Background: Multiresistant bacteria have become a major cause of nosocomial infection and serious diseases worldwide. Antibiotic resistance due to overuse is a factor that causes treatment failure. Several herbal plants have been investigated for various useful properties such as antimicrobial, anti-inflammatory and antioxidant activities as an alternative to modern medicine.
Objective: To overcome bacterial multiresistance, development of products from plants with potential antibacterial properties was conducted.
Material and Method: Bacterial strains including Staphylococcus aureus, Methicillin-resistant Staphylococcus aureus (MRSA), Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobactor baumannii, were clinical isolates collected from Thammasat University Hospital. Crude extracts were taken from the wooden part of Caesalpinia sappan Linn. and dried flower bud of Syzygium aromaticum (Linn.) Merr. & Perry (clove). The herbal plants extractions were performed by maceration and decoction. Antibacterial activity was carried out by broth dilution method. The potential antibacterial extracts were formulated for a hand washing gel. Stability of the product was subsequently tested.
Results: The results revealed that C. sappan Linn. exhibited better antibacterial activity against both Gram-positive and Gram-negative bacteria as compared to clove extract. The combination of two herbal extracts did not produce an apparent antibacterial synergistic effect. Minimum inhibitory concentration values of hand washing gel containing C. sappan Linn. extract alone ranged from 1.25 to 20 mg/ml.
Conclusion: This study identified C. sappan Linn. as a potential herbal plant for development of an alternative treatment of bacterial infection in the future.

Keywords: Caesalpinia sappan Linn., Multi-resistant bacteria, Antibacterial activity, Herbal product, Hand washing gel