LC-MS based metabolic profiling and wound healing activity of a chitosan nanoparticle-loaded formula of Teucrium polium in diabetic rats

Healing of wounds is the most deteriorating diabetic experience. Felty germander (Teucrium polium) possesses antioxidant, anti-inflammatory and antimicrobial activities that could accelerate wound healing. Further, nanohydrogels help quicken healing and are ideal biomaterials for drug delivery. In the current study, the chemical profiling, and standardization of T. polium methanolic extract by LC-ESI/TOF/MS/MS and quantitative HPLC-DAD analyses were achieved. The wound healing enhancement in diabetic rats by T. polium nano-preparation (TP-NP) as chitosan nanogel (CS-NG) and investigating the potential mechanisms were investigated. The prepared hydrogel-based TP-NP were characterized with respect to particle size, zeta potential, pH, viscosity, and release of major components. LC-ESI/TOF/MS/MS metabolomic profiling of T. polium revealed the richness of the plant with phenolic compounds, particularly flavonoids. In addition, several terpenoids were detected. Kaempferol content of T. polium was estimated to be 7.85 +/- 0.022 mg/ g of dry extract. The wound healing activity of TP-NP was explored in streptozotocin-induced diabetic rats. Diabetic animals were subjected to surgical wounding (1 cm diameter). Then they were divided in 5 groups (10 each). These included Group 1 (untreated control rats), Group 2 received the vehicle of CS-NG; Group 3 (0.5 g of TP prepared in hydrogel), Group 4 (0.5 g of TP-NP), Group 5 represented a positive control treated with 0.5 g of a commercial product. All treatments were applied topically for 21 days. Application of TP-NP on skin wounds of diabetic animals accelerated the healing process as evidenced by epithelium regeneration, formation of granulation tissue followed by epidermal proliferation, along with keratinization as verified by H&E. This was confirmed through enhanced collagen synthesis, as shown by raised hydroxyproline content and Col1A1 gene expression. Moreover, TP-NP significantly alleviated wound oxidative burst and diminished the expressions of inflammatory biomarkers. Meanwhile, TP-NP could enhance the expressions of transforming growth factor beta1 (TGF-beta 1), in addition to the angiogenic markers; vascular endothelia growth factor A (VEGFA) and platelet-derived growth factor receptor alpha (PDGFR alpha). Collectively, chitosan nanogel of T. polium accelerates wound healing in diabetic rats, which could be explained - at least partly - through alleviating oxidative stress and inflammation coupled with pro-angiogenic capabilities.