Osteoporosis is a public health concern associated with an increased risk of bone fractures and vascular calcification. Vitamin K presents unique benefits on these issues, although understudied. The two main forms of vitamin K are phylloquinone (vitamin K) and menaquinone (vitamin K). In this study, it was especially investigated the action of vitamin K in bones and vessels. Vitamin K has shown to stimulate bone formation by promoting osteoblast differentiation and carboxylation of osteocalcin, and increasing alkaline phosphatase, insulin-like growth factor-1, growth differentiation factor-15, and stanniocalcin 2 levels. Furthermore, vitamin K reduces the pro-apoptotic proteins Fas and Bax in osteoblasts, and decreases osteoclast differentiation by increasing osteoprotegerin and reducing the receptor activator of nuclear factor kappa-B ligand. In blood vessels, vitamin K reduces the formation of hydroxyapatite, through the carboxylation of matrix Gla protein and Gla rich protein, inhibits the apoptosis of vascular smooth muscle cells, by increasing growth arrest-specific gene 6, and reduces the transdifferentiation of vascular smooth muscle cells to osteoblasts. The commonly used dosage of vitamin K in human studies is 45 mg/day and its application can be an interesting strategy in benefitting bone and vascular health, especially to osteoporotic post-menopausal women.

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This review article describes the use of some of the most popular chiral auxiliaries in the asymmetric synthesis of biologically active compounds. Chiral auxiliaries derived from naturally occurring compounds, such as amino acids, carbohydrates, and terpenes, are considered essential tools for the construction of highly complex molecules. We highlight the auxiliaries of Evans, Corey, Yamada, Enders, Oppolzer, and Kunz, which led to remarkable progress in asymmetric synthesis in the last decades and continue to bring advances until the present day.

One manner in which plant-derived compounds exert their antibiotic potential is the synergism, a positive interaction between two compounds. Studies indicate that the use of plant extracts combined with antimicrobials may promote a significant reduction of the minimum inhibitory concentrations of antibiotics for bacterial strains. this study aimed to evaluate the activity of plant extracts and antibiotics as well as their combination on Staphylococcus aureus. the activity of 15 plant extracts was evaluated using diffusion assay. The minimum inhibitory concentrations (MICs) and the interactions between the extracts and antibiotics as well as compound emodin were evaluated with the checkerboard method. the active extracts were a hexane extract of the leaves of Baccharis dracunculifolia and the ethanol extracts of the leaves of Plectranthus ornatus, Inga edulis, Salvia officinalis and Senna macranthera. the Plectranthus ornatus extract displayed synergism with ampicillin (a β-lactam), kanamycin and gentamicin (aminoglycosides), with 8-fold reductions in the MIC. the same reduction was observed for the extracts of Salvia officinalis and Senna macranthera, which displayed the lowest MIC. Using these combinations resulted in a reduction in the minimum dose required for effective antimicrobial effects, which is interesting because it may decrease both the risk of side effects and the costs of treatment.

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