Identification of antibacterial compounds from glycyrrhizae radix, borneo camphor, and coptidis Rhizoma towards Streptococcus pyogenes and Staphylococcus aureus

Abstract

Glycyrrhizae radix, borneo camphor, and coptidis rhizoma are dried plants that have been used as herbal medicine. Ethanol extracts of coptidis rhizoma, glycyrrhizae radix, and borneo camphor showed minimum inhibitory concentration (MIC) towards Staphylococcus aureus of 20, 20, and 40 mg/ml, respectively, with inhibitory zone diameter of 9.31 ± 2.88, 2.00 ± 1.33, and 3.33 ± 3.31 mm, respectively. MIC to Streptococcus pyogenes for these 3 extracts were similar, i.e 40 mg/ml with inhibitory zone diameter of 7.83 ± 4.38, 1.50 ± 2.87, and 3.07 ± 0.60 mm, respectively. Ethanol extracts from coptidis rhizoma had maximum inhibitory to S. pyogenes and S. aureus. According to its qualitative assays, they contained alkaloids and saponins. The ultraviolet spectra showed maximum absorption at λ 227 nm. The infrared spectrum also showed the existence of –OH, CH sp2, –C=C, C-C aryl, C-N, and C-X. Based on contrast orthogonal tests, combinations of ethanol extracts from coptidis rhizoma, glycyrrhizae radix, and borneo camphor (1:1:1) showed significant differences in inhibiting S. aureus growth, indicating that combinations of the three extracts showed no synergy properties in inhibiting S. aureus growth. Combinations of ethanol extracts from coptidis rhizoma, glycyrrhizae radix, and borneo camphor (1:1:1) did not show significant differences in inhibiting S. pyogenes growth, meaning that combinations of the three extracts showed synergy properties in inhibiting S. pyogenes growth.