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The activities of the crude ethanol extract from Piper cubeba seeds, (-)-cubebin and its semi-synthetic derivatives were evaluated against oral pathogens. The crude ethanol extract was more active against Streptococcus salivarius (MIC value of 80 microg/mL). (-)-Cubebin displayed MIC values ranging from 0.20 mm for Streptococcus mitis to 0.35 mm for Enterococcus faecalis. The natural product (-)-cubebin and its semi-synthetic derivative (-)-hinokinin displayed bacteriostatic activity at all evaluated concentrations, as well as fungicidal activity against Candida albicans at 0.28 mm. The O-benzyl cubebin derivative showed fungistatic and fungicidal effects against C. albicans at 0.28 mm and 0.35 mm, respectively. Also, the other dibenzylbutyrolactone derivatives [(-)-6,6'-dinitrohinokinin and (-)-O-(N,N-dimethylaminoethyl)-cubebin] displayed bacteriostatic and fungistatic effects at the evaluated concentrations. Moreover, the semi-synthetic derivative (-)-6,6'-dinitrohinokinin was the most active compound against all the evaluated microorganisms. Therefore, it may be suggested that the presence of the carbonyl group at C-9 plus the introduction of polar groups in the aromatic rings improve the antimicrobial activity of dibenzylbutyrolactone compounds.

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Copper-carbene [Tp(x)Cu=C(Ph)(CO2Et)] and copper-diazo adducts [Tp(x)Cu{η(1)-N2C(Ph)(CO2Et)}] have been detected and characterized in the context of the catalytic functionalization of O-H bonds through carbene insertion by using N2=C(Ph)(CO2Et) as the carbene source. These are the first examples of these type of complexes in which the copper center bears a tridentate ligand and displays a tetrahedral geometry. The relevance of these complexes in the catalytic cycle has been assessed by NMR spectroscopy, and kinetic studies have demonstrated that the N-bound diazo adduct is a dormant species and is not en route to the formation of the copper-carbene intermediate.

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The neurotransmitter transporters of the SLC6 family play critical roles in the regulation of neurotransmission and are the primary targets of therapeutic agents used to treat clinical disorders involving compromised neurotransmitter signaling. The dopamine and norepinephrine transporters have been implicated in clinical disorders such as attention deficit hyperactivity disorder (ADHD) and substance abuse. The GABA transporters (GATs) serve as a target for anxiolytic, antidepressant, and antiepileptic therapies. In this work, the interaction with neurotransmitter transporters was characterized for a derivative of the lignan (-)-cubebin (1), namely, (-)-hinokinin (2). Using in vitro pharmacological assays, 2 selectively inhibited the human dopamine and norepinephrine transporters, in a noncompetitive manner possibly mediated by binding to a novel site within the transporters, and displayed low affinity for the serotonin transporter. Compound 2 also specifically inhibited the GAT-1 GABA transporter subtype. Compound 2 is not a substrate of the carriers as it had no effect on the efflux of either of the neurotransmitters investigated. This compound is inactive toward glutamate and glycine transporters. These results suggest that 2 may serve as a tool to develop new therapeutic drugs for ADHD and anxiety that target the DAT, NET, and GAT-1 transporters.