In the present study, Serpylli herba’s waste extracts were prepared using 50% ethanol (pH 6) and 50%
ethanol with hydrochloric acid (pH 1.2), using maceration (25 °C) and heat-assisted extraction (HAE,
80 °C). The best extraction conditions were determined via analyzing total polyphenol (TPC) and
flavonoid contents (TFC), antioxidant capacity, extraction yield, zeta potential, density, and surface
tension. In maceration and HAE, TPC were 1.18±0.06 and 1.43±0.05 mg GAE/mL (pH 6), and
0.69±0.05 and 0.86±0.02 mg GAE/mL (pH 1.2). The same trend is noticed in the case of TFC:
0.33±0.01 and 0.42±0.02 mg CE/mL (pH 6) and 0.24±0.01 and 0.27±0.01 mg CE/mL (pH 1.2). ABTS
radical scavenging activity was 775.0±3.5 and 623.8±5.1 mmol Trolox/mL (pH 6), and 269.2±3.1
and 327.9±7.7 mmol Trolox/mL (pH 1.2). In DPPH assay, IC50 was 1.64±0.04 and 1.48±0.03 mg/mL
(pH 6), and 7.59±0.07 and 5.11±0.09 mg/mL (pH 1.2). Extraction yield was 0.541±0.049 and
0.583±0.019% (pH 6), and 0.938±0.057 and 0.889±0.060% (pH 1.2). Zeta potential was -2.58±0.02
and -2.08±0.10 mV (pH 6), and 1.49±0.37 and 1.08±0.09 mV (pH 1.2). Density was 0.945±0.001
and 0.949±0.001 g/mL (pH 6), and 1.008±0.001 and 1.010±0.001 g/mL (pH 1.2). Surface tension
was 29.2±0.3 and 30.5±1.0 mN/m (pH 6), and 32.6±2.3 and 36.5±2.3 mN/m (pH 1.2). The best
properties were determined in the extract obtained in HAE at pH 6. The aim of this study is to provide
evidence of the physico-chemical properties of Serpylli herba’s waste extracts that can add value and
improve the quality of existing food, pharmaceutical, and cosmetic products.
