hKv1.5 channel
Oxypeucedanin targets the hKv1.5 channel (IC50 = 76.12 ± 8.07 nM; Hill coefficient = 1.04 ± 0.07) [1].
Oxypeucedanin has no effect on the HERG channel at 1 μM [1].
Oxypeucedanin hydrate monoacetate targets the PI3K/Akt signalling pathway, down-regulating the expression of pPI3K and pAkt in Caco-2 cells in a dose-dependent manner [2].

Oxypeucedanin (1 μM) inhibited hKv1.5 currents expressed in Ltk- cells, characterized by accelerated current decay during depolarization with relatively fewer effects on peak amplitude. It reduced both peak current and steady-state current elicited by pulses to +60 mV. The inhibition was concentration-dependent (IC50 = 76.12 ± 8.07 nM). The block increased steeply between -40 and 0 mV, corresponding to the voltage range of channel opening. Oxypeucedanin (100 nM) slowed the deactivation time course, causing a “crossover” phenomenon in tail currents, indicating open-channel block. It prolonged the action potential duration (APD90) of rat atrial and ventricular muscles in a concentration-dependent manner. Oxypeucedanin (1 μM) had no effect on HERG current expressed in HEK-293 cells, as shown by steady-state I-V relationship and peak tail currents [1].
Oxypeucedanin hydrate monoacetate inhibited Caco-2 cell proliferation in a dose- and time-dependent manner. MTT assay showed IC50 values of 36.4 μM (72 h), 42.1 μM (48 h), and 46.3 μM (24 h). Colony formation assay revealed a significant reduction in the number of cancer colony-forming cells in a dose-dependent manner (0, 24, 48, 150 μM). In vitro wound healing assay demonstrated anti-migratory effects: after 12, 24, and 48 hours treatment with 24, 48, and 150 μM, cell migratory abilities decreased considerably compared to DMSO control, with larger wound areas. Fluorescence microscopy with acridine orange/ethidium bromide staining showed early apoptotic changes (yellow-green spots) at lower doses and late apoptotic events (orange staining, chromatin condensation, apoptotic bodies) at higher doses. Western blotting revealed that oxypeucedanin hydrate monoacetate significantly down-regulated the expression of pPI3K and pAkt in Caco-2 cells in a dose-dependent manner, while total Akt protein levels remained constant [2].

For oxypeucedanin, the hKv1.5 channel current was recorded using the whole-cell patch-clamp technique. Electrical signals were amplified with a patch-clamp amplifier, digitized by a signal converter, and stored on a computer. Micropipettes (resistance 1-2 MΩ) were pulled by a two-stage pipette puller. The intracellular pipette solution contained: 100 mM KCl, 10 mM HEPES, 5 mM K4BAPTA, 5 mM K2ATP, and 1 mM MgCl2 (pH 7.2). The extracellular bath solution contained: 130 mM NaCl, 4 mM KCl, 1.8 mM CaCl2, 1 mM MgCl2, 10 mM HEPES, and 10 mM glucose (pH 7.35). Membrane potentials were held at -80 mV, and 250 ms depolarizing pulses from -80 to +60 mV in 10 mV steps were applied every 20 s. Outward currents were followed by decaying outward tail currents upon repolarization to -50 mV. To quantify voltage dependence, relative current (I_oxypeucedanin/I_control) was plotted as a function of membrane potential. Deactivation kinetics were analyzed from tail currents during a repolarizing step to -50 mV [1].
For HERG current recording, similar whole-cell patch-clamp techniques were used in HEK-293 cells. Current traces were recorded before and 20 min after exposure to 1 μM oxypeucedanin, and I-V relationships of steady-state current and peak tail currents were constructed [1].

For oxypeucedanin studies: The hKv1.5 or HERG channels were expressed in a clonal mouse Ltk- cell line or HEK-293 cell line. Transfected cells were cultured in Dulbecco’s modified Eagle’s medium supplemented with 10% horse serum and 0.25 mg/mL G418 under a 5% CO2 atmosphere. Before experiments, subconfluent cultures were incubated with 2 μM dexamethasone for 12 h to induce hKv1.5 channel expression. Cells were removed from the dish with a rubber policeman, leaving most cells intact. Whole-cell currents were recorded using the patch-clamp technique as described above [1].
For oxypeucedanin hydrate monoacetate studies: Caco-2 human colon cancer cells were grown in Dulbecco’s modified Eagle’s medium supplemented with 10% fetal bovine serum, 100 U/mL penicillin, and 100 μg/mL streptomycin, in a CO2 incubator (95% air, 5% CO2) at 37°C. For MTT cell viability assay, cells were seeded in 96-well plates (1×10^6 cells/well) and treated with various doses of the compound (0, 4, 12, 24, 48, 96, 150 μM) for 24, 48, and 72 h. MTT solution (5 mg/mL) was added to each well, incubated for 4 h, then formazan precipitate dissolved in 500 μL dimethyl sulfoxide, and absorbance measured at 570 nm. Inhibitor ratio (%) = (OD control – OD treated)/OD control × 100%. IC50 values were calculated. For colony formation assay, cells were suspended in 1 mL medium containing 0.5% agarose and 10% FBS, plated on a bottom layer containing 0.8% agarose and 10% FBS in 6-well plates (triplicate). After 4 days, plates were stained with 0.3% gentian violet and colonies counted under a light microscope. For in vitro wound healing assay, Caco-2 cells (1×10^6 cells/mL) were seeded in 6-well plates and incubated until 100% confluent monolayer. After 10 h starvation, a straight cell-free wound was made with a pipette tip. Wells were washed with PBS, then exposed to 0, 24, 48, and 150 μM of the compound. After 48 h, cells were fixed and stained with 3% ethanol containing 0.5% crystal violet for 30 min, and migrated cells were counted under a light microscope. For apoptosis morphology, cells (3×10^5 cells/mL, 2 mL) were seeded on sterile coverslips in 6-well plates. After treatment with 0, 24, 48, 150 μM of the compound, coverslips were inverted on glass slides with 10 μL of acridine orange/ethidium bromide stain (50 μg/mL), and images were recorded using a UV fluorescence microscope (400× magnification). For Western blot assay, after treatment with the compound, total proteins were extracted with RIPA lysis buffer containing 1% cocktail and 1% PMSF. Protein concentrations were measured. Equivalent amounts of proteins were separated by 8-12% SDS-PAGE and electrotransferred to nitrocellulose membranes. Membranes were incubated with corresponding secondary antibodies (1:10000) and probed for pPI3K, Akt, pAkt, Bcl-2, Bax, Bcl-xl, Bad, cytochrome C, cleaved caspase-3, cleaved-PARP, and β-actin overnight at 4°C. Signals were detected using ECL Chemiluminescence on X-ray film [2].

For oxypeucedanin studies on action potential duration: Rat atrial and ventricular muscles were used (ex vivo tissue preparation, not in vivo animal experiments). Hearts of rats were rapidly excised and transferred to a dissection bath filled with Tyrode’s solution oxygenated with 97% O2 and 3% CO2. Atrial and ventricular muscles were carefully dissected and mounted horizontally in a narrow channel of a tissue chamber, continuously superfused with oxygenated Tyrode’s solution at 37°C. The mural end of muscles was fixed with an insect pin to the bottom of the chamber coated with Sylgard. Stimulating electrodes were used to elicit action potentials and contractions. Action potentials were elicited by stimulating cardiac cells with square pulses of 1 ms duration at 1 Hz (20-30% above threshold voltage) via a stimulator and stimulus isolation unit. Action potentials were recorded with a 3 M KCl-filled microelectrode (10-20 MΩ) connected to an amplifier and displayed on an oscilloscope. Tracings were photographed and recorded on a chart recorder. Rat atrial and ventricular muscles were superfused with Tyrode’s solution at a constant rate (5 mL/min). Tyrode’s solution contained: 137 mM NaCl, 5.4 mM KCl, 1.05 mM MgCl2, 0.45 mM NaH2PO4, 11.9 mM NaHCO3, 1.8 mM CaCl2, and 5 mM dextrose. The APD90 (90% repolarization) was measured [1].

Oxypeucedanin (1 μM) had no effect on HERG channels, which are involved in prolongation of ventricular APD leading to long QT/Torsades de Pointes syndrome. This suggests that oxypeucedanin might not produce ventricular APD prolongation and thus may have a lower risk of Torsades de Pointes compared to known antiarrhythmic drugs [1]

[1]. Effects of oxypeucedanin on hKv1.5 and action potential duration.Biol Pharm Bull. 2005 Apr;28(4):657-60.

[2]. Oxypeucedanin hydrate monoacetate isolated from Angelica dahurica induces apoptosis in Caco-2 colon carcinoma cells through the mediation of PI3K-signalling pathway and inhibition of cancer cell migration.

(R)-Oxopsoralen is one of the psoralen compounds. It has been reported that 4-[(3,3-dimethylepoxyethylene-2-yl)methoxy]furano[3,2-g]chromene-7-one exists in citron (Citrus medica), custard apple (Prangos latiloba), and other organisms with relevant data. See also: Oxopsoralen (note moved to).

---

Oxypeucedanin is an open-channel blocker of hKv1.5 channels, as evidenced by initial fast decline of current during depolarization, voltage-dependent block in the channel opening range (-40 to 0 mV), and slowed deactivation tail current crossover phenomenon. Since hKv1.5 channels are preferentially expressed in human atria and correspond to the IKUR current, selective blockade of hKv1.5 prolongs atrial action potential duration without affecting ventricular repolarization (HERG-negative), making oxypeucedanin an ideal candidate for treating atrial fibrillation. Although not tested on human ventricular muscle, the lack of HERG effect indirectly suggests low proarrhythmic risk. The compound prolonged APD in rat atrial and ventricular muscles, a class III antiarrhythmic property [1].
Oxypeucedanin hydrate monoacetate induces apoptosis in Caco-2 colon cancer cells via the PI3K/Akt signalling pathway. It down-regulates pPI3K and pAkt, leading to early and late apoptotic morphological changes (chromatin condensation, nuclear margination, apoptotic bodies). It also inhibits cancer cell migration, a key feature of cancer progression and metastasis. These effects suggest potential as a chemotherapeutic agent for colon cancer. The compound’s anti-proliferative effect on epidermoid carcinoma cells (A-431) has been previously reported elsewhere (not in this study) [2].

C16H14O5

286.2794

286.084

737-52-0

737-52-0

160544

White to off-white solid

1.4±0.1 g/cm3

469.6±45.0 °C at 760 mmHg

141-142 °C

237.8±28.7 °C

0.0±1.2 mmHg at 25°C

1.634

2.17

0

5

3

21

471

0

O1C([H])(C([H])([H])OC2=C3C([H])=C([H])C(=O)OC3=C([H])C3=C2C([H])=C([H])O3)C1(C([H])([H])[H])C([H])([H])[H]

QTAGQHZOLRFCBU-UHFFFAOYSA-N

InChI=1S/C16H14O5/c1-16(2)13(21-16)8-19-15-9-3-4-14(17)20-12(9)7-11-10(15)5-6-18-11/h3-7,13H,8H2,1-2H3

4-[(3,3-dimethyloxiran-2-yl)methoxy]furo[3,2-g]chromen-7-one

Oxypeucedanin

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO: 24~50 mg/mL (83.8~174.7 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (8.73 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

---

Solubility in Formulation 2: ≥ 2.5 mg/mL (8.73 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

---

 (Please use freshly prepared in vivo formulations for optimal results.)