A desirable attribute of novel antimicrobial agents for bacterial diarrhea is decreased toxicity toward host intestinal microbiota. In addition, gut dysbiosis is associated with an increased risk of developing intestinal cancer. In this study, the selective growth-inhibitory activities of ten phytochemicals and their synthetic analogs (berberine, bismuth subsalicylate, ferron, 8-hydroxyquinoline, chloroxine, nitroxoline, salicylic acid, sanguinarine, tannic acid, and zinc pyrithione), as well as those of six commercial antibiotics (ceftriaxone, ciprofloxacin, chloramphenicol, metronidazole, tetracycline, and vancomycin) against 21 intestinal pathogenic/probiotic (e.g., Salmonella spp. and bifidobacteria) bacterial strains and three intestinal cancer/normal (Caco-2, HT29, and FHs 74 Int) cell lines were examined in vitro using the broth microdilution method and thiazolyl blue tetrazolium bromide assay. Chloroxine, ciprofloxacin, nitroxoline, tetracycline, and zinc pyrithione exhibited the most potent selective growth-inhibitory activity against pathogens, whereas 8-hydroxyquinoline, chloroxine, nitroxoline, sanguinarine, and zinc pyrithione exhibited the highest cytotoxic activity against cancer cells. None of the tested antibiotics were cytotoxic to normal cells, whereas 8-hydroxyquinoline and sanguinarine exhibited selective antiproliferative activity against cancer cells. These findings indicate that 8-hydroxyquinoline alkaloids and metal-pyridine derivative complexes are chemical structures derived from plants with potential bioactive properties in terms of selective antibacterial and anticancer activities against diarrheagenic bacteria and intestinal cancer cells.

Essential oils isolated from six Philippine plant species, namely Alpinia brevilabris C. Presl, Alpinia cumingii K. Schum., Alpinia elegans (C. Presl) K. Schum., Callicarpa micrantha Vidal, Cinnamomum mercadoi S. Vidal, and Piper quinqueangulatum Miq. were assessed for their in vitro growth-inhibitory effect against pneumonia causing bacteria (Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus) using the broth microdilution volatilization method. Additionally, a modified thiazolyl blue tetrazolium bromide assay was performed for evaluation of their cytotoxic activity to human lung cells. All essential oils exhibited some antibacterial efficacy in liquid phase; however, only A. cumingii oil was active in the vapour as well. Both A. cumingii and A. elegans oils showed the most effective antibacterial potential against H. influenzae in liquid medium with the minimum inhibitory concentration of 256 μg/mL. Using dual-column/dual-detector system GC/MS analysis, hedycaryol, β-pinene, caryophyllene epoxide, aristolochene, borneol, and linalool were identified as the major components of A. brevilabris, A. cumingii, A. elegans, C. micrantha, C. mercadoi, and P. quinqueangulatum leaves oils, respectively.

Diarrhoea remains an important public health concern, particularly in developing countries, and has become difficult to treat because of antibacterial resistance. The development of synergistic antimicrobial agents appears to be a promising alternative treatment against diarrhoeic infections. In this study, the combined effect of tetracycline together with either nitroxoline, sanguinarine, or zinc pyrithione (representing various classes of plant-based compounds) was evaluated in vitro against selected diarrhoeic bacteria (Enterococcus faecalis, Escherichia coli, Listeria monocytogenes, Shigella flexneri, Vibrio parahaemolyticus, and Yersinia enterocolitica). The chequerboard method in 96-well microtiter plates was used to determine the sum of the fractional inhibitory concentration indices (FICIs). Three independent experiments were performed per combination, each in triplicate. It was observed that the combination of tetracycline with either nitroxoline, sanguinarine, or zinc pyrithione produced synergistic effects against most of the pathogenic bacteria tested, with FICI values ranging from 0.086 to 0.5. Tetracycline–nitroxoline combinations produced the greatest synergistic action against S. flexneri at a FICI value of 0.086. The combinations of the agents tested in this study can thus be used for the development of new anti-diarrhoeic medications. However, studies focusing on their in vivo anti-diarrhoeic activity and safety are required before any consideration for utilization in human medicine.

Local markets are still an integral part of the food system in developing economies of tropical regions including Samoa. This small South Pacific country is largely dependent on the production of crops in village agriculture, where traditional markets play an important role in sustainability of food supply. Similarly as many small island developing economies, Samoa is currently facing several challenges such as food security and high dependence on food imports. Therefore, we decided to monitor the diversity of plant foods on Samoan local markets and their economic and geographic indicators through interviews with the vendors. Our results suggest that assortment and economical value of plant food products have potential to increase sustainable food security of the local population and support economic growth of the region. For example, underutilized crops available at local markets are prospective species for development of new food products with beneficial nutritional and health properties. Moreover, certain commodities (e.g., papaya, kava and Samoan cocoa) seem to be promising for export. In addition, our findings suggest that development of appropriate processing technologies and the optimization of the logistics of crop products sold at local markets can contribute to an increase in efficiency of the regional agricultural sector.

Musculoskeletal infections (MIs) are among the most difficult-to-treat staphylococcal diseases due to antibiotic resistance. This has encouraged the development of innovative strategies, such as combination therapy, to combat MI. The aim of this study was to investigate the in vitro antistaphylococcal activity of anti-inflammatory drugs and the combined antimicrobial effect of celecoxib and oxacillin. The minimum inhibitory concentrations (MICs) of 17 anti-inflammatory drugs against standard strains and clinical isolates of S. aureus, including methicillin-resistant strains (MRSAs), were determined using the broth microdilution method. The fractional inhibitory concentration indices (FICIs) were evaluated using checkerboard assays. Celecoxib produced the most potent antistaphylococcal effect against all tested strains (MICs ranging from 32 to 64 mg/L), followed by that of diacerein against MRSA3 and MRSA ATCC 33592 (MIC 64 mg/L). Several synergistic effects were observed against the tested S. aureus strains, including MRSA (FICI ranging from 0.087 to 0.471). The strongest synergistic interaction (FICI 0.087) was against MRSA ATCC 33592 at a celecoxib concentration of 2 mg/L, with a 19-fold oxacillin MIC reduction (from 512 to 26.888 mg/L). This is the first report on the combined antistaphylococcal effect of celecoxib and oxacillin. These findings suggest celecoxib and its combination with oxacillin as perspective agents for research focused on the development of novel therapies for MI caused by S. aureus. This study further indicates that celecoxib could resensitize certain MRSA strains, in some cases, to be susceptible to β-lactams (e.g., oxacillin) that were not previously tested. It is essential to mention that the in vitro concentrations of anti-inflammatory drugs are higher than those typically obtained in patients. Therefore, an alternative option for its administration could be the use of a drug delivery system for the controlled slow release from an implant at the infection site.