Sinapic acid-loaded gel accelerates diabetic wound healing process by promoting re-epithelialization and attenuating oxidative stress in rats

Impaired wound healing is a critical health concern for individuals with diabetes. Sinapic acid, a phyto-compound, has wound-healing potential owing to its various bioactivities. In this study, we explored the wound-healing ability of sinapic acid in diabetes. Full-thickness excisional wounds were created in streptozotocin-induced diabetic rats. Sinapic acid-loaded gels (1%, 2%, and 3%) were prepared and applied topically to diabetic skin wounds. On day 7 post-wounding, rats were sacrificed, and macroscopic, histopathological, and oxidative markers of wound healing activity were evaluated in the collected wound tissues. Sinapic acid-loaded gels showed better recovery in re-epithelialization (p < 0.05) and angiogenesis (p < 0.05) compared to the negative control group. Sinapic acid-loaded gels (1%, 2%, and 3%) showed 87.46%, 79.53%, and 68.78% wound contraction, respectively. They increased collagen content (28.05 ± 1.66, 17.30 ± 2.19, and 11.64 ± 1.25, respectively) and decreased malondialdehyde (MDA) levels (17.49 ± 1.61, 18.44 ± 1.24, and 19.16 ± 1.77, respectively) compared to the negative control group (6.76 ± 0.89, and 43.58 ± 3.70, respectively) (p < 0.05). Moreover, sinapic acid-loaded gel groups demonstrated enhanced antioxidant capacity (approximately 2-2.5-fold) compared to the negative control group (p < 0.05). Sinapic acid 1% loaded gel showed the best effect on the diabetic healing process, whereas sinapic acid 2% loaded gel and reference drug showed similar effects. The results of this study, for the first time, suggest that the topical application of sinapic acid can promote diabetic wound healing, especially at low doses.