Antioxidant properties from leaves of various citrus species and optimization studies of selected citrus leaves extract

Abstract

This research reports a study on assessment of antioxidants properties from leaves of various citrus species. Natural antioxidants was most favoured as it possessed less toxicity compared to the synthetic antioxidants which lead to carcenogenic effects. Extraction was done on chosen leaves of various citrus species which were C. aurantifolia, C. maxima, and C. hystrix in order to assess their antioxidants properties. Leaves of various citrus species was extracted by using different types of solvent which include methanol, ethanol, and water. Methanol extracts of C. hystrix promotes highest antioxidant activity and total phenolic compound (0.5875 GAE, mg/g) compared to other solvents which are 73.97% when compared with water (70.20%, 0.4729 GAE, mg/g), and ethanol (70.88%, 0.5442 GAE, mg/g). Thus, C. hystrix was proceeded with screening and optimization process. Single factor experiment utilizing the one factor at a time (OFAT) technique was done to study about the impact of each extraction parameter which are frequency, temperature and time. The extraction condition in each parametric examination which results in highest antioxidants activity was utilized as the centre level of optimization process utilizing Response Surface Methodology (RSM) combined with Central Composite Design (CCD). The ideal conditions were at 40 kHz frequency, 35°C temperature and 30 minutes time which result in antioxidant activity of 76.53%. The confirmation of RSM appeared that the model used to predict the antioxidants activity was legitimate and satisfactory with the test parameters.