Extraction Optimization, Antioxidant, Cosmeceutical and Wound Healing Potential of Echinacea purpurea Glycerolic Extracts.

Echinacea purpurea is a plant with immunomodulating properties, often used in topical preparations for treatment of small superficial wounds. In the presented study, the best conditions for ultrasound-assisted extraction of caffeic acid derivatives (caftaric and cichoric acid) (TPA-opt extract), as well as the conditions best suited for preparation of the extract with high radical scavenging activity (RSA-opt extract), from E. purpurea aerial parts were determined. A Box-Behnken design based on glycerol content (%, w/w), temperature (°C), ultrasonication power (W) and time (min) as independent variables was performed. Antioxidant, antiaging and wound healing effects of the two prepared extracts were evaluated. The results demonstrate that glycerol extraction is a fast and efficient method for preparation of the extracts with excellent radical scavenging, Fe2+ chelating and antioxidant abilities. Furthermore, the extracts demonstrated notable collagenase, elastase and tyrosinase inhibitory activity, indicating their antiaging properties. Well-pronounced hyaluronidase-inhibitory activities, with IC50 values lower than 30 µL extract/mL, as well as the ability to promote scratch closure in HaCaT keratinocyte monolayers, even in concentrations as low as 2.5 µL extract/mL (for RSA-opt), demonstrate promising wound healing effects of E. purpurea. The fact that the investigated extracts were prepared using glycerol, a non-toxic and environmentally friendly solvent, widely used in cosmetics, makes them suitable for direct use in specialized cosmeceutical formulations.

Comparison of Maceration and Ultrasonication for Green Extraction of Phenolic Acids from Echinacea purpurea Aerial Parts.

Echinacea purpurea is used in herbal medicinal products for the prevention and treatment of the common cold, as well as for skin disorders and minor wounds. In this study, the efficiency of traditional maceration using water and ethanol was compared with the maceration using mixtures of water and glycerol, a non-toxic, biodegradable solvent from renewable sources. It was found that the glycerol-water mixtures were as effective as ethanol/water mixtures for the extraction of caffeic acid derivatives. All the prepared extracts demonstrated notable antiradical properties. Furthermore, an efficient ultrasound-assisted extraction using glycerol-water mixtures was developed using six independent variables. Their levels needed for the maximum extraction of caffeic acid derivatives were as follows: glycerol 90% (m/m), temperature 70 °C, ultrasound power 72 W, time 40 min, and ascorbic acid 0 mg/mL. Under the optimized conditions, ultrasound-assisted extraction was superior to maceration. It achieved significantly higher yields of phenolic acids in shorter extraction time. The presence of zinc in plant material may contribute to the beneficial effects of E. purpurea preparations. Since glycerol is a non-toxic solvent with humectant properties, the prepared extracts can be directly used for the preparation of cosmetics or oral pharmaceutical formulations without the need for solvent removal.