Dear Editor,

Kaempferol (3,5,7-trihydroxy-2-(4-hydroxyphenyl)-4H-chromen-4-one) is a natural flavonol exhibiting different metabolic functions. It is most commonly found in a variety of plants and plant derived foods including grapes, kale, bean, broccoli, tomatoes, spinach, tea, and ginkgo biloba leaves (Cid-Ortega and Monroy-Rivera, 2018[8]; Devi et al., 2015[11]).

The biosynthesis of kaempferol is completed in four major steps. In the first step, a phenylpropanoid metabolic pathway occurs in which phenylalanine is converted into 4-coumaroyl-CoA. Subsequently, 4-coumaroyl-CoA is combined with three molecules of malonyl-coA to form naringenin chalcone (a tetrahydroxychalcone) through the action of chalcone synthase. In the third step, naringenin chalcone is exchanged with naringenin, and its hydroxyl group is involved in the formation of dihydrokaempferol. Finally, dihydrokaempferol, which has a double bond, is converted into kaempferol (Calderón-Montaño et al., 2011[5]; Santos-Buelga et al., 2019[39]).

Several papers have reported the positive effects of dietary kaempferol in reducing the risk of chronic diseases, such as cancer, liver injury, obesity, and diabetes (Imran et al., 2019[20]; Wong et al., 2019[47]). Kaempferol exhibits anti-inflammatory properties and has been used to cure many acute and chronic inflammation-induced diseases, such as intervertebral disc degeneration and colitis, post-menopausal bone loss, and acute lung injury (Ren et al., 2019[37]). Herein, we summarize the most recent published findings on the biological and pharmacological activities of kaempferol (Table 1(Tab. 1); References in Table 1: Adhikary et al., 2018[1]; Alkhalidy et al., 2018[2][3]; Beg et al., 2018[4]; Chen et al., 2020[6]; Chien et al., 2019[7]; Cui et al., 2019[9]; Da et al., 2019[10]; Du et al., 2018[12]; El-Kott et al., 2020[13]; Fernández-Del-Río et al., 2017[14]; Gao et al., 2018[16]; Gao et al., 2019[15]; Gómez-Zorita et al., 2017[17]; Guo et al., 2017[18]; Han et al., 2018[19]; Jiang et al., 2019[21]; Kim et al., 2018[23]; Kim, 2017[22]; Kouhestani et al., 2018[24]; Lei et al., 2019[25]; Li et al., 2017[28]; Li et al., 2018[26]; Li et al., 2019[27]; Liu et al., 2017[29]; Mahobiya et al., 2018[30]; Ming et al., 2017[31]; Moradzadeh et al., 2018[32]; Özay et al., 2019[33]; Pan et al., 2018[34]; Qian et al., 2019 [35]; Rabha et al., 2018[36]; Santos et al., 2019[38]; Sharma and Nam, 2019[40]; Suchal et al., 2017[41]; Torres-Villarreal et al., 2019[42]; Varshney et al., 2017[43]; Vishwakarma et al., 2018[44]; Wang et al., 2018[46]; Wang et al., 2019[45]; Wu et al., 2017[49]; Wu et al., 2018[48]; Yang et al., 2019[50]; Yao et al., 2019[51]; Yeon et al., 2019[52]; Zhang and Ma, 2019[53]; Zhang et al., 2017[55]; Zhang et al., 2019[54]; Zhao et al., 2017[57]; Zhao et al., 2020[56]; Zhong et al., 2018[58]; Zhou et al., 2018[59]; Zhu et al., 2018[60]; Zhuang et al., 2017[61]).

This research was supported by Golden Seed Project (213006051WTE11) funded by the Ministry of Agriculture, Food and Rural Affairs (MAFRA), the Ministry of Oceans and Fisheries (MOF), the Rural Development Administration (RDA), and the Korea Forest Service (KFS), Republic of Korea.

The authors declare no conflict of interest.