Investigation of Polyphenol Content and Antioxidative Activity of Cucurbita pepo L. Leaf Extracts Obtained by Ultrasonic Extraction
Lamija Kolarević *
Department of Pharmacognosy, Faculty of Pharmacy, University of Tuzla, Urfeta Vejzagića 8, 75 000 Tuzla, Bosnia and Herzegovina.
Emir Horozić
Department of Organic Chemistry, Faculty of Technology, University of Tuzla, Urfeta Vejzagića 8, 75 000 Tuzla, Bosnia and Herzegovina and Catholic School Centre "St. Francis", Klosterska 10, 75 000 Tuzla, Bosnia and Herzegovina.
Zahida Ademović
Faculty of Forestry, University of Sarajevo, Zagrebačka 20, 71 000 Sarajevo, Bosnia and Herzegovina.
Ermina Cilović Kozarević
Department of Pharmacognosy, Faculty of Pharmacy, University of Tuzla, Urfeta Vejzagića 8, 75 000 Tuzla, Bosnia and Herzegovina.
*Author to whom correspondence should be addressed.
Abstract
In this research, the antioxidant activity and its correlation with the polyphenolic content in pumpkin leaf extracts (Cucurbita pepo L.) were examined. Dried and pulverized pumpkin leaves were used as extraction material. Various solvents (water, methanol, ethanol, acetone) and their mixtures, in a ratio of 50:50 (v/v) (water: methanol, water: ethanol, water: acetone) were used for extraction. The solid-to-solvent ratio was 1:10. The influence of solvents on phenolic extraction, as well as the effect of ultrasonic extraction was investigated. The samples were subjected to ultrasound for 15 minutes. The total phenolic content was determined by the Folin-Ciocalteu method and the antioxidant activity of the extracts by FRAP and DPPH methods. The obtained results indicate the importance of choosing an adequate extraction solvent for phenolic isolation from plant material. Mixtures of organic solvents and water, especially a mixture of water and acetone, are the most suitable for the extraction of phenolic compounds. At the same time, a positive correlation was established between the content of total phenols and the antioxidant activity of the extracts. This suggests that phenols contribute significantly to the antioxidant properties of pumpkin leaves. The results showed the potential medicinal properties of pumpkin leaves but further studies are needed to identify, characterize and isolate different bioactive components, which could be used as a basis for obtaining new drugs for the treatment of various diseases.
Keywords: Pumpkin, extraction, UAE, phenolic compounds, antioxidant activity