Fabrication of Co-Assembly from Berberine and Tannic Acid for Multidrug-Resistant Bacteria Infection Treatment

Long-term antibiotic use induces drug resistance in bacteria. This has given rise to the challenge of refractory infections, which have become a global health threat. Berberine (BBR) and tannic acid (TA) from plants exhibit promising antibacterial activities and may overcome antibiotic resistance. However, poor solubility and/or low penetration capability have limited their application. Carrier-free co-assembled nanocomposites composed entirely of BBR and TA exhibit improved or new properties and produce improved efficacy. Herein, we demonstrated that an ordered nanostructure could be spontaneously co-assembled by the solvent evaporation method using the two natural products. These co-assembled berberine-tannic acid nanoparticles (BBR-TA NPs) exhibited the best antibacterial effect compared with the corresponding physical mixture, pristine BBR, and some first-line antibiotics (benzylpenicillin potassium-BP and ciprofloxacin-Cip) against Staphylococcus aureus (S. aureus) and multidrug-resistant Staphylococcus aureus (MRSA). Even if the concentration of BBR-TA NPs was as low as 15.63 μg/mL, the antibacterial rate against S. aureus and MRSA was more than 80%. In addition to the synergistic effect of the two compounds, the antibacterial mechanism underlying the nanostructures was that they strongly adhered to the surface of the bacterial cell wall, thereby inducing cell membrane damage and intracellular ATP leakage. Furthermore, the in vivo wound healing effect of BBR-TA NPs was verified using an MRSA wound infection mouse model. The BBR-TA NPs achieved the best efficacy compared with BP and Cip. Moreover, cytotoxic and histopathological evaluations of mice revealed that the nanodrug had good biological safety. This facile and green co-assembly strategy for preparing nanoparticles provides a feasible reference for the clinical treatment of bacterial infection.

Antibacterial effects of biologically active ingredients in hop provide promising options to fight infections by pathogens including multi-drug resistant bacteria

Antibiotic resistance constitutes a global threat to the health care systems. The number of infections due to multidrug-resistant (MDR) bacteria increases progressively resulting in an estimated annual number of 750,000 fatal cases worldwide. Additionally, the lack of novel antibiotic compounds worsens the dilemma. Hence, there is an urgent need for alternative ways to fight antibiotic resistance. One option may be natural compounds with antibacterial properties such as hop and its biologically active ingredients which are used in traditional medicine since ancient times. This prompted us to perform an actual literature survey regarding the antibacterial properties of biologically active ingredients in hop including humulone, lupulone and xanthohumol. The 20 included studies revealed that lupulone and xanthohumol do in fact inhibit the growth of Gram-positive bacteria in vitro. In combination with distinct antibiotic compounds the hop ingredients can even exert synergistic effects resulting in enhanced antibiotic activities against defined Gram-positive and Gram-negative bacteria. In conclusion, biologically active ingredients in hop including lupulone and xanthohumol may be potential antibiotic compounds which either alone or in combination with other antibacterial substances open novel avenues in the combat of infections caused by pathogenic including MDR bacteria.

HPLC-PDA-ESI-MS/MS Profiling and Anti-Biofilm Potential of Eucalyptussideroxylon Flowers

The development of multidrug-resistant bacterial strains is a worldwide emerging problem that needs a global solution. Exploring new natural antibiofilm agents is one of the most important alternative therapies in combating bacterial infections. This study aimed at testing the antimicrobial potential of Eucalyptus sideroxylon flowers extract (ESFE) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans prior to testing the antibiofilm activity against S. aureus, P. aeruginosa and C. albicans. ESFE demonstrated antimicrobial activity and promising inhibition activity against methicillin-resistant S. aureus (MRSA) biofilm formation up to 95.9% (p < 0.05) at a concentration of 0.05 mg/mL and eradicated C. albicans biofilm formation up to 71.2% (p < 0.05) at a concentration of 0.7 mg/mL. LC-MS analysis allowed the tentative identification of eighty-three secondary metabolites: 21 phloroglucinol, 18 terpenes, 16 flavonoids, 7 oleuropeic acid derivatives, 7 ellagic acid derivatives, 6 gallic acid derivatives, 3 phenolic acids, 3 fatty acids and 2 miscellaneous. In conclusion, E. sideroxylon is a rich source of effective constituents that promote its valorization as a promising candidate in the management of multidrug-resistant bacterial infections.