5 μg/mL), breast adenocarcinoma (MCF-7, TGI = 2.3 μg/mL) and glioma (U251, TGI = 3.6 μg/mL) ( Fig. 4 and Table 2). The most potent antiproliferative

effect observed for this quercetin-3-glucoside mixture might be related to the specific transport system, glucose transport carrier SGLT1. It was reported that glucose conjugation to a phenyl compound resulted in active absorption from mucosal side to serosal side by glucose transport system ( Mizuma, Ohta, Hayashi, & Awazu, 1992). Experimental evidence has suggested that quercetin-3-glucoside and quercetin-4′-glucoside can be transported by sodium-dependent Selleck GSI-IX glucose transporter (SGLT1) and subsequently deglycosylated within enterocyte by cytosolic β-glucosidase ( Wolffram, Blöck, & Ader, 2002). Quercetin itself was not transported by SGLT1 or GLUT2 ( Kwon et al., 2007). Quercetin, but not rutin, has been shown to express anti-proliferative effects on the human colon cancer cell line (HT-29), in a dose-dependent and time-dependent manner ( Kim, Bang, & Kim, 2005). You et al. (2010) recently related that quercetin-3-glucoside produced by removal of rhamnose sugar by crude enzyme GSK2118436 manufacturer extract of Aspergillus niger showed growth-inhibitory

effects in colon (HT-29 and HCT 116), breast (MCF-7), hepatocellular (HepG2), and lung cancer (A549) cells with the IC50 value between 15 and 25 μM, while quercetin was greater than 80 μM. Quercetin-3-glucoside is not an abundant flavonol glycoside in foods; however, its bioavailability has been shown to be one and a half times greater

than quercetin in rats ( Morand, Manach, Crespy, & Remesy, 2000) and in dogs ( Reinboth, Wolffram, Abraham, Ungemach, & Cermak, 2010). On the other hand, investigations of protective mechanism of quercetin and its derivatives against oxidative damage of in vitro rat C6 glioma cells showed that quercetin to be an active cell protector but not rutin or quercetin-3-glucoside ( Chen, Jeng, Lin, Wu, & Chen, 2006). The enzymatic reaction catalyzed by heated hesperidinase from Penicillium sp. efficiently converted rutin into its mono-glycoside to form, quercetin-3-glucoside. Quercetin-3-glucoside and quercetin showed similar antioxidant capacity as evaluated by DPPH assay, but quercetin-3-glucoside showed lower inhibitory effects on xanthine oxidase and as antioxidant when evaluated by the β-carotene assay. However, this derivative exerted a more potent antiproliferative effect than quercetin or rutin on various cancer cell lines. The results obtained from this study indicate that quercetin-3-glucoside could be a promising functional derivative obtained by rutin hydrolysis and further in vivo evaluations are needed. The authors gratefully acknowledge the financial support of FAPESP (Grant Proc. 09/09224-3; 2011/12394-8 and 2008/58035-6) and CAPES (Brazil). “
“The tamarillo (Solanum betaceum Cav. syn Cyphomandra betacea Sendt.