Detection of Cellular Senescence in Human Primary Melanocytes and Malignant Melanoma Cells In Vitro.

Detection and quantification of senescent cells remain difficult due to variable phenotypes and the absence of highly specific and reliable biomarkers. It is therefore widely accepted to use a combination of multiple markers and cellular characteristics to define senescent cells in vitro. The exact choice of these markers is a subject of ongoing discussion and usually depends on objective reasons such as cell type and treatment conditions, as well as subjective considerations including feasibility and personal experience. This study aims to provide a comprehensive comparison of biomarkers and cellular characteristics used to detect senescence in melanocytic systems. Each marker was assessed in primary human melanocytes that overexpress mutant BRAFV600E, as it is commonly found in melanocytic nevi, and melanoma cells after treatment with the chemotherapeutic agent etoposide. The combined use of these two experimental settings is thought to allow profound conclusions on the choice of senescence biomarkers when working with melanocytic systems. Further, this study supports the development of standardized senescence detection and quantification by providing a comparative analysis that might also be helpful for other cell types and experimental conditions.

Quantification of co-, n-, and ad-lupulone in hop-based dietary supplements and phytopharmaceuticals and modulation of their contents by the extraction method.

Hop ß-bitter acids (lupulones) are health-beneficial components of Humulus lupulus L. showing, for example, antidepressant-like effects in vitro. Despite of the widespread use of hops for medicinal purposes, the concentrations of lupulones in hop-based drugs have not been reported yet. The present study developed, validated, and applied a method with external calibration, which allows for the first time separate quantification of co-, n-, and ad-lupulone in hop-based drugs by UHPLC‒DAD. Concentrations between 'not detectable' and 2.7 mg/mL co-lupulone, 2.2 mg/mL nlupulone, or 0.7 mg/mL ad-lupulone were measured in nine different commercial dietary supplements and phytopharmaceuticals. Only one hop tincture contained sufficient lupulone to possibly exert potential antidepressant effects. Aiming for products with increased lupulone content, the extraction efficiency of different solvents was investigated. Complete extraction of lupulones from raw hops was achieved by organic solvents including methanol and ethanol, whereas aqueous mixtures resulted in low recovery. These results indicate that adapted extraction conditions may result in more effective hops products.