Dry eye disease (DED) is a common chronic ocular surface disease. Available therapies are effective but often associated with side effects. This study investigates the potential of a Malva sylvestris L. flower extract and two defined preparations, a mucilage and a polyphenol rich fraction, on cells that are essential for the DED pathology. Furthermore, single compounds were isolated and characterised out of the polyphenol fraction. The M. sylvestris extract and its two fractions reduced reactive oxygen species (ROS) in an ultraviolet-induced model and promoted wound healing capacity of HCE-T cells, but only the polyphenol fraction and the flower extract exhibited significant radical scavenging activity. The flower extract and the polyphenol fraction inhibited cytokine secretion (IL-6, TNF-α, IL-8) from HCE-T cells and THP-1 cells. In contrast, the mucilage fraction led to an increase in mediator secretion. The NF-κB activity and calcium influx in THP-1 and Jurkat cells, respectively was decreased by treatment with the flower extract and the polyphenol fraction, whereas the mucilage fraction had no influence on these parameters. Moreover, the flower extract and the mucilage fraction at low concentration could stimulate meibomian gland cells' lipid accumulation. The isolated single compounds showed no effect on analysed parameters, except a coumarin derivative and malvin which showed ROS inhibition effects.

Lactic acid (LA) fermentation of dog’s mercury (M. perennis L.) herbal parts was investigated in samples inoculated with either Lactobacteria (Lactobacillus plantarum and Pediococcus pentosaceus, LBF) or whey (WF). Depending on fermentation time, LA concentrations were monitored in a range of 3.4–15.6 g/L with a concomitant pH decline from 6.5 to 3.9. A broad spectrum of cinnamic acids depsides containing glucaric, malic and 2-hydroxyglutaric acids along with quercetin and kaempferol glycosides were detected by LC-DAD-ESI-MSⁿ. Moreover, in this study novel constituents were also found both in unfermented and fermented extracts. Furthermore, amino acids and particular Lactobacteria metabolites such as biogenic amines (e.g., putrescine, 4-aminobutyric acid, cadaverine) and 5-oxoproline were assigned in WF extracts by GC-MS analysis after silylation. Enhanced NFκB and cytokine expression (IL-6, TNFα, IL-8 and IL-1β) was induced by all extracts, both non-fermented and fermented, in NFκB-THP-1 reporter cells, showing a concentration-dependent immunostimulatory effect. The WF extracts were tested for micronuclei formation in THP-1 cells and toxicity in luminescent bacteria (V. fischeri), whereby no mutagenic or toxic effects could be detected, which corroborates their safe use in pharmaceutical remedies.

Copper functions as a cofactor and antioxidants in a large number of enzymes that are important for cellular respiration and the nervous system. In the last century scholars have explored copper’s relationship with the immune system, with copper deficiency drastically upsetting the overall function of the immune system, as seen in symptoms such as increased susceptibility to pathogens, decreased proliferation of lymphocytes, and impaired function of both cytotoxic T lymphocytes and helper T cells. Among copper’s various forms, copper bis-glycinate (Cbg) has been used as an official EU-approved oral supplement to promote health. In this study, we observed the influence of Cbg on human epithelial cells (HCE-T cells) to determine its cytotoxicity, anti-reactive oxygen (ROS), and wound healing capabilities. We also evaluated Cbg’s anti-inflammatory immune cells like primary human mononuclear cells (PBMCs), monocytic THP-1, and Jurkat cells in the context of anti-inflammation. At all the investigated concentrations of Cbg (0.05–100 μg/mL), ther was no considerable impact detected on the epithelial cells. However, the proliferation rate of stimulated PBMCs was affected progressively (3–50 μg/mL). In CD4⁺ helper T cells, interleukin (IL)-17 and IL-2 cytokine levels were decreased in a dose-dependent manner, while interferon (IFN)-γ and IL-2 levels were slightly decreased with no noticeable changes between each treated concentration. Furthermore, stimulated monocytic THP-1 cells treated with Cbg reduced IL-6 and significantly reduced tumor necrosis factor (TNF)-α cytokines secretion. Lastly, stimulated Jurkat intracellular Ca²⁺ influx was significantly inhibited in a dose-dependent manner. Taken together, this study demonstrated that copper possesses modulatory effects on immune cells but not on epithelial cells, but further studies are needed to underline this hypothesis.