Quercetin and its role in biological functions: an updated review

Abstract

 Dear Editor, Quercetin is an important flavonol among the members of six subclasses of flavonoid compounds. The name quercetin was derived from quercetum (after Quercus, i.e., oak), and has been used since 1857 (Fischer et al., 1997[21]). It has been named as 3,3′,4′,5,7-pentahydroxyflavone by the International Union of Pure and Applied Chemistry (IUPAC). It is also known by its synonym 3,3′,4′,5,7-pentahydroxy-2-phenylchromen-4-one (Li et al., 2016[33]). Quercetin is the most widely distributed and extensively studied flavonoid found in various food sources, including fruits, vegetables, nuts, wine, and seeds (Oboh et al., 2016[44]). Quercetin has various biological properties, including antioxidant, anti-inflammatory, antibacterial, antiviral, radical-scavenging, gastroprotective, and immune-modulatory activities (Anand David et al., 2016[6]; Massi et al., 2017[39]). In addition, in several recently-filed patents the wide therapeutic applications of quercetin and its derivatives have been described in detail (Chen et al., 2016[15]; Eid and Haddad, 2017[19]; Sharma et al., 2018[50]). Quercetin exhibits a wide range of biological activities and therapeutic applications, which are of interest to the pharmaceutical, cosmetic, and food industries (Biler et al., 2017[10]). Here, we summarize the recent studies that have evaluated the biological and pharmacological activities of quercetin (Table 1(Tab. 1); References in Table 1: Abdelhalim et al., 2018[1]; Afifi et al., 2018[2]; Aghapour et al., 2018[3]; Ahmed et al., 2018[4]; Al-Asmari et al., 2018[5]; Ansar et al., 2016[7]; Atef et al., 2017[8]; Beghoul et al., 2017[9]; Calgarotto et al., 2018[11]; Chan et al., 2018[12]; Chang et al., 2017[13]; Chen et al., 2017[14]; Damiano et al., 2018[16]; Dong et al., 2017[17]; Duranti et al., 2018[18]; Esrefoglu et al., 2017[20]; Funakoshi et al., 2017[22]; Guo et al., 2017[23]; He et al., 2016[24]; Huang et al., 2017[25]; Jeon et al., 2017[26]; Ji et al., 2017[27]; Ju et al., 2018[28]; Kee et al., 2016[29]; Lan et al., 2017[30]; Lazo-Gomez and Tapia, 2017[31]; Li et al., 2018[32]; Liu and Zhou, 2017[34]; Liu et al., 2017[35]; Lu et al., 2018[36]; Maciel et al., 2016[37]; Maksymchuk et al., 2017[38]; Mitani et al., 2017[40]; Mkhize et al., 2017[41]; Naseer et al., 2017[42]; Pandya et al., 2017[45]; Patrizio et al., 2018[46]; Qin et al., 2017[47]; Ren et al., 2018[48]; Sameni et al., 2018[49]; Singh et al., 2018[51]; Sohn et al., 2018[52]; Tinay et al., 2017[53]; Veith et al., 2017[54]; Wu et al., 2018[55]; Xingyu et al., 2016[56]; Yang et al., 2017[57]; Yang et al., 2018[58]; Yarahmadi et al., 2017[60]; Yarahmadi et al., 2018[59]; Yazıcı et al., 2018[61]; Yuan et al., 2016[63]; Yuan et al., 2018[62]; Zhang et al., 2018[64]; Zhao et al., 2017[65]; Zhu et al., 2018[66]). Acknowledgements This work was supported by a grant from the Next-Generation BioGreen 21 Program (SSAC, Project #. PJ013328)" Rural Development Administration, Republic of Korea. Conflict of interest The authors declare no conflict of interest.