Ikarisoside A inhibits acetylcholine-induced catecholamine secretion and synthesis by suppressing nicotinic acetylcholine receptor-ion channels in cultured bovine adrenal medullary cells

Comparative analysis of chemical components in different parts of Epimedium Herb

Epimedium herb is a well-known traditional Chinese medicine (TCM) that is used for treating kidney-yang deficiency, impotence and rheumatism, and flavonoids are the main active ingredients. The leaves and rhizomes of Epimedium herb are two separate kinds of medicinal materials with different functional indications and clinical applications. This study aimed to comprehensively analyze the chemical components of different parts of the herb from three Epimedium species (Epimedium sagittatum, E. pubescens and E. myrianthum) by using ultra high-performance liquid chromatography coupled with photo-diode array and quadrupole time-of-flight mass spectrometry (UHPLC-PDA-Q-TOF/MS) and multivariate statistical analysis to clarify the differences. Firstly, the workflow of UHPLC-Q-TOF/MS combined with UNIFI informatics was developed for characterizing the chemical compounds in different parts of Epimedium herb. Based on the exact mass information, the fragmentation characteristics and the retention times of compounds, all chromatographic peaks (74 chemical components) were identified. Secondly, 21 potential chemical markers for differentiating different parts of Epimedium herb were selected through PCA and PLS-DA analysis. The characteristic components in the leaves included flavonoids with Anhydroicaritin (type A, C-4' linked methoxy) as the backbone, and the characteristic components in the stems and rhizomes were Magnoline and flavonoids with Demethylanhydroicaritin (type B, C-4' linked hydroxyl) as the backbone. Thirdly, the UHPLC-PDA combined with heatmap visualization was employed to clarify the distribution of chemical components with high content in different parts of Epimedium herb. The results showed clear differences in the contents of chemical components in leaves, stems and rhizomes. The levels of flavonoids with Anhydroicaritin backbone were high in the leaves, and levels of flavonoids with Demethylanhydroicaritin backbone were high in the rhizomes. The levels of Magnoline in stems and rhizomes were higher than that in leaves. The contents of most of the compounds in stems remained low. The leaves and the other two parts (stems and rhizomes) can be distinguished by qualitative and semi-quantitative analysis of Magnoline and Epimedoside A (type B backbone). These results indicated that the different plant parts of Epimedium herb can be quickly and accurately distinguished by this method, establishing a foundation for the application of Epimedium herb.

The Inhibition Effects of Shenmai Injection on Acetylcholine-Induced Catecholamine Synthesis and Secretion by Modulating Nicotinic Acetylcholine Receptor Ion Channels in Cultured Bovine Adrenal Medullary Cells

Shenmai injection (SMI) has been widely used for the treatment of cardiovascular diseases in China. Cardiovascular disorders are often related to excessive catecholamine (CA) secretion. Here, we report the effects of SMI on CA secretion and synthesis in cultured bovine adrenal medullary cells. We found that SMI significantly reduced CA secretion induced by 300 μM acetylcholine (ACh). Cotreatment with SMI (10 μL/mL) and either of the ACh receptor α-subunit inhibitors, HEX (α3) or DhβE (α4β2), did not produce any further inhibition, indicating that SMI may play a role through α3 and α4β2 channels. Furthermore, SMI reduced tyrosine hydroxylase (TH) activity induced by ACh by inhibiting the phosphorylation of TH at Ser19 and Ser40. TH is phosphorylated at Ser19 by Ca²⁺/calmodulin-dependent protein kinase II (CaM kinase II) and at Ser40 by protein kinase A (PKA). KN-93 and H89, the antagonists of CaM kinase II and PKA, respectively, inhibited the ACh-induced phosphorylation at Ser19 and Ser40, and the addition of SMI did not augment the inhibitory effect. Taken together, our results show that SMI likely inhibits CA secretion by blocking TH activity at its Ser19 and Ser40 sites.

A simple and selective LC-MS/MS method for quantification of ikarisoside A in rat plasma and its application to a pharmacokinetic study

Ikarisoside A is a natural flavonoid isolated from Epimedium plants. To further evaluate its medicinal potential, a sensitive and robust LC-MS/MS method was developed and validated for the assay of ikarisoside A in rat plasma. Orientin was used as an internal standard. The electrospray ionization was operated in its negative ion mode while ikarisoside A and IS were measured by selected reaction monitoring using precursor-to-product ion transitions of m/z 499.1 → 353.0 and m/z 446.9 → 327.6, respectively. This LC-MS/MS method had good sensitivity (LLOQ = 1.5 ng/mL), accuracy (both intra- and inter-day RE ≤ ±11.9%) and precision (both intra- and inter-day RSD ≤8.5%). The pharmacokinetics of ikarisoside A was subsequently profiled in Sprague-Dawley rats. Following oral administration (35 mg/kg), ikarisoside A reached maximum plasma concentration (C_max , 207.6 ± 96.7 ng/mL) attained at 1.10 ± 0.42 h. Following oral administration, the clearance and terminal half-life were 42.9 ± 26.5 L/h/kg and 3.15 ± 0.80 h by oral route, respectively.

Inhibitory effects of pine nodule extract and its component, SJ-2, on acetylcholine-induced catecholamine secretion and synthesis in bovine adrenal medullary cells

Extract of pine nodules (matsufushi) formed by bark proliferation on the surface of trees of Pinus tabulaeformis or Pinus massoniana has been used as an analgesic for joint pain, rheumatism, neuralgia, dysmenorrhea and other complaints in Chinese traditional medicine. Here we report the effects of matsufushi extract and its components on catecholamine secretion and synthesis in cultured bovine adrenal medullary cells. We found that matsufushi extract (0.0003-0.005%) and its component, SJ-2 (5-hydroxy-3-methoxy-trans-stilbene) (0.3-100 μM), but not the other three, concentration-dependently inhibited catecholamine secretion induced by acetylcholine, a physiological secretagogue. Matsufushi extract (0.0003-0.005%) and SJ-2 (0.3-100 μM) also inhibited ⁴⁵Ca²⁺ influx induced by acetylcholine in a concentration-dependent manner, similar to its effect on catecholamine secretion. They also suppressed ¹⁴C-catecholamine synthesis and tyrosine hydroxylase activity induced by acetylcholine. In Xenopus oocytes expressing α3β4 nicotinic acetylcholine receptors, matsufushi extract (0.00003-0.001%) and SJ-2 (1-100 μM) directly inhibited the current evoked by acetylcholine. The present findings suggest that SJ-2, as well as matsufushi extract, inhibits acetylcholine-induced catecholamine secretion and synthesis by suppression of nicotinic acetylcholine receptor-ion channels in bovine adrenal medullary cells.