Most of the literature methods are focused on the hydrophilic extracts, thus using polar solvents for extraction. I need to determine the antioxidant activity assay due to the lipophylic compounds.
Thank you very much Alok. I checked the paper. The problem that I see is that the authors use a polar solvent (ethanol) to extract primarily hydrophobic compounds. DPPH is also mainly miscible in hidrophilic solvents. Now we are looking at the ABTS assay which can be used for both hidrophilic and hidrophobic compounds.
Ethanol is the only FDA approved solvent in preparing extracts oriented fto the formulation of phytodrugs. Solvents such as chloroform, hexane, etc metabolized by CYP450 generating reactive metabolites and hence are toxic.
Ethanol is a relatively polar solvent, but you can play with the% ethanol: water extraction times, the contact surface, etc in the extraction process. This gives very good results when testing the efficacy and safety of extracts obtained.
Thank you very much for your answer María Eugenia. Actually we will perform solvent extractions only for antioxidant determinations of functional foods. We will not use such extracts after the assays. You are right, we can use different solvent ratios. Now we are thinking on acetone:hexane for carotene extraction and the ABTS antiox assay.
The crocin bleaching is the only one. You have to use the2,2’-Azobis(2-Amidinopropane) hydrochloride (APAB) as radical source and have to use solvent such as n-hexane and toluene, in which you can extract tocopherols, carotenoids, licopene and so on.
Bors W., Michel C., Saran M. (1984) Inhibition of the bleaching of the carotenoid crocin a rapid test for quantifying antioxidant activity. BIOCHIM BIOPHYS ACTA. 796: 312-319.
Ordoudi S.A. and Tsimidou M.Z. (2006) Crocin Bleaching Assay step by step: observations and suggestions for an alternative validated protocol. J. AGRIC. FOOD CHEMISTRY. 54(5): 1663-1671.
Finotti E., D’Ambrosio M., Paoletti F., Vivanti V., Quaglia G. (2000) Synergistic effects of α-tocopherol, β-sitosterol and squalene on antioxidant activity assayed by crocin bleaching method. NAHRUNG. 44: 373-374.
Finotti E.; Bersani A.; Bersani E. (2007) Total qualità index for extra virgin olive oil. J. of Food Quality 30, 911-931.
Finotti E., Paoletti F, Bertone A, Galassi P and Quaglia G. (1998) Antioxidant capacity determination of extra virgin olive oils unsaponifiable fraction by crocin bleaching inhibition method. Nahrung, Vol 42, n° 5, pp 324-325.
Finotti E., Beye C., Nardo N., Quaglia G., Milin C., Giacometti J., (2001) Physico-chemical characteristics of olives and olive oil from two mono-cultivars during various ripening phases. Nahrung/Foof 45, n°5, pp. 350-352.
Enrico, I just found an antioxidant capacity assay for b-Carotene called the bleaching method and it is based on the oxidative decomposition of b-carotene in the presence of linoleic acid. Perhaps the reagent used in this method is less expensive than crocin. What is your opinion about this? Here I attach the reference.