In Vitro Toxicity Evaluation of Some Plant Extracts and Their Potential Application in Xerosis cutis

Xerosis cutis represents one of the most common dermatological diagnoses, which, when untreated, can be the trigger for open wounds, infections, and other skin diseases. Plant extracts are a valuable option for long-term treatments for xerosis due to their phytocompounds, especially polyphenols, flavonoids, triterpenes, and polysaccharides, with antioxidant, anti-inflammatory, antimicrobial, moisturizing, and reparatory effects. Active substances have different mechanisms; therefore, evaluating the effects on the cells can be a key indicator, providing valuable information in terms of both cytotoxicity and efficacy. The in vitro and in vivo toxicity tests performed for Betulae extractum, Liquiritiae extractum, and Avenae extractum highlighted potential toxic effects at higher concentrations in a dose-dependent relationship, but at lower levels they can be considered safe (12.5 µg/mL for birch and licorice extracts, 50 µg/mL for oat extract). Concerning the re-epithelialization process, the results revealed that all three dry extracts effectively stimulate skin cell migration, highlighting a potential anti-inflammatory effect by increasing the cell migration rate in conditions of induced inflammation associated with oxidative stress. Among the tested concentrations with a potential contribution to wound healing, the following standout: are birch bark extract 3 μg/mL, licorice root extract 7.5 µg/mL, and oat herb (harvested before flowering) extract 7.5 µg/mL.