RESUMO
The Prosopis alba seed is a waste material in the process to produce pod flour. To suggest a potential use of these seeds it is necessary to determine the nutritional, phytochemical and functional quality of cotyledon flour from Prosopis alba. This flour showed high level of proteins (62%), low content of total carbohydrate and fat. Free polyphenol (1150±20mg GAE/100g flour) and carotenoids (10.55±0.05mg ß-CE/100g flour) compounds were the dominant compounds. The main identified constituents in the polyphenolic extracts were C- glycosyl flavones, including schaftoside, isoschaftoside, vicenin II, vitexin and isovitexin. The extract enriched in polyphenolic compounds exhibited ABTS(+) reducing capacity and scavenging activity of H2O2; and was able to inhibit phospholipase, lipoxygenase and cyclooxygenase, three pro-inflammatory enzymes. According to our results, the P. alba cotyledon flour could be considered as a new alternative in the formulation of functional foods or food supplements.
Assuntos
Cotilédone/química , Farinha/análise , Compostos Fitoquímicos/análise , Prosopis/química , Antioxidantes/química , Apigenina/análise , Carotenoides/análise , Glucosídeos/análise , Polifenóis/análise , Sementes/químicaRESUMO
Geoffroea decorticans (chañar), is widely distributed throughout Northwestern Argentina. Its fruit is consumed as flour, arrope or hydroalcoholic beverage. The chañar fruits flour was obtained and 39 phenolic compounds were tentatively identified by HPLC-MS/MS(n). The compounds comprised caffeic acid glycosides, simple phenolics (protocatechuic acid and vanillic acid), a glycoside of vanillic acid, p-coumaric acid and its phenethyl ester as well as free and glycosylated flavonoids. The polyphenols enriched extract with and without gastroduodenal digestion inhibited enzymes associated with metabolic syndrome, including α-amylase, α-glucosidase, lipase and hydroxyl methyl glutaryl CoA reductase. The polyphenolic extract exhibited antioxidant activity by different mechanisms and inhibited the pro-inflammatory enzymes (ciclooxygenase, lipoxygenase and phospholipase A2). The polyphenolic extract did not showed mutagenic effect by Ames test against Salmonella typhimurium TA98 and TA100 strains. These findings add evidence that chañar fruit flour may be considered a functional food with preventive properties against diseases associated with oxidative stress, inflammatory mediators and metabolic syndrome.
Assuntos
Anti-Inflamatórios/farmacologia , Antioxidantes/farmacologia , Fabaceae/química , Síndrome Metabólica/tratamento farmacológico , Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Farinha , Frutas/química , Inibidores de Glicosídeo Hidrolases/farmacologia , Humanos , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , alfa-Amilases/antagonistas & inibidoresRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Zuccagnia punctata Cav. (Fabaceae) is a monotypic species distributed in western Argentina and is traditionally used for the treatment of bacterial and fungal infections. The aim of this study was to demonstrated the antibacterial activity of the Zuccagnia punctata standardized extract and the structurally related non-methoxylated flavonoids with similar pattern of substitution and differences in ring C present in this plant species: 7-hydroxyflavanone (HF), 2',4'-dihydroxychalcone (DHC) and 3,7-dihydroxyflavone (DHF), against Streptococcus pneumoniae clinical isolates using in vitro and in vivo models. MATERIALS AND METHODS: MIC values of natural products were determined by agar macrodilution method. In vivo activities were investigated in a Streptococcus pneumoniae infection model in mice. Lung and blood samples were obtained for bacterial cell counts. The serum was used by biochemical analysis (alanine transaminase, aspartate transaminase, urea and creatinine) in order to evaluate the toxicity of natural products. RESULTS: All samples showed antimicrobial activity in vitro with MIC values between 50 and 500µg/ml. Zuccagnia punctata extract (1mg/mice) and HF (1mg/mice) significantly reduced the number of viable Streptococcus pneumoniae in lung (p<0.01) while lower quantities has not effect. Therefore, the present study has shown that intake once or twice a day of 1mg of Zuccagnia punctata extract or HF for seven days did not result in toxicity. CONCLUSIONS: Our results showed that Zuccagnia punctata extract as well as one of its isolated flavonoids, 7-hydroxyflavanone, could be useful for the development of a novel respiratory infections treatment.
Assuntos
Antibacterianos/uso terapêutico , Fabaceae/química , Flavonoides/uso terapêutico , Fitoterapia , Extratos Vegetais/uso terapêutico , Infecções Respiratórias/tratamento farmacológico , Streptococcus pneumoniae/efeitos dos fármacos , Animais , Antibacterianos/farmacologia , Argentina , Contagem de Colônia Microbiana , Modelos Animais de Doenças , Flavonoides/isolamento & purificação , Flavonoides/farmacologia , Pulmão/efeitos dos fármacos , Pulmão/microbiologia , Camundongos , Camundongos Endogâmicos , Testes de Sensibilidade Microbiana , Extratos Vegetais/farmacologia , Padrões de Referência , Infecções Respiratórias/microbiologia , Streptococcus pneumoniae/crescimento & desenvolvimentoRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Fabiana species (Solanaceae family) extracts have long been used in Argentinean traditional medicine as anti-inflammatories, antiseptic, bone fractures and others diseases, but there is no scientific evidence which supports their use. AIM OF THE STUDY: The present study was conducted to evaluate the ability of aqueous and ethanolic extracts of four Fabiana species (Fabiana bryoides Phil., Fabiana punensis A.C. Arroyo, Fabiana densa J. Rèmy and Fabiana patagonica Speg.) to inhibit key enzymes in inflammatory processes, free radical scavenging properties and genotoxic effects. MATERIALS AND METHODS: HPLC-DAD of aqueous and ethanolic extracts from four Fabiana species was established. All Fabiana extracts were evaluated on their ability to inhibit hyaluronidase and lipoxygenase enzymes to assess their activity against inflammatory mediators. Antioxidant capacity was determined using the 2,2'-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging assays and ß-carotene-linolenic acid assay. Genotoxicity was evaluated by the Ames assay. RESULTS: The results indicated that the chromatographic patterns of four Fabiana species were different in quantity and absorption intensity of peaks. The alcoholic extract of Fabiana punensis was the most active scavenger of DPPH and ABTS(+) radicals (SC(50) values of 3.85 ± 0.24 and 2.56 ± 0.10 µgGAE/mL, respectively). Fabiana patagonica extracts exhibited the highest peroxyl radical scavenging activity compared with the other three taxa (IC(50) values between 1.00 ± 0.04 and 4.46 ± 0.40 µg GAE/mL for all extracts) and anti-lipoxygenase activity with IC(50) values between 12.5 and 15.5 µg GAE/mL. The absence of mutagenicity indicates that the DNA does not seem to be a relevant target for these extracts. Fabiana bryoides ethanolic extract showed an interesting effect: it inhibited spontaneous mutagenesis, which could be considered as an antimutagenic effect in the TA98 (+S9) and TA100 (+S9/-S9) strains. The potency differences found between the species could be consequence of the different phytochemical pattern observed by HPLC. CONCLUSIONS: The inhibitory effects on lipoxygenase and hyaluronidase, free radical scavenging activities and lack of genotoxicity of Fabiana extracts may support the folk use of Fabiana punensis, Fabiana patagonica, Fabiana bryoides and Fabiana densa as inhibitor of inflammatory mediators.
Assuntos
Anti-Inflamatórios/farmacologia , Antimutagênicos/farmacologia , Etanol/química , Sequestradores de Radicais Livres/farmacologia , Extratos Vegetais/farmacologia , Solanaceae , Solventes/química , Água/química , Anti-Inflamatórios/química , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/toxicidade , Antimutagênicos/química , Antimutagênicos/isolamento & purificação , Antimutagênicos/toxicidade , Argentina , Benzotiazóis , Compostos de Bifenilo/química , Cromatografia Líquida de Alta Pressão , Dano ao DNA , DNA Bacteriano/efeitos dos fármacos , Relação Dose-Resposta a Droga , Etnofarmacologia , Sequestradores de Radicais Livres/química , Sequestradores de Radicais Livres/isolamento & purificação , Sequestradores de Radicais Livres/toxicidade , Hialuronoglucosaminidase/antagonistas & inibidores , Hialuronoglucosaminidase/metabolismo , Cinética , Inibidores de Lipoxigenase/farmacologia , Medicina Tradicional , Picratos/química , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/toxicidade , Plantas Medicinais , Salmonella typhimurium/efeitos dos fármacos , Salmonella typhimurium/genética , Solanaceae/química , Ácidos Sulfônicos/química , Tiazóis/química , Ácido alfa-Linolênico/química , beta Caroteno/químicaRESUMO
The antimicrobial activity of samples of Northern Argentine propolis (Tucumán, Santiago del Estero and Chaco) against phytopathogenic bacteria was assessed and the most active samples were identified. Minimal inhibitory concentration (MIC) values were determined by agar macrodilution and broth microdilution assays. Strong antibacterial activity was detected against Erwinia carotovora spp carotovora CECT 225, Pseudomonas syringae pvar tomato CECT 126, Pseudomonas corrugata CECT 124 and Xanthomonas campestris pvar vesicatoria CECT 792. The most active propolis extract (Tucumán, T1) was selected to bioguide isolation and identified for antimicrobial compound (2',4'-dihydroxychalcone). The antibacterial chalcone was more active than the propolis ethanolic extract (MIC values of 0.5-1 µg ml(-1) and 9.5-15 µg ml(-1), respectively). Phytotoxicity assays were realized and the propolis extracts did not retard germination of lettuce seeds or the growth of onion roots. Propolis solutions applied as sprays on tomato fruits infected with P. syringae reduced the severity of disease. Application of the Argentine propolis extracts diluted with water may be promising for the management of post harvest diseases of fruits.
Assuntos
Antibacterianos/farmacologia , Chalconas/farmacologia , Pectobacterium carotovorum/efeitos dos fármacos , Doenças das Plantas/microbiologia , Própole/química , Pseudomonas syringae/efeitos dos fármacos , Xanthomonas campestris/efeitos dos fármacos , Antibacterianos/química , Antibacterianos/isolamento & purificação , Argentina , Chalconas/química , Chalconas/isolamento & purificação , Lactuca/efeitos dos fármacos , Lactuca/crescimento & desenvolvimento , Solanum lycopersicum/microbiologia , Testes de Sensibilidade Microbiana , Cebolas/efeitos dos fármacos , Cebolas/crescimento & desenvolvimento , Pectobacterium carotovorum/patogenicidade , Raízes de Plantas/efeitos dos fármacos , Pseudomonas syringae/patogenicidade , Sementes/efeitos dos fármacos , Xanthomonas campestris/patogenicidadeRESUMO
We determined the anti-inflammatory activity of standardized extracts of four medicinal plant species (Baccharis incarum, B. boliviensis, Chuquiraga atacamensis, Parastrephia lucida) that grow in the Argentine Puna (3800 m above sea level) and that are used to reduce oxidative stress and alleviate gout and arthritic pain. The extracts of plant aerial parts were standardized in terms of total phenolic compounds and flavone/flavanone content and free radical scavenging activity. All extracts showed high phenolic compound concentration (0.5-1.6 mg/mL), mainly flavones and flavonols (0.1-0.8 mg/mL). The extracts showed hydrogen donating ability (DPPH and ABTS) and reactive oxygen species scavenging activity (O2-, OH-, H2O2). The ability of the extracts to inhibit cyclooxygenase enzymes (COX-1 and COX-2) was determined by calculating percent inhibition of PGE2 production measured by enzyme immunoassay. All extracts inhibited both enzymes with IC50 values of 2.0 to 16.7 microg/mL. The anti-inflammatory activity of B. incarum and C. atacamensis extracts was higher than that of B. boliviensis and P. lucida. The IC50 values obtained for indomethacin were 0.11 and 0.78 microM for COX-1 and COX-2, respectively. The present results are consistent with the anecdotal use of these species in phytotherapic preparations.
Assuntos
Anti-Inflamatórios/farmacologia , Asteraceae/química , Inibidores de Ciclo-Oxigenase/farmacologia , Extratos Vegetais/farmacologia , Anti-Inflamatórios/isolamento & purificação , Argentina , Asteraceae/classificação , Baccharis/química , Inibidores de Ciclo-Oxigenase/isolamento & purificação , HumanosRESUMO
We determined the anti-inflammatory activity of standardized extracts of four medicinal plant species (Baccharis incarum, B. boliviensis, Chuquiraga atacamensis, Parastrephia lucida) that grow in the Argentine Puna (3800 m above sea level) and that are used to reduce oxidative stress and alleviate gout and arthritic pain. The extracts of plant aerial parts were standardized in terms of total phenolic compounds and flavone/flavanone content and free radical scavenging activity. All extracts showed high phenolic compound concentration (0.5-1.6 mg/mL), mainly flavones and flavonols (0.1-0.8 mg/mL). The extracts showed hydrogen donating ability (DPPH and ABTS) and reactive oxygen species scavenging activity (O2●-, OH-, H2O2). The ability of the extracts to inhibit cyclooxygenase enzymes (COX-1 and COX-2) was determined by calculating percent inhibition of PGE2 production measured by enzyme immunoassay. All extracts inhibited both enzymes with IC50 values of 2.0 to 16.7 µg/mL. The anti-inflammatory activity of B. incarum and C. atacamensis extracts was higher than that of B. boliviensis and P. lucida. The IC50 values obtained for indomethacin were 0.11 and 0.78 µM for COX-1 and COX-2, respectively. The present results are consistent with the anecdotal use of these species in phytotherapic preparations.
Assuntos
Humanos , Anti-Inflamatórios/farmacologia , Asteraceae/química , Inibidores de Ciclo-Oxigenase/farmacologia , Extratos Vegetais/farmacologia , Argentina , Anti-Inflamatórios/isolamento & purificação , Asteraceae/classificação , Baccharis/química , Inibidores de Ciclo-Oxigenase/isolamento & purificaçãoRESUMO
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 microg/ml. Baccharis boliviensis and Fabiana bryoides were more active than the other plant species on Enterococcus faecalis with different phenotype. The most interesting activity on multi-resistant gram-negative strains was obtained from Chuquiraga atacamensis. Parastrephia species showed activity against Enterobacter cloacae, Pseudomonas aeruginosa and Proteus mirabilis. The ethanolic extracts exhibited stronger activity and broader spectrum of action than aqueous extracts. The extracts were bactericidal in most cases. CONCLUSIONS: The presence of antibacterial activity in Puna plant extracts against multi-resistant bacteria give support to their traditional use for treating conditions associated with microorganisms in humans and animals and consequently seems promising for the treatment of multi-resistant bacteria.
Assuntos
Anti-Infecciosos/farmacologia , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Plantas Medicinais/química , Anti-Infecciosos/química , Argentina , Cromatografia em Camada Fina , Meios de Cultura , Etnofarmacologia , Medicina Tradicional , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Fenóis/química , Fenóis/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologiaRESUMO
The purpose of the present study was to investigate the antibacterial activity of seven ethanolic extracts and three aqueous extracts from various parts (leaves, stems and flowers) of A. aroma against 163 strains of antibiotic multi-resistant bacteria. The disc diffusion assay was performed to evaluate antibacterial activity of the A. aroma crude extracts, against several Gram-positive bacteria (E. faecalis, S. aureus, coagulase-negative stahylococci, S. pyogenes, S. agalactiae, S. aureus ATCC 29213, E. faecalis ATCC 29212) and Gram-negative bacteria (E. coli., K. pneumoniae, P. mirabilis, E. cloacae, S. marcescens, M morganii, A. baumannii, P. aeruginosa, S. maltophilia, E. coli ATCC 35218, P. aeruginosa ATCC 27853, E. coli ATCC 25922). All ethanolic extracts showed activity against gram-positive bacteria. Among all obtained extracts, only leaf and flower fluid extracts showed activity against Gram-negative bacteria. Based on this bioassay, leaf fluid extracts tended to be the most potent, followed by flower fluid extracts. Minimal inhibitory concentration (MIC) values of extracts and antibiotics were comparatively determined by agar and broth dilution methods. Both extracts were active against S. aureus, coagulase-negative stahylococci, E. faecalis and E. faecium and all tested Gram-negative bacteria with MIC values from 0.067 to 0.308 mg/ml. In this study the minimal bactericidal concentration (MBC) values were identical or twice as high than the corresponding MIC for leaf extracts and four or eight times higher than MIC values for flower extracts. This may indicate a bactericidal effect. Stored extracts have similar antibacterial activity as recently obtained extracts. The A. aroma extracts of leaves and flowers may be useful as antibacterial agents against Gram- negative and Gram-positive antibiotic multi-resistant microorganisms.
Assuntos
Acacia/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana , Antibacterianos/química , Bioensaio , Cromatografia em Camada Fina , Etanol , Testes de Sensibilidade Microbiana , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Estruturas Vegetais/química , Sais de Tetrazólio , Tiazóis , ÁguaRESUMO
Propolis is used in Argentine folk medicine. We have examined its possible protective action against oxidative modification of lipid in unfractionated serum. The kinetics of copper-induced oxidation was continuously monitored by measuring the formation of conjugated dienes, as the increase in the absorbance at 234 nm. According to the kinetics of oxidation, the propolis were classified in three different groups. Group I (CE, CO, BO, MO, BE) inhibited lipid oxidation during the initiation and propagation phases even at low concentrations. Group II (SP, CA, AM) increased the lag-phase for conjugated diene formation. All propolis in groups I and II diminished the maximal rate of diene production and the maximal amount of dienes produced. Group III (PA, RA, FE, VR, TV) had no effect on the lipid oxidation. The extent of lipoprotein oxidation was measured by the thiobarbituric acid reactive substance assay. Generation of malondialdehyde-like substances was inhibited and delayed by the presence of propolis extracts from group I and II. Our results justify the use of propolis (groups I and II) as a source of natural antioxidants.
Assuntos
Antioxidantes/farmacologia , Sangue/efeitos dos fármacos , Própole/farmacologia , Antioxidantes/classificação , Antioxidantes/isolamento & purificação , Argentina , Sangue/metabolismo , Humanos , Cinética , Lipoproteínas LDL/sangue , Medicina Tradicional , Oxirredução/efeitos dos fármacos , Própole/classificação , Própole/isolamento & purificaçãoRESUMO
Propolis is extensively used in Argentine folk medicine. Alcoholic extracts of propolis from different regions of Argentina were prepared. The extracts were analysed for the determination of total flavonoid content (from 13.3 to 42.6 mg/g of propolis) by using the aluminum nitrate method, UV spectrophotometry and thin layer chromatography. All of them contained high total flavonoid content. It was also observed that all samples of ethanolic extracts of propolis showed free radical-scavenging activity in terms of scavenging of the radical DPPH but the highest activities were found for samples from Tucumán and Santiago del Estero. In all cases with 20 microg/ml of soluble principles, the percentage of DPPH degradation was different (Banda Oeste: 67.5%; Verónica: 45%; Forres: 35%; Saenz Peña: 20% and Juan José Castelli: 55%). These results may justify their use as a source of natural antioxidants.
Assuntos
Sequestradores de Radicais Livres/farmacologia , Picratos , Própole/farmacologia , Argentina , Bepridil/análogos & derivados , Bepridil/química , Compostos de Bifenilo , Cromatografia Líquida , Cromatografia em Camada Fina , Flavonoides/análise , Sequestradores de Radicais Livres/análise , Radicais Livres/química , Indicadores e Reagentes , Própole/análiseRESUMO
Three fractions with invertase activity (beta-D-fructofuranoside fructohydrolase, EC 3.2.1.26) were isolated from mature Solanum tuberosum tubers: acid soluble invertase, invertase I and invertase II. The first two invertases were purified until electrophoretic homogeneity. They are made by two subunits with an apparent M(r) value of 35,000 and their optimal pH is 4.5. Invertase I was eluted from cell walls with ionic strength while invertase II remained tightly bound to cell walls after this treatment. This invertase was solubilized by enzymatic cell wall degradation (solubilized invertase II). Their K(m)s are 28, 20, 133 and 128 mM for acid soluble invertase, invertase I, invertase II and solubilized invertase II, respectively. Glucose is a non-competitive inhibitor of invertase activities and fructose produces a two site competitive inhibition with interaction between the sites. Bovine serum albumin produces activation of the acid soluble invertase and invertase I while a similar inhibition by lectins and endogenous proteinaceous inhibitor from mature S. tuberosum tubers was found. Invertase II (tightly bound to the cell walls) shows a different inhibition pattern. The test for reassociation of the acid soluble invertase or invertase I on cell wall, free of invertase activity, caused the reappearance of all invertase forms with their respective solubilization characteristics and molecular and kinetic properties. The invertase elution pattern, the recovery of cell wall firmly bound invertase and the coincidence in the immunological recognition, suggest that all three invertases may be originated from the same enzyme. The difference in some properties of invertase II and solubilized invertase II from the other two enzymes would be a consequence of the enzyme microenvironment in the cell wall or the result of its wall binding.
Assuntos
Parede Celular/enzimologia , Glicosídeo Hidrolases/metabolismo , Solanum tuberosum/enzimologia , Anticorpos/imunologia , Western Blotting , Catálise , Inibidores Enzimáticos/metabolismo , Glicosídeo Hidrolases/antagonistas & inibidores , Glicosídeo Hidrolases/isolamento & purificação , Concentração de Íons de Hidrogênio , Cinética , Lectinas/metabolismo , Lectinas de Plantas , Especificidade por Substrato , beta-FrutofuranosidaseRESUMO
Propolis is extensively used in Argentine folk medicine. Alcoholic extracts of propolis from four localities of Amaicha del Valle (El Paraiso, La Banda Este, La Banda Oeste and El Molino), Province of Tucumán and from Cerrillos, Province of Santiago del Estero, Argentina were prepared. All showed antibacterial activity against Gram positive bacteria, the propolis from La Banda Este being the most active (MIC = 7.8 microg/ml) against Streptococcus piogenes, an antibiotic resistant bacterium. Thin layer chromatographic (TLC) separation profiles of propolis from Amaicha del Valle region were similar but differ from the alcoholic extract of the propolis from Cerrillos, another phytogeographical region of Argentina (provincia chaqueña). Bioautographic assays of the TLC profiles showed that several separated compounds of the Amaicha del Valle propolis have antibacterial activity. The difference in composition between Amaicha del Valle and Cerrillos propolis coincides with a different phytogeographical formation.
Assuntos
Antibacterianos/farmacologia , Extratos Vegetais/farmacologia , Própole/química , Argentina , Autorradiografia , Cromatografia em Camada Fina , Avaliação Pré-Clínica de Medicamentos , Resistência Microbiana a Medicamentos/fisiologia , Bactérias Gram-Positivas/efeitos dos fármacos , Medicina Tradicional , Testes de Sensibilidade Microbiana , Solubilidade , Streptococcus pyogenes/efeitos dos fármacosRESUMO
The soluble acid invertase (beta-D-fructofuranoside fructohydrolase, EC 3.2.1.26) from potato (Solanum tuberosum L. cv. Kennebec) tubers was located in the vacuoles. Although the functionality of this invertase in the vacuoles has been assumed, the activity of the enzyme has never been shown within isolated vacuoles. Vacuoles were prepared by gentle osmotic shock from free protoplasts obtained by enzymic digestion of tuber tissues. The mean volume of these vacuoles, (0.26 +/- 0.05) x 10(-2) microliters, was estimated by optical microscopy. Sucrose, glucose and fructose concentrations were calculated to be 100 mM, 20 mM and 40 mM, respectively, in the vacuoles. Sucrose hydrolysis and the increase in glucose and fructose concentrations within the vacuoles were measured during vacuolar incubations. An almost identical pattern of sucrose hydrolysis by invertase was found by an in-vitro assay reproducing the vacuolar conditions. In view of the determinations of internal vacuolar pH (5.2), the possibility of spontaneous hydrolysis of sucrose was disregarded. Vacuoles were shown to be free from proteinaceous inhibitors, confirming the extravacuolar location of these inhibitors. The vacuolar hydrolytic pattern of sucrose confirms the regulatory role of the reaction products previously proposed for in-vitro assays.