Lipote (Syzygium polycephaloides (C. B. Rob.) Merr.) is a Philippine endemic tree whose
berries have a potential for functional food development. This study aimed to investigate
the effect of the ...maturity stage (unripe, half-ripe or fully ripe) and processing (blanching
at 90±5°C for 2 mins and steaming at 105±5°C for 5 mins) on the antioxidant content
(total phenolic content (TPC), total flavonoid content (TFC), and total anthocyanin
content (TAC)) and antioxidant activity by DPPH, ABTS, and FRAP assays, of lipote
flesh and skin (referred herein as flesh) and seeds. Results showed that maturity and
processing significantly affect the antioxidant contents and activities of fresh lipote flesh
and seeds. Blanched lipote flesh generally had higher TPC, TFC, and antioxidant activities
than their unprocessed and steamed counterparts. Blanched unripe flesh had the highest
TPC (33.57±0.27 mg gallic acid equivalents GAE/g) and antioxidant activity measured
by ABTS, FRAP, and DPPH assay (92.31±1.28 mg Trolox equivalents TE/g,
123.83±0.86 mg TE/g, and 74.02±0.33 mg TE/g, respectively) while blanched fully ripe
flesh had the highest TFC (27.98±0.08 mg quercetin equivalents QE/g) and TAC
(18.11±0.11 mg cyanidin-3-glucoside equivalents C3GE/g). Lipote seeds, especially
unripe ones, have appreciable antioxidant contents and antioxidant activity, even greater
than that of lipote flesh. Unprocessed unripe seeds had the greatest TPC, TFC and
antioxidant activity by DPPH assay (123.56±0.94 mg GAE/g, 111.90±0.14 mg QE/g and
465.89±1.86 mg TE/g, respectively). It is recommended that blanching be used as a
processing step to increase the antioxidant content of lipote flesh while lipote seeds should
be investigated further for nutraceutical applications due to their high antioxidant
properties.
Twenty-four exotic Colombian fruits were evaluated for antioxidant activity and total soluble phenolics (TP) (edible part, seed and peel) and ascorbic acid content (edible part). The antioxidant ...activities were evaluated by ABTS (free radical-scavenging capacity) and FRAP (ferric reducing antioxidant power) methods. The ABTS, FRAP, TP and ascorbic acid values in the edible part were 3.25 to 175μM Trolox equiv/g fresh weight (FW), 6.29 to 144μM Trolox equiv/g FW, 15.7 to 1018mg gallic acid equiv/100g FW, and 0.53 to 257mg ascorbic acid/100g FW respectively. There were positive correlations between antioxidant activity (assessed by both ABTS and FRAP) and TP and ascorbic acid with the FRAP and ABTS methods. The edible part of banana passion fruits (P. tarminiana and P. mollisima) exhibited the highest values of antioxidant activity and total phenolics, while the highest level of ascorbic acid was recorded in the edible part of guava apple and cashew. The seeds with the highest values of antioxidant activity and total phenols were cashew, algarrobo, arazá and coastal sapote, while the peel of coastal sapote and algarrobo had the highest values of antioxidant activity and total phenolics. To the best of our knowledge, this paper reports the first evaluation of pulp, seed and skin of Colombian tropical fruits with a view to their knowledge utilization for the development of novel functional food products.
The present study was undertaken to evaluate the antioxidant effect of alcoholic extract of Chlorella vulgaris and Spirulina platensis on extending the shelf life of rainbow trout (Oncorhynchus ...mykiss) fillet in 4 ± 1 °C. The experiments were performed on 5 samples (1 blank and 4 treatments) and in triplicate. The results from DPPH and FRAP assays represents the higher antioxidant activity of Chlorella (42.96% and 0.33) at concentration of 200 μg/ml and Spirulina (62.46% and 0.41; 77.12% and 0.46) at concentrations of 400 and 600 μg/ml, respectively. The results from performed chemical tests compared to the blank sample showed that samples treated with algae extracts were able to control the increase in these parameters. Among the treated samples, maximum control of peroxide value, thiobarbituric acid and free fatty acid, respectively pertained to the treatments containing 0.1% of Spirulina (3.14, 2.93 and 2.25) and Chlorella (3.21, 3.06 and 2.28) extracts. The results of sensory evaluation showed that except the sample containing 0.05% of Chlorella, in other samples containing the algae extract, less negative effects on color, odor, texture and taste were observed. Consequently, Chlorella and Spirulina extracts can delay lipid oxidation process and maintain or improve sensory properties of refrigerated fish.
•Chlorella vulgaris and Spirulina platensis extracts prolonged shelf life of fish.•These algae could significantly delay lipid oxidation (P < 0.05).•Shelf life of samples were efficiently extended by 0.1% of each algae.
Available synthetic antioxidants have been reported to have mutagenic and toxic effects. On the other hand, natural antioxidants show their superiority as they are not or less toxic. Passiflora ...foetida has the potential as an antioxidant, but the investigation of the antioxidant activity of the P. foetida chromatography column fraction has not been reported. This studied aims to investigate the antioxidant activity of the column chromatographic fractions of P. foetida leaves. An antioxidant assay using the DPPH and FRAP methods. The extraction was carried out by graded maceration, then fractionation using column chromatography. The antioxidant activity test was carried out using the DPPH and FRAP methods. Thin Layer Chromatography analysis was performed to determine the chromatogram pattern. The EC50 using DPPH method from n-hexane extract: 129.035 µg/mL, ethyl acetate extract: 206.398 µg/mL, methanol extract: 97.453 µg/mL, while the EC50 using FRAP method from n-hexane extract: 67.851 µg/mL, ethyl acetate extract : 68.981 µg/mL, and methanol extract: 58.787 µg/mL. Column chromatography fractions have antioxidant activity, with FMetPF6 as the fraction with the best activity, with percent inhibition 41.85±1.96 at concentration 25 µg/mL (DPPH), and with percent antioxidant activity 26.03±0.84 at concentration 9 µg/mL (FRAP). Passiflora foetida leaves have great potential as an antioxidant; both the extract and its fractions have antioxidant activity. The FMetPF6 has the best activity compare to other extracts and fractions. Further analysis to determine the various compounds in FMetPF6 using LC-MS/MS will facilitate the active compound's isolation.
•“Cephalandole A” analogues 19a-y and 20a-d were synthesised rapidly under microwave irradiation using PTSA as catalyst.•In vitro antioxidant activity using DPPH assay provided 19a, 19f, 19n and 20a ...as the most potent molecules. In addition, testing in FRAP assay provided 19d and 19v as potential antioxidants.•In silico studies were performed to validate the wet results.•To the best of our knowledge, this is the first report demonstrating ‘Cephalandole A’ analogues as a new class of antioxidant agents.
Herein, a novel series of natural product alkaloid ‘Cephalandole A’ analogues 19a-y, and 20a-d were rapidly synthesised under microwave irradiation conditions using PTSA in catalytic amount dissolved in acetonitrile at 90 °C for 15 min. The developed one-pot protocol is operationally simple, rapid (15 min) and furnished the target analogues in up to 90 % yield. All the synthesised analogues of Cephalandole A were evaluated for their in vitro antioxidant activity using DPPH free-radical scavenging and FRAP assays. The in vitro studies of DPPH radical scavenging assay provided 19a (IC50 = 11.87 ± 0.14 µg/mL), 19f (IC50 = 16.34 ± 0.27 µg/mL), 19n (IC50 = 15.37 ± 0.11 µg/mL) and 20a (IC50 = 14.54 ± 0.31 µg/mL) respectively, as the most active compounds of the series. In addition, the analogous 19d (556.3 ± 13.1 µM) and 19v (551.9 ± 14.2 µM) showed promising activity in FRAP assay. However, the standard reference drug ascorbic acid showed an IC50 value of 4.57 µg/mL in the DPPH assay, and BHT showed C0.5FRAP = 546.0 ± 13.6 μM in the FRAP assay. In silico studies were performed to validate the wet results. To the best of our knowledge, this is the first report demonstrating ‘Cephalandole A’ analogues as a new class of antioxidant agents.
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The influence of different roasting degrees on the content of bioactive compounds and the antioxidant activity (AA) of arabica and robusta coffees was evaluated. AA was estimated by Folin–Ciocalteau, ...FRAP and ABTS methods. The results were analyzed by principal components analysis. While the levels of 5-CQA (5-caffeoylquinic acid), trigonelline, furfural and HMF (hydroxymethylfurfural) decreased with the degree of roasting, the level of melanoidins increased. Changes in the levels of the bioactive compounds were more intense that those observed for AA. PC 1 (principal component 1) was mainly correlated with the levels of, furfural, HMF, 5-CQA, trigonelline, and melanoidins. PC2 was mainly correlated with AA and caffeine content. Different compounds contribute to the AA of the coffee and the final result for AA is dependent on the balance of the compounds formed and degraded during the roasting process.
•The AA of a roasted coffee results from the contribution of different compounds.•Robusta coffee shows greater AA than arabica coffees because of the caffeine content.•Phenolic compounds and melanoidins contribute to AA of roasted coffee.•In dark roasting, phenolic losses may not be compensated by melanoidins formation.
High performance liquid chromatography coupled with post column derivatisation (HPLC-PCD) may be used to profile the antioxidant content of a sample. There are, however, drawbacks in the use of ...HPLC-PCD setups; namely the high volume reaction coils that are typically used lowering the observed separation efficiency. Reaction flow chromatography has the ability to overcome these inefficiencies by using a more efficient mixing technique inside the outlet fitting itself, post column reaction loops can be removed with resulting improvement in signal to noise response, plus the separation efficiency is maintained. We assessed two methods of HPLC-PCD antioxidant analysis based on the ferric reducing antioxidant power (FRAP) assay in both conventional and reaction flow HPLC-PCD modes. It was found that the reaction flow technique demonstrated significant advantages over the conventional technique in terms of signal to noise, linear range, precision and observed separation efficiency.
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•Post column derivatisation (PCD) using FRAP reagent was used for the first time in reaction flow (RF) chromatography.•RF columns with FRAP reagent produced comparable signal response to conventional FRAP- PCD protocols.•Separation efficiency using RF columns was far greater than conventional columns using FRAP-PCD.
In this study, MgAl2O4/gC3N4 composite material was successfully synthesized by the impregnation method and characterized by XRD, SEM, EDAX, and UV-visible analysis. The structural properties of the ...material are obtained from XRD analysis, and the optical properties are investigated by a UV-visible study. The morphological characteristics and compositional analysis of the nanomaterial are studied by SEM with EDAX spectra. The antioxidant activity of the material was examined through a FRAP assay, and the results show it has 90% activity.
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