## 3 Results  
### Impact of Single Factors on Antioxidant Compounds and Activity  
Regarding the various solvents utilized in the MAE process, the yield, TPC, and TFC were as follows: methanol > ethanol > acetone. Under these conditions, methanol emerged as the optimal solvent, yielding the highest percentage at 16.78 \(\pm\) 0.10% (Figure 2a). Moreover, it resulted in the highest TPC at 13.17 \(\pm\) 0.72 mg GAE/g and the highest TFC at 13.17 \(\pm\) 0.35 mg QE/g. Methanol's high polarity and hydrogen-bonding capability make it highly effective in extracting polyphenols, as it interacts well with their polar groups, enhancing solubility and extraction efficiency. This property makes methanol a preferred solvent for achieving high yields of polyphenols (TPC and TFC) from _C. iners_ due to its ability to preserve the desired antioxidants' chemical structural stability [18]. Regarding the DPPH assay, it was elucidated that the methanol (191.45 \(\pm\) 3.55 \(\upmu\)g/mL) and ethanol (141.81 \(\pm\) 19.11 \(\upmu\)g/mL) extracts showed higher antioxidant activities than acetone (680.17 \(\pm\) 4.11 \(\upmu\)g/mL) extracts. The DPPH experiment revealed that the methanol and ethanol extracts exhibited greater antioxidant capacity compared to the acetone extracts. The antioxidant capacity of extracts is closely associated with TPC and TFC. Stronger quantities of total phenolics in the extracts are also associated with stronger antioxidant activity. The solubility of certain antioxidant chemicals and the estimate of antioxidant activity are impacted by variations in solvent polarity [19]. Figure 2b shows that the different MAE time obtained various values for extraction yield (12.72 \(\pm\) 0.38 to 14.01 \(\pm\) 0.33%), TPC (12.87 \(\pm\) 0.36 to 14.79 \(\pm\) 0.06 mg GAE/g), TFC (13.34 \(\pm\) 0.35 to 15.90 \(\pm\) 0.16 mg QE/g), and IC\({}_{50}\) (105.11 \(\pm\) 1.83 to 95.05 \(\pm\) 3.76 \(\upmu\)g/mL). The MAE time that provided the highest yield, TPC, and TFC was 20 min, with values as follows: yield, 14.01 \(\pm\) 0.33%; TPC, 14.79 \(\pm\) 0.06 mg GAE/g; and TFC, 15.90 \(\pm\) 0.16 mg QE/g extract. The MAE time of 20 min also yielded the best antioxidant capacity in the cinnamon leaf extract, with an IC\({}_{50}\) value of 95.05 \(\pm\) 3.76 \(\upmu\)g/mL. Prolonged extraction times are known to cause the degradation of antioxidants in the extract [20]. Figure 2c shows that different levels of microwave power led to the obtention of various values for extraction yield (12.28 \(\pm\) 0.06 to 14.01 \(\pm\) 0.33%), TPC (11.92 \(\pm\) 0.35 to 13.68 \(\pm\) 0.04 mg GAE/g), TFC (11.95 \(\pm\) 0.18 to 15.93 \(\pm\) 0.08 mg QE/g), and IC\({}_{50}\) (118.49 \(\pm\) 4.22 to 97.91 \(\pm\) 3.52 \(\upmu\)g/mL). At a microwave power of 210 W, the extraction achieved the highest yield of 14.01 \(\pm\) 0.33%, a TPC of 13.68 \(\pm\) 0.04 mg GAE/g, a TFC of 15.93 \(\pm\) 0.08 mg QE/g, and the best IC\({}_{50}\) antioxidant capacity of 97.91 \(\pm\) 3.52 \(\upmu\)g/mL. Higher microwave power accelerates extraction by disrupting hydrogen bonds and enhancing solvent penetration, but beyond a certain point, further increases may not improve yield and may instead lead to the degradation of phenolic compounds due to excessive heat [21]. Figure 2: Effects of (**a**) type of solvent, (**b**) MAE time, (**c**) microwave power, and (**d**) solid–liquid ratio on the yield, TPC, TFC, and DPPH assay of cinnamon leaf extract. Figure 2d shows that different solid-liquid ratios led to the obtention of various values for extraction yield (15.75 \(\pm\) 0.13 to 22.04 \(\pm\) 0.66%), TPC (14.65 \(\pm\) 0.21 to 21.40 \(\pm\) 0.60 mg GAE/g), TPC (13.43 \(\pm\) 0.56 to 19.12 \(\pm\) 0.64 mg QE/g), and IC\({}_{50}\) (134.40 \(\pm\) 6.60 to 76.95 \(\pm\) 2.31 ug/mL). With a solid-to-liquid ratio of 1:240 g/mL, the extraction reaches its highest values, yielding 22.04 \(\pm\) 0.66%, with a TPC of 21.40 \(\pm\) 0.60 mg GAE/g and a TPC of 19.12 \(\pm\) 0.64 mg QE/g.