Abstract

Recently, multiple resistances in human pathogenic microorganisms have developed and caused serious nosocomial infections, especially Acinetobacter baumannii. In this study, we aim to look for new antimicrobial substances against drug resistance strains from Chinese herbal medicines. By using the disc diffusion method, 58 ethanol extracts of Chinese herbal medicines were screened for the antimicrobial activity against 78 clinical A. baumannii isolates. Among the 58 plant extracts, the extracts of Picarpium trichosanthis showed substantial higher broad antibacterial spectrum against the entire test organisms. The ethyl acetate (EA) fraction obtained from partition extraction revealed the antibacterial activity with MIC value at 1.9 mg/mL. The EA fraction ofP. trichosanthis could be a bactericide based on the killing curve. The chemical components of the extracts were analyzed by GC-MS; 4-hydroxybenzoic and isovanillic acid were evidenced to provide the antibacterial and antioxidant activity, respectively. Moreover, the results obtained from SEM observation showed that the active extract might inhibit the function of outer membrane of the organisms. Overall, the extracts of P. trichosanthis present antibacterial and antioxidant activity indeed have the valuable to be developed into the antibiotic medicines.

Key words: Chinese herbal medicines, Picarpium trichosanthis, antibacterial activity, antioxidant activity.