Effect of harvest period and extraction method on oleuropein content, cytotoxicity, and in vitro wound healing potential of olive leaf extracts

Abstract

This study investigated the oleuropein content, cytotoxic effects, and in vitro wound healing potential of olive leaf extracts obtained from Sarımazı Sarı Ulak and Kırıkhan Halhalı olive leaf material harvested in May and November using boiling and infusion methods. Oleuropein content varied depending on cultivar, harvest period, and extraction method. The highest oleuropein levels were observed in November-harvested samples, particularly in Sarımazı Sarı Ulak (3404 ppm, boiling; 3593 ppm, infusion) and Kırıkhan Halhalı (3524 ppm, infusion), while May samples showed lower concentrations (1481–3011 ppm). Cytotoxicity was evaluated using the MTT assay on L929 fibroblast cells, where cell viability values generally exceeded the 70% threshold at lower concentrations, reaching up to 108.27% and 101.65% in certain extract dilutions, indicating low cytotoxicity and potential proliferative effects. Oleuropein standard treatments also demonstrated dose-dependent response in cell viability (76.54–99.36%). Scratch assay results revealed enhanced fibroblast migration, particularly in extracts with higher oleuropein content and lower cytotoxicity. Overall, November-harvested olive leaf extracts, especially those obtained by infusion, exhibited higher oleuropein content, improved cell viability, and greater wound healing potential, suggesting their promising application as natural bioactive agents in therapeutic and pharmaceutical formulations.

Keywords

• Olive leaf
• Oleuropein
• MTT test
• Scratch assay (in vitro wound healing)

Supporting Institution

Hitit University Coordinatorship of Scientific Research Projects

Project Number

HÜBTUAM19001.21.002

Ethical Statement

This article does not require ethical approval as there are no experiments with human or animal subjects

Zeytin yaprağı ekstrelerinin oleuropein içeriği, sitotoksisitesi ve in vitro yara iyileştirme potansiyeli üzerine hasat dönemi ve ekstraksiyon yönteminin etkisi

Abstract

Bu çalışmada, Mayıs ve Kasım aylarında hasat edilen Sarımazı Sarı Ulak ve Kırıkhan Halhalı zeytin çeşitlerinden elde edilen zeytin yaprağı ekstraktlarının kaynatma ve infüzyon yöntemleri kullanılarak oleuropein içeriği, sitotoksik etkileri ve in vitro yara iyileştirme potansiyeli araştırılmıştır. Oleuropein içeriği, çeşide, hasat dönemine ve ekstraksiyon yöntemine bağlı olarak değişiklik göstermiştir. En yüksek oleuropein seviyeleri, özellikle Sarımazı Sarı Ulak (3404 ppm, kaynatma; 3593 ppm, infüzyon) ve Kırıkhan Halhalı (3523 ppm, infüzyon) çeşitlerinde olmak üzere Kasım ayında hasat edilen örneklerde gözlemlenirken, Mayıs örneklerinde daha düşük konsantrasyonlar (1480–3011 ppm) tespit edilmiştir. Sitotoksisite, L929 fibroblast hücreleri üzerinde MTT testi kullanılarak değerlendirilmiş olup, hücre canlılığı değerleri genellikle düşük konsantrasyonlarda %70 eşiğini aşarak, bazı ekstrakt seyreltmelerinde %108.27 ve %101.65'e ulaşmış, bu da düşük sitotoksisite ve potansiyel proliferatif etkilere işaret etmiştir. Oleuropein standart uygulamaları ayrıca hücre canlılığında doza bağlı yanıt (76.54–99.36%) göstermiştir. İn vitro yara iyileşme testi sonuçları, özellikle daha yüksek oleuropein içeriğine ve daha düşük sitotoksisiteye sahip özütlerde fibroblast göçünün arttığını ortaya koymuştur. Genel olarak, Kasım ayında hasat edilen zeytin yaprağı özütleri, özellikle infüzyon yoluyla elde edilenler, daha yüksek oleuropein içeriği, gelişmiş hücre canlılığı ve daha büyük yara iyileştirme potansiyeli sergilemiş olup, terapötik ve farmasötik formülasyonlarda doğal biyoaktif ajanlar olarak umut vadeden uygulamalarını göstermektedir.

Keywords

• Zeytin Yaprağı
• Oleuropein
• MTT testi
• Scratch assay (in vitro yara iyileşmesi)

Supporting Institution

Hitit Üniversitesi Bilimsel Araştırma Projeleri Koordinatörlüğü

Project Number

HÜBTUAM19001.21.002

Ethical Statement

Bu makale, insan veya hayvan denekler üzerinde herhangi bir deney içermediğinden etik kurul onayı gerektirmez.

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