In the following centuries, Kazan grew to become a major industrial, cultural and religious centre of Russia. The city was seized (and largely destroyed) during Pugachev's Rebellion (1773–1775), but was later rebuilt during the reign of Catherine the Great. Historically, Kazan was the capital of the Khanate of Kazan, and was conquered by Ivan the Terrible in the 16th century, at which point the city became a part of the Tsardom of Russia.

Kazan is the fifth-largest city in Russia, being the most populous city on the Volga, as well as within the Volga Federal District. The city lies at the confluence of the Volga and the Kazanka Rivers, covering an area of 425.3 square kilometres (164.2 square miles), with a population of over 1.3 million residents, and up to nearly 2 million residents in the greater metropolitan area. The results suggest that one molecule of arbutin reduced two ABTS radical cation molecules to ABTS and then cleaved the third ABTS radical cation molecule to generate two products, an arbutin-ABTS fragment adduct and 3-ethyl-6-sulfonate benzothiazolone.ĪBTS radical cation adduct formation antioxidant arbutin radical-scavenging activity.Kazan ( / k ə ˈ z æ n, - ˈ z ɑː n/ kə- ZAN, -⁠ ZAHN Russian: Казань, IPA: Tatar: Казан, IPA: ) is the largest city and capital of Tatarstan, Russia. A time-course study of the radical-scavenging reactions of arbutin and the two reaction products suggested that one molecule of arbutin scavenges three ABTS radical cation molecules to generate an arbutin-ABTS fragment adduct as a final reaction product. The two reaction products were purified and identified to be a covalent adduct of arbutin with an ABTS degradation fragment and 3-ethyl-6-sulfonate benzothiazolone. HPLC analysis of the reaction mixture of arbutin and ABTS radical cation indicated the existence of two reaction products.

This study investigated the reaction mechanism of arbutin against ABTS radical cation that caused high stoichiometry of arbutin in an ABTS radical cation-scavenging assay. Arbutin, a glucoside of hydroquinone, has shown strong 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cation-scavenging activity, especially in reaction stoichiometry.

Azino nhb