Lactobacillus-Fermented Aloe Vera Gel as a Source of Bioactive Phytochemicals with Enhanced Antioxidant, Cytoprotective and Anti-Aging Properties and Its Application in a Skin Gel Formulation

In addition to its well-documented biological properties, Aloe barbadensis Miller (Aloe vera) can serve as an effective substrate for fermentation involving lactic acid bacteria. In this study, Aloe vera gel was fermented using Lactobacillus strains (L. plantarum, L. rhamnosus, L. fermentum, L. paracasei). The chemical composition of the gel and its fermented products were analyzed using chromatographic methods, identifying key bioactive compounds, including the predominant aloesin. Antioxidant activity was assessed using chemical methods (DPPH, ABTS, FRAP) and in an in vitro cellular model, analyzing superoxide dismutase activity and the level of reactive oxygen species in skin cells. The L. rhamnosus ferment exhibited the strongest antioxidant properties. Cytoprotective properties were evaluated in HaCaT and HDF cell lines. The tested samples showed no cytotoxicity, and the ferments often outperformed the unfermented gel. Moreover, the developed model cosmetic gel based on fermented Aloe gel stimulated keratinocyte proliferation. Additionally, it was demonstrated that the ferments effectively inhibit the activity of enzymes associated with skin aging processes (collagenase, elastase, hyaluronidase), often more effectively than the unfermented Aloe gel. The results obtained indicate the potential of fermented Aloe vera gel as an ingredient in products that protect the skin.