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ABSTRACT Edwardsiella ictaluri and Flavobacterium covae are two bacteria species that cause diseases in farm‐raised channel catfish (Ictalurus punctatus) that cause heavy economic damage to the aquaculture industry, particularly to the channel catfish farming. In search for environmentally benign antibacterial compounds active against E. ictaluri and F. covae, we investigated the constituents isolated from Brazilian red, brown and green propolis. We have also synthetically modified active constituents to see if lipophilicity plays a role in enhancing antibacterial activities. Vestitol, neovestitol and methylvestitol were found to be the active constituents with minimum inhibitory concentration (MIC) relative to drug control florfenicol (RDCF) values (MIC−RDCF) of 7.6, 7.6 and 7.9 mg/L, respectively, against F. covae. The activity against E. ictaluri was not significant. [ABSTRACT FROM AUTHOR]

Artepillin C, drupanin, and plicatin B are prenylated phenylpropanoids that naturally occur in Brazilian green propolis. In this study, these compounds and eleven of their derivatives were synthesized and evaluated for their in vitro antimicrobial activity against a representative panel of oral bacteria in terms of their minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Plicatin B (2) and its hydrogenated derivative 8 (2′,3′,7,8-tetrahydro-plicatin B) were the most active compounds. Plicatin B (2) displayed strong activity against all the bacteria tested, with an MIC of 31.2 μg/mL against Streptococcus mutans, S. sanguinis, and S. mitis. On the other hand, compound 8 displayed strong activity against S. mutans, S. salivarius, S. sobrinus, Lactobacillus paracasei (MIC = 62.5 μg/mL), and S. mitis (MIC = 31.2 μg/mL), as well as moderate activity against Enterococcus faecalis and S. sanguinis (MIC = 125 μg/mL). Compounds 2 and 8 displayed bactericidal effects (MBC: MIC ≤ 4) against all the tested bacteria. In silico studies showed that the complexes formed by compounds 2 and 8 with the S. mitis, S. sanguinis, and S. mutans targets (3LE0, 4N82, and 3AIC, respectively) had energy score values similar to those of the native S. mitis, S. sanguinis, and S. mutans ligands due to the formation of strong hydrogen bonds. Moreover, all the estimated physicochemical parameters satisfied the drug-likeness criteria without violating the Lipinski, Veber, and Egan rules, so these compounds are not expected to cause problems with oral bioavailability and pharmacokinetics. Compounds 2 and 8 also had suitable ADMET parameters, as the online server pkCSM calculates. These results make compounds 2 and 8 good candidates as antibacterial agents against oral bacteria. [ABSTRACT FROM AUTHOR]

Helicobacter pylori is associated with gastrointestinal diseases, and its treatment is challenging due to antibiotic-resistant strains, necessitating alternative therapies. Brazilian red propolis (BRP), known for its diverse bioactive compounds with pharmaceutical properties, was investigated for its anti-H. pylori activity, focusing on biofilm formation inhibition and eradication. BRP was tested against H. pylori (ATCC 43526) using several assays: time–kill, nucleotide leakage, biofilm formation inhibition (determining the minimum inhibitory concentration of biofilm of 50%—MICB50, and cell viability), and biofilm eradication (determining the minimum eradication concentration of biofilm of 99.9%—MBEC). Standardization of H. pylori biofilm formation was also conducted. In the time–kill assay, BRP at 50 µg/mL eliminated all H. pylori cells after 24 h. The nucleotide leakage assay showed no significant differences between control groups and BRP-treated groups at 25 µg/mL and 50 µg/mL. H. pylori formed biofilms in vitro at 109 CFU/mL after 72 h. The MICB50 of BRP was 15.6 µg/mL, and at 500, 1000, and 2000 µg/mL, BRP eradicated all bacterial cells. The MBEC was 2000 µg/mL. These findings suggest that BRP has promising anti-H. pylori activity, effectively inhibiting and eradicating biofilms. Further studies are necessary to elucidate BRP's mechanisms of action against H. pylori. [ABSTRACT FROM AUTHOR]

TheCopaifera oleoresins are widely used in folk medicine to treat various diseases. The goal of this study was to develop a validated reverse-phase high-performance liquid chromatography method with photodiode array detection (RP-HPLC-PDA) to quantify eight terpenes: ent-hardwickiic acid, ent-copalic acid, ent-7α-acetoxy hardwickiic acid, ent-16-hydroxy-3,13-clerodadiene-15,18-dioic acid, ent-5,13-labdadiene-15-oic acid, junenol, ent-kaurenoic acid, and 13E-ent-labda-7,13-dien-15-oic acid in the oleoresins of Copaifera pubiflora L. (OCP), Copaifera trapezifolia L. (OCT) and Copaifera langsdorffii L. (OCL). The linearity of the method was confirmed in the range of 20.00–500 µg.mL−1 (r2 > 0.999). The limit of quantification was between 1,05 and 16.89 µg.mL−1. Precision and accuracy ranges were found to be %RSD <0.2 and 96% to 110%, respectively. Based on the obtained results, the developed analytical method is rapid, precise, accurate, and sensitive for quantifying these terpenes in Copaifera's oleoresins. [ABSTRACT FROM AUTHOR]

Lignan dinitrohinokinin displays important biological activities, which led to the preparation of its poly-ε-caprolactone nanoparticles. Kinetics analysis revealed initially slow drug release followed by a prolonged, moderate release 6 h later due to DNHK diffusion through the polymeric matrix. Molecular dynamics simulations show that DNHK molecules that interact stronger with other DNHK molecules near the PCL/DNHK surface are more difficult to dissociate from the nanoparticle. The smaller diameter nanocapsules with negative surface charge conferred good colloidal stability. The formulations showed a size distribution with monodisperse systems formation. In vivo evaluation of schistosomicidal activity against Schistosoma mansoni showed that DNHK, when incorporated into nanoparticles, caused egg number reduction of 4.2% and 28.1% at 40 mg/kg and 94.2% and 84.4% at 400 mg/kg in the liver and the spleen, respectively. The PCL nanoparticles were stable in aqueous dispersion and could be optimized to be used as a promising lignan release agent. [ABSTRACT FROM AUTHOR]