Oncopreventive effects of theanine and theobromine on dimethylhydrazine-induced colon cancer model

Theanine and cancer: A systematic review of the literature

“…The main characteristics and results of the included studies are summarized in Tables 2 and 3. Of the 14 included articles, three were in vitro (Ayoub & Melzig, 2006; Friedman et al, 2007; Xin et al, 2018), four were in vivo (Fujii & Inai, 2008; Shojaei‐Zarghani, Khosroushahi, & Rafraf, 2020a; Sugiyama & Sadzuka, 1998; W.‐J. Zeng et al, 2018; G. Zhang et al, 2002), and seven were designed by a different combination of in vitro, ex vivo, and in vivo methods (Fan et al, 2020; Ji et al, 2014; J. Liu et al, 2016; Q. Liu et al, 2009; G. Zhang et al, 2016; G. Zhang et al, 2001; Zhao et al, 2019).…”

“…Six of the nine in vivo studies used randomization for allocating animals in different experimental groups (Fujii & Inai, 2008; Ji et al, 2014; J. Liu et al, 2016; Shojaei‐Zarghani, Khosroushahi, & Rafraf, 2020a; G. Zhang et al, 2016; Zhao et al, 2019), although none of them explained their randomization procedure. Only two studies provided details of housing, husbandry conditions, and the number of animals in each cage (Fujii & Inai, 2008; Shojaei‐Zarghani, Khosroushahi, & Rafraf, 2020a). The sample size calculation and blinding of the research personnel were mentioned in none of the included studies.…”

“…The sample size calculation and blinding of the research personnel were mentioned in none of the included studies. Only in one investigation, the outcome assessors were unaware of the experimental groups (Shojaei‐Zarghani, Khosroushahi, & Rafraf, 2020a). Finally, six examinations of the total were classified as tier 1 (Fujii & Inai, 2008; Ji et al, 2014; J. Liu et al, 2016; Shojaei‐Zarghani, Khosroushahi, & Rafraf, 2020a; G. Zhang et al, 2016; Zhao et al, 2019) and three as tier 2 (Fan et al, 2020; Sugiyama & Sadzuka, 1998; G. Zhang et al, 2002), according to OHAT's tier system.…”

“…Liu et al, 2016;. The effect of theanine on the tumor incidence was examined in three studies, and the preventive effects of theanine were reported (Fujii & Inai, 2008;Shojaei-Zarghani, Khosroushahi, & Rafraf, 2020a;G. Zhang et al, 2002).…”

L-Theanine: A Unique Functional Amino Acid in Tea (Camellia sinensis L.) With Multiple Health Benefits and Food Applications

“…Furthermore, L-theanine and its semi-synthesized derivative (R)-2-(6,8-dibromo-2-oxo-2H-chromene-3-carboxamido)-5-(ethylamino)-5-oxopentanoic ethyl ester (DTBrC) also restrained the growth and migration of human hepatocellular carcinoma (HHC) cells in in vitro , ex vivo , and in vivo HHC models, and the mechanism of this effect was that L-theanine and DTBrC blocked the Met/EGFR/vascular endothelial growth factor receptor (VEGFR)-Akt/NF-κB pathways ( 72 ). Then, L-theanine alone or in combination with theobromine could effectively inhibit tumor production in male Wistar rats with colon cancer induced by dimethylhydrazine, and the mechanism of action was related to downregulating the Akt/mTOR (mammalian target of rapamycin) and JAK2/STAT3 pathways and increasing the mRNA and protein expression of tumor suppressor Smad2 ( 73 ).…”