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Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis plays an important part in the development of depressive symptoms. In this study, the effects of a commercial St. Johnʼs wort extract (STW3-VI), hyperforin, miquelianin, and the selective serotonin reuptake inhibitor citalopram on the expression of genes relevant to HPA axis function were investigated in human neuronal cells. SH-SY5Y cells were treated with STW3-VI (20 µg/mL), hyperforin (1 µM), miquelianin (10 µM), or citalopram (10 µM) in the presence of the glucocorticoid receptor agonist dexamethasone (DEX,10 µM) for 6 h and 48 h, respectively. Quantitative real-time polymerase chain reaction was used to determine the expression of FKBP5 (FK506 binding protein 51), CREB (cAMP responsive element binding protein), GRIK4 (glutamate ionotropic receptor kainate type subunit 4), VEGF (vascular endothelial growth factor), NET (norepinephrine transporter), and ARRB (β-arrestins), promising biomarkers of antidepressant therapy. Using DEX to mimic stress conditions, it was shown that the gene expression pattern of FKBP5, CREB, GRIK4, VEGF, NET, and ARRB2 in SH-SY5Y cells is time- and treatment-dependent. Most pronounced effects were observed for FKBP5: after 6 h of co-incubation, only STW3-VI could reverse the DEX-induced increase in FKBP5 expression, and after 48 h, citalopram, miquelianin, and hyperforin also reversed the glucocorticoid-induced increase in FKBP5 mRNA expression. The effects observed on FKBP5, CREB, GRIK4, VEGF, NET, and ARRB2 are in good correlation with published data, suggesting that this in vitro model could be used to screen the responsiveness of antidepressants under stress conditions.

Hypericin is a natural polycyclic quinone found in Hypericum perforatum. Although hypericin reportedly has numerous pharmacological activities, only a limited number of studies have been performed on the absorption and transport characteristics of this compound, presumably because hypericin is a highly lipophilic compound that is poorly soluble in a physiological medium. The major aim of this study was to get a detailed understanding of the exposure and fate of hypericin in the Caco-2 cell system under different experimental conditions. The permeation characteristics of hypericin (5 µM) in the absence or presence of the model flavonoid quercitrin (20 µM) were studied in the absorptive direction, without or with the addition of 10 % FBS to the transport buffer apically. Following the application of hypericin to the apical side of the monolayer, only negligible amounts of the compound were found in the basolateral compartment when the experiment was performed with a transport buffer. The amount of hypericin in the basolateral compartment increased in the presence of quercitrin (from 0 to 4 %). The majority of hypericin was found after cell extraction (44 % in the absence and 64 % in the presence of quercitrin). When 10 % FBS was added to the transport buffer in the apical compartment to improve the solubility of hypericin in the aqueous solution, around 68 % of hypericin was bound to the serum proteins. Under these experimental conditions, the amount of hypericin in the cells/cell membrane was only 13 % in the absence and 18 % in the presence of quercitrin. The low recovery and significant amounts of hypericin found after cell extraction and bound to the surface of the culture dish made a correct estimation of permeability constants impossible. Fluorescence microscopy and imaging analysis revealed that hypericin is mainly accumulated in the cell membrane. The precise mechanism through which hypericin might overcome the hydrophobic barrier of cell membranes remains to be elucidated. However, our experiments demonstrated that regardless of the experimental conditions, the permeation characteristics of hypericin improved in the presence of the model flavonoid quercitrin.

During saffron (Crocus sativus) spice production, large amounts of floral biowaste are generated. It was the aim of this study to develop a value-added product from saffron floral biowaste to be used as a natural cosmetic ingredient. HPLC-PDA-MS analysis of saffron flower extracts revealed the presence of flavonols with the highest amounts in the acetone extract. Kaempferol-3-O-sophoroside was identified as the main flavonoid in the acetone extract (saffron flower acetone extract). Saffron flower acetone extract and kaempferol-3-O-sophoroside were tested in HaCaT cells for potential effects on cell migration, proliferation, and for anti-inflammatory properties. Saffron flower acetone extract concentration dependently (50–200 µg/mL) augmented cell proliferation, as indicated by an increased BrdU-incorporation, while kaempferol-3-O-sophoroside (1–50 µM) had no effect. Furthermore, treatment of HaCaT cells with saffron flower acetone extract, but not with kaempferol-3-O-sophoroside, concentration-dependently increased vascular endothelial growth factor secretion (control 49.72 pg/mL vs. saffron flower acetone extract at 200 µg/mL 218.60 pg/mL). Cell migration was determined using time-lapse microscopy and a modification of the scratch-wound assay in which saffron flower acetone extract significantly improved wound closure compared to the untreated control. Overproduction of the proinflammatory cytokines interleukin-8 and interleukin-6 in HaCaT cells was induced by TNF-α. Kaempferol-3-O-sophoroside (10–50 µM), but not saffron flower acetone extract, inhibited TNF-α-induced IL-8 secretion. The effect was comparable to 10 µM hydrocortisone (positive control). Interestingly, saffron flower acetone extract further increased IL-6 levels in TNF-α-treated HaCaT cells in a concentration-dependent manner. In summary, the pronounced wound healing properties of saffron flower acetone extract present a promising application for the cosmetic industry.