## 4 Discussion
In the previous study [24], BGR at 10-15 days contained the highest TCC (40.8 \(\pm\) 0.8 mg/g extract), and BGR at 5-7 days contained the highest TAC (22.13 \(\pm\) 0.002 mg cyanidin 3-glucose (C\({}_{3}\)GE)/g extract), whereas RD6 at 5-7 days comprised the highest TFC and TPC (34.2 \(\pm\) 3.4 mg quercetin equivalent (QE)/g extract, and 44.8 \(\pm\) 1.6 mg gallic acid equivalent (GAE)/g extract, respectively). Moreover, the proximate compositions with 100 g fresh weight of the rice sprout from both BGR and RD6 had a total ash 2.86 to 5.78 g, moisture 64.72 to 79.11 g, fat 0.32 to 1.2 g, protein 3.38 to 5.99 g, carbohydrate 12.22 to 24.54 g, and energy 73.44 to 124.0 Kcal. The dietary fiber of BGR at 10-15 days was 1.4 times higher than that of RD6 (16.92, and 11.98 and g/100 g fresh weight, respectively). The higher TPC was observed in the BGR group at 10-15 days in the previous study (31.9 \(\pm\) 1.1 mg GAE/g extract) than our result of BGR at the same age (29.72 \(\pm\) 1.42 mg GAE/g extract). In the previous study, the highest TAC was found in BGR at 5-7 days (22.13 \(\pm\) 0.002 mg C\({}_{3}\)GE/g extract). The highest TAC in our present study was found in BGR at 20-25 days only at 0.86 \(\pm\) 0.096 mg C\({}_{3}\)GE/g extract. The TAC in the present study was less than the presvious reported result, which might be due to the different extraction methods. Interestingly, the total bioactive compounds (TAC and TPC) were well correlated to the increasing of BGR ages (r \(>\) 0.6 with \(p\) \(<\) 0.05), not RD6 (r \(<\) 0.6 with \(p\) \(>\) 0.05) (Supplementary Materials, Figure S1 and Figure S2). In contrast, there is no correlation between BGR ages and FRAP (r = 0.314 with \(p\) \(>\) 0.05) (Supplementary Materials, Figure S1), whereas RD6 age was correlated to only DPPH (r = 0.606 with \(p\) \(<\) 0.05) (Supplementary Materials, Figure S2). TAC displayed no correlation with both DPPH and FRAP but TPC from both BGR and RD6 demonstrated well correlation to FRAP (r = 0.891 and = 0986, respectively with \(p\) \(<\) 0.05). The result implied that TPC was the major bioactive constituents that contribute to the direct antioxidative activity of BGR and RD6 _in vitro_. Moreover, BGR displayed the time-dependent cytotoxic activity to the sensitive cell lines (Jurkat and HCT116), whereas RD6 possessed less potency to the treated cell lines, except SK-MEL-2, with no time-dependent cytotoxicity. The correlation data indicated that Jurkat cell viability increased as BGR ages increased from young to old age at 24h (r = 0.952 with \(p\) \(<\) 0.05) and at 48h (r = 0.586 with \(p\) \(<\) 0.05), while HCT116 cell viability decreased with ages (r = \(-\)0.951 with \(p\) \(<\) 0.05) and at 48h (r = \(-\)0.609 with \(p\) \(<\) 0.05) (Supplementary Materials, Figure S3). Since Jurkat was the most sensitive cell line to BGR, the further correlation analysis between BGR ages and intracellular biological activities (ROS reduction, increase in GSH, caspase activity,and apoptosis induction) had been performed. BGR decreased intracellular ROS (r = -0.943 with \(p<0.05\)) and increased intracellular GSH (r = 0.922 with \(p<0.05\)), with increasing ages. The good correlation between the reduction of intracellular ROS and an increase in GSH was observed (r = -0.891 with \(p<0.05\)). Caspase 3/7 activity (r = 0.782 with \(p<0.005\)) and the percentage of apoptotic cells (r = 0.824 with \(p<0.05\)) were increased with the increasing ages (Supplementary Materials, Figure S1). The antioxidant capacity in the cell-based assays (from DCFH-DA and GSH assays) was directly correlated with TPC (r \(>0.6\); \(p<0.05\)), while cytotoxicity was inversely correlated with TPC (r \(<\) -0.6; \(p<0.05\)). Results implied that TPC predominantly contributed to antioxidant activities _in vitro_ and indirectly enhanced intracellular GSH, resulting in a lower intracellular ROS. In addition, TPC could trigger cancer cells to undergo apoptosis as indicated by the increase in caspase 3/7 activity.