Journal of agricultural and food chemistry, Jan 23, 2005
Twenty-five samples of propolis were collected from seven different regions in northern Argentina... more Twenty-five samples of propolis were collected from seven different regions in northern Argentina; ethanolic extracts of propolis were prepared from all samples, and the respective samples were examined for UV absorption spectra, RPHPTLC, RPHPLC, antimicrobial activity, antiradical activity, and total phenolic content. It was found that 16 of the 25 samples showed a phenolic profile similar to that found in samples from southern Brazil and corresponding to poplar-based propolis and that the rest of the samples showed a different profile and higher antimicrobial and antiradical activities.
ABSTRACT Prosopis species are considered multipurpose trees and shrubs by FAO and their fruit con... more ABSTRACT Prosopis species are considered multipurpose trees and shrubs by FAO and their fruit constitute a food source for humans and animals. According to the "Código Alimentario Argentino", "algarrobo flour" is produced by grinding the whole mature pod, but in the traditional process most of the seeds are discarded. In this paper, the flour from seed was obtained. Then, the proteins were extracted and enzymatic hydrolysis was carried out. According to their amino acid profile and chemical score (>100%), the Prosopis alba proteins, are not deficient in essential amino acids considering the amount of amino acid necessary by adults. The protein isolate showed a good solubility (pH 7.4-9), emulsificant capacity, oil binding capacity and water adsorption capacity. The antioxidant ability of proteins was significantly increased with hydrolysis (SC50 values: 50-5μg/mL, respectively). Inhibitory activity of pro-inflammatory enzymes (lipoxygenase and phospholipase) was described. The mutagenicity/antimutagenicity of proteins and protein hydrolysates from seed flour were also analysed. The results suggest that P. alba cotyledon flour could be a new alternative in the formulation of functional foods not only for its high protein content but also by the biological and functional properties of its proteins and protein hydrolysates.
The aims of the present study were to determine the antibacterial and antifungal activity as well... more The aims of the present study were to determine the antibacterial and antifungal activity as well as mutagenicity of Sechium edule fluid extract and to obtain a pharmaceutical formulation with them. The extract exhibited antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens, Morganella morganii, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Candida spp. and Aspergillus spp. isolated from clinical samples from two hospitals of Tucuman, Argentina. Non-toxicity and mutagenicity on both Salmonella typhimurium TA98 and TA 100 strains until 100 microg/plate were observed. A hydrogel with carbopol acrylic acid polymer containing S. edule fluid extract as antibacterial, antimycotic and antioxidant agent was obtained. Microbiological, physical and functional stability of pharmaceutical formulation conserved at room temperature for 1 year were determined. Addition of antioxidant preservatives to store the pharmaceutical formulation was not necessary. The semisolid system showed antimicrobial activity against all gram positive and gram negative bacteria and fungi assayed. The minimal inhibitory concentration (MIC) values ranged from 20 to 800 microg/mL. Its activity was compared with a pharmaceutical formulation containing commercial antibiotic and antifungal. A pseudoplastic behavior and positive thixotropy were observed. Our current finding shows an antimicrobial activity of hydrogel containing S. edule extract on a large range of gram negative and gram positive multi-resistant bacteria and fungi. This topical formulation may be used as antimycotic and as antibacterial in cutaneous infections.
This study evaluates the toxic, genotoxic/mutagenic, and antimutagenic effects of propolis extrac... more This study evaluates the toxic, genotoxic/mutagenic, and antimutagenic effects of propolis extract from Amaicha del Valle, Tucumán, Argentina. The cytotoxicity assays carried out with the lethality test of Artemia salina revealed that the LD50 was around 100 microg/mL. Propolis extracts showed no toxicity to Salmonella typhimurium TA98 and TA100 strains and Allium cepa at concentrations that have antibiotic and antioxidant activities. Otherwise, for the testing doses, neither genotoxicity nor mutagenicity was found in any sample. The propolis extracts were able to inhibit the mutagenesis of isoquinoline (IQ) and 4-nitro o-phenylenediamine (NPD) with ID50 values of 40 and 20 microg/plate, respectively. From this result, the studied propolis may be inferred to contain some chemical compounds capable of inhibiting the mutagenicity of direct-acting and indirect-acting mutagens. A compound isolated from Amaicha del Valle propolis, 2',4'-dihydroxychalcone, showed cytotoxic activity (LC50 values of 0.5 microg/mL) but was not genotoxic or mutagenic. Furthermore, this compound was able to inhibit the mutagenicity of IQ (ID50 values of 1 microg/plate) but was unable to inhibit the mutagenicity of NPD. Our results suggest a potential anticarcinogenic activity of Amaicha del Valle propolis and the chalcone isolated from it.
... Instituto de Estudios Vegetales "Dr. Antonio R. Sampietro". ... de flavonoides tota... more ... Instituto de Estudios Vegetales "Dr. Antonio R. Sampietro". ... de flavonoides totales se determinó espectrofotométricamente a 420 nm utilizando el método de Woisky y Salatino (19). ... Planta Med 2000; 66: 541-4. 5-Nostro A, Germano MP, D'Angelo V, Marino A, Cannatelli MA. ...
The invertase of Tropaeolum majus leaves was partially purified. Its optimum pH was ca 5.25 and i... more The invertase of Tropaeolum majus leaves was partially purified. Its optimum pH was ca 5.25 and its K, values for sucrose, raffinose, and stachyose were 5.3, 17 and 25 mM respectively. The products of the reaction were in uitro inhibitors of the enzyme. Fructose was a partial competitive inhibitor (K, 49 mM) and glucose was a noncompetitive classical inhibitor (K, 57 mM). Proteins were activators of the enzyme. As activation by proteins suppressed the inhibitory effects of the reaction products, product inhibition does not appear to be involved in the physiological regulation of the enzyme.
Fruits are known as good sources of phytochemicals, essential to prevent degenerative diseases li... more Fruits are known as good sources of phytochemicals, essential to prevent degenerative diseases like cancer and cardiovascular diseases. They contain a variety of antioxidants, which are useful to scavenge radical oxygen species (ROS). Considering the importance of natural products as a functional food, comparative studies between the antioxidant activity (AOA) and antimutagenic properties as well as phytochemical profile of Cactaceae
Traditionally, the content of total phenolics (flavonoid phenolics (FP) and non-flavonoid phenoli... more Traditionally, the content of total phenolics (flavonoid phenolics (FP) and non-flavonoid phenolics (NFP)) and flavonoids (flavone/flavonol and flavonone/dihydroflavonol) in propolis has been determined by different methodologies. Until now, the percentage of total phenolic (TP) compounds that corresponds to FP and NFP, expressed in the same units by a spectrophotometric method, has not been determined. The current study proposes a quick and simple methodology that separates FP and NFP in propolis samples and determines TP, FP, and NFP by the same method. Propolis samples from five Argentine provinces (Tucumán, Santiago del Estero, Salta, Misiones, and Jujuy) were used. Extraction of TP from the propolis samples was carried out by maceration with 80% ethanol and quantified by Folin-Ciocalteu reagent (FC-R). Then, FP was precipitated with formaldehyde in acid medium. After centrifugation, NFP were determined in the supernatant using FC-R. FP content was calculated as the difference between the content of TP and NFP. The method was also validated using commercial flavonoids and chalcones. FP recovery in all experiments was between 85.95% and 98.29%. Propolis from Tucumán had significantly higher amounts of total phenols than propolis from other provinces. SE5 showed higher content of FP (81.52%) followed by SA1 (74.75%). The propolis from TUC4, SA4, SE3, and MI showed the lowest FP content and highest content of NFP. This method provides a simple, reliable, and specific spectrophotometric assay to estimate the content of NFP, FP, and TP in propolis samples.
Hydroalcoholic and aqueous extracts of some climber species from the Bignoniaceae family that gro... more Hydroalcoholic and aqueous extracts of some climber species from the Bignoniaceae family that grow in the north of Argentina were evaluated for in vitro antibacterial activity against Gram-positive and Gram-negative strains. By means of bioautography and disc diffusion methods, it could be determined that all infusions were not active, whereas the hydroalcoholic extracts of seven species were able to inhibit bacterial growth. The minimum inhibitory concentration and minimum bactericidal concentration observed were between 62.5 and 1000 μg gallic acid equivalent (GAE)/mL and between 125 and 1000 μg GAE/mL, respectively. The tested extracts were more active against Gram-positive microorganisms. Time-kill experiments indicated that all extracts have bacteriostatic activity. Phytochemical screening showed the presence of terpenoids, phenols and flavonoids. The amount of phenolic compounds and flavonoids was higher in tinctures when compared with infusions. These results suggest the presence of antibacterial substances in the hydroalcoholic extracts, which could be used for the treatment of infections.
Propolis was included in the Argentine Food Code as a functional food. The chemical parameters an... more Propolis was included in the Argentine Food Code as a functional food. The chemical parameters and antioxidant properties of propolis samples from the same colonies of Apis mellifera in San Juan (Cuyo region, Western Argentine) were compared every month for 1 year using two collection methods. Chemical parameters were analyzed by the spectrophotometric method and fingerprinting using high-performance liquid chromatography with ultraviolet detection. The antioxidant activities of propolis samples were measured using model systems including the analysis of the scavenging activities for 2,2 0 -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and the b-carotene bleaching assay. The results showed that propolis had a higher free radical scavenging and lipid peroxidation inhibitory capacity than butylated hydroxytoluene and quercetin, antioxidants used in the pharmaceutical and food industries. The concentration required to scavenge 50% of free radicals (SC 50 ) values differed depending on the sample collection month. Samples collected in November had the highest antioxidant capacity. In all cases, SC 50 values of propolis samples obtained by scraping were similar to those collected from a wire mesh (5 mg=mL for ABTS and 20-30 mg=mL for DPPH radicals). A significant positive correlation was found between the antioxidant capacity and flavonoid content of each analyzed extract. The chemical profiles were very similar. Galangin (3,5,7-trihydroxyflavone), an antioxidant compound, was detected in all samples as a major compound. The chromatographic profile suggests that of Baccharis sp., which would be one of the botanical sources of propolis from western Argentina, and the content of galangin can be used as a parameter for evaluating propolis quality. Our results suggest that Argentine propolis from Cuyo is a promising source of bioactive compounds as ingredients for developing functional foods with a beneficial impact on oxidative stress.
Zuccagnia punctata extracts (ZpE) are used in ethnomedicine as antimicrobial and anti-inflammator... more Zuccagnia punctata extracts (ZpE) are used in ethnomedicine as antimicrobial and anti-inflammatory drugs. The pharmacological properties of ZpE and their polyphenolic components suggest that they may be used as potential modulators on the P-glycoprotein (P-gp) multidrug transporter. P-gp is well known for its role in the acquired drug resistance by tumors following chemotherapy, causing a low drug bioavailability by extruding them out of the cells. To evaluate the effects of ZpE and three of their phenolic components: 7-hydroxyflavanone (HF), 3,7-dihydroxyflavone (DHF) and 2',4'-dihydroxychalcone (DHC) on P-gp activity and expression. The effects of natural products on ABCB1/P-gp function and expression were evaluated by R-123 accumulation assay and western blot analysis using HK-2 cells as experimental model. The ABCB1 mRNA content was determined by SQRT-PCR. The accumulation of R-123 in HK-2 cells was significantly increased by ZpE and DHF, and to a lesser extent by DHC, indicating their roles on the efflux transporter activity. However, HF did not show any effect. HK-2 cells maintained in the presence of ZpE or DHF for 72 h, showed an increase in P-gp expression whereas activity was unchanged or decreased. No changes were observed in ABCB1 mRNA content. Furthermore, in these assay conditions, more sensibility of HK-2 cells to the cytotoxic action of cyclosporine A (P-gp substrate) was observed. These results may suggest an impact of Zuccagnia punctata and some of its components on the pharmacokinetics of drugs that are P-gp substrates, as well as a potential role on multidrug resistance modulation.
Ethnopharmacological relevance: The Argentinean highland plant Parastrephia lucida (Meyen) Cabrer... more Ethnopharmacological relevance: The Argentinean highland plant Parastrephia lucida (Meyen) Cabrera is used in traditional medicine as an antiseptic and anti-inflammatory crude drug. Aim of the study: To relate the antimicrobial effect of the crude drug with the constituents of the active fractions and traditional use. Materials and methods: Assay-guided isolation of the methanol (MeOH) plant extract was carried out using bacteria and yeasts as target organisms. Both ATCC and local strains were included in the study. The antimicrobial fractions and compounds were detected by bioautographic assays. Minimum inhibitory concentrations (MIC) of each extract and fraction were determined and compared with reference antibiotics. Fractions were analyzed by HPLC-DAD, GC-MS, 1 H NMR and 13 C NMR. Results: From the MeOH extract of the plant, assay-guided isolation of the antimicrobial constituents led to 12 phenylpropanoids and two simple phenolics. Most of the compounds occurring in the active fractions were E-caffeoyl or E-cinnamoyl esters including prenyl and phenethyl derivatives. The MIC values of the most active fractions ranged between 12.5 and 200 mg/mL against reference strains and local isolates of Staphylococcus aureus and Enterococcus faecalis. Conclusions: The antimicrobial effect found in the crude drug was associated with mixtures of phenylpropanoids, including prenyl and phenethyl esters of caffeic and cinnamic acids. The results support at least in part the traditional use of the plant as local antiseptic.
a b s t r a c t Aim: The plant species reported here are traditionally used in the "Puna" or "Alt... more a b s t r a c t Aim: The plant species reported here are traditionally used in the "Puna" or "Altiplano" of Argentina for ailments related to bacterial infections. The aim of this study was to evaluate their antimicrobial properties against a panel of sensitive and multi-resistant Gram-positive and Gram-negative bacteria. Materials and methods: The antimicrobial activity of tinctures and aqueous extracts (Baccharis boliviensis, Chiliotrichiopsis keidelii, Chuquiraga atacamensis, Fabiana bryoides, Fabiana densa, Fabiana punensis, Frankenia triandra, Parastrephia lucida, Parastrephia lepidophylla, Parastrephia phyliciformis, Tetraglochin cristatum) was determined using the agar macrodilution and broth microdilution methods recommended by the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS). The antibiotic resistant clinical strains were isolated from nosocomial infection in human lesions of skin and soft parts. Results: The ethanolic extracts of 11 plant species inhibited the growth of one or more of the following strains: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Morganella morganii, Pseudomonas aeruginosa. Ethanol extracts (tinctures) of aerial parts of Baccharis, Fabiana and Parastrephia showed the highest levels of antibacterial activity on methicillin, oxacillin and gentamicin resistant Staphylococcus with MIC values from 20 to 150 g/ml.
Journal of Enzyme Inhibition and Medicinal Chemistry, 2002
The invertase inhibitory protein isolated from Cyphomandra betacea Sendt and Solanum tuberosum in... more The invertase inhibitory protein isolated from Cyphomandra betacea Sendt and Solanum tuberosum inhibited the invertase activity from different species, genera and even plant family. Furthermore, proteinaceous inhibitors are not invertase specific; fungal, bacterial and higher plant enzymes including polygalacturonase, pectinase, pectin lyase, alpha-L-arabinofuranosidase and beta-glucosidase are also shown to be inhibited. Both inhibitors exhibited an in vitro antibacterial action against phytopathogenics strains of Xanthomonas campestris pvar vesicatoria CECT 792, Pseudomonas solanacearum CECT 125, Pseudomonas corrugata CECT 124, Pseudomonas syringae and Erwinia carotovora var carotovora.
Twenty-five samples of propolis were collected from seven different regions in northern Argentina... more Twenty-five samples of propolis were collected from seven different regions in northern Argentina; ethanolic extracts of propolis were prepared from all samples, and the respective samples were examined for UV absorption spectra, RPHPTLC, RPHPLC, antimicrobial activity, antiradical activity, and total phenolic content. It was found that 16 of the 25 samples showed a phenolic profile similar to that found in samples from southern Brazil and corresponding to poplar-based propolis and that the rest of the samples showed a different profile and higher antimicrobial and antiradical activities.
The singlet oxygen ( 1 O 2 ) quenching and free radical (DPPH + , ABTS + ' and O 2 + ( ) scavengi... more The singlet oxygen ( 1 O 2 ) quenching and free radical (DPPH + , ABTS + ' and O 2 + ( ) scavenging ability of three structurallyrelated flavonoids (7-hydroxyflavanone HF, 2?,4?-dihydroxychalcone DHC and 3,7-dihydroxyflavone DHF) present in the Argentinean native shrub Zuccagnia punctata Cav. were studied in solution by combining electrochemical and kinetic measurements, mass spectroscopy, end-point antioxidant assays and computational calculations. The results showed that the antioxidant properties of these flavonoids depend on several factors, such as their electron-and hydrogen atom donor capacity, the ionization degree of the more acidic group, solvatation effects and electrostatic interactions with the oxidant species. The theoretical calculations for both the gas and solution phases at the B3LYP level of theory for the Osanger reaction field model agreed with the experimental findings, thus supporting the characterization of the antioxidant mechanism of the Z. punctata flavonoids.
We report a new colorimetric assay to quantify endo-polygalacturonase activity, which hydrolyzes ... more We report a new colorimetric assay to quantify endo-polygalacturonase activity, which hydrolyzes polygalacturonic acid to produce smaller chains of galacturonate. Some of the reported polygalacturonase assays measure the activity by detecting the appearance of reducing ends such as the Somogyi-Nelson method. As a result of being general towards reducing groups, the Somogyi-Nelson method is not appropriate when studying polygalacturonase and polygalacturonase inhibitors in plant crude extracts, which often have a strong reducing power. Ruthenium Red is an inorganic dye that binds polygalacturonic acid and causes its precipitation. In the presence of polygalacturonase, polygalacturonic acid is hydrolyzed bringing about a corresponding gain in soluble Ruthenium Red. The described assay utilizes Ruthenium Red as the detection reagent which has been used previously in plate-based assays but not in liquid medium reactions. The new method measures the disappearance of the substrate polygalacturonic acid and is compared to the Somogyi-Nelson assay. The experimental results using lemon peel, a fern fronds and castor leaf crude extracts demonstrate that the new method provides a way to the quickly screening of polygalacturonase activity and polygalacturonase inhibitors in plant crude extracts containing high amounts of reducing power. On the other hand, the Ruthenium Red assay is not able to determine the activity of an exo-polygalacturonase as initial velocity and thus would allow the differentiation between endo-and exo-polygalacturonase activities.
El objetivo de este trabajo fue realizar un estudio comparativo de la capacidad antioxidante de e... more El objetivo de este trabajo fue realizar un estudio comparativo de la capacidad antioxidante de extractos de Baccharis incarum obtenidos a través de diferentes técnicas de extracción a presión normal ya presiones criticas (Pc) comprendidas entre 85 a 95 atm. Se realizaron ...
An autographic assay suitable for the detection of antioxidant compounds in a complex matrix (liq... more An autographic assay suitable for the detection of antioxidant compounds in a complex matrix (liquid and semi-solid pharmaceutical formulations) or in isolated compounds was described. The preformed radical monocation of 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS •+ ) was generated by oxidation of ABTS with potassium persulfate and reduced in the presence of hydrogendonating antioxidants. For a further comparative estimation of its applicability and sensitivity, different medicinal plant extracts, hydrogels and antioxidant compounds were dot seeded or chromatographed on silica gel (TLC) and revealed with ABTS •+ solution (System I) or ABTS •+ immobilized by gel entrapment (System II). Both systems were effective and able to detect antioxidant activity in a micromolar range in seconds. System II was more sensitive and reproducible than System I. This micromethod is quick, inexpensive, and particularly helpful whether it works with numerous samples or on a small scale.
Journal of agricultural and food chemistry, Jan 23, 2005
Twenty-five samples of propolis were collected from seven different regions in northern Argentina... more Twenty-five samples of propolis were collected from seven different regions in northern Argentina; ethanolic extracts of propolis were prepared from all samples, and the respective samples were examined for UV absorption spectra, RPHPTLC, RPHPLC, antimicrobial activity, antiradical activity, and total phenolic content. It was found that 16 of the 25 samples showed a phenolic profile similar to that found in samples from southern Brazil and corresponding to poplar-based propolis and that the rest of the samples showed a different profile and higher antimicrobial and antiradical activities.
ABSTRACT Prosopis species are considered multipurpose trees and shrubs by FAO and their fruit con... more ABSTRACT Prosopis species are considered multipurpose trees and shrubs by FAO and their fruit constitute a food source for humans and animals. According to the "Código Alimentario Argentino", "algarrobo flour" is produced by grinding the whole mature pod, but in the traditional process most of the seeds are discarded. In this paper, the flour from seed was obtained. Then, the proteins were extracted and enzymatic hydrolysis was carried out. According to their amino acid profile and chemical score (>100%), the Prosopis alba proteins, are not deficient in essential amino acids considering the amount of amino acid necessary by adults. The protein isolate showed a good solubility (pH 7.4-9), emulsificant capacity, oil binding capacity and water adsorption capacity. The antioxidant ability of proteins was significantly increased with hydrolysis (SC50 values: 50-5μg/mL, respectively). Inhibitory activity of pro-inflammatory enzymes (lipoxygenase and phospholipase) was described. The mutagenicity/antimutagenicity of proteins and protein hydrolysates from seed flour were also analysed. The results suggest that P. alba cotyledon flour could be a new alternative in the formulation of functional foods not only for its high protein content but also by the biological and functional properties of its proteins and protein hydrolysates.
The aims of the present study were to determine the antibacterial and antifungal activity as well... more The aims of the present study were to determine the antibacterial and antifungal activity as well as mutagenicity of Sechium edule fluid extract and to obtain a pharmaceutical formulation with them. The extract exhibited antimicrobial activity against Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Serratia marcescens, Morganella morganii, Acinetobacter baumannii, Pseudomonas aeruginosa, Stenotrophomonas maltophilia, Candida spp. and Aspergillus spp. isolated from clinical samples from two hospitals of Tucuman, Argentina. Non-toxicity and mutagenicity on both Salmonella typhimurium TA98 and TA 100 strains until 100 microg/plate were observed. A hydrogel with carbopol acrylic acid polymer containing S. edule fluid extract as antibacterial, antimycotic and antioxidant agent was obtained. Microbiological, physical and functional stability of pharmaceutical formulation conserved at room temperature for 1 year were determined. Addition of antioxidant preservatives to store the pharmaceutical formulation was not necessary. The semisolid system showed antimicrobial activity against all gram positive and gram negative bacteria and fungi assayed. The minimal inhibitory concentration (MIC) values ranged from 20 to 800 microg/mL. Its activity was compared with a pharmaceutical formulation containing commercial antibiotic and antifungal. A pseudoplastic behavior and positive thixotropy were observed. Our current finding shows an antimicrobial activity of hydrogel containing S. edule extract on a large range of gram negative and gram positive multi-resistant bacteria and fungi. This topical formulation may be used as antimycotic and as antibacterial in cutaneous infections.
This study evaluates the toxic, genotoxic/mutagenic, and antimutagenic effects of propolis extrac... more This study evaluates the toxic, genotoxic/mutagenic, and antimutagenic effects of propolis extract from Amaicha del Valle, Tucumán, Argentina. The cytotoxicity assays carried out with the lethality test of Artemia salina revealed that the LD50 was around 100 microg/mL. Propolis extracts showed no toxicity to Salmonella typhimurium TA98 and TA100 strains and Allium cepa at concentrations that have antibiotic and antioxidant activities. Otherwise, for the testing doses, neither genotoxicity nor mutagenicity was found in any sample. The propolis extracts were able to inhibit the mutagenesis of isoquinoline (IQ) and 4-nitro o-phenylenediamine (NPD) with ID50 values of 40 and 20 microg/plate, respectively. From this result, the studied propolis may be inferred to contain some chemical compounds capable of inhibiting the mutagenicity of direct-acting and indirect-acting mutagens. A compound isolated from Amaicha del Valle propolis, 2',4'-dihydroxychalcone, showed cytotoxic activity (LC50 values of 0.5 microg/mL) but was not genotoxic or mutagenic. Furthermore, this compound was able to inhibit the mutagenicity of IQ (ID50 values of 1 microg/plate) but was unable to inhibit the mutagenicity of NPD. Our results suggest a potential anticarcinogenic activity of Amaicha del Valle propolis and the chalcone isolated from it.
... Instituto de Estudios Vegetales "Dr. Antonio R. Sampietro". ... de flavonoides tota... more ... Instituto de Estudios Vegetales "Dr. Antonio R. Sampietro". ... de flavonoides totales se determinó espectrofotométricamente a 420 nm utilizando el método de Woisky y Salatino (19). ... Planta Med 2000; 66: 541-4. 5-Nostro A, Germano MP, D'Angelo V, Marino A, Cannatelli MA. ...
The invertase of Tropaeolum majus leaves was partially purified. Its optimum pH was ca 5.25 and i... more The invertase of Tropaeolum majus leaves was partially purified. Its optimum pH was ca 5.25 and its K, values for sucrose, raffinose, and stachyose were 5.3, 17 and 25 mM respectively. The products of the reaction were in uitro inhibitors of the enzyme. Fructose was a partial competitive inhibitor (K, 49 mM) and glucose was a noncompetitive classical inhibitor (K, 57 mM). Proteins were activators of the enzyme. As activation by proteins suppressed the inhibitory effects of the reaction products, product inhibition does not appear to be involved in the physiological regulation of the enzyme.
Fruits are known as good sources of phytochemicals, essential to prevent degenerative diseases li... more Fruits are known as good sources of phytochemicals, essential to prevent degenerative diseases like cancer and cardiovascular diseases. They contain a variety of antioxidants, which are useful to scavenge radical oxygen species (ROS). Considering the importance of natural products as a functional food, comparative studies between the antioxidant activity (AOA) and antimutagenic properties as well as phytochemical profile of Cactaceae
Traditionally, the content of total phenolics (flavonoid phenolics (FP) and non-flavonoid phenoli... more Traditionally, the content of total phenolics (flavonoid phenolics (FP) and non-flavonoid phenolics (NFP)) and flavonoids (flavone/flavonol and flavonone/dihydroflavonol) in propolis has been determined by different methodologies. Until now, the percentage of total phenolic (TP) compounds that corresponds to FP and NFP, expressed in the same units by a spectrophotometric method, has not been determined. The current study proposes a quick and simple methodology that separates FP and NFP in propolis samples and determines TP, FP, and NFP by the same method. Propolis samples from five Argentine provinces (Tucumán, Santiago del Estero, Salta, Misiones, and Jujuy) were used. Extraction of TP from the propolis samples was carried out by maceration with 80% ethanol and quantified by Folin-Ciocalteu reagent (FC-R). Then, FP was precipitated with formaldehyde in acid medium. After centrifugation, NFP were determined in the supernatant using FC-R. FP content was calculated as the difference between the content of TP and NFP. The method was also validated using commercial flavonoids and chalcones. FP recovery in all experiments was between 85.95% and 98.29%. Propolis from Tucumán had significantly higher amounts of total phenols than propolis from other provinces. SE5 showed higher content of FP (81.52%) followed by SA1 (74.75%). The propolis from TUC4, SA4, SE3, and MI showed the lowest FP content and highest content of NFP. This method provides a simple, reliable, and specific spectrophotometric assay to estimate the content of NFP, FP, and TP in propolis samples.
Hydroalcoholic and aqueous extracts of some climber species from the Bignoniaceae family that gro... more Hydroalcoholic and aqueous extracts of some climber species from the Bignoniaceae family that grow in the north of Argentina were evaluated for in vitro antibacterial activity against Gram-positive and Gram-negative strains. By means of bioautography and disc diffusion methods, it could be determined that all infusions were not active, whereas the hydroalcoholic extracts of seven species were able to inhibit bacterial growth. The minimum inhibitory concentration and minimum bactericidal concentration observed were between 62.5 and 1000 μg gallic acid equivalent (GAE)/mL and between 125 and 1000 μg GAE/mL, respectively. The tested extracts were more active against Gram-positive microorganisms. Time-kill experiments indicated that all extracts have bacteriostatic activity. Phytochemical screening showed the presence of terpenoids, phenols and flavonoids. The amount of phenolic compounds and flavonoids was higher in tinctures when compared with infusions. These results suggest the presence of antibacterial substances in the hydroalcoholic extracts, which could be used for the treatment of infections.
Propolis was included in the Argentine Food Code as a functional food. The chemical parameters an... more Propolis was included in the Argentine Food Code as a functional food. The chemical parameters and antioxidant properties of propolis samples from the same colonies of Apis mellifera in San Juan (Cuyo region, Western Argentine) were compared every month for 1 year using two collection methods. Chemical parameters were analyzed by the spectrophotometric method and fingerprinting using high-performance liquid chromatography with ultraviolet detection. The antioxidant activities of propolis samples were measured using model systems including the analysis of the scavenging activities for 2,2 0 -azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and the b-carotene bleaching assay. The results showed that propolis had a higher free radical scavenging and lipid peroxidation inhibitory capacity than butylated hydroxytoluene and quercetin, antioxidants used in the pharmaceutical and food industries. The concentration required to scavenge 50% of free radicals (SC 50 ) values differed depending on the sample collection month. Samples collected in November had the highest antioxidant capacity. In all cases, SC 50 values of propolis samples obtained by scraping were similar to those collected from a wire mesh (5 mg=mL for ABTS and 20-30 mg=mL for DPPH radicals). A significant positive correlation was found between the antioxidant capacity and flavonoid content of each analyzed extract. The chemical profiles were very similar. Galangin (3,5,7-trihydroxyflavone), an antioxidant compound, was detected in all samples as a major compound. The chromatographic profile suggests that of Baccharis sp., which would be one of the botanical sources of propolis from western Argentina, and the content of galangin can be used as a parameter for evaluating propolis quality. Our results suggest that Argentine propolis from Cuyo is a promising source of bioactive compounds as ingredients for developing functional foods with a beneficial impact on oxidative stress.
Zuccagnia punctata extracts (ZpE) are used in ethnomedicine as antimicrobial and anti-inflammator... more Zuccagnia punctata extracts (ZpE) are used in ethnomedicine as antimicrobial and anti-inflammatory drugs. The pharmacological properties of ZpE and their polyphenolic components suggest that they may be used as potential modulators on the P-glycoprotein (P-gp) multidrug transporter. P-gp is well known for its role in the acquired drug resistance by tumors following chemotherapy, causing a low drug bioavailability by extruding them out of the cells. To evaluate the effects of ZpE and three of their phenolic components: 7-hydroxyflavanone (HF), 3,7-dihydroxyflavone (DHF) and 2',4'-dihydroxychalcone (DHC) on P-gp activity and expression. The effects of natural products on ABCB1/P-gp function and expression were evaluated by R-123 accumulation assay and western blot analysis using HK-2 cells as experimental model. The ABCB1 mRNA content was determined by SQRT-PCR. The accumulation of R-123 in HK-2 cells was significantly increased by ZpE and DHF, and to a lesser extent by DHC, indicating their roles on the efflux transporter activity. However, HF did not show any effect. HK-2 cells maintained in the presence of ZpE or DHF for 72 h, showed an increase in P-gp expression whereas activity was unchanged or decreased. No changes were observed in ABCB1 mRNA content. Furthermore, in these assay conditions, more sensibility of HK-2 cells to the cytotoxic action of cyclosporine A (P-gp substrate) was observed. These results may suggest an impact of Zuccagnia punctata and some of its components on the pharmacokinetics of drugs that are P-gp substrates, as well as a potential role on multidrug resistance modulation.
Ethnopharmacological relevance: The Argentinean highland plant Parastrephia lucida (Meyen) Cabrer... more Ethnopharmacological relevance: The Argentinean highland plant Parastrephia lucida (Meyen) Cabrera is used in traditional medicine as an antiseptic and anti-inflammatory crude drug. Aim of the study: To relate the antimicrobial effect of the crude drug with the constituents of the active fractions and traditional use. Materials and methods: Assay-guided isolation of the methanol (MeOH) plant extract was carried out using bacteria and yeasts as target organisms. Both ATCC and local strains were included in the study. The antimicrobial fractions and compounds were detected by bioautographic assays. Minimum inhibitory concentrations (MIC) of each extract and fraction were determined and compared with reference antibiotics. Fractions were analyzed by HPLC-DAD, GC-MS, 1 H NMR and 13 C NMR. Results: From the MeOH extract of the plant, assay-guided isolation of the antimicrobial constituents led to 12 phenylpropanoids and two simple phenolics. Most of the compounds occurring in the active fractions were E-caffeoyl or E-cinnamoyl esters including prenyl and phenethyl derivatives. The MIC values of the most active fractions ranged between 12.5 and 200 mg/mL against reference strains and local isolates of Staphylococcus aureus and Enterococcus faecalis. Conclusions: The antimicrobial effect found in the crude drug was associated with mixtures of phenylpropanoids, including prenyl and phenethyl esters of caffeic and cinnamic acids. The results support at least in part the traditional use of the plant as local antiseptic.
a b s t r a c t Aim: The plant species reported here are traditionally used in the "Puna" or "Alt... more a b s t r a c t Aim: The plant species reported here are traditionally used in the "Puna" or "Altiplano" of Argentina for ailments related to bacterial infections. The aim of this study was to evaluate their antimicrobial properties against a panel of sensitive and multi-resistant Gram-positive and Gram-negative bacteria. Materials and methods: The antimicrobial activity of tinctures and aqueous extracts (Baccharis boliviensis, Chiliotrichiopsis keidelii, Chuquiraga atacamensis, Fabiana bryoides, Fabiana densa, Fabiana punensis, Frankenia triandra, Parastrephia lucida, Parastrephia lepidophylla, Parastrephia phyliciformis, Tetraglochin cristatum) was determined using the agar macrodilution and broth microdilution methods recommended by the Clinical and Laboratory Standards Institute (CLSI, formerly NCCLS). The antibiotic resistant clinical strains were isolated from nosocomial infection in human lesions of skin and soft parts. Results: The ethanolic extracts of 11 plant species inhibited the growth of one or more of the following strains: Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Enterobacter cloacae, Morganella morganii, Pseudomonas aeruginosa. Ethanol extracts (tinctures) of aerial parts of Baccharis, Fabiana and Parastrephia showed the highest levels of antibacterial activity on methicillin, oxacillin and gentamicin resistant Staphylococcus with MIC values from 20 to 150 g/ml.
Journal of Enzyme Inhibition and Medicinal Chemistry, 2002
The invertase inhibitory protein isolated from Cyphomandra betacea Sendt and Solanum tuberosum in... more The invertase inhibitory protein isolated from Cyphomandra betacea Sendt and Solanum tuberosum inhibited the invertase activity from different species, genera and even plant family. Furthermore, proteinaceous inhibitors are not invertase specific; fungal, bacterial and higher plant enzymes including polygalacturonase, pectinase, pectin lyase, alpha-L-arabinofuranosidase and beta-glucosidase are also shown to be inhibited. Both inhibitors exhibited an in vitro antibacterial action against phytopathogenics strains of Xanthomonas campestris pvar vesicatoria CECT 792, Pseudomonas solanacearum CECT 125, Pseudomonas corrugata CECT 124, Pseudomonas syringae and Erwinia carotovora var carotovora.
Twenty-five samples of propolis were collected from seven different regions in northern Argentina... more Twenty-five samples of propolis were collected from seven different regions in northern Argentina; ethanolic extracts of propolis were prepared from all samples, and the respective samples were examined for UV absorption spectra, RPHPTLC, RPHPLC, antimicrobial activity, antiradical activity, and total phenolic content. It was found that 16 of the 25 samples showed a phenolic profile similar to that found in samples from southern Brazil and corresponding to poplar-based propolis and that the rest of the samples showed a different profile and higher antimicrobial and antiradical activities.
The singlet oxygen ( 1 O 2 ) quenching and free radical (DPPH + , ABTS + ' and O 2 + ( ) scavengi... more The singlet oxygen ( 1 O 2 ) quenching and free radical (DPPH + , ABTS + ' and O 2 + ( ) scavenging ability of three structurallyrelated flavonoids (7-hydroxyflavanone HF, 2?,4?-dihydroxychalcone DHC and 3,7-dihydroxyflavone DHF) present in the Argentinean native shrub Zuccagnia punctata Cav. were studied in solution by combining electrochemical and kinetic measurements, mass spectroscopy, end-point antioxidant assays and computational calculations. The results showed that the antioxidant properties of these flavonoids depend on several factors, such as their electron-and hydrogen atom donor capacity, the ionization degree of the more acidic group, solvatation effects and electrostatic interactions with the oxidant species. The theoretical calculations for both the gas and solution phases at the B3LYP level of theory for the Osanger reaction field model agreed with the experimental findings, thus supporting the characterization of the antioxidant mechanism of the Z. punctata flavonoids.
We report a new colorimetric assay to quantify endo-polygalacturonase activity, which hydrolyzes ... more We report a new colorimetric assay to quantify endo-polygalacturonase activity, which hydrolyzes polygalacturonic acid to produce smaller chains of galacturonate. Some of the reported polygalacturonase assays measure the activity by detecting the appearance of reducing ends such as the Somogyi-Nelson method. As a result of being general towards reducing groups, the Somogyi-Nelson method is not appropriate when studying polygalacturonase and polygalacturonase inhibitors in plant crude extracts, which often have a strong reducing power. Ruthenium Red is an inorganic dye that binds polygalacturonic acid and causes its precipitation. In the presence of polygalacturonase, polygalacturonic acid is hydrolyzed bringing about a corresponding gain in soluble Ruthenium Red. The described assay utilizes Ruthenium Red as the detection reagent which has been used previously in plate-based assays but not in liquid medium reactions. The new method measures the disappearance of the substrate polygalacturonic acid and is compared to the Somogyi-Nelson assay. The experimental results using lemon peel, a fern fronds and castor leaf crude extracts demonstrate that the new method provides a way to the quickly screening of polygalacturonase activity and polygalacturonase inhibitors in plant crude extracts containing high amounts of reducing power. On the other hand, the Ruthenium Red assay is not able to determine the activity of an exo-polygalacturonase as initial velocity and thus would allow the differentiation between endo-and exo-polygalacturonase activities.
El objetivo de este trabajo fue realizar un estudio comparativo de la capacidad antioxidante de e... more El objetivo de este trabajo fue realizar un estudio comparativo de la capacidad antioxidante de extractos de Baccharis incarum obtenidos a través de diferentes técnicas de extracción a presión normal ya presiones criticas (Pc) comprendidas entre 85 a 95 atm. Se realizaron ...
An autographic assay suitable for the detection of antioxidant compounds in a complex matrix (liq... more An autographic assay suitable for the detection of antioxidant compounds in a complex matrix (liquid and semi-solid pharmaceutical formulations) or in isolated compounds was described. The preformed radical monocation of 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS •+ ) was generated by oxidation of ABTS with potassium persulfate and reduced in the presence of hydrogendonating antioxidants. For a further comparative estimation of its applicability and sensitivity, different medicinal plant extracts, hydrogels and antioxidant compounds were dot seeded or chromatographed on silica gel (TLC) and revealed with ABTS •+ solution (System I) or ABTS •+ immobilized by gel entrapment (System II). Both systems were effective and able to detect antioxidant activity in a micromolar range in seconds. System II was more sensitive and reproducible than System I. This micromethod is quick, inexpensive, and particularly helpful whether it works with numerous samples or on a small scale.
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