Development and Characterization of Phlomis brachyodon Extract-Loaded Thermoresponsive In Situ Gels: Antioxidant Activity, Wound-Healing Evaluation in a Rat Excision Model, and Potential Anticancer Activity

This study aimed to characterize butanol and methanol extracts of Phlomis brachyodon (P. brachyodon) and incorporate them into thermoresponsive in situ gels (F1 and F2, respectively) to evaluate their wound-healing activity. Total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of the extracts were determined. Extracts were profiled by LC–MS. The rheological properties of the gels, using a controlled-stress rheometer, and their wound-healing activity and histological examinations were evaluated. Cell viability assays of the extracts were conducted against human gingival fibroblasts (HGF) and a small-cell lung cancer cell line (H69). The methanol extract showed higher TPC and TFC values and stronger antioxidant activity than the butanol extract (IC50, 55.82 ± 8.94 versus 144.11 ± 10.95 µg/mL). F1 and F2 underwent a sol–gel transition at temperatures suitable for topical application and exhibited shear-thinning behavior with predominantly elastic behavior. Both extract-loaded gels promoted wound contraction, with F2 producing the greatest reduction in wound area and near-complete closure by day 15. F1 and F2 gels showed complete re-epithelialization. LC–MS profiling detected 37 constituents and showed greater chemical diversity in the methanol extract. Both extracts had selectivity indices greater than 30 against H69 cancer cells, with IC50 values of 3.16 and 2.24 µg/mL for the butanol and methanol extracts, respectively. P. brachyodon extract-loaded thermoresponsive gels, particularly the methanol extract formulation, showed promising antioxidant and wound-healing activity. In conclusion, these findings support the development of P. brachyodon topical formulations and demonstrate anticancer activity, particularly against H69 lung cancer cells, for P. brachyodon extracts.