(−)-Naringenin 4′,7-dimethyl Ether Isolated from <i>Nardostachys jatamansi</i> Relieves Pain through Inhibition of Multiple Channels

oleh: Ru-Rong Gu, Xian-Hua Meng, Yin Zhang, Hai-Yan Xu, Li Zhan, Zhao-Bing Gao, Jun-Li Yang, Yue-Ming Zheng

Format: Article
Diterbitkan: MDPI AG 2022-03-01

Deskripsi

(−)-Naringenin 4′,7-dimethyl ether ((−)-NRG-DM) was isolated for the first time by our lab from <i>Nardostachys jatamansi</i> DC, a traditional medicinal plant frequently used to attenuate pain in Asia. As a natural derivative of analgesic, the current study was designed to test the potential analgesic activity of (−)-NRG-DM and its implicated mechanism. The analgesic activity of (−)-NRG-DM was assessed in a formalin-induced mouse inflammatory pain model and mustard oil-induced mouse colorectal pain model, in which the mice were intraperitoneally administrated with vehicle or (−)-NRG-DM (30 or 50 mg/kg) (<i>n</i> = 10 for each group). Our data showed that (−)-NRG-DM can dose dependently (30~50 mg/kg) relieve the pain behaviors. Notably, (−)-NRG-DM did not affect motor coordination in mice evaluated by the rotarod test, in which the animals were intraperitoneally injected with vehicle or (−)-NRG-DM (100, 200, or 400 mg/kg) (<i>n</i> = 10 for each group). In acutely isolated mouse dorsal root ganglion neurons, (−)-NRG-DM (1~30 μM) potently dampened the stimulated firing, reduced the action potential threshold and amplitude. In addition, the neuronal delayed rectifier potassium currents (I<sub>K</sub>) and voltage-gated sodium currents (I<sub>Na</sub>) were significantly suppressed. Consistently, (−)-NRG-DM dramatically inhibited heterologously expressed Kv2.1 and Nav1.8 channels which represent the major components of the endogenous I<sub>K</sub> and I<sub>Na</sub>. A pharmacokinetic study revealed the plasma concentration of (−)-NRG-DM is around 7 µM, which was higher than the effective concentrations for the I<sub>K</sub> and I<sub>Na</sub>. Taken together, our study showed that (−)-NRG-DM is a potential analgesic candidate with inhibition of multiple neuronal channels (mediating I<sub>K</sub> and I<sub>Na</sub>).