Antiaging Properties of Kalanchoe blossfeldiana Ethanol Extract—Ex Vivo and In Vitro Studies

Species of the genus <i>Kalanchoe</i> have a long history of therapeutic use in ethnomedicine, linked to their remarkable medical properties. These species include <i>Kalanchoe blossfeldiana</i> succulents, which grow in tropical regions. Despite the great interest in this plant, there are no reports about its therapeutic effects on the skin. In this study, the antioxidant properties of <i>K. blossfeldiana</i> ethanol extracts and the skin permeation of a topical hydrogel containing the extract (HKB) were assessed. Additionally, the content of active compounds in the <i>K. blossfeldiana</i> extract was evaluated by UHPLC-MS and HPLC-UV. The extract was analyzed with three antioxidant assays: ABTS, DPPH, and FRAP. Furthermore, the antielastase and antihialuronidase properties of the tested extract were assessed. Ex vivo penetration studies were performed using the Franz diffusion cells. The estimation of the cytotoxicity of HKB was performed by using an MTT assay ((4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) on the human fibroblasts HFF-1. The results obtained show that the antioxidant properties of <i>K. blossfeldiana</i> extract were similar to those of ascorbic acid, while antielastase and antihialuronidase tests indicated the strong antiaging and anti-inflammatory activity of the extract (IC₅₀ was 26.8 ± 0.13 and 77.31 ± 2.44 µg/mL, respectively). Moreover, active ingredients contained in <i>K. blossfeldiana</i> extract penetrated through the human skin and accumulated in it. The cytotoxicity test showed that HKB had no significant effect on human fibroblasts at a concentration up to 0.5%. In conclusion, the hydrogel containing the <i>K. blossfeldiana</i> extract can be considered as an interesting and new alternative to dermatologic and cosmetic preparations.