Optimized Sambucus nigra L., Epilobium hirsutum L., and Lythrum salicaria L. Extracts: Biological Effects Supporting Their Potential in Wound Care

This study aimed to optimize the extraction of phytocompounds intended for wound care applications from three plant species, <i>Sambucus nigra</i> L. flowers and <i>Epilobium hirsutum</i> L. and <i>Lythrum salicaria</i> L. aerial parts, by using a Quality by Design approach. The effects of different extraction methods (ultra-turrax and ultrasonic-assisted extraction), ethanol concentrations (30%, 50%, 70%), and extraction times (3, 5, 10 min) were studied, and during the optimization step, the polyphenol and flavonoid contents were maximized. The phytochemical profiles of the optimized HEs (herbal extracts) were assessed using LC-MS/MS methods. The antioxidant capacity of the optimized HEs was determined using DPPH (2,2-diphenyl-1-picrylhydrazyl radical scavenging capacity) TEAC (Trolox equivalent antioxidant capacity), and FRAP (ferric reducing antioxidant power) assays, while the antibacterial activity was evaluated against <i>Escherichia coli</i>, <i>Pseudomonas aeruginosa</i>, and MSSA-methicillin-sensitive <i>Staphylococcus aureus</i> and MRSA-methicillin-resistant <i>Staphylococcus aureus</i>). Cell viability and antioxidant and wound healing potential were assessed on keratinocytes and fibroblasts. The anti-inflammatory effect was assessed on fibroblasts by measuring levels of interleukins IL-6 and IL-8 and the production of nitric oxide from RAW 264.7 cells. The major compounds of the optimized HEs were rutin and chlorogenic acid. The <i>Lythrum salicaria</i> optimized HE showed the strongest antibacterial activity, while the <i>Sambucus nigra</i> optimized HE demonstrated high cell viability. <i>Lythrum salicaria</i> and <i>Epilobium hirsutum</i> optimized HEs showed increased antioxidant capacities. All extracts displayed anti-inflammatory effects, and the <i>Epilobium hirsutum</i> optimized HE exhibited the best in vitro wound-healing effect.