Development, safety profile, and wound-healing efficacy of a quality-controlled Oroxylum indicum (L.) Kurz. fruit extract ointment in non-infectious and Staphylococcus aureus-infected wound models

Abstract

Pheka ( Oroxylum indicum (L.) Kurz.) is a Thai medicinal plant that has been used for traditional purposes for a long time. Pheka extracts possess significant antioxidant and antibacterial properties, yet their topical application for wound healing remains underexplored. This study aimed to develop a quality-controlled pheka fruit extract-based ointment and evaluate its skin irritation potential in rabbits ( n = 3) and wound-healing efficacy in non-infectious using Sprague Dawley rats ( n = 18) and Staphylococcus aureus -infected using Jcl: SD SPF rats ( n = 12) animal models. The ointment was formulated using pheka fruit extract quality-controlled for total phenolic, total flavonoid, and flavone contents. In the first reported skin irritation assessment for this extract, the ointment exhibited negligible skin irritation within 72 h, confirming its safety for topical use. For A non-infectious wounds, the pheka ointment demonstrated significant healing activity, achieving more than 90% wound closure by Day 14, comparable to a commercial benchmark product. Importantly, in the S. aureus -infected wound model, the pheka ointment exhibited robust therapeutic efficacy. By Day 7 post-infection, the pheka ointment group achieved approximately 65% wound contraction, significantly outperforming the 52% reduction observed in the ointment base control group ( p < 0.05). Microbiological analysis demonstrated that pheka ointment caused a profound 900-fold reduction in bacterial bioburden, driving the S. aureus load down from 1.5 ⋅ 10 6 CFU/ml on Day 0 to 1.67 ⋅ 10 3 CFU/ml by Day 14, which was significantly lower than the ointment base control by Day 7 ( p < 0.05). Semi-quantitative micropathological skin scoring confirmed advanced tissue maturation in the pheka ointment cohort (score: 13.25 ± 1.71) compared to the ointment base control (score: 15.33 ± 3.05). Histological analysis revealed effective collagen rearrangement and reduced inflammation similar to the standard treatment. These findings present the first evidence of a quality-controlled O. indicum fruit ointment as a safe, effective, and quality-controlled phytopharmaceutical alternative for managing both non-infectious and infectious cutaneous wounds.