## 3 Results and Discussion
### The Total Flavonoids Content (TFC) of Medicinal Plant Extracts  
Figure 6 shows the TFC for the CS/FG samples extracted by CES, UAE, and MWE. Figure 6a,c,e present the content of total flavonoids (TFC) expressed as mgQE/g dry matter (DM) using CES, UAE, and UWE. Figure 6b,d,f present the increasing/decreasing of TFC (%) after different preparations of the sample (FG/CS) calculated according to Equation (2). Flavonoids are secondary plant metabolites with antioxidant in vitro and in vivo activity due to the presence of free OH groups, especially 3-OH [52]. The level of TFC varied between 0.11 and 2.50 mgQE/g DM for samples of CS extracted by CES, between 2.88 and 11.87 mgQE/g DM for samples extracted using UAE, and between 0.83-5.06 mgQE/g DM when MWE was applied. The maximum content of flavonoids was recorded for the CES procedure, MP, LA, and AM extracts. For the UAEprocess, in the case of OV, MO, and HP extracts, and when MWE was used for MP, EP, and HP extracts (Figure 5(a),c,e). Regarding the samples analyzed in powder form (FG), the TFC values varied in the range of 1.02-3.46 mgQE/g DM when CES was used, between 2.36-12.09 mgQE/g DM for UAE extraction, and between 1.22-9.63 mgQE/g DM in the case of the MWE procedure. With respect to the UAE, favoring the flavonoid extraction process was observed in the case of the crushed version compared to the powder sample for some of the analyzed samples. The percentage of TFC increased when the vegetal matrix was prepared in powder form (FG) compared to coarse shredding (CS), and both extracts by CES recorded the highest value in the LA sample and the lowest in the OV extract (Figure 5(b)). On the contrary, coarse grinding (CS) favors TFC extraction compared to plant material in powder form (GV) in the case of MP, TS, AM, OV, HP, CO, and SO1 extracts, and the percentage of decrease is between 13.4 and 34.42%. For EP, HO, LA, and MO SO2 extracts, a slight increase is recorded in the case of the powder form compared to the crushed version (Figure 5(d)). Processing in the form of powder (FG) leads to a significant increase in TFC compared to the crushed version (CS) if the extraction is carried out using microwaves (MWE) (Figure 5(f)). Between the processing in the form of powder (FG) and coarse shredding (CS), significant statistical differences were recorded for all plants extracted using CES. No significant differences were obtained for the TS, AM, EP, SO2, MO, and CO extracts when the extraction was done by UAE or for the MP extract processed by MWE. Figure 7 presents the TFC comparatively for the three extraction procedures (CES, UAE, and MWE) and for the two preparation types (CS/FG). Significant statistical differences (\(p<0.05\)) were recorded between the 3 procedures for the majority of the analyzed plants, prepared in coarse shredding (CS) form. The exceptions were the pairs CES/UAE for MP, AM, SO2, and CO extracts. Regarding the FG form, no significant statistical differences (\(p<0.05\)) were obtained between the pairs CES/UAE for the EP extract and between the pairs UAE and MWE for the TS, CO, and SO2 extracts. The results are similar to those reported in the specialized literature. Literature studies reported TFC in the sage extract at 6.91 mg QE/g [13], 0.923 mg QE/g [42], and 5 mg QE/g, respectively [41]. In the thyme aqueous extract, the TFC content was 3.17 mg QE/g [38], respectively, between the 1.412-2.076 mg QE/g values reported for Thymus species extracted in different solvents [45] and _Thymus vulgaris_ L. methanolic extract [46]. Higher values were reported in the study of [PERSON] et al. in EP extract when classical extraction was used (33.3 mg/g). Also, these authors reported a reduction in TFC when ultrasound extraction was performed (27.0 mg/g) [50]. Figure 5: The AA (expressed as FRAP) compared for the 3 extraction methods (**a**) CS; (**b**) FG. According to the \(t\)-test, the different lower-case letters (a–c) represent the significant differences (\(p<0.05\)) between samples from the same plant obtained by different extraction methods.