Synthesis, Spectral and Antioxidant Properties of Tin(II)-Rutin Complex

Abstract

Rutin is one of the most common flavonoids present in nature that has a wide range of biological properties. A Tin(II)-rutin complex was synthesized from the raw material rutin and SnCl 2 in an alkaline solution. The complex was characterized by UV-vis, IR, 1 H NMR, and 13 C NMR spectroscopy. We evaluated the free radical scavenging activity using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) method, and the results showed that pure rutin was more effective than the Tin(II)-rutin complex in terms of antioxidant activity. Supplementing diet by foods rich in rutin and other flavonoids, such as vegetables and fruits, may contribute to removing free radicals and heavy metal ions in our body.Tinplate, commonly known as tin-plated steel sheet, is a kind of cold-rolled low-carbon steel sheet coated with pure tin on both sides. This material combines the durable strength of steel with the corrosion resistance of tin in one. These characteristics are the reasons why tinplate is widely used in the manufacture of rigid containers, especially for food and beverage packaging. Normally the concentration of tin in the majority of foods should be less than 1 part per million (ppm); however, in canned foods, especially those with an acidic pH, noticeably higher levels or more may be found [e.g., 100-500 ppm (0.01-0.05%)]. Regular consumption of these foods will cause symptoms of tin poisoning, such as vomiting, diarrhea, and anorexia [1].Chelation therapy is the preferred method for reducing the heavy metal induced toxicity. Chelating agents tightly bind to toxic metal ions to form complex structures that are easily excreted from the body [2]. Flavonoids are polyphenolic natural products widely distributed in plant foods, with a wide range of biological activities and pharmacological properties such as cardiovascular protection, anti-cancer, anti-ulcer, anti-oxidation, anti-viral, and anti-inflammatory; in addition, flavonoids are also natural antioxidants, free radical scavengers, and metal chelators [3]. Rutin is one of the most common flavonoids present in nature that has a wide range of biological properties, such as anti-inflammatory [4], anticancer [5], antioxidant [6], and so on. Rutin is an effective metal chelator [7, 8]. The complexation of metal cations by rutin has already been reported for a large number of metals: Zn (II), Al (III) [9], Cu (II) [10], Co (II) [11], Fe (II) [12], Fe (III) [13], Mn (II) [14], V (II) [15], U (II) [16], and Au (III) [17]. Rutin has attracted the attention of many researchers because of these special properties [18]. Supplementing regular diet with foods rich in rutin and other flavonoids, such as ginkgo biloba and buckwheat, may contribute to removing free radicals and heavy metal ions in our body [19,20].The purpose of this investigation was to study the chelating properties of rutin with tin cations [Sn(II)] and investigate the variation in antioxidant properties of rutin after chelation.The UV-vis spectrum of free rutin and Tin(II)-rutin complex in MeOH is reported in Fig. 1. Rutin exhibit...