Silke Meier's research while affiliated with Goethe-Universität Frankfurt am Main and other places

... Appropriate amount of umbelliferone, nodakenin, psoralen, xanthotoxin and bergapten was weighted precisely and dissolved with methanol to obtain stock standard solution with the concentration of 42.0000, 41.0000, 41.0000, 86.0000 and 56.0000 μg·mL −1 , respectively. The standard solution above was stored at 4 • C. Standard solution was precisely absorbed and dissolved with methanol (finally adjusted volume 5 mL) to obtain the mixed standard solution with concentration of umbelliferone (0.0672, 1.3440, 6.7200, 16.8000 and 42.000 μg·mL −1 ), nodakenin (0.0656, 1.3120, 6.5600, 16.4000 and 41.0000 μg·mL −1 ), psoralen (0.0656, 1.3120, 6.5600, 16.4000 and 41.0000 μg·mL −1 ), xanthotoxin (0.1376, 2.7520, 13.7600, 34.4000 and 86.0000 μg·mL −1 ), bergapten (0.0896, 1.7920, 8.9600, 22.4000 and 56.0000 μg·mL −1 ). The solution was shaken well and filtered through a 0.45 μm membrane filter before UPLC analysis. ...

... Opioid agonists exert their antinociceptive actions through the activation of opioid receptors, particularly µ-opioid receptors (MORs), both peripherally and centrally (spinal and supraspinal MOR activation) [2]. Although the site of action of clinically available analgesics is considered to be central, MOR-mediated peripheral analgesia has also been identified in human and experimental pain models [3][4][5][6][7][8][9][10]. The current consensus is that opioid agonists are the most effective analgesics for treating mild to severe acute and chronic pain types, yet in the case of neuropathic pain, their effect is up for debate [11][12][13]. ...

... Under our experimental conditions, however, the expression of CYP1A1 and CYP1A2 mRNAs and CYP1A2 protein was significantly increased at 5 μM xanthotoxin (Fig. 2), albeit CYP1A1 protein expression was elevated only at 10 μM of xanthotoxin after 72 h treatment. On the other hand, when this compound was orally administered in human (1 mg/kg body weight), the plasma concentration of xanthotoxin was shown to be the highest after 2 h while the concentration was approximately 1.6 ng/mL (Brautigam et al. 2003). Although it is difficult to extrapolate such effects to metabolic outcomes because of the inherent limitations of in vitro experiments, it is important to note that dietary exposure to O. javanica may modulate phase I enzymes and thereby affect various xenobiotic metabolism. ...