Nutrient Use Efficiency

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Al-Quds University Nutrient Use Efficiency Research Group

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Browsing Nutrient Use Efficiency by Subject "Olive leaves"

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    Development and validation of a simple reversed phase HPLC-UV method for determination of oleuropein in olive leaves
    (Elsevier, 2014-09-04) Al-Rimawi, Fuad
    A simple, precise, accurate, and selective method is developed and validated for the determination of oleuropein, which is the main phenolic compound in olive leaves. Separation was achieved on a reversed-phase C18 column (5 mm, 150 4.6 mm inner diameter) using a mobile phase consisting of acetonitrile/phosphate buffer pH 3.0 (20:80, v/v), at a flow rate of 1.0 mL/minute and UV detection at 280 nm. This method is validated according to the requirements for new methods, which include accuracy, precision, selectivity, robustness, limit of detection, limit of quantitation, linearity, and range. The current method demonstrates good linearity over the range of 3e1000 ppm of oleuropein, with r2 > 0.999. The recovery of oleuropein in olive leaves ranges from 97.7% to 101.1%. The method is selective, in that oleuropein is well separated from other compounds of olive leaves with good resolution. The method is also precisedthe relative standard deviation of the peak areas of replicate injections of oleuropein standard solution is <1%. The degree of reproducibility of the results obtained as a result of small deliberate variations in the method parameters and by changing analytical operators has proven that the method is robust and rugged. The low limit of detection and limit of quantitation of oleuropein when using this method enable the detection and quantitation of oleuropein at low concentrations.
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    Formulation and evaluation of a moisturizing day cream containing olive leaves extract
    (Elsevier, 2014-10-25) Al-Rimawi, F.; Yateem, H.; Afaneh, I.
    The purpose of the current work is to investigate the incorporation of olive leaves extract standardized for oleuropein which have antioxidant, anti inflammatory, skin protectant and antiaging properties into stable topical moisturizing day cream formulations. The physiochemical and rheological properties, and accelerated stability tests of three cream formulas containing different concentrations (0.1%, 0.4% and 1.0% w/w) of olive leaf extracts were assessed and compared with commercial cream product containing no olive leaf extract. A questionnaire was distributed to 100 volunteers to use the prepared creams containing olive leaf extracts and to compare with the commercial cream containing no olive leaves extract. All physical and rheological properties of the prepared formulations were found to be the same as the commercial cream product. Stability studies showed a stable homogenous appearance and effective cream during three months of storage at room temperature. Most of the volunteers are satisfied with the creams containing olive leaves extract, and have noticed significant differences between these creams and the cream containing no olive leaves extract.