Cochlospermum regium Leaf Extract Gel: A Natural Strategy Against Methicillin-Resistant Staphylococcus aureus

Skin infections caused by Staphylococcus aureus represent a major public health concern, and plant extracts, such as those from Cochlospermum regium, have emerged as promising therapeutic alternatives.

This study developed carbopol-based gel formulations containing ethanolic leaf extracts of C. regium (CRG 0.5% and 1%) and evaluated their physicochemical stability, antibacterial activity against S. aureus and a methicillin-resistant wound isolate, antioxidant potential, and biocompatibility.

Both CRG 0.5% and 1% were physically stable and maintained antibacterial activity for up to 90 days at 8 °C, while at 25 °C only CRG 1% retained activity throughout the evaluation period. In ex vivo pig skin assays, CRG 1% reduced methicillin-resistant S. aureus contamination by 99%, outperforming the conventional topical antibacterial agent (neomycin + bacitracin), which achieved 66% inhibition. The extract also exhibited high antioxidant activity without mutagenic or hemolytic effects. Although phenolic and flavonoid contents decreased over time, CRG 1% preserved adequate levels for therapeutic application.

These findings indicate that CRG 1% has potential as a stable, safe, and effective alternative for the treatment of topical infections, particularly those caused by methicillin-resistant S. aureus.