[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] In order to explore the protective effect of TBHQ (tert-butyl hydroquinone) and BCA (butylated caffeic acid) on tocopherols in oils and fats, various physicochemical indexes of oil samples and changes of tocopherols content during high temperature frying and Rancimat accelerated oxidation were determined. The results showed that the addition of appropriate amount of TBHQ and BCA in oils and fats greatly improved the antioxidant activity, and the added TBHQ and BCA could effectively reduce the loss of tocopherols during the heating process of fats and oils and played a certain role in the protection of tocopherols. In comparison, BCA had a stronger protective effect, especially for the protection of δ-tocopherol. (paper)

[en] Highlights: • The citrus bioflavonoids may possess dipeptidyl peptidase-4 (DPP-4) inhibition activity similar to gliptins. • Various citrus bioflavonoids may have a variable DPP-4 inhibition activity. • The measurement of the DPP-4 inhibition activity can be done using DPP-4 inhibition kit. • Commercial citrus bioflavonoid supplements contain various citrus bioflavonoids with different DPP-4 inhibition activities. This study compared dipeptidyl peptidase-4 (DPP-4) inhibitory activity of citrus bioflavonoid nutraceuticals compared with three gliptins. Citrus bioflavonoid standards and three commercially available citrus bioflavonoid supplements (Thompson's Super Bioflavonoid Complex^®(SB), Ethical Nutrients Bioflavonoids Plus Vitamin C^®(EN), and Country Life Citrus Bioflavonoids and Rutin^®(CB)) were considered in this study. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis was undertaken to identify and quantitate the citrus bioflavonoids present in each supplement. The DPP-4 inhibitory activity was determined by fluorometric assay. All of the tested individual citrus flavonoids demonstrated DPP-4 inhibitory activity, with IC₅₀ values ranging from 485 μM (rutin) to 5700 μM (hesperitin and eriodictyol). Similarly, the flavonoid supplements had IC₅₀ values of 16.9 mg/mL (EN), 3.44 mg/mL (SB) and 2.72 mg/mL (CB). These values compare with gliptin IC₅₀ values of 0.684 μM (sitagliptin), 0.707 μM (saxagliptin) and 2.286 μM (vildagliptin). The supplement flavonoid content varied from 11.98% (CB) to 5.26% (EN) and 14.51% (SB) of tablet mass, corresponding to daily flavonoid doses of around 300, 150 and 400 mg, respectively, with CB and SB containing rutin at levels of 7.0% and 7.5% of tablet mass, respectively. While our data demonstrated that citrus bioflavonoid based supplements do possess DPP-4 inhibitory activity, they are several orders of magnitude less potent than gliptins. Further studies using higher concentrations of citrus bioflavonoids, as well as investigations into antioxidant properties which may add additional benefit are warranted.

[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] Psidium guajava or commonly known as guava is useful to treat gastroenteritis, dysentery, stomach pain and indigestion. In this study, the leaves of this species were screened for its phytochemical and antioxidant activity. The phytochemicals were extracted by sequential maceration by using n-hexane, chloroform and methanol, while phytochemical screening was performed using various chemical tests. Meanwhile, its antioxidant activity was assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Steroids and terpenoids were found to be present in the n-hexane extract, while phenols and terpenoids were detected in the chloroform extract. The methanol extract contained flavonoids, steroids, saponins, phenols and terpenoids. Among the tested extracts, the methanolic extract demonstrated strong DPPH radical scavenging activity with an IC₅₀ value of 45.52 μg/mL. (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)