In recent years, consumers have developed an ever-increasing interest in natural products as alternatives for artificial additives or pharmacologically relevant agents. Among them, essential oils have gained great popularity in the food, cosmetic, as well as the pharmaceutical industries. Constituting an array of many lipophilic and highly volatile components derived from a great range of different chemical classes, essential oils are known to be susceptible to conversion and degradation reactions. Oxidative and polymerization processes may result in a loss of quality and pharmacological properties. Despite their relevance for consumers, there is a paucity of information available addressing this issue. Therefore, the present review provides a comprehensive summary on possible changes in essential oils and factors affecting their stability. Focusing on individual essential oils, the various paths of degradation upon exposure to extrinsic parameters are outlined. Especially temperature, light, and oxygen availability are recognized to have a crucial impact on essential oil integrity. Finally, analytical methods to assess both genuine as well as altered essential oil profiles are evaluated with respect to their suitability to track chemical alterations. It is believed that only a careful inspection of essential oils by a set of convenient methods allows profound quality assessment that is relevant to producers and consumers alike.

No abstract

A high-performance liquid chromatography (HPLC) method was established using an analytical reversed-phase column and gradient elution to achieve chromatographic separation of typical compounds in essential oils. For detection, a diode array detector monitoring different wavelengths simultaneously as well as a mass spectrometer (MS) were used. Atmospheric pressure chemical ionization operating in the positive mode turned out to be a suitable tool to detect volatiles of different chemical classes and to identify them in essential oil matrices. Characteristic fingerprints of eucalyptus, lavender, may chang, pine, rosemary, thyme, and turpentine essential oils monitored at a representative wavelength (220 nm) demonstrated the suitability of HPLC in essential oil analysis. Additional monitoring wavelengths (210, 250, and 280 nm) provided useful information about the identity of the specific component and opened the possibility to differentiate presumably coeluting compounds by means of their distinct absorption behavior. Finally, peak assignment in seven essential oils was performed on the basis of characteristic retention times and UV and MS data of a broad set of reference volatiles.

This study evaluates a set of analytical parameters to track changes during essential oil storage. On this basis, quality alterations can be monitored.

No abstract

Background The therapeutic use of Helleborus niger L. is manifold due to its specific phytochemical composition. Two compound groups, the ranunculin derivates including protoanemonin and the steroidal saponins, are also associated with toxicity (genotoxicity, disintegration of membrane structures). Therefore, in vitro investigations were performed on safety aspects of a Helleborus niger aqueous fermented extract ( HNE ). In addition its therapeutic potential against various cancer cell lines was assessed to gain insight into the respective mechanisms of action. Methods To evaluate the safe use of HNE , Ames and hemolytic tests were carried out. Two angiogenesis assays in 2D and 3D design were conducted to assess the anti-angiogenetic potential, for which human umbilical vein endothelial cells (HUVEC) were chosen. A panel of tumor cell lines was used in 2D and 3D proliferation assays as well in the migration- and invasion-assay. All investigations were performed with HNE compared to reference substances. The 2D proliferation assay was additionally performed with isolated compounds of HNE (characteristic steroidal saponins). Results HNE did not exhibit any genotoxic potential. Concentrations up to 10 μl/ml were classified as non-hemolytic. HNE exerted anti-angiogenetic effects in HUVEC and anti-proliferative effects in five cancer cell lines, whereas hellebosaponin A and D as well macranthosid I did not show comparable effects neither singly nor in combination. Due to the inherent instability of protoanemonin in isolated form, parallel investigations with protoanemonin could not be performed. HNE (600–1000 μg/ml) inhibited the migration of certain cancer cells by > 80% such as Caki-2, DLD-1 and SK-N-SH. Conclusion HNE exhibit neither genotoxic nor hemolytic potential. The present investigations verify the anti-angiogenetic effects on HUVEC, the anti-proliferative effects and migration-inhibiting properties on tumor cells. The lower effect of the relevant steroidal saponins compared to the whole extract underlines the fact that the latter is more effective than a blend of isolated pharmacologically active components. Electronic supplementary material The online version of this article (10.1186/s12906-019-2517-5) contains supplementary material, which is available to authorized users.

No abstract

ZusammenfassungDie Wundheilung ist ein komplexer Prozess, der durch eine auf den jeweiligen Wundzustand abgestimmte Versorgung unterstützt werden kann. Der Artikel betrachtet bekannte (Arnika, Johanniskraut, Ringelblume/Calendula), aber auch in Vergessenheit geratene Heilpflanzen (Beinwell, Brennnessel, Deutsche Schwertlilie, Lebensbaum/Thuja, Waldbingelkraut, Wundklee) im Hinblick auf ihr wundheilungsförderndes und antimikrobielles Potenzial bei topischer Anwendung. Auf Grundlage aktueller Literaturdaten aus In-vitro- und In-vivo-Untersuchungen sowie klinischen Studien werden die Pflanzen und ihre Wirkmechanismen den Wundheilungsphasen zugeordnet. Besonderes Augenmerk wird zudem auf die Vorteile der Kombination von Heilpflanzen gelegt, um ein breiteres Wirkspektrum über verschiedene Phasen der Wundheilung hinweg zu erhalten und eine umfassende Unterstützung dieser anzustreben.