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[en] In recent years, increasing consumption of herbal tea is a worldwide trend because of their refreshing taste, positive potential health effect, convenience, abundant resources and also cheaper in price. However, different maturity stages of plants being used as raw material could affect the antioxidant activity, colour and mineral content in herbal tea. Thus, this present study was aimed at determining antioxidant activity, colour and mineral content of herbal tea prepared from Cosmos caudatus (C. caudatus) leaves at three different maturity stages namely young, mature and old. All prepared herbal tea were analysed for total phenolic content (TPC), total flavonoid content (TFC), ferric reducing antioxidant power (FRAP), 2-2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, colour and mineral content. The results demonstrated that herbal tea prepared from young leaves had strong (p<0.05) antioxidant activity compared to mature and old leaves for all assays tested. Pearsons correlation coefficient also revealed that TPC and TFC exhibited a strong positive correlation with reducing power but negatively correlated with DPPH scavenging activity indicating that these compounds are major contributors to the antioxidant activity. In fact, the darker (p<0.05) colour of C. caudatus herbal tea prepared from young leaves relates to their higher antioxidant activity as compared to mature and old leaves. However, C. caudatus herbal tea prepared from old leaves showed significantly higher in mineral content compared to mature and young leaves. Hence, it can be concluded that, as maturity increased, antioxidant activity and colour in C. caudatus herbal tea decreased and vice-versa for mineral content. (author)
[en] Radiation induces the formation of reactive oxygen species (ROS), which can damage cells. Antioxidants (AO) can decrease these damage. In addition to radiation, ROS is normally generated by metabolic processes in our bodies. Alteration of ROS and AO levels is related to several diseases and pathologic conditions e.g. cancer, diabetes, Alzheimer, AIDS, and aging. In addition, emotion such as stress can change ROS and AO levels. Antioxidants from nutrient and happy mind will make us healthy, decrease radiation-induced damage, reduce the medical cost, and consequently assist in the development of our economy
[en] In Asia Aquilaria has long been used in many traditional medicines due to its enrichment inseveral active ingredients such as flavonoids, tannins, and cardiac glycosides. The objective of this work is to investigate and evaluate antioxidant and γ-radiation induced oxidative stress protection activities of the Aquilaria leaf extract. The leaf was extracted by Soxhlet extractor in which both the upper fraction (filtrate) and the lower fraction (precipitate) were kept separately for evaluation. In terms of antioxidant activity, 2, 2-diphenyl-1-picrylhydrazyl (DPPH) was used in a free radical scavenging assay. The precipitate of 3.13, 6.25, 12.50, 25.00, 50.00 and 100 μg/ml exhibited 17.70%, 33.52%, 45.80%, 60.49%, 76.30% and 85.71% DPPH inhibition, respectively. The filtrate at the same concentrations showed approximately 50% less inhibition than the precipitate. The extracts did not exhibit any cytotoxicity by MTT assay. However, the precipitate at 10, 20, 100 μg/ml and the filtrate at 50, 100, 200 μg/ ml could not protect human dermal fibroblast cells from irradiation damage when the cells were treated for 45 min or 24 h prior to exposure to gamma radiation at 0, 3 and 10 Gy. In conclusion, the Aquilaria leaf extract contained a potent antioxidant activity, but not μ-radiation induced oxidative stress protection activity.
[en] In spite of their efficiency, the use of synthetic antioxidants such as tert-butyl hydroquinone (TBHQ) has been questioned because of their possible carcinogenic effects. The purpose of this study was to establish a mixture of natural antioxidants that provides the optimum oxidative stability for margarine. Antioxidant treatments included 10 various mixtures (F1- F10) containing 100-500 ppm tocopherol mixture (Toc), 100-200 ppm ascorbyl palmitate (AP), 100-200 ppm rosemary extract (Ros) and 1000 ppm lecithin(Lec) along with a control or F0 (with no antioxidant) and F11 containing 120 ppm TBHQ. The effect of antioxidant mixtures on the stability of margarine samples during an oven test (60 +-1 deg. C), rancimat test at 110 deg. C and storage at 4 deg. C was evaluated. The final ranking of the natural antioxidant mixtures was as follows: F2, F10>F5, F9>F8>F1, F3, F4>F6, F7. Considering the results of this research and ranking criteria, F2 (200 ppmAp + 200 ppmRos) and F10 (200 ppmRos + 200 ppm Toc + 1000 ppm Lec) were recommended as substitutes for TBHQ to maintain the quality and increase the shelf-life of margarine. (author)
[en] Full Text: The termophysical properties of fibroins of natural polymer are investigated. It is established, that at injecting of antioxidants N-(3,5-ditret-buty-4-hydroxyfenil) salicylaldimin into the structure of fibroins, by additional fertilizing of caterpillars by last-named amorphous sites increase and thus the stability of silk to external influences raises, i.e. the stabilization occurs due to sewing action of antioxidant
[en] The newly manufactured N-isopropylacrylamide (NIPAM) polymer gel is composed of four components, i.e., gelatin, monomer (NIPAM), crosslinker (N,N'-methylenebisacrylamide, Bis), and antioxidant (tetrakis hydroxymethyl phosphonium chloride, THPC). In this study, we investigated the effects of gel composition on the dose response of NIPAM polymer gel. A statistical experiment to analyze the contribution of each composition to the linearity and sensitivity of NIPAM gel was performed. Results indicate that the amount of gelatin, NIPAM (15.17%), Bis, and THPC have dominant effects on the sensitivity of the gel, with contributions of 59.73, 15.17, 10.64, and 14.45%, respectively. The amount of gelatin and Bis mainly affected the linearity of the gel, with contributions of 44.70 and 50.99%, respectively. The linearity of most compositions of the gel was greater than 0.99 when (%C)/(%T) was lower than 8.0. Optimal (%C)/(%T) for higher sensitivity should be in the range of 4-9. The temporal stability experiment showed that the dose response curve attained stability at about 5 h after irradiation and persisted up to 3 months. (author)
[en] The effect of a medium dose of gamma radiation on antioxidant activity of Amoora rohitaka was studied. Radiation doses were 0, 1, 3 and 5 kGy. Antioxidant activity was screened by using different assay. With increasing dose the formation of Maillard reaction products (MRPs) contributes to the increase in the antioxidant activity. MRPs are formed as a result of Maillard reaction. In ABTS [2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid di-ammonium salt] assay, ethanol extract showed increase in scavenging activity. It also showed a marked increase in polyphenolic contents. The present study reveals that gamma irradiation can be an efficient process to increase antioxidant activity of Amoora rohitaka. (author)
[en] This study assessed the potential of different composts at different maturity stages to supply N and their effect on the vegetative growth of lettuce and Amaranthus. Five composts aged 1, 3, 6, 9, and 12 months, were mixed with soil at the rate of 5%, 10% and 15% then seeded with lettuce and Amaranthus. Results showed that 1, 3 and 6 month aged composts had a negative effect on plant height of lettuce and Amaranthus as 1-15.78% and 4.78 to 29.45% decrease in plant height over control was recorded respectively. On the other hand 9 and 12 month aged composts had a significant positive effect on plant height of lettuce and Amaranthus where 43.48% and 34.8% increase over control was recorded with the application of 15% of 12 month aged compost respectively. A similar effect was observed on fresh biomass of both lettuce and Amaranthus where a 386% and 59.43% increase over control was recorded with the application of 15% of 12 month aged compost respectively. One and three month aged composts revealed a negative effect on N absorption by lettuce whereas 1, 3, 6 and 9 month aged composts had a negative effect on N absorption by Amaranthus. 30.39% and 21.48% increases over control in N absorption by lettuce and Amaranthus respectively were recorded with the application of 15% of 12 month aged compost. (author)
[en] This study examined the storage stability of tocochromanols and carotenoids in the oils prepared from microwave pre-treated (MV) rapeseeds (2-10 min, 800W) during storage at 20 °C for 12 months. In line with lipophilic antioxidant degradation throughout the storage period, changes in the antioxidant capacity of the oil were monitored. Microwaving significantly affected the concentration of lipophilic antioxidants in the oil. After 10 min of MV pre-treatment the highest content of total tocochromanols (76.64 mg/100g) was achieved, whereas a maximum carotenoid concentration (861.28 μg/100g) was obtained following 6 min seed MV pre-treatment. The degradation kinetics for the tocochromanols and carotenoids followed a zero-order kinetic model. From the kinetic analysis, it was shown that the degradation rate constant (k) of both tocochromanols and carotenoids decreased with longer seed exposure to MV radiation. The kinetics of antioxidant capacity degradation during the storage of oils followed a zero-order reaction. The rate of antioxidant capacity degradation in the control oil was higher (k=9.1 x 10-2 mmol TEAC/l/month) compared with oils prepared from MV pre-treated seeds (k=6.8-8.0 x 10-2 mmol TEAC/l/month).
[es]En este estudio se determinó la estabilidad de tococromanoles y carotenoides de aceites preparados a partir de semillas de colza pretratadas con microondas (MV) (2-10 min, 800 W) durante el almacenamiento a 20 °C durante 12 meses. De acuerdo con la degradación de los antioxidantes lipófilos durante el periodo de almacenamiento, se monitorizó el cambio en la capacidad antioxidante del aceite. El microondas afectó significativamente a la concentración de antioxidantes lipofilícos en el aceite. Después de 10 minutos de pretratamiento con MV, se obtuvo el contenido más alto de tocromanoles totales (76,64 mg/100 g), mientras que se obtuvo una concentración máxima de carotenoides (861,28 g/100 g) después de un pretratamiento con MV de 6 minutos. La cinética de degradación para los tococromanoles y carotenoides siguió un modelo cinético de orden cero. A partir del análisis cinético, se demostró que la constante de velocidad de degradación (k) tanto de los tococromanoles como de los carotenoides disminuía con una exposición más prolongada de las semillas a la radiacion de MV. La cinética de la degradación de la capacidad antioxidante durante el almacenamiento de los aceites siguió una reacción de orden cero. La tasa de degradación de la capacidad antioxidante en el aceite testigo fue mayor (k = 9,1 × 10-2 mmol TEAC / l / mes) en comparación con los aceites preparados a partir de semillas pretratadas con MV (k = 6,8-8,0 × 10-2 mmol TEAC / l /mes).