Effect of Solvent Variation on Polyphenolic Profile and Total Phenolic Content of Olive Leaf Extract

Abstract

Olive tree is one of the oldest plants, evergreen and of which fruits, leaves and trunk can be used for many different purposes. Olive has become a nutritional source widely used for especially in the Mediterranean diet and due to its extensive metabolic effects attracting everyone's attention recently. Olive and olive leaves are rich in polyphenolic compounds. Oleuropein is the most available and most active polyphenolic compound. Hydroxytyrosol, tyrosol and verbascoside are other important active compounds. Oleuropein has antioxidant, antidiabetic and antimicrobial effects. This study was investigated the effects of solvent variation on the amount of polyphenolic compounds and total phenolic content in olive leaves. The olive leaves were extracted using water, methanol/water and methanol solvents. The content of olive leaves extract was investigated by chromatographic analysis. Also total phenolic content was determined using Folin-Ciocalteu method by spectrophotometric method. The chromatographic analysis showed that methanolic solvents more effectively extracted oleuropein from olive leaf. However, when water was used as a solvent, hydroxytyrosol, tyrosol and verbascoside were extracted better from olive leaf. When solvents were compared in respect to their total phenolic content; the order from highest to lower was respectively methanol, methanol/water, and water. Consequently, due to their high hydrophilic character; polyphenolic compounds can more efficiently be extracted in methanolic solvents with high polarity. © 2017, Centenary University. All rights reserved.