Sodium alginate hydrogels loaded with surfactant-free emulsions based on a vegetal extract (Petiveria alliacea) and chitosan for wound healing

Hydrogels loaded with surfactant-free emulsions provide suitable platforms for the application and release of bioactive compounds. This research comprises the extraction of active compounds from the root of Petiveria alliacea , the preparation of chitosan-stabilized O/W emulsions, the design of emulsion-filled alginate hydrogels, in silico analysis, and in vitro biological assays involving cell viability and scratch. In the vegetal extract, the compounds with the highest concentrations were: Benzenemethanethiol, benzaldehyde, benzyl alcohol, dibenzyl disulfide, octyl-3-pentyl ester of 1,2-cyclohexanedicarboxylic acid, and stilbene. The droplet size in emulsions stabilized with chitosan CHB and CH56, determined by Dynamic Light Scattering (DLS), was close to 857 nm and 638 nm with CHB and CH56, respectively. Likewise, the particle size estimated by Digital Image Analysis (DIA) was around 798 nm and 763 nm using CHB and CH56, respectively. The emulsion with a 1:5 (extract-to-polymer) ratio and polymer concentration of 10 mg/mL provided a suitable number of particles, viscosity, and pH for loading into the hydrogels. On the other hand, emulsion-filled hydrogels with alginate at 7.5 mg/mL exhibited good extensibility, avoided agglomeration of emulsion particles, and maintained an appropriate turbidity for monitoring long-term stability. In molecular docking, dibenzyl disulfide showed the best binding affinity energy (−8.2 kcal/mol) with matrix metalloproteinase-9 (MMP-9). In biological assays, the extract induced a biphasic dose-response (≤10 μg/mL promoted cell proliferation, and >25 μg/mL induced cell death). Furthermore, the extract was more cytotoxic to SiHa and C-33 A cancer cells than to fibroblasts, suggesting potential anticancer activity. The root extract and the emulsion-loaded hydrogel showed statistically significant differences at 24 h (40% closure) compared to the negative controls (23% closure) and led to a superior healing effect compared to a commercial gel.