Botanical Nanofiber Wound Dressing Loaded with Psidium guajava Leaf Extract: Preparation, Characterization, and In Vivo Evaluation

<b>Background/Objectives</b>: This study aimed to develop botanical nanofibers loaded with <i>Psidium guajava</i> leaf extract to heal wounds effectively. <b>Methods</b>: A 2³ factorial design was conducted to study the impact of freeze-drying parameters-freezing time, vacuum, and lyophilization time-on the total phenolic and flavonoid content in the lyophilized extract. Then, a polyurethane-based nanofiber dressing loaded with <i>Psidium guajava</i> leaf extract was fabricated using a one-step electrospinning technique. The nanofiber was evaluated considering total polyphenol and flavonoid content, surface roughness, and morphological assessment by scanning electron microscopy. Finally, the nanofiber was evaluated using in vivo wound-healing studies, histopathological analyses, and assessments of tissue levels of tumor necrosis factor-alpha, interleukin-6, matrix metalloproteinase, and growth factors. <b>Results</b>: The optimal conditions for freeze-drying the aqueous extract of <i>Psidium guajava</i> leaves were a freezing time of 24 h, a vacuum adjusted to 0.02 bar, and a lyophilization time of 48 h. The total polyphenol and flavonoid content within the nanofiber was 96 ± 1.2% and 91.83 ± 2.4%, respectively. Incorporating lyophilized extract in the nanofiber led to a decreased roughness average and root mean square roughness of the nanofiber. The nanofiber was continuous and had a smooth, uniform surface. The in vivo wound-healing assay showed superior wound-healing compared to the commercial Panthenol cream. These results were confirmed with histopathological studies. <b>Conclusions</b>: The extraction technique and lyophilization parameters significantly affect the bioactive content of <i>Psidium guajava</i> leaf extract. The botanical-loaded nanofiber showed greater wound-healing potential than a commercial cream, confirming its potential in regenerative medicine and wound repair applications.