Browsing by Autor "N Flores"

Now showing 1 - 3 of 3

Antiparasitic activity of flavonoids from Piper species
(Thieme Medical Publishers (Germany), 2010) Juan C. Ticona; N Flores; David Gutiérrez; A. Giménez; Ignacio A. Jiménez; Isabel L. Bazzocchi
Parasitic diseases, including leishmaniasis, chagas and malaria, are serious problems for public health throughout the world, especially in tropical and subtropical regions [1]. Due to the absence of effective vaccines, inadequate chemotherapy and the emergence of drug resistance, currently, there is an urgent need to search for novel, effective and safe drugs for the treatment of these diseases [2]. Several Piper species have been used in the traditional medicine in Latin America, including for the treatment of parasitic diseases [3]. As part of our research aiming to uncover antiparasitic compounds from Bolivian Piper species, we studied the dichloromethane extract from the leaves of Piper aduncum, P. acutifolium, P. glabratum, P. heterophyllum, P. pilliraneum and P. rusbyi. This study has led to the isolation of eight known flavonoids and a new compound, 5,5′-dihydroxy-7,3′-dimethoxy-flavanone. Their structures were elucidated on the basis of spectroscopic data, including homo- and heteronuclear correlation NMR experiments (COSY, ROESY, HSQC and HMBC). In the search for new antiparasitic agents, these compounds were evaluated in vitro against three strains of Leishmania (L. amazonensis, L. braziliensis and L. donovani), Trypanosoma cruzi and Plasmodium falciparum. 4′,7-Dimethoxy-5-hydroxy-flavanone (IC50 4.0µg/mL) showed a moderate activity against P. falciparum. The most active compound against promastigote forms of the three Leishmania strains was flavokavain B (IC50 5.4µg/mL), with twice the activity of the control pentamidine (IC50 10.0µg/mL). These results support the use of Piper species as a traditional remedy in the treatment of parasitic diseases.
Antiplasmodial activity of amides and amines from Withania aristata, an endemic species of the Canary islands
(Thieme Medical Publishers (Germany), 2010) GG Llanos; Oliver Callies; David Gutiérrez; N Flores; Ignacio A. Jiménez; A. Giménez; Isabel L. Bazzocchi
Malaria continues to be a major health challenge in most tropical and subtropical regions. The most severe form of human malaria is caused by Plasmodium falciparum, responsible for more than one million deaths per year. Due to the emergence and spread of drug resistance to the available antiplasmodial drugs, its treatment has become a serious problem. Therefore, new molecules with novel mechanisms of action are required [1]. In this context, natural products can deliver new lead compounds for more effective drugs than those currently in clinical use [2]. As part of our research for bioactive metabolites from natural sources, Withania aristata (Aiton) Pauquy (Solanaceae), an endemic species of the Canary Islands used in folk medicine, was studied. The phytochemical analysis of the dichloromethane extract from the leaves of this plant led to the isolation of 3 amide and 6 amine type metabolites, two of them, 2-(4-hydroxy-3,5-dimethoxyphenyl)-3-oxetanamine and N-4-(3-furoylamine)-1-butanol, not previously reported. Their structures were determined by means of spectroscopic studies, including 1D and 2D NMR experiments. The antiplasmodial activity of the compounds was evaluated against a strain of Plasmodium falciparum (F-32 Tanzania). N-cis-feruloyltyramine and 4-O-methyldopamine showed moderate activity (IC50 4.2 and 3.0µg/mL, respectively), whereas the activity of the most potent compound, N-cis-p-coumaroyltyramine, was comparable to that of the control chloroquine (IC50 0.7 and 0.1µg/mL, respectively). A preliminary structure-activity relationship study indicated that the configuration of the double bond in the amides and the regiosubstitution of the aromatic ring in the amines play an important role in the activity.
Flavonoids as quorum sensing inhibitors: A promising strategy to fight against bacteria
(Thieme Medical Publishers (Germany), 2014) IL Bazzocchi; Alberto J. Martín‐Rodríguez; JC Ticona; I. Albajar Gómez; Erica Marzaro; IA Jiménez; N Flores; D Benjumea; Victor S. Martı́n; José J. Fernández
Bacterial biofilms are an increasing concern in several areas: in clinics, they cause up to a 1000-fold increase in bacterial antibiotic resistance; in industry, they are a cause of clogging and operative problems; environmentally, they are a first stage in biofouling. Bacterial biofilm formation relies on a process of chemical communication between bacterial cells called quorum sensing (QS) [1]. Since QS blockers do not target bacterial growth, they do not exert a selective pressure on bacterial populations and consequently, they have emerged as a promising alternative to antibiotic and biocidal treatments. Natural products are a major source of chemical diversity and have provided important therapeutic agents for many bacterial diseases [2]. In that context, flavonoids, a family of plant-derived compounds, have been revealed as potential inhibitors of biofilm formation and the production of virulence factors in the pathogenic bacteria by interfering with QS mechanisms [3]. In the present study, nine flavonoids, including seven chalcones and two flavanones, isolated from Piper delineatum (Piperaceaea) and Renealmia alpinia (Zingiberaceae) were screened for their capacity to reduce the production of violacein, a QS-regulated phenotype, in the reporter strain Chromobacterium violaceum CV026. Several compounds exhibited significant QS inhibitory activities. Particularly, a compound of this series exhibited a very promising profile in the µM range. Given that the activities of this family of compounds have been reported at the mM level [4], further studies are in course to characterise the bioactive potential of this molecule.