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Item The Passiflora tripartita (Banana Passion) Fruit: A Source of Bioactive Flavonoid C-Glycosides Isolated by HSCCC and Characterized by HPLC-DAD-ESI/MS/MSAutores: Simirgiotis, M.J.; Schmeda-Hirschmann, G.; Borquez, J.; Kennelly, E.J.The banana passion fruit (Passiflora tripartita Breiter, Passifloraceae) known as "tumbo" is very appreciated in tropical and subtropical countries of South America. Methanolic extracts from peel and the fruit juice of P. tripartita growing in Chile were analyzed for antioxidant capacity as well as for flavonoid and phenolic content. A chromatographic method was developed for the rapid identification of the main phenolics in the samples by HPLC-DAD and HPLC-MS. The fast fingerprint analysis allowed the detection of eighteen flavonoid C-glycosides and four flavonoid O-glycoside derivatives which were characterized by UV spectra and ESI-MS-MS analysis. Several of the C-glycosides detected are structurally related to the orientin derivative 4'-methoxy-luteolin-8-C-(6 '' acetyl)-beta-D-glucopyranoside (31), fully elucidated by spectroscopic methods. The antioxidant derivative 31 along with schaftoside, vicenin II, orientin and vitexin were isolated from the fruit extract by high-speed countercurrent chromatography (HSCCC). A suitable method for the preparative isolation of flavonol C-glycosides from "tumbo" extracts by HSCCC is reported. The pulp of the fruits showed good antioxidant capacity (12.89 +/- 0.02 mu g/mL in the DPPH assay). The peel presented the highest content of flavonoids (56.03 +/- 4.34 mg quercetin/100 g dry weight) which is related to the highest antioxidant power (10.41 +/- 0.01 mu g/mL in the DPPH assay).Item Free radical scavengers and antioxidants from lemongrass (Cymbopogon citratus (DC.) Stapf.)Autores: Cheel, J.; Theoduloz, C.; Rodriguez, J.; Schmeda-Hirschmann, G.Methanol, MeOH/water extracts, infusion, and decoction of Cymbopogon citratus were assessed for free radical scavenging effects measured by the bleaching of the 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radical, scavenging of the superoxide anion, and inhibition of the enzyme xanthine oxidase (XO) and lipid peroxidation in human erythrocytes. The extracts presented effect in the DPPH and superoxide anion assay, with values ranging between 40 and 68% and 15-32% at 33 and 50 mu g/mL, respectively, inhibited lipid peroxidation in erythrocytes by 19-71% at 500 mu g/mL and were inactive toward the XO at 50 mu g/mL. Isoorientin, isoscoparin, swertiajaponin, isoorientin 2"-O-rhamnoside, orientin, chlorogenic acid, and caffeic acid were isolated and identified by spectroscopic methods. Isoorientin and orientin presented similar activities toward the DPPH (IC50: 9-10 mu M) and inhibited lipid peroxidation by 70% at 100 gamma g/mL. Caffeic and chlorogenic acid were active superoxide anion scavengers with IC50 values of 68.8 and 54.2 mu M, respectively, and a strong effect toward DPPH. Caffeic acid inhibited lipid peroxidation by 85% at 100 mu g/mLItem Cutting propagation and tannin and flavonoid concentration in leaves of two Ugni molinae provenances from the Maule Region (Chile)Autores: Doll, U.; Rodriguez, I.; Soto, C.; Razmilic, I.The high content of active compounds with antioxidant power found in Ugni molinae leaves, an understory shrub of native forests, caused a search for promising material for cultivation. The aims of this study were to determine the rooting capacity of cuttings of two provenances from the northern distribution limit of the species, and the effect of sun exposure and leaf age on tannin and flavonoid concentration. The rooting trial was carried out in a warm rooting-bed over cuttings coming from 10 mother plants of each provenance. After three months, more than 70% of cuttings rooted; Cordillera de Los Andes provenance outdid Cordillera de la Costa provenance. The application of rooting hormone at the base of cuttings significantly improved the share of successful rooting and the quality of roots formed. Leaves of five sun plants and five shadow plants were collected from each provenance for quantification of active compounds. Sun leaves show higher flavonoid concentration than did shadow leaves in both provenances. Cordillera de los Andes sun leaves contain more tannin than that contained by shadow leaves of the same provenance. Leaf age has no impact on the concentration of active compounds.Item Free radical scavengers and antioxidants from Baccharis grisebachiiAutores: Tapia, A.; Rodriguez, J.; Theoduloz, C.; Lopez, S.; Feresin, G.E.; Schmeda-Hirschmann, G.The exudate and seriated extracts from the aerial parts of Baccharis grisebachii (Asteraceae) which is recommended as a digestive and to relieve gastric ulcers in Argentina, showed activity as free radical scavengers and inhibited lipoperoxidation in erythrocytes. Assay-guided isolation led to seven p-coumaric acid derivatives and six flavonoids as the main active constituents of the crude drug. The activity towards the superoxide anion was mainly due to the flavonoid constituents. 5,7,4'-Trihydroxy-6-methoxyflavone and quercetin presented high activity (64 and 79%) even at 12.5 mug/ml. The xanthine oxidase inhibitory effect of the extracts can be related with the p-coumaric acid derivatives drupanin, 4-acetyl-3,5-diprenylcinnamic acid and trans-ferulic acid O-hexan-3-onyl-ether which showed IC50 values in the range 28-40 mug/ml. Both p-coumaric acid derivatives and flavonoids inhibited lipoperoxidation in erythrocytes. The highest activity was found for the p-coumaric acid derivatives 4-acetyl-3-prenyl-ethoxycinnamate, 3-prenyl-4-(4'-hydroxydihydrocinnamoyloxy)-cinnamate and trans-ferulic acid O-hexan-3-onyI-ether (69-82%) and the flavonoids 5,7,4'-trihydroxy-6-methoxyflavone, quercetin, 5,7,4'-trihydroxy-6,3'-dimethoxyflavone and 5,7,4'-trihydroxy-6,8-dimethoxyflavone (64-84%) at 100 mug/ml.Item Anticaries effect of an antioxidant-rich apple concentrate on enamel in an experimental biofilm-demineralization modelAutores: Giacaman, RA.; Contzen, MP.; Yuri, J.A.; Munoz-Sandoval, C.Aims: To assess the anticaries activity of an antioxidant-rich apple concentrate (ARAC) in an experimental biofilm caries model on enamel. Methods and Results: A validated caries model with Streptococcus mutans UA159 biofilms was used. Biofilms were formed on enamel slabs during 5 days. To mimic cariogenic challenges, triplicate slabs were exposed three times per day for 5 min to 10% sucrose followed by five additional minutes of exposure to serial dilutions of ARAC in 0.9% NaCl. A triplicate slab exposed to 10% sucrose followed by 0.9% NaCl served as caries-positive control. Acidogenicity was estimated by medium pH twice per day. After the experimental phase, biofilms were recovered to determine biomass, viable bacteria and intra-and extracellular polysaccharides. Slabs were used to estimate demineralization by the percentage of surface microhardness loss (% SHL). Differences among treatments were analysed by ANOVA and Bonferroni test (P < 0.05). Streptococcus mutans biofilms were exposed to ARAC after a cariogenic challenge with sucrose-induced lower enamel demineralization than the positive control. The highest dilution of ARAC at 1 : 100 000 (v/v) showed the most marked reduction in demineralization of about 57%. Although no differences were observed in the number of bacterial cells, the intracellular polysaccharides or in the biomass (P > 0.05), the highest dilution of the apple concentrate induced significantly lower extracellular polysaccharide formation by the biofilm. Conclusions: An apple concentrate in low concentrations appears to have a potential anticaries activity on enamel. Data suggest a metabolic rather than an antimicrobial mechanism, but further research is needed. Significance and Impact of the Study: Phenolic compounds contained in apple concentrates seem to have anticaries properties that may be effective even in the presence of sucrose and in very low doses. Nutritional interventions that do not require rescinding from sucrose might be derived from these findings.Item Changes in antioxidant capacity during development and ripening of goldenberry (Physalis peruviana L.) fruit and in response to 1-methylcyclopropene treatmentAutores: Valdenegro, M.; Fuentes, L.; Herrera, R.; Moya-Leon, M.A.Goldenberry (Physalis peruviana) is a climacteric fruit and its ripening is regulated by ethylene. Reports indicate that the fruit contains high level of antioxidant compounds. To elucidate the role of ethylene on the antioxidant capacity of this fruit during ripening and storage, the effect of 1-methylcyclopropene (1-MCP, 0.2 mu L L-1), a blocker of the ethylene receptor, and ethylene (2000 mu L L-1 Ethrel) were tested. During ripening of the fruit the ethylene production and respiration rates increased constantly until the end of the process, similar to the SSC/acidity ratio. Firmness reduction started early during development and continued throughout ripening. The measurement of total antioxidant capacity revealed a high antioxidant level in unripe fruit, and a clear increment in antioxidant capacity, ascorbic acid and polyphenol contents was observed throughout ripening with maximum values at the ripe stage. Nevertheless, after harvest the antioxidant capacity was rapidly reduced during the shelf-life period (20 degrees C) and ethylene treatment increased this reduction. Significant preservation of the antioxidant capacity, vitamin C and polyphenol content was observed in 1-MCP treated fruit. The results indicate that 1-MCP treatment could be useful to preserve the high antioxidant capacity of goldenberry fruit during storage. (C) 2012 Elsevier B.V. All rights reserved.
