Valorization of papaya (Carica papaya L.) agroindustrial waste through the recovery of phenolic antioxidants by supercritical fluid extraction.

In this work, supercritical fluid extraction (SFE) for the recovery of phenolic antioxidants from papaya agroindustrial waste (seeds) was explored, making use of neat supercritical CO2 and CO2 added with ethanol (CO2-EtOH). A full factorial design played on in order to evaluate the effect of CO2 extraction parameters (temperature between 40 and 60 °C, and pressure between 10 and 30 MPa) on yield and total phenols content (TPC), then ethanol was applied as a co-solvent and its effect on the recovery of phenolics was analyzed. The SFE was compared to the conventional extraction using ethanol. The antioxidant activity of all extracts was evaluated, and the phenolic composition in selected extracts was assessed by HPLC-ESI-MS. The highest extraction yields (21.02-26.46%) and TPC (15.34-34.23 mgGAE/g) were found in extracts obtained with CO2-EtOH and ethanol. Good and selective phenolic recovery was obtained by using CO2-EtOH, (44.81% of TPC recovered). The CO2-EtOH extracts showed high radical scavenging activity and higher antioxidant effect against lipid oxidation. Some phenolic acids and flavonoids were observed in the extracts with better antioxidants properties. The results showed that SFE is a suitable green technology for the phenolic recovery from papaya agroindustrial waste, and also an alternative for its valorization.

Valorization of agroindustrial wastes: Identification by LC-MS and NMR of benzylglucosinolate from papaya (Carica papaya L.) seeds, a protective agent against lipid oxidation in edible oils.

In the present study we report the characterization of benzylglucosinolate (BG) isolated from papaya (Carica papaya L.) seeds. A methanolic extract was fractionated and further purified by solid phase extraction (SPE). It was analyzed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS), and nuclear magnetic resonance spectroscopy ((1) H and (13) C-NMR) as well, and the target compound BG was identified by these two techniques. The effect of BG on lipid oxidation in edible vegetable oil (EO) was shown by observing some lipid oxidation products (linoleic acid hydroperoxides, LHP; hexanal, HEX; nonanal, NON; thiobarbituric acid reactives species, TBARS). BG reduced lipid oxidation production in EO by over 80%, as compared to a control sample and in this way has proved to be a useful antioxidant, even more effective than some antioxidants used by food industry.

Comparison of an indirect format ELISA on modified graphite and polystyrene surfaces against triazines.

An indirect format enzyme-linked immuno-sorbent assay (ELISA) on graphite rods ( 0.8 mm x 20 mm) and, for comparison, on microtiter plates has been developed against terbuthylazine. For this purpose, a series of 2-aminoalkyl-4-chloro-6-terbuthyl-s-triazine-2,6-diamine ELISA haptens with alkyl spacer lengths of 2, 4, 6, and 8 CH2 groups has been synthesized. The graphite rods or the microtiter plates were covered by a polymerized glutaraldehyde network, and the ELISA haptens have been coupled by imino coupling to the free aldehyde groups of that network. epsilon-Aminocaproic acid has been used as an agent to block unspecific binding sites. The ELISA was run in a competitive mode, where the immobilized ELISA hapten and the solute terbuthylazine as a target analyte compete for the solute antibody.

Thymidylate synthase and dihydropyrimidine dehydrogenase mRNA expression levels: predictors for survival in colorectal cancer patients receiving adjuvant 5-fluorouracil.

PURPOSE: Despite adjuvant 5-fluorouracil (5-FU) therapy, approximately 30% of patients with International Union against Cancer stage II and III colorectal cancer develop recurrence. In this study, we determined the prognostic value of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) expression in colorectal cancer patients treated with adjuvant 5-FU. EXPERIMENTAL DESIGN: A real-time reverse transcription-PCR technique for quantitation of relative gene expression from paraffin-embedded specimen was established first. In a second step, archival paraffin-embedded primary tumor tissue of 309 patients who participated in adjuvant colorectal cancer trials was analyzed for TS and DPD mRNA expression. RESULTS: TS mRNA expression determined by real-time reverse transcription-PCR correlated with TS protein levels determined by TS immunoblot and immunohistochemistry in cultured colon cancer cell lines and paraffin-embedded primary tumor tissue. TS mRNA levels in fresh-frozen tissues also correlated with TS mRNA levels in corresponding paraffin sections. Among the patients receiving adjuvant 5-FU therapy, those with high TS survived longer than those with low TS, and in each TS subgroup, the ones with low DPD survived longer than the ones with high DPD levels. Multiple Cox regression analysis showed that besides tumor stage (P = 0.010), only the combination of TS and DPD expression turned out to be an independent prognostic factor for survival (P = 0.030). CONCLUSIONS: This suggests that TS and DPD quantitation may be helpful to evaluate prognosis of patients receiving adjuvant 5-FU and that patients with high TS and low DPD may benefit from adjuvant 5-FU chemotherapy.

Association of time to recurrence with thymidylate synthase and dihydropyrimidine dehydrogenase mRNA expression in stage II and III colorectal cancer.

Patients with International Union Against Cancer (UICC) stage IIb and III colon cancer and stage II and III rectal cancer may receive adjuvant chemotherapy with 5-fluorouracil (5-FU). High levels of thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD) have been associated with resistance to 5-FU in advanced colorectal cancer. The aim of this study was to investigate the association of TS and DPD mRNA levels with recurrence-free survival in patients with colorectal cancer who are receiving adjuvant 5-FU-based chemotherapy. TS and DPD mRNA quantitation was retrospectively performed in primary colorectal cancer specimens from patients receiving adjuvant 5-FU using a reverse transcription- polymerase chain reaction technique. The median TS mRNA level in patients with a recurrence (n = 142) was 0.68, and in patients without a recurrence (n = 206) the median level was 0.80 (P < 0.01). Patients with a recurrence who had a low TS level (TS < or = 0.9; n = 102) had a median recurrence-free survival of 18 months (range 3.0 to 54 months), and those with a high TS level (TS > 0.9; n = 40) had a median recurrence-free survival of 11 months (range 1.7 to 53 months; P = 0.0024). There was no difference in the median recurrence-free survival of patients with low and high DPD mRNA levels. The TS mRNA level may be a useful marker to predict the time to recurrence in patients with colorectal cancer who are receiving adjuvant 5-FU treatment.

Incomplete degradation of linear alkylbenzene sulfonate surfactants in Brazilian surface waters and pursuit of their polar metabolites in drinking waters.

In Brazil more than 90% of the population are not connected to municipal wastewater treatment plants. As a consequence, surface waters receive continuously considerable amounts of untreated domestic sewage containing surfactants as a major constituent. Such polluted waters gave rise to special interest if they are used as a source for the production of drinking water. In this work, the river Rio Macacu (State Rio de Janeiro, Brazil) was monitored for the occurrence of the most widely used anionic surfactant linear alkylbenzene sulfonate (LAS) together with its main degradative product, sulfophenyl carboxylates (SPC). In order to pursue the fate of both compounds after emission into the river, samples were collected at several locations along the river bank, and analyzed applying liquid chromatography-mass spectrometry after enrichment by solid-phase extraction. The LAS concentrations ranged between 14 and 155 microg l(-1) and the levels of their metabolic intermediates were found from 1.2 to 14 microg l(-1). The self-purification capacity of the water was impressively demonstrated in the upper course of the river downstream of a town considered as one major discharge point, whereas in the lower course the relative constant concentrations of both analytes were detected which was explained with an overall increasing level of pollution. Furthermore, a series of drinking water samples from Niterói and São Gonçalo, supplied by the same waterworks treating surface waters from the Rio Macacu, were taken during two sampling periods and examined for the presence of the strongly polar SPC which is suspected of by-passing the purification processes. The levels detected in the drinking water ranged between 1.6 and 3.3 microg l(-1). For the analyses of drinking and surface waters the peak pattern of a selected SPC homologue composed by several positional isomers served as an indicator to describe the progression of SPC degradation occurred in the river and could be used to distinguish drinking waters of different origins.

Presence of organochlorine pesticides in breast milk samples from Colombian women.

The presence of organochlorine pesticides (OCPs) in biological and environmental samples has been studied for decades in many countries. Nonetheless, studies in Latin American countries like Colombia have been scarce. Determining the presence of OCPs in breast milk will be of relevance to assess exposures, potential health risks, and for surveillance among Latin American populations. Thirty-two breast-feeding mothers were selected to voluntarily participate in the study. Breast milk samples were analyzed for 10 OCPs (α-, ß-, γ-, δ-HCH, Heptachlor, α-, γ-Chlordane, 4,4' DDT, 4,4' DDE, 4,4' DDD). Milk samples were analyzed using liquid-liquid extraction, followed by sulfuric acid clean-up, and quantified using GC/µECD. Results were confirmed by GC/MS. OCPs concentrations were normalized using fat content. In all but one sample, 4,4' DDE was quantified in concentrations ranging between<17 and 14948 ng g(-1) (ng of OCP per g of lipids), with a mean value of 203 ng g(-1). One woman had 4,4' DDE concentrations that were orders of magnitude above the average concentrations observed worldwide. Concentrations of 4,4' DDE in a second breast milk sample collected in a different time period of lactation from a sub-group of 13 women from the original participants, showed no statistically significant difference with the concentrations found in the first sample. Based on the results obtained from the Persistent Organic Pollutants Global Monitoring Plan report of 2009 of the Stockholm Convention, Colombia ranks fourth from bottom to top in terms of 4,4' DDE average concentrations.