Evaluation of the Antioxidant, Cytotoxic, and Potential Anti-Aging Properties of Extracts and Kombucha Ferments from Flowers of Melliferous Plants: Tilia L. and Calluna vulgaris L

The growing demand for natural cosmetic ingredients has increased interest in plant-derived sources of bioactive compounds and their potential enhancement through fermentation. The aim of this study was to evaluate the biological properties of kombucha extracts and ferments obtained from the flowers of two melliferous plants, Tilia L. and Calluna vulgaris L. The preparations were assessed for total phenolic and flavonoid content and antioxidant activity using FRAP and CUPRAC Assays. Cytotoxicity was assessed using the Neutral Red Assay, while potential anti-aging activity in vitro was assessed by determining the intracellular of collagenase, elastase, and hyaluronidase protein levels. Regenerative potential was assessed using a scratch assay on human dermal fibroblasts (HDF) and keratinocytes (HaCaT). Among the preparations tested, the 7-day fermented preparation (F7) demonstrated the most favorable overall biological activity. At a concentration of 500 µg/mL, the Calluna vulgaris L. preparation demonstrated FRAP and CUPRAC activities 571.54 and 743.93 µM TE/L, respectively. The Neutral Red Assay showed that sample concentrations up to 250 µg/mL had no cytotoxic effect. The Calluna vulgaris L. F7 formulation produced the greatest reduction in intracellular elastase, collagenase, and hyaluronidase protein levels. In the scratch test, the F7 formulation demonstrated the strongest effect on wound closure, with the Calluna vulgaris L. preparations demonstrating a more favorable effect than the Tilia L. preparations. Overall, the results indicate that the tested fermentation products may represent in vitro candidates for further investigation of their potential cosmetic applications, including formulation development, skin penetration, and safety evaluation.