JOLDA ZOTAJ,ARLINDA ҪAÇI, KRENAIDA TARE, JOANA KOKALARI, ALKETA LAME, EFROSINI KOKALARI (TELI
Department of Chemistry, Faculty of Natural Sciences Tirana
Department of Biotechnology, Faculty of Natural Sciences
*Corresponding author E-mail: joldazotaj @yahoo.com
Abstract
Flavonoids are polyphenol substances that are common in many plants and possess a wide spectrum of biological activities. Among them, an important polyphenol compound is quercetin. This compound is contained in red onion 19.93mg/100g and in yellow onion 13.27mg/100g. Quercetin has anti-inflammatory, anti-histamine, anti-cancer effects and other biological activities. In recent years quercetin is proved to be an efficient inhibitor against the corrosion of metals and alloys. Both inorganic and organic synthetized compounds, have a toxic effect upon environment and human lives. A great interest are represented corrosion’s inhibitors, which are extracted from different plants, known as green inhibitors. These compounds are cheap and safety handled to be used as corrosion inhibitors.
The extract of quercetin from onion skin, represents a great inhibitive action against corrosion of metals and alloys in acidic media. Quercetindiglucoside and monoglucoside account for up to 93% of total flavonol content in onion.
Quercetin from the onion skin was obtained by alcoholic and water extraction. The extract was stored at 4oC and in the dark.
The product of extraction was analyzed with infrared (IR) and ultraviolet (UV) spectroscopy, in order to define its chemical structure. Also we defined the yield, density and molecular weight of the product. The product of extraction was quercetin and we propose to use it as corrosion inhibitor.
Keywords: extraction, onion skin, quercetin, corrosion inhibitor.
