Saponins increase susceptibility of vancomycin-resistant enterococci to antibiotic compounds

Abstract

The resistance of commensal bacteria to first and second line antibiotics has reached an alarming level in many parts of the world and endangers the effective treatment of infectious diseases. In this study, the influence of the plant-derived natural saponins glycyrrhizic acid, β-aescin, α-hederin, hederacoside C, and primulic acid 1 on the susceptibility of vancomycin-resistant enterococci (VRE) against antibiotics of clinical relevance was investigated in 20 clinical isolates. Furthermore, the antibacterial properties of saponins under study against VRE were determined in vitro. Results reveal that the susceptibility of VRE against gentamicin, teicoplanin, and daptomycin was enhanced in the presence of the saponin glycyrrhizic acid. Most importantly, glycyrrhizic acid (1 mg/ml) diminished the minimal inhibitory concentration (MIC) of gentamicin in gentamicin low-level intrinsic resistant VRE from 2 ->8 mg/l to ≤ 0.125-1 mg/l. The adding of β-aescin, α-hederin, hederacoside C, and primulic acid 1 to the antibiotics under study showed, compared to glycyrrhizic acid, less influence on the antibiotic potency. Only glycyrrhizic acid (1 mg/ml) and α-hederin (0.2 mg/ml) showed weak antibacterial properties against the clinical isolates. Our study points towards a therapeutic potential of saponins in the coapplication with antibiotics for bacterial infections.

Antibacterial activity of Tribulus terrestris methanol extract against clinical isolates of Escherichia coli

“…The results of our experiment showed that gentamicin decreased the dose of T. terrestris, so it had a synergistic effects with gentamicin. The synergistic effects of saponins with amphotericin B, itraconazole [31], mancozeb [32], and vancomycin [33] were confirmed, while saponins had no synergistic effects with ampicillin, streptomycin and ciprofloxacin against clinical isolates [27]. The synergy between T. terrestris methanol extract and gentamicin were confirmed by two methods in this study and are reported for the first time.…”

Hainosan (painongsan) suppresses the biofilm formation of Porphyromonas gingivalis and Prevotella intermedia in vitro

“…On account of their antibacterial effects, saponins presumably serve the plants as defense against infection. A higher uptake of the antibiotic drugs into the bacterial cell might have been induced by the interaction of the saponins with the bacterial membrane and, hence, might have been responsible for the observed beneficial effects . Further investigation on how saponins contribute to the bacterial biofilm effect is needed.…”

GC-MS and NMR analysis of the bioactive compounds from the crude extracts of Waltheria indica and the histopathological changes induced in albino rats challenged with Naja nigricollis venom

“…Saponins are also known to have antibiotic activity and many anti-tumour drug preparations used for chemotherapeutic management of various types of cancer contain saponins in their chemical formulations [21][22][23][24][25]. Even more, previous reports exist on the claims of the use of W. indica for experiential treatment of snakebites [6].…”