its antioxidant and cholinesterase inhibitory properties(Journal of Enzyme Inhibition and Medicinal Chemistry, 2018-05-10) Jiménez-González, Andrea; Quispe, Cristina; Bórquez, Jorge; Sepúlveda, Beatriz; Riveros, Felipe; Areche, Carlos; Nagles, Edgar; García-Beltrán, Olimpo; Simirgiotis, MarioUHPLC/ESI/MS identification of organic compounds is the first step in the majority of screening techniques for the characterization of biologically active metabolites in natural sources. This paper describes a method for the fast identification and characterisation of secondary metabolites in Leptocarpha rivularis DC. (Palo negro) extracts by HPLC/UV (DAD)–Mass Spectrometry (HPLC/MS). The plant is used for the treatment of several diseases since pre-hispanic Mapuche times. Thirty-seven compounds were detected in the aqueous edible extract for the first time including 4 sesquiterpenes, 10 flavonoids, 9 oxylipins, 2 organic acids, and 11 phenolic acids. In addition, phenolic content antioxidant and cholinesterase inhibitory activities were measured for the first time using the edible infusion. The total polyphenol content of the infusion was 230.76 ± 2.5 mmol GAE/kg dry weight, while the antioxidant activity was 176.51 ± 28.84; 195.28 ± 4.83; and 223.92 ± 2.95 mmol TE/kg dry weight, for the DPPH, ABTS, and FRAP assays, respectively. The cholinesterase inhibitory activity was 7.38 ± 0.03 and 5.74 ± 0.06 mmol GALAE/kg, for the inhibition of acetylcholinesterase AChE and BChE, respectively, showing that this plant is a candidate for the isolation of compounds that can be useful for the treatment of neurodegenerative diseases. Furthermore, this plant could serve also as a raw material for the production of dietary supplements, due to its content of polyphenolic compounds.