In Vitro Characterization of Centella asiatica Extracellular Vesicles and Their Skin Repair Effects in a UVB-Irradiated Mouse Model

This study characterized extracellular vesicles (EVs) isolated from medicinal herb <i>Centella asiatica</i> tissue culture and investigated their therapeutic properties using in vitro assays and a ultraviolet (UV)-induced damage mouse model. EVs were isolated from <i>C. asiatica</i> tissue culture and characterized by nanoparticle tracking analysis, and cytotoxicity, antioxidant, anti-melanin, and anti-inflammation properties were evaluated by in vitro assays. <i>C. asiatica</i> EVs were found to contain high levels of polyphenols and mitigate hydrogen peroxide-induced intracellular reactive oxygen species (ROS). The EVs were further able to reduce intracellular melanin content and tyrosinase activity. They exhibited anti-inflammatory effects by downregulating the expression of pro-inflammatory genes, COX2, as well as nitric oxide production. In the UV-induced photodamage mouse model, gels with or without EVs were applied to the UV-damaged site, skin appearance was observed daily, and skin histopathology was analyzed on day 7. In mice with UV-induced skin damage, the daily application of <i>C. asiatica</i> EV gel reduced skin epidermis thickness and inflammation compared to UV-only or blank gel at seven days after UV irradiation. The beneficial effects of <i>C. asiatica</i> EVs on skin quality warrant further studies as promising agents in skin care applications.