Antibacterial Profile in vitro and in vivo of New 1,4-Naphthoquinones Tethered to 1,2,3-1H-Triazoles against the Planktonic Growth of Streptococcus mutans

The cariogenic processes are mainly caused by the bacterium Streptococcus mutans (S. mutans) and consist of the demineralization of the tooth that occurs when the acid production overcomes the natural repair or if a problem occurs in the last one. In this work, we performed the synthesis of twenty-one 1,4-naphthoquinones tethered to 1,2,3-1H-triazoles (8a-8k and 9a-9j), antibacterial evaluation against the S. mutans in vitro and the acute toxicity of the better ones in vivo. We observed strong inhibition results in the disc diffusion test ranging, the halos of inhibitions, from 18.66 (± 0.57) to 29 (± 2.64) mm, and good values in the minimum inhibitory concentration (5 to 50 μg), for the compounds 9e, 9h, 9i and 9j. Furthermore, they do not have a cytotoxic effect at the concentrations tested. Besides that, in the in vivo test, they show some slight alteration in the histopathological analyses and the biochemistry. Thus, we found four potential candidates to become instruments for the treatment of cavities.

Physicochemical and phytochemical standardization, and antibacterial evaluation of Cassia alata leaves from different locations in Indonesia

Physicochemical analysis for simplicia and extract, respectively: water content 2.12–4% for simplicia; drying losses 3.93–5.47% and 8.51–19.76%; total ash 5.14–9.41% and 6.22–17.07%; total ash acid-insoluble content 0.29–5.41% and 0.52–3.82%; total ash water-soluble content 1.26–7.14% and 1.43–8.54%; water-soluble content 19.60–39.43% and 58.45–77.51%; ethanol-soluble content 13.99–33.76% and 59.79–75.39%. The phytochemical analysis showed that the extracts contain alkaloids, flavonoids, saponins, tannins, and terpenoids. Total flavonoids and total phenolics content were 9.86–15.74% QE/g and 6.67–7.65% GAE/g, respectively. Based on LC-MS results, the extract contained emodin, kaempferol, kaempferol-3,7-diglucoside, and kaempferol-3-O-β-D-glucopyranoside. The extracts possessed antibacterial activity against bacteria tested.

Synthesis, Antibacterial Evaluation and in Silico Study of DOTA-fluoroquinolone Derivativessynthesis, Antibacterial Evaluation and in Silico Study of DOTA-fluoroquinolone Derivatives

A series of water-soluble fluoroquinolones based upon DOTA modification were synthesized and characterized by NMR and HRMS spectra. All the newly prepared quinolones compounds exhibited potent antimicrobial activities against MRSA, P. aeruginosa and E. coli. Molecular docking study indicated they could form stable complex with DNA gyrase and topoisomerase IV-DNA respectively, ADMET prediction showed they were low toxicity to the mice as whole. Among them, water-soluble quinolone 4c exhibited promising antibacterial potency, its MIC, MBC value for MRSA and P. aeruginosa was (1.56, 6.25) µg/mL, (3.1, 12.5) µg/mL respectively. Atomic Force Microscope (AFM) imaging revealed 4c could effectively destroy MRSA bacterial membrane and wall, causing its contents to leak out. Cytotoxicity assay showed 4c had low toxicity to L-02, A549 and MCF-7, over 80% cell viability even at 100 µmol/L. These results showed that water-soluble compound 4c was a promising antibacterial candidate.