Çözücü Farkının Zeytin Yaprağı Ekstraktı’nın Polifenolik Profiline ve Toplam Fenolik Madde Miktarına Etkisi

Öz

Zeytin ağaçları her dem yeşil, pek çok farklı amaç için meyveleri, yaprakları ve gövdesi kullanılabilen en eski bitkilerinden birisidir. Zeytin, özellikle Akdeniz diyetinde ve son zamanlarda da herkesin ilgisini çeken geniş metabolik etkileriyle çok kullanılan bir besin kaynağı haline gelmiştir. Zeytin ve yaprağı polifenolik bileşikler bakımından zengindir. Polifenolik bileşikler arasında da oleuropein en bol bulunan ve en aktif olanıdır. Diğer önemli aktif bileşikler ise hidroksitirozol, tirozol ve verbaskozittir. Oleuropein antioksidan, antidiyabetik ve antimikrobiyal etkilere sahiptir. Bu çalışma; çözücü farkının zeytin yaprağındaki polifenolik bileşiklerin miktarlarına ve toplam fenolik madde miktarına etkisinin araştırılması amacıyla planlanmıştır. Saf su, metanol/su ve metanol solventleri kullanılarak zeytin yaprağı ekstrakte edilmiştir. Elde edilen ekstraktta, içerik tayini kromatografik analiz kullanılarak araştırılmıştır. Ayrıca toplam fenolik madde miktarı Folin-Ciocalteu metodu ile spektrofotometrik yöntem kullanılarak tespit edilmiştir. Kromatografik analizler sonucunda metanolik solventlerin oleuropeini zeytin yaprağından daha etkin bir şekilde ekstrakte ettiği bulunmuştur. Solvent olarak su kullanıldığında ise hidroksitirozol, tirozol ve verbaskozitin daha iyi ekstrakte edildiği tespit edilmiştir. Ekstrakte edilen toplam fenolik madde miktarı bakımından solventler karşılaştırıldığında sırasıyla metanol, metanol/su ve suda en yüksek miktarlar bulunmuştur. Sonuç olarak, yüksek hidrofilik karakterlerinden dolayı polifenolik bileşiklerin, polaritesi fazla olan metanolik solventlerde daha verimli ekstrakte edilebileceği belirlenmiştir.

Anahtar Kelimeler

• Ekstraksiyon,HPLC,Oleuropein,Zeytin,Toplam fenolik madde

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.

Keywords

• Extraction,HPLC,Oleuropein,Olive,Total phenolic content

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