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Optimisation of the extraction of olive (Olea europaea) leaf phenolics using water/ethanol-based solvent systems and response surface methodology.
Anal Bioanal Chem. 2008 Nov; 392(5):977-85.AB

Abstract

An experimental setup based on a 2(3) full-factorial, central-composite design was implemented with the aim of optimising the recovery of polyphenols from olive leaves by employing reusable and nontoxic solutions composed of water/ethanol/citric acid as extracting media. The factors considered were (i) the pH of the medium, (ii) the extraction time and (iii) the ethanol concentration. The model obtained produced a satisfactory fit to the data with regard to total polyphenol extraction (R(2) = 0.91, p = 0.0139), but not for the antiradical activity of the extracts (R(2) = 0.67, p = 0.3734). The second-order polynomial equation obtained after analysing the experimental data indicated that ethanol concentration and time mostly affected the extraction yield, but that increased pH values were unfavourable in this regard. The maximum theoretical yield was calculated to be 250.2 +/- 76.8 mg gallic acid equivalent per g of dry, chlorophyll-free tissue under optimal conditions (60% EtOH, pH 2 and 5 h). Liquid chromatography-electrospray ionisation mass spectrometry of the optimally obtained extract revealed that the principal phytochemicals recovered were luteolin 7-O-glucoside, apigenin 7-O-rutinoside and oleuropein, accompanied by smaller amounts of luteolin 3',7-O-diglucoside, quercetin 3-O-rutinoside (rutin), luteolin 7-O-rutinoside and luteolin 3'-O-glucoside. Simple linear regression analysis between the total polyphenol and antiradical activity values gave a low and statistically insignificant correlation (R(2) = 0.273, p > 0.05), suggesting that it is not the sheer amount of polyphenols that provides high antioxidant potency; instead, this potency is probably achieved through interactions among the various phenolic constituents.

Authors+Show Affiliations

Department of Chemistry, University of Crete, P.O. Box 2208, 71003, Voutes, Heraklion, Greece.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

18762919

Citation

Mylonaki, Stefania, et al. "Optimisation of the Extraction of Olive (Olea Europaea) Leaf Phenolics Using Water/ethanol-based Solvent Systems and Response Surface Methodology." Analytical and Bioanalytical Chemistry, vol. 392, no. 5, 2008, pp. 977-85.
Mylonaki S, Kiassos E, Makris DP, et al. Optimisation of the extraction of olive (Olea europaea) leaf phenolics using water/ethanol-based solvent systems and response surface methodology. Anal Bioanal Chem. 2008;392(5):977-85.
Mylonaki, S., Kiassos, E., Makris, D. P., & Kefalas, P. (2008). Optimisation of the extraction of olive (Olea europaea) leaf phenolics using water/ethanol-based solvent systems and response surface methodology. Analytical and Bioanalytical Chemistry, 392(5), 977-85. https://doi.org/10.1007/s00216-008-2353-9
Mylonaki S, et al. Optimisation of the Extraction of Olive (Olea Europaea) Leaf Phenolics Using Water/ethanol-based Solvent Systems and Response Surface Methodology. Anal Bioanal Chem. 2008;392(5):977-85. PubMed PMID: 18762919.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Optimisation of the extraction of olive (Olea europaea) leaf phenolics using water/ethanol-based solvent systems and response surface methodology. AU - Mylonaki,Stefania, AU - Kiassos,Elias, AU - Makris,Dimitris P, AU - Kefalas,Panagiotis, Y1 - 2008/09/02/ PY - 2008/05/08/received PY - 2008/08/14/accepted PY - 2008/08/04/revised PY - 2008/9/3/pubmed PY - 2008/12/23/medline PY - 2008/9/3/entrez SP - 977 EP - 85 JF - Analytical and bioanalytical chemistry JO - Anal Bioanal Chem VL - 392 IS - 5 N2 - An experimental setup based on a 2(3) full-factorial, central-composite design was implemented with the aim of optimising the recovery of polyphenols from olive leaves by employing reusable and nontoxic solutions composed of water/ethanol/citric acid as extracting media. The factors considered were (i) the pH of the medium, (ii) the extraction time and (iii) the ethanol concentration. The model obtained produced a satisfactory fit to the data with regard to total polyphenol extraction (R(2) = 0.91, p = 0.0139), but not for the antiradical activity of the extracts (R(2) = 0.67, p = 0.3734). The second-order polynomial equation obtained after analysing the experimental data indicated that ethanol concentration and time mostly affected the extraction yield, but that increased pH values were unfavourable in this regard. The maximum theoretical yield was calculated to be 250.2 +/- 76.8 mg gallic acid equivalent per g of dry, chlorophyll-free tissue under optimal conditions (60% EtOH, pH 2 and 5 h). Liquid chromatography-electrospray ionisation mass spectrometry of the optimally obtained extract revealed that the principal phytochemicals recovered were luteolin 7-O-glucoside, apigenin 7-O-rutinoside and oleuropein, accompanied by smaller amounts of luteolin 3',7-O-diglucoside, quercetin 3-O-rutinoside (rutin), luteolin 7-O-rutinoside and luteolin 3'-O-glucoside. Simple linear regression analysis between the total polyphenol and antiradical activity values gave a low and statistically insignificant correlation (R(2) = 0.273, p > 0.05), suggesting that it is not the sheer amount of polyphenols that provides high antioxidant potency; instead, this potency is probably achieved through interactions among the various phenolic constituents. SN - 1618-2650 UR - https://www.unboundmedicine.com/medline/citation/18762919/Optimisation_of_the_extraction_of_olive__Olea_europaea__leaf_phenolics_using_water/ethanol_based_solvent_systems_and_response_surface_methodology_ L2 - https://dx.doi.org/10.1007/s00216-008-2353-9 DB - PRIME DP - Unbound Medicine ER -