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Assessment of Secondary Metabolites in the Yams of Dioscorea oppositifolia L. & Dioscorea pentaphylla L.
Published in Parimelazhagan Thangaraj, Phytomedicine, 2020
S. Vivek, Y. Aron Santhosh Kumar, M. Palanisamy
The 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) decolorization assay involves the generation of the ABTS+ chromophore by the oxidation of the ABTS+ with potassium per sulfate. It is applicable for both hydrophilic and lipophilic compounds. The scavenging activity of the extract on the ABTS+ radical cation was measured at 734 nm (Giao et al. 2007). ABTS+ solution is prepared by following methods. An equal volume of 7 mM ABTS+ is mixed with 2.45 mM Potassium per sulphate. The mixture was allowed to stand in the dark place at room temperature for 12–16 hours. The sample is prepared by the addition of 1 ml of diluted ABTS+ with 10 µL of tuber extract in different concentration (50–250 µg/mL) 10 µL of ethanol is served as control. Ascorbic acid was used as the positive control. The absorbance was read at 734 nm after 6 minutes, and the percentage inhibitions were calculated. The inhibition was calculated according to the equation:
Antioxidant assays
Published in Roger L. McMullen, Antioxidants and the Skin, 2018
Like the DPPH assay, the 2,2ʹ-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay, also known as the Trolox equivalent antioxidant assay (TEAC), finds widespread use in testing in vitro antioxidant efficacy for biological systems as well as many finished formulations used in the food and cosmetic industries.15–18 The assay is actually based on changes in the absorbance spectrum of the radical form of ABTS, which we will refer to as ABTS•+ (Figure 6.6). As discussed in the following, ABTS•+ absorbs in the visible region of the electromagnetic spectrum, whereas ABTS does not. In this assay, the radical, ABTS•+, reacts with the antioxidant of interest and produces ABTS. The experiment begins with ABTS, which one may purchase from a specialty chemical supplier. The radical, ABTS•+, is then generated by utilizing one of the systems shown in Table 6.1, which are allowed to react with ABTS.
Determination of Kinetic Parameters of Oxygen Radicals by Competition Studies
Published in Robert A. Greenwald, CRC Handbook of Methods for Oxygen Radical Research, 2018
Wolf Bors, Christa Michel, Manfred Saran
The most interesting reference substances are those which can be used to determine relative rate constants of several radicals — despite the drawback that those radicals have to be identified by prior selective scavenging studies, if they are not formed in specific reactions. 2.2′-Azino-bis-(3-ethylbenzthiazoline-6-sulfonate) (ABTS; Structure 1), is very versatile
Phytochemical composition, cytotoxicity, antioxidant and antimicrobial responses of Lavandula dentata L. grown under different levels of heavy metals stress condition
Published in Drug and Chemical Toxicology, 2023
Souhila Terfi, Zineb Djerrad, Soumeya Krimat, Fatma Sadi
ABTS•+ radical scavenging activity was carried according to Aazza et al. (2011). The ABTS•+ was prepared by mixing equal volumes of ABTS (7 mM) and K2S2O8 oxidant solution (2.4 mM). The mixture was incubated in the dark for 16 h. After, the resultant solution was diluted with ethanol to get 0.700 ± 0.001 absorbance value at 734 nm. 1000 μL of the ABTS•+ radical solution was added to 10 μL from various concentrations (0.05 − 0.25 mg/mL) of each sample and left to react in the dark for 6 min. The absorbance against prepared blank was determined at 734 nm. The radical scavenging activity was then calculated from the equation: ABTS•+ radical scavenging activity = [(Abscontrol − Abssample)/Abscontrol] × 100, where Abscontrol is the absorption of the blank sample and Abssample is the absorbance of the tested extract. Results were expressed as IC50 value, efficient concentration that could scavenge 50% of the ABTS•+ radicals.
Formulation and performance evaluation of emulgel platform for combined skin delivery of curcumin and propolis
Published in Pharmaceutical Development and Technology, 2023
Rafaela Said dos Santos, Jéssica Bassi da Silva, Camila Felix Vecchi, Katieli da Silva Souza Campanholi, Hélen Cassia Rosseto, Mariana Carla de Oliveira, Francielle Pelegrin Garcia, Rodolfo Bento Balbinot, Lidiane Vizioli de Castro Hoshino, Tânia Ueda Nakamura, Celso Vataru Nakamura, Mauro Luciano Baesso, Wilker Caetano, Marcos Luciano Bruschi
The ABTS (2,2′-azino-bis (3-ethylbenzothiazolino-6-sulfonic acid) method was performed according to Rufino and collaborators (2007), with minor modifications (Rufino, Alves, Brito, Morais, Sampaio 2007). Briefly, a stock solution of ABTS (7 mM) and potassium persulfate (140 mM) was prepared, properly identified, and stored. An ABTS radical solution was prepared from the reaction of 5 ml of the ABTS stock solution with 88 µl of the potassium persulfate solution. The preparation was kept at room temperature and protected from light for 16 h. Afterwards, an amount of 1.0 ml of this mixture was diluted in ethanol until an absorbance of 0.650 − 0.750 was obtained. Subsequently, aliquots of 30 µl of these different samples were submitted for the evaluation of the antioxidant activity by the addition of 3 ml of ABTS solution. The disappearance or decrease of the absorbance of the radical was determined at λ = 734 nm, six minutes after the beginning of the reaction. A calibration curve was prepared using Trolox (linear range: 100–2000 µM). Ethyl alcohol was used as blank (compensatory solution), and 3 ml of ABTS plus 30 µl of ethanol was used as a negative control. The analyses were performed in at least three replicate samples (Rufino et al., 2007; de Francisco et al. 2018).
Morel mushroom, Morchella from Kashmir Himalaya: a potential source of therapeutically useful bioactives that possess free radical scavenging, anti-inflammatory, and arthritic edema-inhibiting activities
Published in Drug and Chemical Toxicology, 2022
Haridas Ramya, Korattuvalappil S. Ravikumar, Zuhara Fathimathu, Kainoor K. Janardhanan, Thekkuttuparambil A. Ajith, Manzoor Ahmad Shah, Ramona Farooq, Zafar A. Reshi
In this assay, the extracts were tested for ABTS.+ (2,2′-azinobis (3-ethylbenzothiazoline-6-sulphonic acid)) radical scavenging activity. Ammonium persulphate (2.45 mM, final concentration) was reacted with ABTS (7 mM) for more than 16 h in dark at room temperature. ABTS and persulphate reacted to form ABTS+ radical. The OD of ABTS+ radical solution was adjusted to an absorbance of 0.75 at 734 nm using ethanol. The extracts at various concentrations were added to 2 ml of ABTS+ reaction mixture. The decrease in the absorbance was measured against ethanol by spectrophotometer after 6 min of initial mixing at 734 nm and expressed as percentage of reduction by comparing to the control. The reaction mixture without extracts served as control (Long and Halliwell 2001).