A new trend in the use of indole alkaloids from natural products is the preparation of topical pharmaceutical formulations with applications in the field of regenerative medicine. These formulations can be characterized through the ease of administration, the proven healing action of indole alkaloids, the protection of skin lesions, and the assurance of oxygen permeability. Based on the numerous benefits that indole compounds extracted from the Vinca minor plant show externally, the purpose of this study was to develop new semi-solid biocomposites for topical application obtained from hydroalcoholic macerates of 40%, 70%, and 96% concentrations from the stems and leaves of the Vinca minor L. plant from the Dobrogea area. A total of 12 pharmaceutical formulations (named P1-P12) were prepared for which the physicochemical properties, pH, thermal stability, spreading capacity, and rheological behavior were determined. The optimal formulas with antioxidant and antimicrobial capacity were evaluated and determined (P3, P4, P9, and P10). Antioxidant activity was elicited using the photochemiluminescence method. The microorganisms used for the evaluation of antimicrobial activity were Gram-positive Staphylococcus aureus (ATCC 25923), Gram-negative Escherichia coli (ATCC 25922), and a fungal species, Candida albicans (ATCC 900288). The study of the rheological profile for the obtained composites revealed Newtonian, pseudoplastic, and thixotropic fluid behaviors. Following determinations using the photochemiluminescence method, the best antioxidant activity was obtained in the P3 and P9 preparations. The results of the antimicrobial analysis confirmed that both the leaves and the stems of the Vinca minor plant represent a valuable source of antibacterial substances, and the biocomposites analyzed may represent an alternative in the realization of new pharmaceutical preparations with topical applications based on hydroalcoholic macerates obtained from the Vinca minor plant.
Keywords: antimicrobial activity; antioxidant capacity; indole alkaloids; inflammation; rheological profile; semisolid pharmaceutical preparations; vincamine.