Ethanol Thymus serpyllum extracts: Evaluation of extraction conditions via total polyphenol content and radical scavenging activity

Abstract

The aim of the present study was the optimization of the extraction conditions (particle size, solid-to-solvent ratio, extraction time and procedure) via total polyphenol content and radical scavenging activity, using wild thyme (Thymus serpyllum L.) as a natural source of polyphenols. According to the total polyphenols yield, particle size, solvent-to-solid ratio, and extraction technique have shown statistically significant influence, whereas the exposure time has not been a relevant factor. In all three extraction procedures (maceration, heat-and ultrasound-assisted extraction), the highest polyphenols yield was reached using the smallest plant particles and the highest solvent-to-solid ratio. Moreover, polyphenols content was significantly higher after ultrasound-assisted extraction, in comparison to the extraction at room and high temperature. According to the antioxidant recovery, the influence of different extraction parameters varied depending on the applied antioxidant tests and extraction procedures. 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid)-ABTS radical scavenging capacity of extracts followed the next trend: maceration and ultrasound-assisted extraction gt heat-assisted extraction , while in 2,2-diphenyl-1-picrylhydrazyl-DPPH neutralization: ultrasound-assisted extraction gt heat-assisted extraction gt gt maceration. The study represents an important step in the formulation of antioxidant-rich extracts with potential use in food, pharmaceutical, and cosmetic industry.