## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multicolumn{2}{c}{**Sample**} & \multicolumn{1}{c}{**TEAC**} & \multicolumn{1}{c}{**AEAC**} & \multicolumn{1}{c}{**TPC**} & \multicolumn{1}{c}{**TFC**} \\
**Sample Code** & **Description** & **(mg TE/g of** & **(mg AAE/g of** & **(mg GA/g of** & **(mg QE/g of** \\  & **Dy Waste)** & **Dry Waste)** & **Dry Waste)** & **Dry Waste)** \\ \hline \multirow{4}{*}{Total Waste Extract—TWE} & Hydroalcoholic Extract & \multirow{2}{*}{110.49 \(\pm\) 0.34 a} & \multirow{2}{*}{57.52 \(\pm\) 0.18 a} & \multirow{2}{*}{40.15 \(\pm\) 0.04 a} & \multirow{2}{*}{4.72 \(\pm\) 3.56 a} \\  & Obtained by PUAE from the & & & & \\  & Obliated by PUAE from the & & & & \\  & Only-Flower Residues & Remaining After the & & & \\  & Distillation of LEO & & & & \\  & & Distillation Wastewater: & & & \\  & Leachate & & & & \\ \hline \hline \end{tabular} All results are reported as mean values \(\pm\)95% confidence intervals (n = 2). In each column, means \(\pm\) 95% confidence intervals followed by different letters (a, b) in superscript are significantly different after ANOVA and Tukey’s Honest Significant Difference tests at \(\alpha\) = 0.05.  
\end{table} 
Table 2: Radical scavenging activity (RSA), total polyphenol content (TPC) and total flavonoid content (TFC) of the solid waste extracts obtained by PUAE: the total waste extract (TWE) and the only-flower waste extract (FWE). The chemical characterization of the corresponding distillation wastewaters (Leachate: LEACH) was reported too. optimized conditions of 1 h at 60 \({}^{\circ}\)C using methanol as extraction solvent, are between 11 and 23 mg of gallic acid per g of dry sample depending on the species. In this work, using an eco-compatible food-grade solvent (a mixture of EtOH and water) and a direct UAE through a probe, which is much more powerful because the ultrasonic intensity is delivered on a small surface (only the tip of the probe) compared to the ultrasonic bath [41], about double extractive yields were obtained (38-40 mg GA/g of dry waste). As regards RSA, [PERSON] et al. [42] reported the antioxidant activity of several medicinal and aromatic plants (i.e., _Artemisia abrotanum_ L., _Pelargonium roseum_ L., _Laurus nobilis_ L., _Rosmarinus officinalis_ L., _Mentha spicata_ L., _Lavandula angustifolia_ L., _Aloysia triphyllla_ L.) in the range between 6.1-47.7 mg of trolox/g of fresh weight. Particularly, the methanolic extract of _L. angustifolia_ (stem and leaves) showed RSA equal to 16.06 mg of Trolox/g of fresh weight. In this work, both the extracts obtained from lavender waste (TWE and FW) showed a higher antioxidant activity (107-110 mg Trolox/g dry waste). In the present study, we observed relatively low contents of flavonoid compounds per g dry weight as compared to TPC (Table 2). TFC values were within the concentration range (between ug/g and mg/g) of those observed by previous authors in distilled straws [1, 43]. Besides the expected variability in flavonoid concentrations between lavender cultivars from different geographic locations, differences in flavonoid quantification may also result from variability in distillation procedures (water and/or steam distillation, distillation time, temperature, etc.) affecting the quality of the remaining plant material. In addition, the use of a AlCl3 chelation method for the quantification of total flavonoids (this study) may result in underestimation of flavonoid concentrations because glycoside sugar moieties can prevent chelation with AlCl3 and the associated bathochromic shifts, rendering undetectable these molecules [44]. Since glycoside flavonoids are frequent in distilled straws [45], flavonoid quantification using colorimetric (through AlCl3 chelation) or chromatographic (quantification of HPLC peaks) may result in significant discrepancies. In the present study, reported TFC values agreed with flavonoid concentrations estimated from the corresponding HPLC peak areas (data not shown).