Int.J.Curr.Microbiol.App.Sci (2014) 3(11) 399-412 399 Original Research Article The effects of solvents polarity on the phenolic contents and antioxidant activity of three Mentha species extracts A.Barchan 1 , M.Bakkali 1 , A. Arakrak 1 , R. Pagán 2 and A. Laglaoui 1 * 1 Team of Research in Biotechnology and Bimolecular Genius (ERBGB), Faculty of Sciences and Techniques, Abdelmalek Essaadi University BP. 416 Tangier Morocco 2 Department of Animal Production and Food Science, Veterinary Faculty, Universidad de Zaragoza, Miguel Servet 177, 50013 Zaragoza, Spain *Corresponding author ABSTRACT Introduction The processes of oxidation are intrinsic in the management of energy of all living organisms and are, therefore, kept under strict control by several cellular mechanisms (Halliwell and Gutteridge, 2007). However, reactive oxygen species (ROS), generated during metabolism, are very unstable and highly reactive, due to the presence of unpaired electrons, which include superoxide anion radicals, hydroxyl radicals, hydroperoxyl radicals, peroxyl and non-free radical species such as hydrogen peroxide, ISSN: 2319-7706 Volume 3 Number 11 (2014) pp. 399-412 http://www.ijcmas.com Keywords Antioxidant activity, Total phenolic content, Mentha species, Polar solvent extracts, Non-polar solvent The present work had two objectives: the first, to compared the total phenolic contents (using Folin Ciocalteu s reagent) and antioxidant activity (using three different in vitro test assays) of three Mentha species and second, to determine whether these parameters changed with change of solvents extract polarity. Mentha spicata, Mentha pulegium and Mentha piperita were successively extracted with solvents of increasing polarity (n-hexane, dichloromethane (DCM), methanol and distilled water) using a soxhlet extractor. Our results reported that water and methanol (polar solvents) extracts, which contained the highest amount of total phenolic contents exerted strong reducing power and scavenging DPPH radical activity, which are almost equal to positive control BHT. Hexane and DCM (non polar solvents) extracts were showed a negligible antioxidant activity with both of test assays. Thus, the results indicate that polar solvents were important for obtaining fractions with high antioxidant activity and total phenolic content. All extracts tested in this study were found to be moderate in antioxidant capacity in the -carotene/linoleic acid test assay and none of the extracts showed activity as strong as BHT. A positive correlation was found between total phenolic level and DPPH radical scavenging (r 2 = 0.82) and reducing power (r 2 = 0.86) assays. Whereas, there was no correlation (r 2 = 0.25) between phenol contents and - carotene/linoleic acid assay.